hdm-#121905-v1-2000 air quality report · table (2.2.2) historical continuous pm 2.5 data collected...

2000 CRD AIR QUALITY MONITORING REPORT

Prepared for:

Capital Regional District Environmental Services Department

Engineering Department 524Yates St. Victoria, B.C.

Attention: Chris Robins

Prepared by:

Levelton Engineering Ltd. # 150 - 12791 Clarke Place

Richmond, B.C. V6V 2H9

Jeff Lundgren M.Sc.

Date: 09/24/2001 File:401-0635

File: 401-0635 ANALYSIS OF AIR QUALITY DATA COLLECTED IN THE CRD FROM NOVEMBER 1999

TO OCTOBER 2000 1

TABLE OF CONTENTS

Executive Summary ……………………………………………………………………… 3

History of Ground Level Ozone and Particulate Matter Air Quality studies within

the CRD ……………………………………………………………………………………….7

Ozone and Particulate Matter Air Quality in the CRD 1999-2000

Ground Level Ozone ……………………………………….……………………….12

Continuous PM Measurements…………………………………………………….22

HiVol Measurements………………………………………………………………..40

Statistical Analysis of Historical Data………………………………………………………47

Recommendations……………………………………………………………………………51

References…………………………………………………………………………………….53

List of Figures

Figure (1.1) Map of Air Quality Monitoring Sites within the CRD………………………11

Figure (2.1.1a) Monthly Average and Maximum of 1-hour Ozone for Saturna Island…..15

Figure (2.1.1b) Monthly Average and Maximum of 1-hour Ozone for Victoria Topaz…..15

Figure (2.1.2a) Ozone Concentration versus Time of day for Saturna Island…………...16

Figure (2.1.2b) Ozone Concentration versus Time of Day for Victoria Topaz ………… ..17

Figure (2.1.3a) Ozone Concentration versus Day of Week for Saturna Island…………..19

Figure (2.1.3b) Ozone Concentration versus Day of Week for Victoria Topaz………… ..20

Figure (2.1.4) Victoria Topaz Ozone vs Saturna Island Ozone………………………… ..21

Figure (2.2.1a) Monthly Average and Maximum of PM2.5 for Victoria Topaz………….. ..25

Figure (2.2.1b) Monthly Average and Maximum PM2.5 for Colwood……………………. ..25


TO OCTOBER 2000 2

Figure (2.2.2a) PM2.5 Concentration versus Time of Day for Victoria Topaz…………... 27

Figure (2.2.2b) PM2.5 Concentration versus Time of Day for Colwood City Hall………. 28

Figure (2.2.3a) PM2.5 Concentration versus Day of Week of Day for Victoria Topaz ….30

Figure (2.2.3b) PM2.5 Concentration versus Day of Week of Day for Colwood City Hall.31

Figure (2.2.4) Victoria Topaz PM2.5 versus Colwood PM2.5…..…… ……………………..32

Figure (2.2.5) Monthly Average and Maximum PM10 from Colwood City Hall…………. .34

Figure (2.2.6) PM10 Concentration versus Time of Day for Colwood City Hall ………. .36

Figure (2.2.7) PM10 Concentration versus Day of Week of Day for Colwood City Hall…37

Figure (2.2.8) Colwood PM10 versus Colwood PM2.55 for (a) All Values (b) Winter (c) Summer…………………………………………………………………. .38

Figure (2.2.9) Average Monthly Hivol measured PM10 ………………………………….. .43

Figure (2.2.10) HiVol PM10 versus corresponding 24-hour average TEOM PM2.5

for Victoria Topaz a) All data b) Winter c) Summer………………………44

List of Tables

Table (1.1) Historical and Current Air Quality Monitoring Sites of the Long Term Monitoring Program (LTMP) in the CRD (From Bhattacharyya, 2001)…………..10

Table (2.1.1) Hours of Exceedence and Percentiles for CRD Ozone 1999-2000………………13

Table (2.2.1) Hours of Exceedence and Percentiles for CRD PM2.5 1999-2000………………. 23

