hdm-#170114-v1-2001 air quality report · 2001 report on air quality in the crd 38091 – 28...

2001 Report on Air Quality In the Capital Regional District

Prepared for:

Capital Regional District Environmental Services Department

Engineering Department 524 Yates Street

Victoria, BC V8W 2S6

Prepared by:

SENES Consultants Limited 1275 West 6th Avenue, Suite 300

Vancouver, BC V6H 1A6

November 2002

2001 Report on Air Quality in the CRD

38091 – 28 November 2002 i SENES Consultants Limited

TABLE OF CONTENTS Page No.

EXECUTIVE SUMMARY .............................................................................................................v

1.0 INTRODUCTION ...............................................................................................................1

2.0 METEOROLOGICAL MONITORING..............................................................................4 2.1 Royal Roads Un iversity ..........................................................................................4 2.2 Victoria Topaz .........................................................................................................4 2.3 Colwood Municipal Hall..........................................................................................5 2.4 Victoria Gonzales.....................................................................................................5 2.5 Victoria Airport........................................................................................................5

3.0 AIR QUALITY MONITORING .......................................................................................12 3.1 Ambient Air Quality Objectives ............................................................................12 3.2 Gaseous Pollutants .................................................................................................15

3.2.1 Ground-level Ozone...................................................................................15 3.2.2 Nitrogen Oxides (NO & NO2 ) ..................................................................20 3.2.3 Sulphur Dioxide (SO2)...............................................................................22 3.2.4 Carbon Monoxide (CO) .............................................................................23

3.3 Airborne Particulates .............................................................................................25 3.3.1 Inhalable Particulate Matter (PM10)...........................................................25 3.3.2 Respirable Particulate Matter (PM2.5)........................................................29

4.0 ANALYSIS AND INTERPRETATION OF RESULTS...................................................38 4.1 Pollutant Correlations at Victoria Topaz ...............................................................38 4.2 Spatial Correlation of Particulate Matter ...............................................................41 4.3 Weekday/Weekend PM2.5 Patterns ........................................................................49 4.4 Seasonal Trends in PM2.5 and PM10 Concentrations..............................................51 4.5 Regionally Concurrent PM2.5 Fluctuations ............................................................54

5.0 CONCLUSIONS & RECOMMENDATIONS..................................................................58 5.1 Meteorological Parameters ....................................................................................58 5.2 Gaseous Pollutants .................................................................................................60 5.3 Particulate Matter...................................................................................................60

5.3.1 Inhalable Particulate Matter (PM10)...........................................................60 5.3.2 Respirable Particulate Matter (PM2.5)........................................................61


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LIST OF TABLES Page No.

1.0-1 Air Quality Monitoring Stations in the Capital Regional District .......................................1 3.1-1 Air Quality Objectives and Standards for Contaminants Monitored in the CRD..............14 3.2-1 Hourly Averaged Ozone Concentrations at Victoria Topaz ..............................................15 3.2-2 24-Hour Running Mean Analysis of Ozone at Victoria Topaz .........................................15 3.2-3 Hourly Analysis of Ozone at Saturna Island......................................................................17 3.2-4 24-Hour Running Mean Analysis of Ozone at Saturna Island ..........................................18 3.2-5 Hourly Analysis of Ozone at Royal Roads University ......................................................19 3.2-6 24-Hour Running Mean Analysis of Ozone at Royal Roads University ...........................20 3.2-7 Hourly Analysis of NO2 at Victoria Topaz........................................................................20 3.2-8 24-Hour Running Mean Analysis of NO2 at Victoria Topaz.............................................21 3.2-9 Hourly Analysis of SO2 at Victoria Topaz ........................................................................22 3.2-10 24-Hour Running Mean Analysis of SO2 at Victoria Topaz .............................................22 3.2-11 Hourly Analysis of CO at Victoria Topaz .........................................................................23 3.2-12 24-Hour Running Mean Analysis of CO at Topaz ...........................................................24 3.3-1 Particulate Matter – November 2000- December 2001 .....................................................26 3.3-2 Hourly Analysis of PM10 at Colwood Municipal Hall.......................................................27 3.3-3 24-Hour Running Mean Analysis of PM10 at Colwood Municipal Hall ...........................28 3.3-4 Hourly Analysis of PM2.5 at Victoria Topaz......................................................................29 3.3-5 24-Hour Running Mean Analysis of PM2.5 at Victoria Topaz...........................................30 3.3-6 Hourly Analysis of PM2.5 at Colwood Municipal Hall ......................................................32 3.3-7 24-Hour Running Mean Analysis of PM2.5 at Colwood Municipal Hall...........................33 3.3-8 Hourly Analysis of PM2.5 Royal Roads University ...........................................................35 3.3-9 24-Hour Running Mean Analysis of PM2.5 at Royal Roads University ............................35 4.3-1 Probability Distributions for PM2.5 at Royal Roads University.........................................49 4.3-2 Probability Distributions for PM2.5 at Colwood Municipal Hall .......................................49 4.3-3 Probability Distributions for PM2.5 at Victoria Topaz .......................................................50 5.1-1 Maximum Observed Pollutant Concentrations (µg/m3) in the CRD .................................59


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LIST OF FIGURES On or Follows

Page No. 1.0-1 Locations of Sampling Sites for the CRD Long Term Monitoring Program ......................3 2.1-1 Wind Rose – Royal Roads Meteorological Station 2001 ....................................................7 2.2-1 Wind Rose – Victoria Topaz Meteorological Station 2001.................................................8 2.3-1 Wind Rose – Colwood Meteorological Station 2001 ..........................................................9 2.4-1 Wind Rose – Victoria Gonzales - Meteorological Station 2001........................................10 2.5-1 Wind Rose – Victoria Airport Meteorological Station 2001 .............................................11 3.2-1 Victoria Topaz – Average Diurnal Pattern for O3 – 2001 .................................................16 3.2-2 Maximum Daily and Average 1-hour Ozone Per Month for Victoria Topaz....................17 3.2-3 Saturna Island – Average Diurnal Pattern for O3 – 2001...................................................18 3.2-4 Maximum Daily and 1-Hour Average Ozone Concentrations Per Month for Saturna Island.............................................................................................19 3.2-5 Victoria Topaz – Average Diurnal Pattern of NO2 – 2001................................................21 3.2-6 Victoria Topaz – Average Diurnal Pattern of SO2 – 2001.................................................23 3.2-7 Victoria Topaz – Average Diurnal Pattern of CO – 2001 .................................................24 3.3-1 PM10 Concentrations at Victoria Topaz Based on Sequential Hi-Vol and Dichotomous Samplers ...............................................................................................26 3.3-2 Colwood Municipal Hall Average Diurnal Pattern PM10 – 2001 ......................................28 3.3-3 Victoria Topaz – Average Diurnal Pattern of PM2.5 – 2001..............................................30 3.3-4 Victoria Topaz – Average Diurnal Pattern of PM2.5 – 2001 Warm Season (April-October)...........................................................................................31 3.3-5 Victoria Topaz – Average Diurnal Pattern of PM2.5 – 2001 Cold Season (November-March) .......................................................................................31 3.3-6 Colwood Municipal Hall – Average Diurnal Pattern of PM2.5 – 2001 ..............................33 3.3-7 Colwood Municipal Hall – Average Diurnal Pattern of PM2.5 – 2001 Warm Season (April-October)...........................................................................................34 3.3-8 Colwood Municipal Hall – Average Diurnal Pattern of PM2.5 – 2001 Cold Season (November-March) .......................................................................................34 3.3-9 Royal Roads University – Average Diurnal Pattern of PM2.5 – 2001................................36 3.3-10 Royal Roads University – Average Diurnal Pattern of PM2.5 – 2001 Warm Season (April-October)...........................................................................................37 3.3-11 Royal Roads University – Average Diurnal Pattern of PM2.5 – 2001 Cold Season (November-March) .......................................................................................37 4.1-1 Correlation Between Concentrations of CO, NO and PM2.5 at the Victoria Topaz Monitoring Site ...............................................................................39 4.1-2 Correlation Between CO and PM2.5 at Victoria Topaz......................................................39 4.1-3 Trends in CO and PM2.5 Concentrations at Victoria Topaz, November 8-10, 2001 .........40


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4.1-4 Trends in NO and PM2.5 at Victoria Topaz, March 22-23, 2001.......................................41 4.2-1 Probability Distributions for PM10 Concentrations in the Capital Regional District.........42 4.2-2 Correlation of PM10 Concentrations at the Oak Bay and Braefoot Monitoring Sites........43 4.2-3 Correlation of PM10 Concentrations at the Keating and Braefoot Monitoring Sites .........43 4.2-4 Correlation of PM10 Concentrations at the Keating and Oak Bay Monitoring Sites .........44 4.2-5 Correlation of PM10 Concentrations at the Victoria Topaz and Oak Bay Monitoring Sites...........................................................................................44 4.2-6 Correlation of PM10 Concentrations at the Victoria Topaz and Braefoot Monitoring Sites...........................................................................................45 4.2-7 Correlation of PM10 Concentrations at the Victoria Topaz and Keating Monitoring Sites ............................................................................................45 4.2-8 Probability Distributions for PM2.5 Concentrations in the Capital Regional District........46 4.2-9 Correlation of 24-Hour Running Mean PM10 Concentrations at Royal Roads University and Colwood Municipal Hall.............................................................................................47 4.2-10 Correlation of 24-Hour Running Mean PM10 Concentrations at Royal Roads University and Victoria Topaz.............................................................................................................48 4.2-11 Correlation of 24-Hour Running Mean PM10 Concentrations at Colwood Municipal Hall and Victoria Topaz.............................................................................................................48 4.3-1 Comparison Between Weekend and Weekday Probability Distributions for Hourly PM2.5 Levels in the CRD..................................................................................50 4.4-1 Trend in PM2.5/PM10 Ratios During Sampling Period.......................................................51 4.4-2 Seasonal Probability Distributions for PM2.5 and PM10 at Victoria Topaz........................52 4.4-3 Seasonal Probability Distributions for PM2.5 and PM10 at Colwood Municipal Hall........53 4.4-4 Correlation of Ambient Temperature and PM2.5/PM10 Ratio in the Capital Regional District..........................................................................................54 4.5-1 Trends in Hourly PM2.5 Concentrations in the CRD During November 2-13, 2001.........55 4.5-2 Trends in Daily PM2.5 Concentrations Within the Georgia Basin – November 2-13, 2001 .....................................................................................................56 4.5-3 Trends in PM2.5 Concentrations in the CRD Versus Nanaimo During November 8-11, 2001 ............................................................................................56


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EXECUTIVE SUMMARY

Air quality and meteorological monitoring data collected at eight stations in the Capital Regional District (CRD) over the period November 2000 to December 2001 were analyzed with respect to established Provincial and Federal ambient air quality objectives and standards. Gaseous pollutants considered included carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ozone (O3). Particulate matter included both the inhalable particulate fraction (PM10) and respirable fraction (PM2.5). Spatial and temporal correlations were evaluated for selected pollutants within the CRD, as well as for some examples of episodic trends in pollutant fluctuations over multi-day time periods. Meteorological data from five monitoring sites was also evaluated. Air quality in the Capital Regional District was within Maximum Acceptable ambient air quality limits applicable in British Columbia or Canada for three gaseous pollutants monitored (i.e., CO, NO2 and SO2). Ground level ozone concentrations were within the Maximum Acceptable level for 1-hour average concentrations, but exceeded the Maximum Acceptable concentration for 24-hour averages within the core area as well as at Royal Roads University and Saturna Island. With two exceptions (one each at Victoria Topaz and Colwood), the levels of inhalable particulate matter (PM10) were within objectives set in British Columbia, and there is some uncertainty about whether the objective level was exceeded at the Victoria Topaz site. The PM10 health Reference Level of 25 µg/m3 was exceeded at all monitoring stations. On the other hand, the 98th percentile levels of fine particulate matter (PM2.5) were approximately half of the numerical value of 30 µg/m3 for the Canada-Wide Standard (CWS). Although the latter standard is based on the 98th percentile, averaged over three consecutive years, it is reasonable to conclude that the PM2.5 concentrations in the CRD are within the CWS based on one year of data alone because, on a statistical basis, levels in subsequent consecutive years would have to more than double in order to raise the 98th percentile value for all three years above the CWS level. However, the PM2.5 health Reference Level of 15 µg/m3 (24-hour average) was exceeded at each of the three PM2.5 monitoring stations to some extent. With respect to meteorological monitoring data, the available record for 2001 from the station located at Royal Roads university was too short to provide any useful data, while the data from the station at the Colwood Municipal Hall appears to be suspect. For the latter station, wind speeds were too low, and there were too many calms reported. The station is located in a sheltered valley, and the instrument exposure may only be representative of localized air flow conditions. It is recommended that the siting of this station be reviewed with a view to re-locating the instruments to provide more appropriate exposure for wind monitoring.


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While only one monitoring station is available for measuring the levels of CO, NO2 and SO2 in the CRD, the station is located in the core area of the region where these pollutants are likely to be at higher concentrations. The data record for the period November 2000 – December 2001 show that SO2 concentrations were less than 10% of the Maximum Acceptable air quality objectives. The concentrations of CO and NO2 were also relatively low, with maximum concentrations within 20-30% of Maximum Acceptable objectives. Ground level ozone concentrations also met all established ambient air quality objectives and standards. The highest 1-hour average concentration of 133 µg/m3 was recorded at Saturna Island, and was less than the Maximum Acceptable objective of 160 µg/m3. However, this level exceeded the Maximum Desirable objective of 100 µg/m3. The latter objective was also exceeded at Royal Roads University (132 µg/m3) and at the Victoria Topaz site (110 µg/m3) in the core area of the CRD. The Maximum Acceptable objective of 50 µg/m3 (24-hour average) was also exceeded at all three monitoring sites. However, all three sites were within the Canada-Wide Standard for 8-hour average ozone concentrations of 127.6 µg/m3. The Provincial PM10 objective of 50 µg/m3 (24-hour average) was exceeded twice during the period of record: once at Victoria Topaz (58 µg/m3 - Hi-Vol sampler) and once at the Colwood site (51 µg/m3 - TEOM sampler). There is some uncertainty about the exceedence at the Victoria Topaz site because a simultaneous sample recorded using the dichotomous sampler estimated the PM10 concentration at only 21 µg/m3. Therefore, only the single exceedence at Colwood is confirmed. With respect to the health Reference Level of 25 µg/m3, the monitoring data show that PM10 concentrations exceeded this level 13% of the time at Victoria Topaz, 5% of the time at the Colwood Municipal Hall, Keating Elementary School, and the Oak Bay Recreational Centre, and 2% of the time at the Braefoot Elementary School. For the respirable fraction of particulate matter (PM2.5), all readings recorded using continuous (TEOM) samplers were well within the established Canada-Wide Standard of 30 µg/m3 (98th percentile). The highest levels were recorded at the Victoria Topaz site based on both the continuous samplers and the dichotomous sampler, but the 98th percentile level was almost half the CWS concentration based on either sampler. With respect to the health Reference Level of 15 µg/m3, the level was exceeded approximately 4.5% of the time at the Victoria Topaz site, less than 2% of the time at the Colwood Municipal Hall, and about 0.1% of the time at Royal Roads University. The analysis and interpretation of the air quality monitoring data leads to the following conclusions:

• The levels of CO, NO and PM2.5 at the Victoria Topaz site are well correlated, indicating that much of the PM2.5 at this site is derived from combustion source emissions.


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Although some of the peak concentrations are associated with motor vehicle emissions during rush hour traffic periods, detailed examination of the temporal trends in concentrations reveals that increased concentration levels of all three pollutants occur in the late evening and night time hours in the cold season. Thus, although meteorological conditions that lead to poor dispersion in evening hours may contribute to elevated pollutant concentrations during the evening hours, the overall conclusion is that residential/commercial space heating appears to be a major source of all three pollutants (i.e., CO, NO and PM2.5) in the CRD.

• The levels of particulate matter (both PM10 and PM2.5) at the Victoria Topaz site are significantly higher than at the other monitoring sites within the CRD. The higher concentrations may be related to the proximity of the monitoring site to a major traffic artery in the core area of the city.

• The PM10 levels measured at the Oak Bay Recreational Centre are not significantly different from those measured at the Braefoot Elementary School site. The stations differ chiefly in the frequency of exceedence of the PM10 health Reference Level of 25 µg/m3 (i.e., 5% at Oak Bay versus 2% at Braefoot).

• The highest levels of PM2.5 in the CRD are measured on weekends rather than weekdays, suggesting that residential wood combustion is a significant contributor to fine particulate loadings within the CRD. The highest PM2.5 concentrations occur in the cold season (November-March).

• The ratio of PM2.5 to PM10 is highest in the winter and lowest in the summer, reinforcing the suggestion that residential heating contributes to higher levels of PM2.5 in the CRD. The ratio is inversely correlated with ambient air temperatures, indicating that the higher proportion of PM2.5 to PM10 in winter is related to increased emissions from combustion sources (i.e., space heating).

• Occasionally, the levels of PM2.5 measured within the CRD are similar in magnitude and temporal variation to those measured at distant locations within the Georgia Basin (i.e., Nanaimo and the Vancouver Airport), suggestive of a regional meteorological influence on PM2.5 concentrations. At such times, the observed pollutant concentrations suggest that the simultaneous rise and fall in PM2.5 concentrations at geographically distant locations is related to increased space heating emissions from local sources during periods of cold air temperatures and relatively poor dispersion conditions at low wind speeds.


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1.0 INTRODUCTION

Air quality and meteorological monitoring data collected at eight stations in the Capital Regional District (CRD) over the period November 2000 to December 2001 were analyzed with respect to established Provincial and Federal ambient air quality objectives and standards. The air contaminants monitored at each station are summarized in Table 1.0-1 below.

Table 1.0-1 Air Quality Monitoring Stations in the Capital Regional District

Parameters Monitored Monitoring Location Type of Site

Gaseous Particulate Matter Meteorology Victoria, Topaz Avenue Core area NAPS1 site CO, NO, NO2

SO2 & O3 PM10 (S-Hi-Vol)

PM10 & PM2.5 (S-Dicot) PM2.5 (C-TEOM)

WS, WD, T, RH

Keating Elementary School

Downwind of core area PM10 (S-Hi-Vol)

Oak Bay Recreational Centre

Special area3 PM10 (S-Hi-Vol)

Braefoot Elementary School

Special area4 PM10 (S-Hi-Vol)

Colwood Municipal Hall Residential/commercial PM10 (C-TEOM) PM2.5 (C-TEOM)

WS, WD, T, RH

Saturna Island CAPMoN2 Site NO, NO2 ,SO2 & O3

WS, WD, T, RH &

Precipitation Royal Roads University Special area5 O3 PM2.5 (C-TEOM) WS, WD,

T, RH

Notes: WS – wind speed; WD – wind direction; T – temperature; RH – relative humidity S-Hi-Vol – sequential sampling using High Volume samplers S-Dicot – sequential sampling using a dichotomous samplers C-TEOM – continuous sampling using Tapered Element Oscillating Microbalance samplers 1- National Air Pollution Surveillance; 2- Canadian Air and Precipitation Monitoring Network; 3- Special area of interest since October 1996; 4- Special area of interest since November 1995; 5- Special area of interest, not part of CRD monitoring network

With the exception of the Victoria Topaz site, Figure 1.0-1 shows the location of the monitoring sites in the CRD. The NAPS station at the S.J. Willis school location was relocated to the nearby site on Topaz Avenue. Gaseous contaminants, including carbon monoxide (CO), sulphur dioxide (SO2), nitrogen oxides (NO and NO2), and ground level ozone (O3), are monitored at a single National Air Pollution Surveillance (NAPS) station located at Topaz Avenue in Victoria. Ground level ozone was also available from the Canadian Air and Precipitation Monitoring (CAPMoN) station located on



Saturna Island, while a short period of O3 monitoring was available from Royal Roads University for the spring of 2001. Particulate matter is monitored at six locations in the CRD using three types of monitors. Sequential PM10 sampling (24-hour average) is conducted at four locations on the one-in-six day NAPS schedule using high volume (Hi-Vol) samplers. The four locations include the Victoria Topaz NAPS site, the Oak Bay Recreational Centre, the Braefoot Elementary School, and the Keating Elementary School. Continuous PM10 sampling (hourly averages) is available from the monitoring station at the Colwood Municipal Hall. The Victoria Topaz site is also equipped with a sequential dichotomous sampler for monitoring the fine particulate matter (PM2.5) and the coarse fraction of PM10 (PM2.5-10) on the same NAPS schedule. The sum of the two size fractions provides a second measure of 24-hour average PM10 concentrations, as well as 24-hour average PM2.5 concentrations. Continuous PM2.5 sampling (hourly averages) is available from three monitoring locations in the CRD, namely: the Victoria Topaz site, the Colwood Municipal Hall and Royal Roads University.



Figure 1.0-1

ROYAL ROADS UNIVERSITY



2.0 METEOROLOGICAL MONITORING

A number of meteorological monitoring stations have been deployed in the CRD area in the past several years. One station located at the Colwood Municipal Hall is operated by the CRD, whereas three others are operated by Environment Canada and one station is operated by Royal Roads University. The typical parameters measured at these stations are wind speed, wind direction, temperature and relative humidity.

2.1 ROYAL ROADS UN IVERSITY

The Royal Roads University monitoring station is located on the Cobourg Peninsula near Esquimalt Lagoon. The monitoring station reports hourly data on wind speed, wind direction, temperature and relative humidity. Pseudo-hourly sigma-theta values, which represent the wind direction deviation, are also reported. The wind roses for the 2001 data are presented in Figure 2.1-1, and show that the winds at this location are predominantly from the north-northwest (approximately 17% of the time), with other dominant vectors from the north and west (approximately 7% of the time, each). Wind speeds were generally light, averaging 2.6 m/s on an annual basis. Calms (e.g., wind speeds less than 1 m/s) occurred 2.35 % of the time.

2.2 VICTORIA TOPAZ

The Victoria Topaz Station is located at 923 Topaz Avenue ( S.J. Willis School near downtown Victoria), and is part of the National Air Pollutant Surveillance (NAPS) program, that is jointly run by the Federal and Provincial Governments. The station is located in a highly urban area, and thus characterizes the urban air environment of Victoria. Meteorological parameters monitored include wind speed, wind direction, temperature and relative humidity. Only a short period of monitoring data in 2001 was available for analysis, from October 19th to December 31st. The wind roses for the available period of record at the Topaz station are presented in Figure 2.2-1. This data shows that the winds predominantly occurred from the north and north-northeast (approximately 20% and 15% of the time, respectively). Flows from the west and southeast occurred approximately 5% and 8% of the time, respectively. Wind speeds were generally light, averaging 3.3 m/s. Calms were observed to occur 0.11 % of the time.



2.3 COLWOOD MUNICIPAL HALL

The Colwood station is located at the Colwood Municipal Hall, and has been collecting data since November 1999. The station is located in a residential/commercial neighbourhood. The meteorological data from 2001 are presented in Figure 2.3-1. The most frequent wind direction is from the SSE, approximately 8% of the time. Winds are also relatively frequent from the ESE (7.5% of the time) and NNW (6.5% of the time). However, the wind speed data show average wind speeds from all directions are less than 1.5 m/s, with an overall annual average of 1.2 m/s on an annual average basis. This is unrealistically low for a station located in a coastal environment. The frequency of calms at 35.5% is also unrealistically high. The sheltered valley location of the monitoring station suggest that it may only be representative of localized wind conditions, and is not representative of overall winds in this part of the CRD.