Table (2.2.2) Historical Continuous PM2.5 Data Collected by the LTMP 1997/98 and 1998/99..23

Table (2.2.3) Hours of Exceedance and Percentiles for CRD PM10 1999-2000…………………33

Table (2.2.4) Historical Continuous PM10 Data Collected by the LTMP 1997/98 and 1998/99..33

Table (2.2.5) Average, Maximum and Exceedences for HiVol data 1999-2000……………….. 40

Table (2.2.6) Comparison of Discrete PM10 Data Collected by the LTMP 1996/97 to 1998/99..41


TO OCTOBER 2000 3

Executive Summary

Ground level Ozone and Particulate Matter data collected within the CRD from November 1999

to October 2000 were examined. The monitoring during this period consisted of a continuous

PM10 analyser and a PM2.5 analyser (both TEOMs) at Colwood Municipal Hall, a PM2.5 TEOM

analyser and a HiVol PM10 sampler at the National Air Pollution Surveillance NAPS Station on

Topaz Avenue in Victoria, and Hivol samplers at Braefoot Elementary School, Keating

Elementary School and the Oak Bay Recreation Centre. Analysis of ozone data collected at the

Saturna Island Canadian Air and Precipitation Monitoring Network (CAPMoN) site and Victoria

Topaz was also conducted.

Overall particulate matter air quality was fairly good with only one exceedence of the BC PM10

objective. However data does show a number of exceedences of the federal reference levels for

PM10 and PM2.5. The health reference level is defined as the concentration above which a health

effect on a receptor has been observed. PM2.5 at the Topaz site showed the greatest number of

exceedences with 628 hours where the rolling 24-hour average exceeded the federal reference

level of 15 μg/m3. This represents approximately 7% of the rolling 24-hour average samples from

the site and is considerably higher than the number of exceedences observed at this site in

previous years. At one site, Keating Elementary School, PM10 concentrations in to the ‘Poor’

range were measured on May 24, 2000. Further, though Ministry criteria are based on 24-hour

running averages, occasional one-hour samples were observed that were several times in

excess of reference levels.

Highest values occur during early winter and late fall and appear to be associated with space

heating, though occasional high values are also observed in spring and fall that may be more a

result of open burning. Diurnal patterns indicate clear evidence of the influence both space

heating and vehicular traffic have on PM levels. The very strong local source influence visible in

the Colwood data indicates that the site should likely be relocated to a more suitable location in

terms of regional measurement.

Higher PM2.5 levels during winter are of some concern and warrant future monitoring. Overall

there is much spatial variation in PM values in both the fine and coarse modes as measured

within the CRD at various sites over the past few years of the Long Term Monitoring Plan

(LTMP). Enhanced spatial coverage of monitors operating for a longer continuous span of

several years is required to resolve these variations.


TO OCTOBER 2000 4

There appears to have been considerable variation in the relation of PM10 to PM2.5 across the

measurement sites where both have been recorded. Enhanced spatial coverage of monitors

operating for a longer continuous span of several years is required to resolve these variations.

Wherever possible, PM10 HiVol monitors should be co-located with continuous PM2.5 TEOM

monitors to further examine the relation between fine mode and coarse mode PM values.

Ozone air quality was generally good, with only a few hours at Saturna and Topaz exceeding the

federal Level A (‘Fair’) objective and no measurements at either in excess of the Level B (‘Poor’)

standard. Ozone levels at Saturna were often higher than at the Topaz site and a lack of

correlation between measurements at the two sites indicates that ozone measurements at the

two sites may have been the results of significantly differing air masses, with the Saturna site

experiencing the influence of longer range transport from either the Puget Sound of Lower

Fraser Valley Areas. Diurnal pattern observed at the Topaz site show that ozone levels

measured there are strongly influenced by local emissions of oxides of nitrogen. As a result, this

site may be too close to core emission sources to be fully representative of regional ozone

values. As peak ozone concentrations in urban environments tend to be spatially and temporal

displaced downwind from emission sources, it is recommended that another ozone monitor be

installed at a location that is downwind of the CRD core during conditions conducive to ozone

production. Keating Elementary School is proposed as the most suitable location for this monitor.