2.4 VICTORIA GONZALES

The Gonzales meteorological monitoring station is located at the Gonzales Hill observatory, and is operated by Environment Canada, Meteorological Services Canada (MSC). The data collected at the station are available from Environment Canada at the Pacific Weather Centre in Vancouver. The parameters collected are wind speed and wind direction. The 2001 meteorological monitoring data are summarized in Figure 2.4-1. Winds were predominantly from the west and west-southwest (approximately 18 and 15% of the time). Another dominant component originates from the north-northeast (approximately 12% of the time). The wind speeds were slightly higher at this location than observed at the other locations in the CRD. The highest wind speeds, averaging approximately 6 m/s and 5.5 m/s, originated from the west and west-southwest. Winds from the north-northeast were approximately 4 m/s on average. Winds from the southeast, which have an extremely low frequency of occurrence (~3%), had a relatively high average speed at approximately 5 m/s. Calms occurred 0.7% of the time.

2.5 VICTORIA AIRPORT

The meteorological monitoring station at the Victoria Airport is operated by Environment Canada, Meteorological Services Canada (MSC). MSC operates a full monitoring station at this location, and collects data on wind speed, wind direction, temperature, and relative humidity. The airport is located on the Saanich Peninsula with two hills immediately north and south of the site.



The 2001 meteorological monitoring data are presented in Figure 2.5-1. The wind roses show that the winds are predominantly from the west (approximately 20% of the time). Another dominant component originates from the south-east (approximately 8% of the time). The highest wind speeds originate from the south-east, and are approximately 4 m/s. Calms occur 10.5% of the time.



Figure 2.1-1 Wind Rose – Royal Roads Meteorological Station 2001

510152025

N NNNE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN

Wind Direction Frequency (%)

2

4

6N NN

NE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN

Average Wind Speed (m/s)

Note: Percentage of Calms = 2.35%



Figure 2.2-1 Wind Rose – Victoria Topaz Meteorological Station

October 19 – December 31, 2001

510152025

N NNNE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN


2468

N NNNE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN





Figure 2.3-1 Wind Rose – Colwood Meteorological Station 2001

5

10N NN

NE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN


1

2N NN

NE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN





Figure 2.4-1 Wind Rose – Victoria Gonzales Meteorological Station 2001

5101520

N NNNE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN


2

4

6N NN

NE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN


Note: Percentage of Calms = 0.7 %



Figure 2.5-1 Wind Rose – Victoria Airport Meteorological Station 2001

5101520

N NNNE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN


2

4

6N NN

NE

EN

E

ESE

SESSESSS

SW

WS

W

WN

NWNN





3.0 AIR QUALITY MONITORING

3.1 AMBIENT AIR QUALITY OBJECTIVES

The Federal and Provincial Governments in Canada have adopted a set of time-based maximum pollutant concentration levels for the protection and preservation of ambient air quality. Criteria for each contaminant are classified as objectives. The ‘objective’ classification is intended to be applied to those air pollutants which are sufficiently ubiquitous in presence (i.e., common contaminants) and potential environmental effect that national limits have been developed. Table 3.1-1 lists the relevant ambient air quality objectives, standards and health Reference Levels for British Columbia and Canada (the Federal Maximum Tolerable objectives are not listed in Table 3.1-1). Canada’s National Ambient Air Quality Objectives (NAAQO) follow a three-tiered system which was developed based on recommendations of the Federal-Provincial Advisory Committee on Air Quality:

• The Maximum Tolerable Level represents a time-based concentration of air contaminant beyond which, due to a diminishing margin of safety, appropriate action is required to protect the health of the general population.

• The Maximum Acceptable Level is intermediate and intended to provide adequate

protection against the effects of pollutants for human health and comfort, soils, water, vegetation, materials, animals, and visibility.

• The Maximum Desirable Level defines the long term goal for air quality and also

provides a basis for an anti-degradation policy in the least polluted parts of the country. British Columbia’s ambient air quality objectives and guidelines (there are no standards) are defined for two or three levels: A, B, and C. Although the objectives were developed in the 1970’s, there are no consistent or official definitions of the Ambient Level A, B, C Objectives. According to one regional BC Environment web site (MELP 2000)1, the objectives and guidelines “..are designed to prevent air pollution, defined as the presence in the environment of substances or contaminants that substantially alter or impair the usefulness of the environment.” According to this government source, the objective levels can be considered as follows:

1 http//www.elp.gov.bc.ca/ske/skeair/assess/aqassess.html



• Level A (approximately equivalent to the Federal Maximum Desirable Level) – designed to provide long-term protection for all environments. This level is reasonable for polluted areas to aim for and to achieve. This level represents a conservative approach of protection the most sensitive receptor, thereby providing a wide margin of safety to protect other less sensitive receptors.

• Level B (approximately equivalent to the Federal Maximum Acceptable Level) –

intended to be the acceptable interim objective. This level provides adequate protection against adverse effects on human health and comfort, vegetation, animals, soil, water, material, and visibility.

• Level C (approximately equivalent to the Federal Maximum Tolerable Level) – defines

the ‘immediate’ ambient objective. Due to a diminishing margin of safety, appropriate action is immediately required to protect the health of the general population when concentrations of air pollutants exceed this level.

The development of CWS for PM2.5 and ozone (as well as other pollutants) grew out of a recognition in the late 1990’s that the existing air quality objectives were not necessarily providing sufficient levels of protection to human health and the environment. Rather than amending the existing objectives, the Federal and Provincial Governments developed a new set of ‘standards’ while leaving the existing objective levels in place. The target date for achievement of the CWS levels is 2010, although provisions under the implementation plans for the CWS require all jurisdictions such as the CRD to “...take remedial and preventative actions to reduce emissions from anthropogenic sources to the extent practicable”. These provisions in the CWS relate to continuous improvement, pollution prevention, and keeping-clean-areas-clean programs even in those areas where ambient PM2.5 concentrations are already below the numerical standard. Reference Levels for human health and environmental impacts were defined as part of the CWS process. They represent the lowest level at which statistically significant effects can be calculated for the available data. Reference Levels are not effects “thresholds”, and the assumption is that damage may be occurring at pollutant concentrations below the health Reference Levels. The health Reference Levels provide a useful benchmark to support area-wide air quality management goals and control strategies.



Table 3.1-1 Air Quality Objectives and Standards

For Contaminants3 Monitored in the CRD

Contaminant Averaging Period Canada

Maximum Desirable

Canada Maximum Acceptable

BC

Level A

BC

Level B

BC

Level C

1-hour 15000 35000 14300 28000 35000 Carbon

Monoxide 8-hour 6000 15000 5500 11000 14300

1-hour 400

24-hour 200 Nitrogen Dioxide

Annual Arithmetic Mean 60 100

1-hour 100 160

24-hour 30 50 Ozone

Annual Arithmetic Mean 30

1-hour 450 900 450 900 900 -1300

24-hour 150 300 160 260 360 Sulphur Dioxide

Annual Arithmetic Mean 30 60 25 50 80

Ambient Air Quality Objectives Established in 1995

PM10 24- hour 50

Canada-Wide Standards Established in June 2000

Ozone 8-hour 127.61

PM2.5 24-hour 302

Health Reference Levels

PM10 24- hour 25

PM2.5 24- hour 15

Notes: 1 Achievement by 2010, based on the 4th highest measurement annually, averaged over 3 consecutive years. 2 Achievement by 2010, based on the 98th percentile ambient measurement annually, averaged over 3 consecutive years. 3 All units in µg/m3



3.2 GASEOUS POLLUTANTS

3.2.1 Ground-level Ozone

Ambient ground-level ozone in the CRD is monitored at the Victoria Topaz and Royal Roads University air quality monitoring stations, in addition to the CAPMoN station located on Saturna Island. The monitoring results from the three stations are discussed in the following subsections, and are compared to the Federal and Provincial ambient air objectives. Victoria Topaz The ozone monitoring results at the Victoria Topaz site for 2001 are presented in Table 3.2-1. This table provides the statistical hourly analysis of the collected information. Samples were collected and analyzed for a total of 8,760 hours, with 1,082 hours (i.e., 12.4 %) missing data. The recorded hourly maximum of 110 µg/m3 is below the 160 µg/m3, Federal Maximum Acceptable value.

Table 3.2-1

Hourly Averaged Ozone Concentrations at Victoria Topaz Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean Std. Dev. # of Hours % of total

hours 0 12 32 50 74 86 110 0 33 23 1082 12.4

Table 3.2-2 presents the statistical analysis of the 24-hour running mean ozone concentrations. The recorded maximum 24-hour average value of 84 µg/m3 exceeds the 50 µg/m3 Federal Maximum Acceptable value. Analysis of the data shows that this value was exceeded 12.9% of the time in 2001.

Table 3.2-2

24-Hour Running Mean Analysis of Ozone at Victoria Topaz

Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3Mean µg/m3

Std. Dev.

Percent of 24-h Averages

>50 µg/m3 # of 24-h Averages % of Total

8 17 29 42 63 75 84 0.4 31 17 12.9 214 2.1



Figure 3.2-1 depicts the average diurnal pattern of ozone concentrations for the site. This profile represents the concentrations for each hour of the day, averaged over the entire year. This average diurnal pattern shows ozone concentrations at about 30 µg/m3 in the early hours of the day, dropping to approximately 22.5 µg/m3 at 7 AM, and then steadily increasing to a peak of 46 µg/m3 at 3 PM, followed by a decrease for the night hours.

Figure 3.2-1

Victoria Topaz – Average Diurnal Pattern of O3 - 2001

05

101520253035404550

1 3 5 7 9 11 13 15 17 19 21 23

Hour

O3

(g/

m3 )

Figure 3.2-2, shows the monthly maximum daily and 1-hour average ozone concentrations at the Victoria Topaz site. As can be seen from the figure, the highest averages were recorded in May.



Figure 3.2-2

Maximum Daily and Maximum 1-Hour Average Ozone Concentration Per Month for Victoria Topaz

Saturna Island Ozone has been monitored at the Canadian Air and Precipitation Monitoring (CAPMoN)) station on Saturna Island since 1989. The station is also equipped with instruments capable of measuring gaseous pollutants such as sulphur and nitrogen compounds, discussed below. A statistical hourly analysis of the 2001 ozone data is presented in Table 3.2-3. Samples were collected and analyzed for a total of 8,404 hours with 356 hours (i.e. 4.1 %) of missing data. The recorded hourly maximum of 133 µg/m3 exceeds the Federal Maximum Acceptable level of 160 µg/m3.

Table 3.2-3 Hourly Analysis of Ozone at Saturna Island Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean Std. Dev.# of Hours % of total

hours 20 37 49 65 84 100 133 2 51 20 356 4.1

0

20

40

60

80

100

120

Jan. 01 Feb. 01 Mar. 01 Apr. 01 May. 01 Jun. 01 Jul. 01 Aug. 01 Sept. 01 Oct. 01 Nov. 01 Dec. 01

Time (month)

Ozo

ne C

once

ntra

tion

(ug/

m3 )

Maximum 1-hour OzoneMaximum of Daily Averages for each month



Table 3.2-2 presents the statistical analysis of the 24-hour running mean ozone concentrations. The recorded maximum 24-hour average value of 99 µg/m3 exceeds the 50 µg/m3 Federal Maximum Acceptable value. Analysis of the data shows that this value was exceeded 39.5% of the time in 2001.

Table 3.2-4

24-Hour Running Mean Analysis of Ozone at Saturna Island


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean Std. Dev.



24 39 50 61 79 86 99 10 50 16 39.5 2,006 19.7 Figure 3.2-3 depicts the average diurnal pattern of ozone concentrations for the site. The profile represents averaged hourly concentrations that were recorded over the entire study period. The profile shows higher average hourly concentrations for all hours of the day as compared to the levels recorded at the Victoria Topaz station (see Figure 3.2-1).

Figure 3.2-3

Saturna Island – Average Diurnal Pattern of O3 - 2001

0

10

20

30

40

50

60

70

1 3 5 7 9 11 13 15 17 19 21 23

Hour

O3 (

ug/m

3 )



Figure 3.2-4 shows the monthly maximum and mean daily 1-hour maximum at the Saturna Island site. Highest averages were recorded in the month of August.