Some sites appear to show improvements from previous years, but lacking a statistical analysis

of data collected up until the present time, it is difficult to make broad assessments as to what

this data reflects about overall air quality trends.

Though some patterns and trends within the CRD air quality data record appear to be discernible

from visual and qualitative analysis, a quantitative statistical analysis is required to establish a

baseline of pollutant levels in the area, and to identify trends in overall magnitude, relation to

background levels, and spatial and temporal patterns of variation of air quality in the CRD.

Based on the results of the present analysis and a review of historical analyses of Air

Quality data collected in the CRD, the following recommendations for the future of the Long-

Term Monitoring campaign are proposed:

1) Increased Spatial Coverage of the Network

Measurements have been conducted at a variety of sites throughout the CRD over the past

several years, but the monitoring sites have either too sparsely located or of too short a


TO OCTOBER 2000 5

duration too provide meaningful overall measurements of CRD air quality. In addition, due to

great spatial variation in meteorological conditions within the CRD, there is a dearth of

meteorological data, as it pertains directly to air quality studies, within the historical record. A

network of at least 4 well located sites measuring continuous PM, ozone and meteorology

for a uninterrupted period of several years is required.

2) Relocation of Colwood site

The Colwood site has been found to be strongly influenced by local industrial and

commercial emissions and is thus not representative of regional air quality conditions in the

area. The station should be re-located to a more suitable site that better represents ambient

air quality conditions in this area.

3) Establishment of a Ozone Site Downwind from Downtown Core

The ozone data from Topaz shows influence of scavenging by local source NOx emissions

on the diurnal ozone pattern. Though the station is well-sited and representative of

conditions close to the urban core, it is possible that ozone concentration are higher away

from immediate areas of NOx emissions. Further it is very common for urban areas to show

highest ozone concentrations downwind from the epicenter of precursor emissions. It is

therefore recommended that another ozone monitor be established at a site that is

downwind of the Topaz site during meteorological conditions that are conducive to the

formation of ground level ozone.

4) Co-location of PM10 and PM2.5 Monitors

Sites within the CRD have shown a wide variation in the relationship or ration of PM10 to

PM2.5. Though PM2.5 is of primary interest, PM10 levels are of a concern in their own right

and, perhaps even more importantly, the relation between PM2.5 and PM10 can be very

elucidating in the determination of particulate sources. For this reason is desirable that each

continuous (TEOM) PM2.5 monitor be co-located with a sequential (Hi-Vol) PM10 instrument.


TO OCTOBER 2000 6

5) Recommendation for a Statistical Analysis or Historical Data

A full statistical analysis of historical air quality is required to establish a reliable air quality

baseline and trends within the CRD. Such an analysis should include:

-Seasonal Classification and Averaging

-Regression Analysis

-Time Series Decomposition Analysis

- Correlation Analysis


TO OCTOBER 2000 7

1.0 History of Ground Level Ozone and Particulate Matter Air Quality Studies within the CRD

Introduction

The Ministry of Water, Land and Air Protection (WLAP), formerly the Ministry of Environment

Lands and Parks (MELP), began monitoring air quality in general including ground level ozone at

the National Air Pollution Surveillance (NAPS) site on Quadra St. in Victoria starting in 1983.

This site was relocated to Topaz Ave. in May of 1998. Ozone has also been monitored by the

federal government at the Canadian Air and Precipitation Monitoring Network (CAPMoN) site on

Saturna Island since 1992.

In 1996, the Capital Regional District (CRD) and The Ministry of Water Land and Air Protection

(WLAP), entered into a partnering arrangement and established a Long Term Monitoring

Program (LTMP) to increase the amount of air quality monitoring data available in the CRD and

to specifically examine the effect of solid waste burning on suspended particulate matter levels in

the CRD.