Figure 3.2-4

Maximum Daily and Maximum 1-Hour Average Ozone Concentration Per Month for Saturna Island

0

20

40

60

80

100

120

140

Jan. 01 Feb. 01 Mar. 01 Apr. 01 May. 01 Jun. 01 Jul. 01 Aug. 01 Sep. 01 Oct. 01 Nov. 01 Dec. 01

Month

Ozo

ne C

once

ntra

tion

(ug/

m3 )

Maximum 1-hour OzoneMaximum of Daily Averages for each month

Royal Roads University Table 3.2-5 provides the statistical analysis of the 2001 hourly ozone data collected at Royal Roads University. Data were only available for the period starting on March 29th and ending on June the 12th. Samples were collected and analyzed for a total of 1,872 hours, with 113 hours (i.e. 6 %) of missing data. The recorded hourly maximum of 132 µg/m3 is below the 160 µg/m3 Federal Maximum Acceptable value.

Table 3.2-5 Hourly Analysis of Ozone at Royal Roads University Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean Std. Dev.# of Hours % of total

hours 14 44 68 84 98 108 132 0 63 27 113 6.0



Table 3.2-6 provides the statistical daily analysis of the collected data. Samples were collected and analyzed for a total of 74 days with zero days of missing data. The recorded maximum daily value of 94 µg/m3 exceeds the Maximum Acceptable level of 50 µg/m3.

Table 3.2-6

24-Hour Running Mean Analysis of Ozone at Royal Roads

March 29 – June 12, 2001


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.



35 51 64 73 89 93 94 25 63 17 74 40 2.3

Due to the short period of observations (i.e., about 2.5 months) at the Royal Roads monitoring site, comparisons of diurnal patterns for ozone concentrations by hour of the day at the Royal Roads site to either the Victoria Topaz or Saturna Island sites are not appropriate.

3.2.2 Nitrogen Oxides (NO & NO2 )

Table 3.2-7 provides the statistical analysis of the 2001 hourly NO2 data collected at Victoria Topaz site. The maximum recorded hourly value for nitrogen dioxide was 113 µg/m3, which is below the Federal objective of 400 µg/m3 for the Maximum Acceptable level (see Table 3.1-1).

Table 3.2-7

Hourly Analysis of NO2 at Victoria Topaz Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev. # of Hours % of total

hours 4 12 19 31 48 59 113 0 22 14 1082 12.5

Table 3.2-8 presents the statistical analysis of the 24-hour running mean NO2 concentrations shows that the maximum recorded value was 49 µg/m3, which is below the 200 µg/m3 Federal guideline for the Maximum Acceptable value.



Table 3.2-8

24-Hour Running Mean Analysis NO2 at Victoria Topaz


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.

Percent of 24-h

Averages >200 µg/m3

% of Total 24-h Averages

10 16 22 27 35 41 49 3 22 8 0 10

The diurnal pattern of NO2 at the Victoria Topaz station is presented in Figure 3.2-5. The figure shows an increase in the concentration of NO2 in the early hours of the day and in the late evening. The peak concentration at 8:00 am in the morning corresponds to the increase in morning rush hour traffic, but the evening peak at about 8:00-9:00 pm may be related to a combination of meteorological factors and increased residential/space heating in the colder months of the year.

Figure 3.2-5

Victoria Topaz – Average Diurnal Pattern of NO2 - 2001

0

5

10

15

20

25

30

1 3 5 7 9 11 13 15 17 19 21 23

Hour

NO2

(g/

m3 )

Error!



3.2.3 Sulphur Dioxide (SO2)

The maximum recorded 1-hour SO2 concentration at Victoria Topaz in 2001 was 83 µg/m3, which is below the 900 µg/m3 Maximum Acceptable value and the 450 μg/m3 Maximum Desirable level as shown in Table 3.2-9.

Table 3.2-9

Hourly Analysis of SO2 at Victoria Topaz Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max µg/m3 Min µg/m3 Mean Std. Dev.

# of Hours % of total hours

0 0 3 5 16 32 83 0 4 6 988 11.3 The maximum 24-hour average SO2 concentration was 28 µg/m3 (Table 3.2-10), which is below both the Federal Maximum Desirable level of 150 µg/m3. The recorded maximums for 1-hour and 24-hour are also below the BC objective/guideline Levels A, B and C, as shown in Table 3.1-1 presented earlier.

Table 3.2-10

24-Hour Running Mean Analysis of SO2 at Victoria Topaz


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3Mean µg/m3

Std. Dev.


>160 µg/m3 % of Total

24-h Averages 0 2 3 5 14 22 28 0 4 4 0.0 8.4

The average diurnal pattern of SO2 at the Victoria Topaz NAPS station is presented in Figure 3.2-6. The pattern for SO2 concentrations shows a morning peak at 8:00 am, declining throughout the day to about 4:00 pm, with a secondary peak in the evening hours between 8:00 and 9:00 pm.



Figure 3.2-6

Victoria Topaz – Average Diurnal Pattern for SO2 - 2001

0

1

2

3

4

5

6

7

1 3 5 7 9 11 13 15 17 19 21 23

Hour

O3

(g/

m3 )

3.2.4 Carbon Monoxide (CO)

Table 3.2-11 provides a statistical summary of the hourly CO monitoring data for the Victoria Topaz site. The maximum 1-hour concentration recorded was 8600 µg/m3. A mean value of 405 μg/m3 was calculated. A total of 8760 hours of sampling data was collected, with 371 hours (4.3 %) recorded as missing.

Table 3.2-11

Hourly Analysis of CO at Victoria Topaz Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev. # of Hours % of total

hours 0 100 200 500 1400 2900 8600 0 405 581 371 4.3

The 8-hour average CO concentrations are summarized in Table 3.2-12, below. There were no exceedences of the Provincial Level A ambient air quality objective of 5,500 µg/m3.



Table 3.2-12

8-Hour Running Mean Analysis of CO at Victoria Topaz


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.

Percent of 8-h Averages >5500 µg/m3

% of Total 8-h Averages

25 138 275 550 1275 2299 4125 0 422 452 0.0 3.8 Figure 3.2-7 presents the average diurnal pattern of CO for the Victoria Topaz station in 2001. Once again, the trend is similar to that seen for NO2 and SO2, suggesting that the morning peak concentrations are related to vehicular peak traffic activity while the evening peak is related to a combination of meteorological influences and increased residential/space heating emissions.

Figure 3.2-7

Victoria Topaz – Average Diurnal Pattern of CO - 2001

0

100

200

300

400

500

600

700

800

1 3 5 7 9 11 13 15 17 19 21 23

Hour

CO

(g/

m3 )



3.3 AIRBORNE PARTICULATES

3.3.1 Inhalable Particulate Matter (PM10)

PM10 sampling data for the CRD are available from five sampling locations. Four sampling sites (Victoria Topaz, Keating Elementary School, Oak Bay Recreational Centre, Braefoot Elementary School) are equipped with sequential high volume (Hi-Vol) samplers (24-hour average, midnight-to-midnight, once every six days), while the fifth site (Colwood Municipal Hall) is equipped with a continuous PM10 sampler (TEOM) recording hourly averaged concentrations. The monitoring site at Victoria Topaz is also equipped with a dichotomous (Dicot) sampler. The Provincial PM10 objective of 50 µg/m3 was only exceeded once at the Victoria Topaz site, and once at the Colwood Municipal Hall. The exceedence at the Victoria Topaz site is uncertain, as the sample collected on the same day using the dichotomous sampler recorded a much lower concentration. The monitoring results for PM10 are discussed in detail below. Interpretation of the results is presented in Section 4.0. Sequential PM10 Sampling Results Table 3.3-1 presents a summary of the Hi-Vol (A) and the Dicot (B) sampling data for the period November 2000 to December 2001, inclusive, at the Victoria Topaz, Oak Bay, Keating and Braefoot monitoring sites. Part A of the table shows average PM10 concentrations ranging from 12-17 µg/m3, and maxima ranging from 31-58 µg/m3. The summary data indicate that overall PM10 levels are quite similar between the three sites at Oak Bay, Keating and Braefoot, while concentrations at the Victoria Topaz site are highest in all aspects. The Dicot results (Part B of the table) shows an average value of PM10 of only 14 µg/m3 as compared to 17 µg/m3 for the same site (Victoria Topaz) based on Hi-Vol sampling data. The maximum PM10 concentration recorded using the dichotomous sampler was 28 µg/m3, compared with the maximum Hi-Vol concentration of 58 µg/m3. The latter concentration derived from Hi-Vol sampling was recorded on November 14, 2000, and exceeds the Provincial ambient air quality objective of 50 µg/m3. By comparison, the measured PM10 concentration on that date based on the dichotomous sampler at the same location was only 21 µg/m3. Thus, both the mean and the maximum PM10 concentrations are higher based on the Hi-Vol sampling data than for the dichotomous sampling data. Wind conditions on that date were light at between 1-3 m/s, and only trace amounts of precipitation were recorded at the Victoria airport.



The bias towards generally higher concentrations for the Hi-Vol sampler is illustrated in Figure 3.3-1. On most sampling days, the Hi-Vol sampler recorded higher PM10 concentrations (data points to the right of the 1:1 line) than the dichotomous sampler. Although some variability between the two samplers can be expected due to the differing design of the sampler inlet (e.g., differences on the order of +30%), such a large degree of variation as depicted in Figure 3.3-1 is not typical for these types of samplers.

Table 3.3-1

Particulate Matter - November 2000 – December 2001

A: Hi-Vol PM10 Results Victoria - Topaz Oak Bay Keating Braefoot

Average (µg/m3) 17 12 12 13 Maximum (µg/m3) 58 34 31 36 Std. Dev. (µg/m3) 9 6 6 6

# >25 ug/m3 6 2 1 1 # >50 ug/m3 1 0 0 0

No. of samples 64 59 63 65 Percent Missing (%) 9.9 16.9 11.3 8.5

B: Victoria Topaz Dicot Results PM10 PM2.5

Average (µg/m3) 14 6 Maximum (µg/m3) 28 18 Std. Dev. (µg/m3) 6 3

98th percentile 27.5 16 # >15 ug/m3 N/A 2 # >25 ug/m3 5 0 # > 50 ug/m3 0 0

No. of samples 61 61 Percent Missing (%) 3.2 3.2

From Figure 3.3-1, it is clear that the high value of 58 µg/m3 recorded using the Hi-Vol sampler at Victoria Topaz is an outlier in the distribution, as are two other samples in which the PM10 concentration based on the dichotomous sampler where much higher than samples collected by the Hi-Vol sampler (all three points denoted in yellow). Leaving out these three points from the sampling distribution produces a much closer correlation between Hi-Vol and Dicot samples (R2 value of 0.745 versus an R2 value of 0.404 with the outlier points included), but does not eliminate the bias toward higher readings on the Hi-Vol sample compared with the dichotomous sampler. Therefore, there is some uncertainty about whether or not the BC Objective of 50 µg/m3 was actually exceeded during the monitoring period on the occasion when the Hi-Vol sampler recorded a maximum concentration of 58 µg/m3.



Figure 3.3-1 PM10 Concentrations at Victoria Topaz Based on Sequential Hi-Vol and Dichotomous Samplers

(November 2000 - December 2001)

R2 = 0.404

R2 = 0.745

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70

Hi-Vol Sampler PM10 (ug/m3)

Dic

hoto

mou

s Sa

mpl

er P

M10

(ug/

m3 )

1:1

Continuous PM10 Sampling Results Continuous PM10 sampling was conducted at the Colwood Municipal Hall. A total of 8,688 hours of sampling data were collected with 211 hours (2.4 %) of missing data. The mean annual concentration of 13 μg/m3 was similar to the mean concentrations recorded at Oak Bay, Braefoot and Keating (see Table 3.3-1). A 1-hour maximum of 286 µg/m3 was recorded at the site, as shown in Table 3.3-2, but hourly concentrations were less than 55 µg/m3 99% of the time. Although the minimum PM10 concentration in the data is 0 µg/m3, the detection limit for PM10 using a TEOM sampler is about 1 µg/m3 at low ambient concentrations. Therefore, the minimum hourly concentration is actually less than 1 µg/m3.

Table 3.3-2

Hourly Analysis of PM10 at Colwood Municipal Hall Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev. µg/m3 # of Hours % of total

hours 3 7 11 15 30 54 286 <1 13 11 211 2.4



The maximum 24-hour average PM10 concentration was 53 µg/m3, as listed in Table 3.3-3. The annual arithmetic mean for 24-hour average concentrations was 13 µg/m3, while the minimum 24-hour average was 4 µg/m3. The daily concentrations were less than 25 µg/m3 over 95% of the time.

Table 3.3-3

24-Hour Running Mean Analysis of PM10 at Colwood Municipal Hall


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.µg/m3



24-h Averages 6 9 12 15 24 32 53 4 13 6 0.2 20

The average diurnal pattern of PM10 concentrations is depicted in Figure 3.3-2. Minimum PM10 concentrations of about 8 µg/m3 occur early in the morning (6:00 am), and are followed by a rapid rise to 15 µg/m3 by 8:00 am. Average concentration decline to about 12.5 µg/m3 by noon, then begin to rise again to about 15 µg/m3 by 4:00 pm in the afternoon. Average PM10 concentrations decline again to about 12 µg/m3 by 5:00 pm, then increase again in the evening to about 14 µg/m3. The elevated PM10 levels during the daytime hours may in part be related to fugitive emissions from the neighbouring public works yard and abandoned gravel pit.

Figure 3.3-2

Colwood Municipal Hall Average Diurnal Pattern of PM10 - 2001

02468

1012141618

1 3 5 7 9 11 13 15 17 19 21 23

PM10

( μg/

m3 )

Hour of the Day



3.3.2 Respirable Particulate Matter (PM2.5)

PM2.5 levels are monitored at three locations in the CRD (Victoria Topaz, Colwood and Royal Roads University). In addition, the Victoria Topaz site is equipped with a dichotomous sampler which provides sequential 24-hour average PM2.5 concentrations on a daily basis (midnight-to-midnight), once every six days. There is currently no ambient air quality objective for PM2.5 in British Columbia, but the province participated in the development of the Canada-Wide Standard (CWS) for PM2.5 which was endorsed by the Canadian Council of Ministers of the Environment (CCME) in June 2000. The CWS for PM2.5 is 30 µg/m3 (24-hour average), based on the 98th percentile, averaged over 3 consecutive years. Although the current analysis only considers data from November 2000 to December 2001, inclusive, and is therefore too short a time period for direct comparison to the CWS, the 98th percentile PM2.5 concentrations for the monitoring period are so low that, from a statistical perspective, PM2.5 concentrations would have to more than double in subsequent years for levels to exceed the CWS. Victoria Topaz Table 3.3-4 lists the summary statistics for PM2.5 monitoring at the Victoria Topaz site. The maximum 1-hour average PM2.5 concentration was 105 µg/m3. The mean hourly concentration was 7 ug/m3. Data was collected for a total of 10,225 hours, with 26 hours (i.e., 0.25%) missing.

Table 3.3-4

Hourly Analysis of PM2.5 at Victoria Topaz

November 2000 – December 2001 Percentile Values (µg/m3) Missing Values

5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3


hours 0 2 5 8 18 41 105 <1 7 7 26 0.25

The maximum 24-hour PM2.5 concentration was 33 µg/m3, as shown in Table 3.3-5. The 98th percentile concentration for 24-hour running mean concentrations was 19 µg/m3, well below the CWS of 30 µg/m3. The reference concentration of 15 µg/m3 was exceeded less than 5% of the time on a 24-hour running mean basis.



Table 3.3-5

24-Hour Running Mean Analysis of PM2.5 at Victoria Topaz

November 2000 – December 2001


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.µg/m3



24-h Averages 2 4 5 8 14 19 33 <1 6 4 4.5 3.8

The mean diurnal pattern for PM2.5 depicted in Figure 3.3-3 illustrates a minimum concentration of 4 µg/m3 around 4:00 am in the morning, with an increase to a peak concentration of about 8 µg/m3 during the period of morning rush hour traffic (i.e., 8:00 am). After 9:00 am, PM2.5 concentrations drop to about 4 µg/m3 between 2:00 pm and 5:00 pm in the afternoon, and then increase to 8 µg/m3 at between 8:00 and 10:00 pm. The daily mean concentration is 6 µg/m3.

Figure 3.3-3

Victoria Topaz – Average Diurnal Pattern of PM2.5 - 2001

0123456789

1 3 5 7 9 11 13 15 17 19 21 23

Hour

PM2.

5 ( μ

g/m

3)

During the warm season (April-October; Figure 3.3-4), the daily PM2.5 profile has an average maximum of 9 µg/m3, which occurs at 8:00 in the morning. The concentration gradually decreases during the daytime to a minimum of 4 µg/m3 at 6:00 pm in the evening, rises slightly to about 6 µg/m3 at 10:00 pm, and then stabilizes overnight.

Hour of the Day



Figure 3.3-4


Warm Season (April – October)

0123456789

10

1 3 5 7 9 11 13 15 17 19 21 23Hourof the Day

PM2.

5 (μg

/m3 )

Figure 3.3-5


Cold Season (November – March)

0

2

4

6

8

10

12

14

1 3 5 7 9 11 13 15 17 19 21 23

Hour of the Day

PM2.

5 (μg

/m3 )

Hour of the Day



The daily PM2.5 profile during the cold season (November – March) is presented in Figure 3.3-5. During this season, the diurnal pattern exhibits two distinct peaks. Average PM2.5 concentrations reach a peak of 9 µg/m3 at 9:00 am in conjunction with morning rush hour traffic, then decline to about 3 µg/m3 in the mid-afternoon. A secondary peak of 12 µg/m3 occurs between 9:00 and 11:00 pm, which is likely to be related to decreased wind speeds and lower mixing heights in the atmosphere, as well as increased emissions from residential/space heating. Colwood Municipal Hall The hourly PM2.5 monitoring data at the Colwood Municipal Hall are summarized in Table 3.3-6 for the year 2001. There were long periods during November and December 2000 when the PM2.5 monitor was not operational. A total of 9,530 hours of sampling data were available for the period November 2000 to December 2001, with 695 hours (i.e., 6.8%) of missing data. The maximum 1-hour PM2.5 concentration recorded at this site was 57 µg/m3, with a mean hourly concentration of 5 ug/m3.

Table 3.3-6 Hourly Analysis of PM2.5 at Colwood Municipal Hall


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3


hours 0 2 4 6 13 22 57 <1 5 5 695 6.8

Table 3.3-7 below summarizes the 24-hour average PM2.5 concentrations at the Colwood monitoring site. The maximum 24-hour average concentration recorded was 26 µg/m3, while the 98th percentile value for 24-hour running mean concentrations of 13 µg/m3 is only 43% of the CWS of 30 µg/m3. The health reference concentration of 15 µg/m3 was exceeded 1.4% of the time on a 24-hour running mean basis.



Table 3.3-7

24-Hour Running Mean Analysis of PM2.5 at Colwood Municipal Hall


5% 25% 50% 75% 95% 98% Max

µg/m3Min

µg/m3Meanµg/m3

Std. Dev.

µg/m3



24-h Averages 1 3 4 6 10 13 26 <1 5 3 1.4 14

The average diurnal pattern of PM2.5 concentrations depicted in Figure 3.3-6 has a bimodal distribution. A peak concentration of 5 µg/m3 occurs between the hours of 8:00 and 10:00 am, corresponding to morning rush hour traffic increases. The concentration drops to about 3.5 µg/m3 by noon, and steadily rising through the afternoon and evening to a high of 7 µg/m3 at 8:00 pm. The daily mean concentration is 4.6 µg/m3.

Figure 3.3-6

Colwood Municipal Hall – Average Diurnal Pattern of PM2.5 - 2001

0

1

2

3

4

5

6

7

1 3 5 7 9 11 13 15 17 19 21 23

Hour of the Day

PM2.

5 (μg

/m3 )

Figure 3.3-7 presents the average diurnal pattern of PM2.5 concentrations during the warm season (April-October). During this season, the diurnal pattern exhibits some similarity to the pattern described for the Victoria Topaz monitoring site. The highest peak occurs at 8:00 am with a value of 5.6 µg/m3, which drops to <4 µg/m3 by noon. Afternoon levels remain around 4 µg/m3, dropping to 3.4 µg/m3by 5:00 pm. Concentrations increase in the evening to peak at 4.6 µg/m3 around 8:00 pm, then gradually decline through the night to a minimum value of 2.5 µg/m3 at 5:00 am.

Hour of the Day



Figure 3.3-7

Colwood Municipal Hall - Average Diurnal Pattern of PM2.5 - 2001


0

1

2

3

4

5

6

1 3 5 7 9 11 13 15 17 19 21 23

Hour of the Day

PM2.

5 (μg

/m3 )

Figure 3.3-8

Colwood Municipal Hall - Average Diurnal Pattern of PM2.5 - 2001


0123456789

10

1 3 5 7 9 11 13 15 17 19 21 23

Hour of the Day

PM2.

5 (μg

/m3 )

Hour of the Day

Hour of the Day



Figure 3.3-8 presents the average diurnal PM2.5 pattern during the cold season (November-March). The pattern exhibits two very definite peaks in the morning and in the late evening hours. The first peak of around 6 µg/m3 occurs at 9:00 am, then declines to a low of 3 µg/m3 at 1:00 pm in the afternoon. Thereafter, PM2.5 concentrations steadily increase to a second peak concentration of 9 µg/m3 at 8:00 pm. This trend is typical of residential heating (oil and/or wood burning stoves) in winter. Royal Roads University A total of 9,504 hours of sampling were available for the period December 2000 through December 2001, with only 34 hours (i.e. 0.4 %) of missing data. No sampling data were available for November 2000. The maximum 1-hour PM2.5 concentration for the site was 43 µg/m3 as shown in Table 3.3-8. The mean concentration was 4 µg/m3. The hourly concentration was less than 15 µg/m3 98.5% of the time during the sampling period.

Table 3.3-8

Hourly Analysis of PM2.5 at Royal Roads University


5% 25% 50% 75% 95% 99% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.µg/m3 # of Hours % of total

hours 0 2 3 6 10 17 43 <1 4 3.7 34 0.4

The maximum 24-hour running mean PM2.5 concentration for the site was 20 ug/m3 as shown in Table 3.3-9. The 98th percentile value for 24-hour running mean concentrations of 10 µg/m3 was one-third of the CWS level of 30 µg/m3. The mean concentration for the site was 4 ug/m3. The health Reference Level of 15 µg/m3 was exceeded less than 0.5% of the time, on a 24-hour running mean basis.

Table 3.3-9 24-Hour Running Mean Analysis of PM2.5 at Royal Roads University


5% 25% 50% 75% 95% 98% Max

µg/m3 Min

µg/m3 Mean µg/m3

Std. Dev.

µg/m3



24-h Averages 1 3 4 5 8 10 20 0.5 4 2.3 0.4 0.0



The average diurnal PM2.5 pattern for the Royal Roads site (Figure 3.3-9) exhibits a peak of 4.5 µg/m3 at 10:00 am, then declines to around 3-4 µg/m3 during the afternoon hours from 1:00 pm to 5:00 pm. Concentration levels rise in the evening hours to about 5.5 µg/m3 at 8:00 pm, then decline throughout the night to reach a minimum value of 3 µg/m3 around 5:00 am.

Figure 3.3-9

Royal Roads University – Average Diurnal Pattern of PM2.5 – 2001

0

1

2

3

4

5

6

1 3 5 7 9 11 13 15 17 19 21 23

PM2.