In 1999 a CRD Air Quality Working Group (AQWG) was formed. The group is made up of

representatives from federal, provincial and regional governments, the local health authority,

post secondary institutions and the Chamber of Commerce. The AQWG identified development

of a short term plan as a priority. That plan has since been developed and prioritised. One of the

priority tasks is a statistical review of historical ozone and particulate matter to determine

whether any trends are evident. Another priority is the annual reporting of CRD ozone and

particulate matter air quality data.

Levelton was retained to provide a high level of analyses for PM and Ozone data collected in the

CRD from November 1999 to October 2000 as well as to recommend methods of statistical

analysis for historical data to determine whether trends are apparent in air quality.

Ground Level Ozone

Ozone monitors at the NAPS station at Victoria Topaz and on Saturna Island are Thermo

Environmental Instruments Inc. model 49 analysers. The operation of these instruments is based

on the principle that ozone molecules absorb light at a wavelength of 254 nanometers. The

ambient sample is irradiated with ultra violet light and the concentration of ozone is directly


TO OCTOBER 2000 8

proportional to the amount of light absorbed. The federal ambient air objectives for ozone (which

are also applied in BC) are 100 μg/m3 for Level A (Fair) and 160 μg/m3 for Level B (Poor) based

on a 1-hour average.

At concentrations above the Level A objective ozone may cause irritation of the mucous

membranes of the eyes nose and throat. It can decrease lung performance affecting athletes or

labourers and persons with pre-existing respiratory and cardiovascular conditions. Certain types

of broad leaf crops and vegetation, particularly soft fruits, may be damaged by acute exposures

above this level. Due to its strong oxidising potential, elevated levels of ambient ozone may also

cause accelerated degradation of industrial materials such as plastics and vulcanised rubber.

Ozone levels, as measured by the CRD, seemed to reach a peak in the late 1980’s and

subsequently declined throughout the early 1990’s (MELP, 1997). This decline was attributed to

a reduction in oil use for heating and reduction in emissions due to stricter standards for mobile

sources. However, in more recent years, while mean ozone has remained roughly constant,

there appears to be an increase in the upper percentile values measured. This increase in

emissions, along with a corresponding rise in NOx species ozone precursors, is due to a growing

population within the CRD (MELP, 1999b).

Particulate Matter:

In 1996, the Victoria Capital Regional District (CRD) and WLAP entered into a partnering

arrangement and established a Long Term Monitoring Program (LTMP). The purpose of this

arrangement was to increase the amount of air quality monitoring data available in the CRD and

more specifically to examine the effect on fine suspended particulate levels (PM10 and PM2.5) of

solid waste combustion such as demolition and land clearing fires, residential wood combustion

and other sources.

Monitoring instruments have been located at several sites throughout the CRD during the study

period. The monitoring program utilises both sequential (HiVol) and continuous (TEOM) PM

analysers. Continuous PM monitoring instruments were added to the NAPS site when it was

relocated to Topaz Ave. Instruments and the dates of their respective operations are

summarised in Table (1.1) A map of the CRD showing the site of instruments referred to in this

document is given in Figure (1.1).

The continuous PM analysers (R&P TEOM model 1400a) measure real-time particulate mass

using an oscillating micro-balance instrument. The sensors are all standard instruments used by


TO OCTOBER 2000 9

WLAP and are connected to a computer based datalogger which electronically calculates hourly

averages and stores all historical data. The HiVol monitors are filter-based samplers in which a

known volume of air is drawn through a filter over a specific time and the PM10 mass is

calculated from the gravimetric analysis of the filter. These samplers are referred to as high

volume (HiVol) due to the large flow rate of air through the instrument of about 40 cubic feet per

minute.

PM10 and PM2.5 samplers for both the HiVol and continuous analysers, are designed to collect

particles with diameters of 10 and 2.5 microns, respectively, with 50% efficiency. Collection

efficiency progressively increases with decreasing particle size. The collected particles are

considered to represent the inhalable fraction (PM10) and respirable fraction (PM2.5) of ambient

particulate matter considered to be a potential health concern.

The BC objective for PM10 is 50 μg/m3 over a 24-hour period. At present there is no BC objective

for PM2.5. The Federal-Provincial Working group on Air Quality Objectives has established a

reference level for PM10 of 25 μg/m3 and for PM2.5 of 15μg/m3 over a 24-hour period. The

reference level is defined as the level above which an effect on a receptor has been

demonstrated.

Both PM10 and PM2.5 have occasionally shown measurements above federal reference levels at

sites in the CRD (MELP, 1997-1999). These generally occur in winter and early fall and appear

to be associated with combustion from space heating, but high levels are sometimes observed in

the spring and autumn months that may be more closely associated with open biomass burning.

Meteorological Data

Though meteorological instrument packages were in operation at the Colwood and Topaz

monitoring sites, the meteorological data from these stations is not included in the BC ministry

archives. As a result no analysis of data collected during the study period of Nov. 1999 to Oct.

2000 is available.

A previous MELP (1999a) study examined several years of wind speed and direction at four sites

within the CRD, including Victoria Airport. Complex topography and proximity of most areas to

water result in a high variation of local winter patterns between different areas of the CRD, but

most sites tend to show a more southerly direction in summer and a more west to northerly

direction in winter. The data from Victoria airport suggests the presence of a sea breeze in the

summer that is manifested at this location as an easterly flow. Closer to the downtown core, an

onshore sea breeze would likely be more southerly. An analysis of winds and PM2.5


TO OCTOBER 2000 10

Table (1.1) Historical and Current Air Quality Monitoring Sites of the Long Term Monitoring Program (LTMP) in the CRD (From Bhattacharyya, 2001).

Operation Dates Location

From To

Monitors Pollutants Measured

Comments

NAPS Victoria (1250 Quadra)

1983 Fall 1997 HiVol, Dichot., Gaseous analysers

PM10, PM2.5, O3, CO, NO2, SO2

Relocated to Topaz site

Naps Victoria (923 Topaz)

May 1998

Present HiVol, Dichot., TEOM, Gaseous analysers

PM10, PM2.5, O3, CO, NO2, SO2

CAPMoN Saturna Island

1992 Present Gaseous Analysers O3, NO2, SO2 and Met.

Royal Oak BC Hydro Oct. 1996

Aug. 1998

HiVol or TEOM PM10 TEOM relocated to All Fun Park

Camosun College Interurban

Oct. 1996

Oct. 1999

HiVol PM10 Relocated to Braefoot Elementary

Oak Bay Rec. Centre Oct. 1996

Present HiVol PM10

All-Fun Park, Langford

Oct. 1996

Nov. 1999

LoVol or TEOM PM10 ,PM2.5 Relocated to Colwood City Hall

Colwood City Hall Nov. 1999

Present Two TEOMs PM10 ,PM2.5

Keating Elementary Nov. 1999

Present HiVol PM10

Braefoot Elementary Nov. 1999

Present HiVol PM10

Figure 1.1 Map of Air Quality Monitoring Sites within the CRD


TO OCTOBER 2000 11


TO OCTOBER 2000 12

measurements at the “All-Fun” site in the Langford area also showed what appears to be a

correlation between high PM measurements and wintertime northerly winds in that region

(MELP, 1999b).

Despite the wide variation in local meteorology, the CRD region also occasionally is under the

influence of large scale anticyclonic patterns that result in stagnant meteorological conditions

that extend throughout the Georgia basin and affect the Lower Fraser Valley and Puget Sound

as well and may produce episodes of reduced air quality.

In general, unbounded topography, favourable dispersive meteorological conditions and a lack of

significant industrial sources tend to favour regional air quality.


TO OCTOBER 2000 13

2.0 Ozone and Particulate Matter Air Quality in the CRD 1999-2000

2.1 Ground Level Ozone

Ozone analysers were located at the NAPS station at the Topaz and Saturna Island sites during

the study period of November 1, 1999 to October 31, 2000.

Annual Statistics

Table (2.1.1) shows the summary statistics for the Topaz and Saturna sites. Topaz data is

present for all but 3 hours of the study period, while Saturna is missing data for 288 hours or

about 12 days total.

Table (2.1.1) Hours of Exceedence and Percentiles for CRD Ozone 1999-2000

Percentile Values (μg/m3)

Station Mean (μg/m3)

Std Dev.