5 (μg

/m3 )

During the warm season (April-October), the diurnal pattern of PM 2.5 concentrations (Figure 3.3-10) exhibits a peak of just over 4 µg/m3 occurring between 8:00 and 11:00 am, then drops to a low of about 3 µg/m3 during the late afternoon hours 0f 4:00 to 5:00 pm. Concentrations then increase to around 4.5 µg/m3 at 8:00 pm, and decline to less than 3 µg/m3 during the night from 2:00 to 5:00 am. During the cold season (Figure 3.3-11), the average diurnal pattern exhibits a peak concentration of about 5 µg/m3 between 9:00 and 10:00 am, then decreases to about 3 µg/m3 during the early afternoon hours of 1:00 to 2:00 pm. Concentrations then increase to over 7 µg/m3 at around 8:00 pm and remain at or above 7 µg/m3 until after 11:00 pm. Thereafter, concentration levels decline through the night to a low of 3 µg/m3 at 5:00 am. The morning peak is related to rush hour traffic, while the evening peak is most likely related to residential heating emissions.

Hour of the Day



Figure 3.3-10

Royal Roads University – Average Diurnal Pattern of PM2.5 - 2001


00.5

11.5

22.5

33.5

44.5

5

1 3 5 7 9 11 13 15 17 19 21 23

Hour

PM2.

5 (μg

/m3 )

Figure 3.3-11

Royal Roads University – Average Diurnal Pattern of PM2.5 - 2001


012345678

1 3 5 7 9 11 13 15 17 19 21 23

Hour

PM2.

5 (μg

/m3 )

Hour of the Day

Hour of the Day



4.0 ANALYSIS AND INTERPRETATION OF RESULTS

The analysis of air pollutant concentrations in the CRD during 2001 revealed a number of relevant temporal patterns between the levels of gaseous pollutants and particulate matter at the Victoria Topaz site, as well as spatial and temporal patterns in the levels of PM10 and PM2.5 between the monitoring sites within the CRD and within the Georgia Basin. The analyses presented below show that:

• the levels of CO, NO and PM2.5 at the Victoria Topaz site are well correlated, indicating that much of the PM2.5 at this site is derived from combustion source emissions;

• the levels of particulate matter (both PM10 and PM2.5) at the Victoria Topaz site are significantly higher than at the other monitoring sites within the CRD;

• the PM10 levels measured at the Oak Bay Recreational Centre are not significantly different from those measured at the Braefoot Elementary School site;

• the highest levels of PM2.5 in the CRD are measured on weekends rather than weekdays, perhaps indicating that residential wood combustion is a significant contributor to fine particulate loadings within the CRD;

• the ratio of PM2.5 to PM10 is highest in the winter and lowest in the summer, reinforcing the suggestion that residential heating contributes to higher levels of PM2.5 in the CRD;

• occasionally, the levels of PM2.5 measured within the CRD are similar in magnitude and temporal variation to those measured at distant locations within the Georgia Basin, suggestive of a regional meteorological influence on pollutant concentrations.

Evidence for these observations is presented in the following sections of the report.

4.1 POLLUTANT CORRELATIONS AT VICTORIA TOPAZ

With the exception of ozone monitoring at the Saturna Island and Royal Roads University sites, the Victoria Topaz site is the only station within the CRD at which both gaseous pollutants such as CO, NO, NO2 and SO2 are monitored in conjunction with particulate matter. Figure 4.1-1 shows that, as would be expected, there is a strong correlation between hourly averaged CO and NO concentrations at this site. Both pollutants are derived from combustion sources such as motor vehicles and residential heating. However, Figure 4.1-1 also indicates that there is a significant correlation between the levels of CO and PM2.5 at this location. While the correlation is not as strong as between CO and NO, the data indicate that up to 49% of the variability in PM2.5 concentrations can be explained by variations in CO concentrations. Figure 4.4-2 shows that, over short time periods, the correlation between these two pollutants can be very significant, with up to 83% of the variability in PM2.5 levels being explained by changes in CO concentrations.



Figure 4.1-1 Correlation Between Concentrations of CO, NO and PM2.5 at the Victoria Topaz Monitoring Site

R2 = 0.853

R2 = 0.493

0

100

200

300

400

500

600

700

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Hourly CO Concentrations (ug/m3)

Hou

rly N

O o

r PM

2.5 C

once

ntra

tions

(ug/

m3 )

CO vs NOCO vs PM2.5Linear (CO vs NO)Linear (CO vs PM2.5)

Figure 4.1-2 Correlation Between CO and PM2.5 at Victoria TopazDecember 2 (9:00 pm) - December 3 (1:00 pm) 2001

R2 = 0.832

0

1000

2000

3000

4000

5000

6000

7000

8000

0 5 10 15 20 25 30 35 40

Hourly PM2.5 Concentration (ug/m3)

Hou

rly C

O C

once

ntra

tion

(ug/

m3 )



The temporal correlation between CO, NO and PM2.5 at the Victoria Topaz site is further illustrated in Figures 4.1-3 and 4.1-4. Figure 4.3-3 depicts the variations in hourly CO and PM2.5 concentrations during a 3-day period in November 2001. This 3-day period had the highest levels of PM2.5 in 2001 (based on 24-hour running mean concentrations). Two of the three morning rush hour peaks (on Thursday, November 8th and Friday, November 9th) show strong association between both pollutants, indicating that motor vehicle emissions are a likely source for both, and there was no significant peak in concentrations on Saturday morning. However, peak concentrations in both CO and PM2.5 occurred on all three days after 6:00 pm in the evening, and could not have been related to afternoon rush hour emissions. These elevated concentrations were more likely to have been associated with a combination of emissions from both motor vehicles and residential heating emissions. Similarly, Figure 4.1-4 shows the relationship between variations in PM2.5 and NO concentrations over a 2-day period in March 2001, when PM2.5 levels were significantly lower than during the peak period in November 2001. Although the morning rush hour period on Wednesday, March 22nd experienced a simultaneous increase in both pollutants, significant increases in both pollutants also occurred after 9:00 pm on both days. Therefore, combustion sources in the CRD related to home heating in the cold season must be regarded as a significant source of emissions for CO, NO and fine particulate matter.

Figure 4.1-3 Trends in CO and PM2.5 Concentrations at Victoria Topaz, November 8-10, 2001

0

1000

2000

3000

4000

5000

6000

7000

8000

0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22

08-Nov 09-Nov 10-Nov

CO

Con

cent

ratio

n (u

g/m

3 )

0

10

20

30

40

50

60

70

PM2.5 C

oncentration (ug/m3)

CO PM2.5

Morning Rush Hour

Evening PeaksEvening Peak



4.2 SPATIAL CORRELATION OF PARTICULATE MATTER

Figure 4.2-1 shows the probability distributions for PM10 at the five PM10 monitoring sites in the CRD network. With the exception of the site at the Colwood Municipal Hall which uses a continuous (TEOM) monitor, four of the sites are equipped with Hi-Vol monitors. The probability distributions show that 98% of the time, the levels at Colwood, Keating, Oak Bay and Braefoot are similar, while levels at Colwood are significantly higher than the other three sites only for the highest concentrations. However, none of the samples collected in the period November 2000 to December 2001 at three of sites exceeded the BC ambient air quality objective level of 50 µg/m3, while the level was exceeded at the Colwood site only 0.2% of the time. In contrast, the PM10 levels at the Victoria Topaz site were generally higher than at the other four sites. As discussed previously in Section 3.3.1 above, the exceedence of the BC ambient air quality objective at the Topaz site is based on a single outlier value as compared to the dichotomous sampler at that site, and there may not have been an actual exceedence of the objective level during the monitoring period.

Figure 4.1-4 Trends in NO and PM2.5 Concentration at Victoria Topaz, March 22-23, 2001

0

5

10

15

20

25

30

35

0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22

22-Mar 23-Mar

PM2.

5 Con

cent

ratio

n (u

g/m

3 )

0

20

40

60

80

100

120

140

160

NO

Concentration (ug/m

3)

PM2.5 NO

Evening PeaksMorning Rush Hour



On the other hand, the PM10 health Reference Levels were exceeded at all four sites to some extent: 13% of the time at Victoria Topaz, about 5% of the time at both Oak Bay and Keating, and 2% of the time at Braefoot.

Figure 4.2-1 Probability Distributions for PM10 Concentrations in the Capital Regional District

0

5

10

15

20

25

30

35

40

45

50

55

60

65

10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 98% 99.9%

Percentiles

24-H

our A

vera

ge P

M10

Con

cent

ratio

ns (u

g/m

3 )

Victoria TopazOak BayKeatingBraefootColwood

BC Ambient Air Quality Objective

Reference Level

Correlation analyses were conducted to determine whether the PM10 levels measured at the four- Hi-Vol equipped monitoring sites experience similar fluctuations in PM10 levels. Concurrent increases and decreases in PM10 levels can be used to determine whether the measured pollutant concentrations are representative of local conditions or representative of larger spatial fluctuations. The results are presented in Figures 4.2-2 to 4.2-7. Figure 4.2-2 shows that, with the exception of two outlier samples in which levels at Oak Bay were significantly higher than at Braefoot, there is reasonably good agreement between PM10 concentrations measured at the Oak Bay Recreational Centre and the Braefoot Elementary School. The regression line between the two sites falls very close to the 1:1 line. On the other hand, the correlation between the Oak Bay and Braefoot PM10 concentrations versus the levels at the Keating Elementary School is somewhat lower, with much more scatter between samples (Figures 4.2-3 and 4.2-4).



Figure 4.2-2 Correlation of PM10 Concentrations at the Oak Bay and Braefoot Monitoring Sites

R2 = 0.791

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35 40

PM10 Concentration (ug/m3) at Braefoot Elementary School

PM10

Con

cent

ratio

n (u

g/m

3 ) at O

ak B

ay

Rec

reat

iona

l Cen

tre

1:1

Figure 4.2-3 Correlation of PM10 Concentrations at the Keating and Braefoot Monitoring Sites

R2 = 0.464

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35

PM10 Concentration (ug/m3) at Braefoot Elementary School

PM10

Con

cent

ratio

n (u

g/m

3 ) at

Kea

ting

Elem

enta

ry S

choo

l 1:1



Figure 4.2-4 Correlation of PM10 Concentrations at the Keating and Oak Bay Monitoring Sites

R2 = 0.362

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35 40

PM10 Concentration (ug/m3) at Oak Bay Recreational Centre

PM10

Con

cent

ratio

n (u

g/m

3 ) at

Kea

ting

Elem

enta

ry S

choo

l

1:1

Figure 4.2-5 Correlation of PM10 Concentrations at the Victoria Topaz and Oak Bay Monitoring Sites

R2 = 0.653

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70

PM10 Concentration (ug/m3) at VictoriaTopaz

PM10

Con

cent

ratio

n (u

g/m

3 ) ar

Oak

Bay

Rec

reat

iona

l Cen

tre

1:1



Figure 4.2-6 Correlation of PM10 Concentrations at the Victoria Topaz and Braefoot Monitoring Sites

R2 = 0.466

0

10

20

30

40

50

60

70

0 5 10 15 20 25 30 35 40

PM10 Concentrations (ug/m3) at Braefoot Elementary School

PM10

Con

cent

ratio

ns (u

g/m

3 ) at V

icto

riaTo

pax

1:1

Figure 4.2-7 Correlation of PM10 Concentrations at the Victoria Topaz and Keating Monitoring Sites

R2 = 0.334

0

10

20

30

40

50

60

70

0 5 10 15 20 25 30 35

PM10 Concentration (ug/m3) at Keating Elementary School

PM10

Con

cent

ratio

n (u

g/m

3 ) at V

icto

ria T

opaz

1:1



The PM10 levels at the Victoria Topaz site are most closely correlated with levels at the Oak Bay site (Figure 4.2-5), but were generally higher at the Topaz site, especially for the highest concentrations. Levels at Victoria Topaz were less correlated with those at Braefoot Elementary School (Figure 4.2-6) and least correlated with those at the Keating Elementary School (Figure 4.2-7). Figure 4.2-8 shows the probability distributions for 24-hour running mean PM2.5 concentrations at the three monitoring sites equipped with continuous (TEOM) PM2.5 monitors. The data indicate that, in general, the PM2.5 concentrations at the Victoria Topaz site are significantly higher than at either the Colwood Municipal Hall or Royal Roads University. Only the maximum concentrations at Colwood approach the levels at Victoria Topaz. However, both Victoria Topaz and Colwood exceeded the health Reference Level of 15 µg/m3 about 4.5% and 1.4% of the time, respectively.

Figure 4.2-8 Probability Distributions for PM2.5 Concentrations in the Capital Regional District


0

5

10

15

20

25

5% 20% 30% 40% 50% 60% 70% 75% 90% 95% 98% 99.9%

Percentiles

24-H

our A

vera

ge P

M2.

5 Con

cent

ratio

n (u

g/m

3 )

Victoria TopazColwoodRoyal Roads

Reference Level

Figure 4.2-9 shows that the PM2.5 concentrations at Royal Roads were well correlated with this at Colwood, on a 24-hour running mean basis. Almost 80% of the variability in PM2.5 concentrations at Royal Roads is explained by variability in the levels at the Colwood site, with the levels at Colwood being higher than those at Royal Roads most of the time.



The same cannot be said for the correlation of PM2.5 levels at either of these two sites with those at the Victoria Topaz monitoring site. Figures 4.2-10 and 4.2-11 show that, although there is general agreement between these two stations and Victoria Topaz, the large degree of scatter indicates that sources influencing PM2.5 concentrations at Victoria Topaz differ in some significant respects from those that affect levels at Colwood and Royal Roads.

Figure 4.2-9 Correlation of 24-Hour Running Mean PM2.5 Concentrations

at Royal Roads University and Colwood Municipal Hall(November 2000 - December 2001)

R2 = 0.788

0

5

10

15

20

25

0 5 10 15 20 25 30

PM2.5 Concentration (ug/m3) at Colwood Municipal Hall

PM2.

5 Con

cent

ratio

n (u

g/m

3 ) at

Roy

al R

oads

Uni

vers

ity

1:1




at Royal Roads University and Victoria Topaz (November 2000 - December 2001)

R2 = 0.581

0

5

10

15

20

25

0 5 10 15 20 25 30

PM2.5 Concentration (ug/m3) at Victoria Topaz

PM2.

5 Con

cent

ratio

n (u

g/m

3 ) at

Roy

al R

oads

Uni

vers

ity

1:1


at Colwood Municipal Hall and Victoria Topaz (November 2000 - December 2001)

R2 = 0.596

0

5

10

15

20

25

30

0 5 10 15 20 25 30

PM2.5 Concentration (ug/m3) at Victoria Topaz

PM2.

5 Con

cent

ratio

n (u

g/m

3 ) at

Col

woo

d M

unic

ipal

Hal

l

1:1

`



4.3 WEEKDAY/WEEKEND PM2.5 PATTERNS

The analysis of the PM2.5 data for the annual report in 2000 concluded that there were no differences in weekend or weekday concentrations in winter, and that average 24-hour concentrations were roughly similar in summer and winter. The current analysis of the PM2.5 data from the period November 2000 – December 2001 indicates that in fact there are differences in the concentrations for weekdays versus weekends, but that these differences are related to the highest concentration levels. Tables 4.3-1 through 4.3-3 list the 24-hour average PM2.5 probability distributions for the three monitoring sites by day of the week.

Table 4.3-1 Probability Distributions for PM2.5 at Royal Roads University

PM2.5 CONCENTRATION (µg/m3) Day of the Week

Percentiles Sun Sat Fri Thu Wed Tue Mon 10% 0 0. 0 0 0 0 0 30% 2 2 2 2 2 2 2 50% 3 4 4 3 3 3 3 70% 5 5 5 5 5 5 5 90% 8 9 9 8 8 8 8 95% 10 10 12 9 10.7 10 10 98% 14 14.7 15 12 13 13 13

99.9% 36.8 37.9 33.1 23.3 29.4 26 22.3

Table 4.3-2

Probability Distributions for PM2.5 at Colwood Municipal Hall PM2.5 CONCENTRATION (µg/m3) Day of the Week

Percentiles Sun Sat Fri Thu Wed Tue Mon 10% 0 0 0 1 1 0 0 30% 2 2 2 2 2 2 2 50% 3 4 4 4 4 3 3 70% 6 6 6 5 6 5 5 90% 9 12 11 9 11 10 9 95% 12 17 14 11 14 13 13 98% 18 23.3 18 16 18 16 17

99.9% 44.5 45.7 33 34.6 37.6 28.2 32.6



Table 4.3-3 Probability Distributions for PM2.5 at Victoria Topaz

PM2.5 CONCENTRATION (µg/m3) Day of the Week

Percentiles Sun Sat Fri Thu Wed Tue Mon 10% 0 0 1 1 0 0 0 30% 2 3 3 3 3 3 2 50% 4 4 5 4 5 4 4 70% 6 7 8 7 8 7 6 90% 12 13 13 11 13 13 12 95% 16 17 18 15 17 17 17 98% 25 25.7 26.7 19.3 23.3 28.2 25.7

99.9% 63.63 55.9 59.6 46.7 42 58 49.6

Figure 4.3-1 Comparison Between Weekend and Weekday Probability Distributions for Hourly PM2.5 Levels in the CRD


0

10

20

30

40

50

60

70

10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 98% 99% 99.5% 99.9%

Percentiles

1-H

our P

M2.

5 Con

cent

ratio

n (u

g/m

3 )

Topaz - SunColwood - SunRoyal Roads - SunTopaz - WedColwood - WedRoyal Roads - Wed

Figure 4.3-1 shows the relative differences between the distributions for each site on Sundays versus Wednesdays. Whereas the differences between peak hourly concentrations at Colwood and Royal Roads differ only above the 99.5th percentile, peak concentrations on Sundays tend to be higher than on Wednesdays. The differences between peak concentrations on Sundays and Wednesdays at the Victoria Topaz site are significant above the 98th percentile value.



4.4 SEASONAL TRENDS IN PM2.5 AND PM10 CONCENTRATIONS

The annual report for air quality monitoring in the CRD for 2000 noted that there was a strong correlation between PM2.5 and PM10 in the winter months, but only a very weak correlation between the two size fractions of particulate matter during the summer months. It was concluded that, for the summer months, PM10 concentrations were essentially independent of PM2.5 concentrations, with the PM2.5 levels being related to combustion sources, while the coarse fraction of the PM10 was “dominated by industrial sources”. The latter conclusion regarding industrial source contributions to the coarse fraction of PM10 levels is erroneous, as discussed below. Figure 4.4-1 depicts the ratio of daily averaged PM2.5 to PM10 in the CRD during the period November 2000 to December 2001. The data for the Colwood monitoring site are based on continuous sampling data (TEOMs), while the ratios for the Victoria Topaz site are based on the dichotomous sampling data. The trend in ratios follows a U-shaped distribution, with the highest ratios occurring in the months of November-December, and the lowest ratios occurring in July. In winter, the PM2.5 fraction accounts from as little as 10% to as much as 84% of the PM10 concentration. In summer, the range of PM2.5 contribution varies from a low of 2% up to 46% of the PM10 concentrations.

Figure 4.4-1 Trend in PM2.5/PM10 Ratios During Sampling Period

R2 = 0.411

R2 = 0.547

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 50 100 150 200 250 300 350 400 450

Sampling Day (November 2000 - December 2001)

PM2.

5/PM

10 R

atio

Topaz Dicot Colwood TEOMs Poly. (Colwood TEOMs) Poly. (Topaz Dicot)



Figure 4.4-2 shows the probability distributions for PM10 and PM2.5 concentrations in the warm season (defined as April to October) versus the cold season (November to March) at the Victoria Topaz site. The data indicate that PM10 concentrations are slightly higher in the warm season than in the cold season, although maximum PM10 concentrations (99.9th percentile) are similar in both seasons. By comparison, PM2.5 concentrations are significantly lower in the warm season than in the cold season for the top 20% of the observed concentrations in each season.

Figure 4.4-2 Seasonal Probability Distributions for PM2.5 and PM10 at Victoria Topaz

(Dicot data - November 2000 - December 2001)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 98% 99.9%

Percentiles

PM2.

5 & P

M10

Con

cent

ratio

n (u

g/m

3 )

PM10 November - MarchPM2.5 November - MarchPM10 April - OctoberPM2.5 April - October

Figure 4.4-3 shows the equivalent distributions at the Colwood Municipal Hall. The overall patterns are similar to those at Victoria Topaz, with the exception that the maximum PM10 concentrations were significantly higher in the warm season at the Colwood site than they were in the cold season months, and the PM2.5 concentrations were higher in the cold season for the top 5% of the observation.



Figure 4.4-3 Seasonal Probability Distributions for PM2.5 and PM10 at Colwood Municipal Hall

(TEOM - data - November 2000 - December 2001)

0

10

20

30

40

50

60

10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 98% 99.9%

Percentiles

PM2.

5 & P

M10

Con

cent

ratio

ns (u

g/m

3 )

PM10 November - MarchPM2.5 November - MarchPM10 April - OctoberPM2.5 April - October

Consequently, the U-shaped distribution of PM2.5/PM10 ratios in the CRD depicted in Figure 4.4-1 is primarily related to fluctuations in the levels of PM2.5 concentrations. The slight increase in PM10 concentrations in the summer may be related to an increase in fugitive emissions during the drier conditions in summer. The reduction in PM2.5 concentrations in the summer, on the other hand, is likely to be related to a reduction in emissions from fuel combustion sources for space heating. During the colder months, PM2.5 concentrations rise in proportion to the demand for residential/commercial space heating. This is illustrated in Figure 4.4-4 in which the ratio of PM2.5/PM10 at Colwood is shown to be inversely related to the average daily temperature. The R2 value of 0.422 indicates that as much as 42% of the variation in the PM2.5/PM10 ratios can be explained by variations in the average daily temperature. A portion of the PM10 concentrations, and to a larger extent PM2.5 concentrations, is composed of secondary aerosols formed in the atmosphere from gaseous pollutants such as sulphur dioxide, nitrogen oxides, volatile organic compounds and ammonia. The atmospheric transformation of these gases into aerosols increases at higher ambient temperatures, such that the relative contribution of these secondary PM2.5 constituents also varies seasonally, which in turn affects the correlation of PM2.5/PM10 ratios with ambient temperature. Nevertheless, the data presented in Figures 4.4-1 to 4.4-4 support the conclusion that directly emitted particulate matter from



space heating is a primary cause of increased PM2.5 concentrations in the winter, and a major contributor to PM10 levels during this season as well.

Figure 4.4-4 Correlation of Ambient Temperature and PM2.5/PM10 Ratio in the Capital Regional District


R2 = 0.422

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

-1 4 9 14 19 24

Average Daily Temperature (0C)

Dai

ly P

M2.

5/PM

10 R

atio

at C

olw

ood

Mun

icip

al H

all

4.5 REGIONALLY CONCURRENT PM2.5 FLUCTUATIONS

Close inspection of the data record for PM2.5 monitoring in the CRD indicates that fluctuations in PM2.5 concentrations occur concurrently at the three monitoring sites. This type of fluctuation is illustrated in Figure 4.5-1 which shows the hourly fluctuations in PM2.5 levels over a multi-day period from November 2nd to 13th, 2001. As noted previously, the highest 24-hour average PM2.5 concentrations in 2001 occurred between November 9th and 10th. During this period, hourly concentrations ranged from less than 1 µg/m3 to over 40 µg/m3 at the Royal Roads site, over 50 µg/m3 at Colwood, and to over 60 µg/m3 at Victoria Topaz. Figure 4.5-1 shows that to a large extent, there was generally good agreement between the three sites in temporal occurrence of periods of high and low concentrations, even if the magnitude of the concentration levels was greater at one station (e.g., Victoria Topaz) compared to the other two. Figure 4.5-2 shows that, on a 24-hour average basis, the concurrence in PM2.5 fluctuations extended to other, more distant locations such as Nanaimo and the western edge of the Lower Mainland at Vancouver Airport. Of these five monitoring sites, the Victoria Topaz site had the



largest degree of fluctuation in PM2.5 concentrations, primarily due to higher levels on November 5-6th and November 9th. Otherwise, there was remarkably good agreement between the four of the five sites, despite the large distances between the stations.

Figure 4.5-1 Trends in Hourly PM2.5 Concentrations in the CRD During November 2-13, 2001

0

10

20

30

40

50

60

70

02-Nov

03-Nov

04-Nov

05-Nov

06-Nov

07-Nov

08-Nov

09-Nov

10-Nov

11-Nov

12-Nov

13-Nov

Hou

rly P

M2.

5 Con

cent

ratio

n (u

g/m

3 )

Royal RoadsColwoodVictoria Topaz

With the exception of the Victoria Topaz site, the peak concentrations occurred on consecutive Saturdays. This fact suggests that local sources of emission from residential space heating, in particular the use of wood stoves and fireplaces on the weekends at this time of year, may explain the higher PM2.5 levels recorded on weenends. As has already been discussed in Section 4.1 above, the fluctuations in PM2.5 levels at Victoria Topaz on November 8th-10th were closely correlated with changes in ambient concentrations of CO (see Figure 4.1-3), and that the timing of some peak hourly levels during evening hours also pointed to residential heating sources as an explanation for the observed fluctuations in PM2.5 concentrations. As indicated in Figure 4.5-3, based on a 3-hour running average, the evening peak in PM2.5 concentrations was evident at Victoria Topaz, Colwood and Nanaimo on Friday, November 9th, and there was excellent agreement between all three sites in the CRD and Nanaimo on the following day, Saturday, November 10th.



Figure 4.5-2 Trend in Daily PM2.5 Concentrations Within the Georgia Basin - November 2-13, 2001

0

5

10

15

20

25

30

2 3 4 5 6 7 8 9 10 11 12 13

Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue

24-H

our P

M2.

5 Con

cent

ratio

n (u

g/m

3 )

NanaimoVancouver AirportColwoodRoyal RoadsVictoria Topaz

Figure 4.5-3 Trends in PM2.5 Concentrations in the CRD Versus Nanaimo During November 8-11, 2001

0

10

20

30

40

50

60

70

0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22 0 2 4 6 8 10 12 14 16 18 20 22

08-Nov 09-Nov 10-Nov 11-Nov

3-H

our R

unni

ng M

ean

PM2.

5 Con

cent

ratio

n (u

g/m

3 )

Royal RoadsColwoodNanaimoVictoria Topaz

Saturday Evening

Peak

Sunday Evening

Peak

Friday Evening

Peak

Thursday Evening

Peak

Friday Morning

Rush Hour



These patterns in PM2.5 levels indicate that residential space heating is a major contributor to the levels of fine particulate matter in the CRD during the cold season, and that the levels are not significantly different from levels in other communities in the region. Furthermore, as indicated in Section 4.3 above, the highest PM2.5 concentrations occur on weekends as opposed to weekdays. Since there is no reason to expect normal space heating in relation to ambient temperatures to be different on weekends versus weekdays during a season, the logical conclusion from the available data is that the peak concentrations in PM2.5 on weekends is partially due to increased emissions from the use of woodstoves and fireplaces.



5.0 CONCLUSIONS & RECOMMENDATIONS

Air quality in the Capital Regional District was within Maximum Acceptable ambient air quality limits applicable in British Columbia or Canada for three gaseous pollutants monitored (i.e., CO, NO2 and SO2). Ground level ozone concentrations were within the Maximum Acceptable concentrations for 1-hour average concentrations, but exceeded the Federal Maximum Desirable and Provincial Level A objectives. The Federal Maximum Acceptable concentration for 24-hour ozone concentrations was exceeded at all three monitoring sites. With two exceptions (one each at Victoria Topaz and Colwood), the levels of inhalable particulate matter (PM10) were within objectives set in British Columbia, and there is some uncertainty about whether the objective level was actually exceeded at the Victoria Topaz site. The PM10 health Reference Level of 25 µg/m3 was exceeded at monitoring stations. On the other hand, the 98th percentile levels of fine particulate matter (PM2.5) were approximately half of the numerical value of 30 µg/m3 for the Canada-Wide Standard (CWS). Although the latter standard is based on the 98th percentile, averaged over three consecutive years, it is reasonable to conclude that the PM2.5 concentrations in the CRD are within the CWS based on one year of data alone because, on a statistical basis, levels in subsequent consecutive years would have to more than double in order to raise the 98th percentile value for all three years above the CWS level. However, the PM2.5 health Reference Level of 15 µg/m3 (24-hour average) was exceeded at each of the three PM2.5 monitoring stations to some extent.

5.1 METEOROLOGICAL PARAMETERS

Of the five meteorological data sets examined for this review, only the data from three sites (Royal Roads University, Victoria Airport, and Victoria Gonzales) provided a suitable set of data. The record for the Victoria Topaz site was limited to the period October 31 to December 31, 2001, and was too short to provide useful statistical analysis. The data for the monitoring station at the Colwood Municipal Hall appears to be suspect. For the latter station, wind speeds were too low, and there were too many calms reported. The station is located in a sheltered valley, and the instrument exposure may only be representative of localized air flow conditions. It is recommended that the siting of this station be reviewed with a view to re-locating the instruments to provide more appropriate exposure for wind monitoring.



Table 5.1-1

Maximum Observed Pollutant Concentrations (μg/m3) in the CRD

(November 2000 – December 2001)

Con

tam

inan

t

Ave

ragi

ng

Peri

od

Mor

e St

ring

ent o

f th

e B

.C. o

r C

anad

a M

axim

um

Acc

epta

ble

Lev

els

Vic

tori

a T

opaz

Oak

Bay

Bra

efoo

t

Kea

ting

Col

woo

d

Roy

al R

oads

Satu

rna

Isla

nd

Carbon Monoxide 1-hour 28000 8600

1-hour 400 113

24-hour 200 44 Nitrogen Dioxide

Annual Mean 100 22

1-hour 160 110 1323 133

24-hour 50 79 943 99 Ozone

Annual Mean 50 31 50

1-hour 900 83

24-hour 300 19 Sulphur Dioxide

Annual Mean 60 4

PM10 24- hour 50 58 (Hi-Vol)

28 (Dicot)

34

(Hi-Vol)

31

(Hi-Vol)

36

(Hi-Vol)

53

(TEOM)

Canada-Wide Standards

PM2.5 24-hour 302

98th Percentile

19

(Dicot & TEOM)

13

(TEOM)

10

(TEOM)

Notes: 1 Achievement by 2010, based on the 4th highest measurement annually, averaged over 3 consecutive years. 2 Achievement by 2010, based on the 98th percentile ambient measurement annually, averaged over 3 consecutive years. 3 Partial record: March 29 – June 12, 2001



5.2 GASEOUS POLLUTANTS

The monitoring results indicate that sulphur dioxide levels in the core area of the CRD are very low, representing less than 10% of the Maximum Acceptable objectives for all averaging periods. Similarly, the levels of nitrogen dioxide are only within 20-30% of the Maximum Acceptable objectives, depending on the averaging period. The levels of carbon monoxide, which is closely related to nitrogen oxide emissions from combustion sources, are also within approximately 30% of the applicable Maximum Acceptable objective. Therefore, air quality within the CRD is relatively good with respect to these three contaminants as measured at the Victoria Topaz site. Ground level ozone concentrations also met all established 1-hour average Maximum Acceptable ambient air quality objectives in 2001, but exceeded the Federal Maximum Desirable and Provincial Level A objectives at all three monitoring sites. The 24-hour average concentrations at all three sites also exceeded the Maximum Acceptable concentrations. The highest ozone concentration was recorded at the Saturna Island site. The lower concentrations recorded in the core area at the Victoria Topaz site may be related to the effect of titration due to higher levels of NOx from motor vehicle emissions.

5.3 PARTICULATE MATTER

5.3.1 Inhalable Particulate Matter (PM10)

Of the four monitoring stations equipped with Hi-Vol PM10 monitors, only one site (Victoria Topaz) recorded a daily concentration exceeding the Provincial objective of 50 µg/m3. However, on that particular date when the Hi-Vol sample estimated a PM10 level of 58 µg/m3, a simultaneous sample collected using a dichotomous sampler at the same location reported a combined (fine plus coarse fraction) PM10 level of only 21 µg/m3, less than half the level recorded by the Hi-Vol sampler. Although it is possible that the measured concentration using the dichotomous sampler was in error, the correlation of PM10 concentrations at this site between the dichotomous and Hi-Vol samplers suggests that the high reading of 58 µg/m3 on the Hi-Vol sample may have been a spurious estimate, and that the B.C. objective level was probably not exceeded. With respect to the continuous (TEOM) sampler at the Colwood Municipal Hall, the maximum 24-hour average PM10 concentration recorded was 53 µg/m3, which exceeds the Provincial PM10 objective level of 50 µg/m3. However, this level was exceeded for only a total of 17 hours at the Colwood site.



On the other hand, the PM10 health Reference Level of 25 µg/m3 was exceeded at all four Hi-Vol sampling sites to some extent: 13% of the time at Victoria Topaz, about 5% of the time at both Oak Bay and Keating, and about 2% of the time at Braefoot. Based on the continuous sampler data, the health Reference Level was exceeded less than 5% of the time at the Colwood monitoring site. The correlation of Hi-Vol samples at the four monitoring sites shows that the levels of PM10 are well-correlated between the Oak Bay and Braefoot sampling locations. The levels are not significantly different and the CRD may wish to re-evaluate the rationale for operating a sampling station at both locations. The correlation of samples between the other Hi-Vol sampling sites are not as well correlated, indicating that PM10 levels are significantly different between these locations.

5.3.2 Respirable Particulate Matter (PM2.5)

For the respirable fraction of particulate matter (PM2.5), all readings recorded using continuous (TEOM) samplers were well within the established Canada-Wide Standard of 30 µg/m3 (98th percentile). The highest levels were recorded at the Victoria Topaz site based on both the continuous samplers and the dichotomous sampler, but the 98th percentile level was almost half the CWS concentration based on either sampler. With respect to the health Reference Level of 15 µg/m3, the level was exceeded approximately 4.5% of the time at the Victoria Topaz site, 1.4% of the time at the Colwood Municipal Hall, and less than 0.5% of the time at Royal Roads University. There was generally good agreement between the PM2.5 levels recorded at Colwood and Royal Roads, but the levels at these two sites were not as well correlated with those at the Victoria Topaz site, indicating that the pollutant concentrations at the latter site were significantly different from the levels reported for the Colwood and Royal Roads locations. At the Victoria Topaz site, the PM2.5 concentrations were correlated with both CO and NO concentrations, indicating that combustion sources are significant contributors to PM2.5 concentrations at the Victoria Topaz site. Examples of the close association in peak concentrations between these three pollutants were identified that were clearly related to morning rush hour traffic periods. However, peak concentrations in the levels of all three pollutants were also identified in late evening hours that were more likely to be related to residential/commercial space heating during the colder months of the year. Furthermore, the analysis of weekday/weekend distributions of PM2.5 concentrations indicates that the highest PM2.5 concentrations tend to occur on weekends rather than weekdays. The analysis of seasonal patterns in PM2.5/PM10 ratios indicates that the levels of PM2.5 are inversely correlated with ambient air temperature, with PM2.5 levels increasing in the colder months of the



year. This supports the suggestion that space heating is a significant contributor to ambient PM2.5 concentrations during the times of the year when concentrations are highest. Examples were also noted where fluctuations in PM2.5 concentrations within the CRD coincide with similar fluctuations at more distant locations in the Georgia Basin (e.g., Nanaimo and Vancouver). In conclusion, the available monitoring data strongly suggests that the peak concentrations in fine particle matter in the CRD are related to combustion sources such as motor vehicles and space heating, including wood stoves and fireplaces in the winter months. Other sources of combustion may also contribute to total pollutant loading, but the association of PM2.5 with CO and NO during morning rush hour traffic periods and in the late evening hours suggests that vehicular traffic and space heating are the primary sources of these pollutants.

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