Missing values (hrs)

Capture Rate %

Max. 1-hour Sample (μg/m3)

Hours > Level A

(100 μg/m3) 5% 25% 50% 75% 95% 99%

Victoria Topaz 32.7 24.1 3 99.7 126 28 2 10 30 52 74 90

Saturna Island 49.6 20.0 298 96.6 125 46 17 37 50 64 83 96

Mean ozone is higher at Saturna Island than at the Topaz site within Victoria proper. Though a

rural environment, Saturna Island is often influenced by the regional scale transport of ozone.

The higher mean is likely due to the influence from the Lower Fraser Valley or from Puget

Sound. Topaz shows a slightly higher 1-hour maximum, but Saturna Island shows more

exceedences of the Level A, or ‘Fair’, objective. Neither site shows any values above the Level B

standard in the ‘Poor’ range.


TO OCTOBER 2000 14

Seasonal Ozone Patterns

Figure (2.1.1) shows the monthly max and mean daily 1-hour maximum at the Saturna and

Topaz sites. Average values for both were highest in April. The month of April is outside of the

photochemical ground level ozone ‘season’. The relatively high mean values seen at this time of

year are likely the result of tropospheric folding episodes that occur as the synoptic pattern in the

Western Pacific changes from the wintertime cyclonic long-wave trough to the summertime

anticyclonic long-wave ridge.

The highest values at both sites occur in early June. Again, this is outside of the typical ozone

‘season’, for which the Pacific Northwest is typically limited to the warmest summer days, from

July through to early September. These high values may or may not be due to locally produced

anthropogenic ozone. Saturna Island also shows Level A exceedences in July and September.

These occurrences of elevated ozone are surely anthropogenic and most likely originate in the

Lower Fraser Valley. Topaz does not show similar high values for these times.

Diurnal Ozone Patterns

Figure (2.1.2) shows the concentration of ozone versus the time of day for the Saturna and

Topaz sites. The Saturna data shows an almost perfect sinusoid, with a higher amplitude during

the summer months. This is as expected for a site removed from local sources while still under

the influence of the transport of ozone from an urban environment, where the timing of the

maximum concentration is driven predominantly by solar insolation.

The Topaz data shows a more typically urban signal. The overall pattern is still roughly

sinusoidal with highest values in both winter and summer occurring as the solar forcing of

photochemical ozone generating chemical reactions is at a maximum. However, in both the

summer and winter seasons, there is a distinct dip in ozone concentrations in the morning hours

as NO is emitted from rush hour vehicle traffic in the vicinity of the Topaz station, scavenging

low-level ozone. In addition, the summer pattern also shows a slight but visible extension of the

high ozone values up until late afternoon (between about 4 to 6 p.m.) as stronger summer solar

radiation continues to drive reactions of ozone precursors.

Figure (2.1.1a) Monthly Average and Maximum of 1-hour Ozone for Saturna Island

0

20

40

60

80

100

120

140

Nov-99

Dec-99

Jan-00

Feb-00

Mar-00

Apr-00

May-00

Jun-00

Jul-00

Aug-00

Sep-00

Oct-00

Ozo

ne C

once

ntra

tion

(ug/

m3)

Maximum 1-hour Ozone

Average Daily 1-hour MaximumOzone

Figure (2.1.1b) Monthly Average and Maximum of 1-hour Ozone for Victoria Topaz

0

20

40

60

80

100

120

140

Nov-99

Dec-99

Jan-00

Feb-00

Mar-00

Apr-00

May-00

Jun-00

Jul-00

Aug-00

Sep-00

Oct-00

Ozo

ne C

once

ntra

tion

(ug/

m3)

Maximum 1-hour Ozone

Average Daily 1-hourMaximum Ozone


TO OCTOBER 2000 15

Figure (2.1.2a) Ozone Concentration versus Time of day for Saturna Island

Winter

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Time of Day (24 hr Clock)

Ozo

ne C

once

ntra

tion

(ug/

m3)

Average Hourly Ozone

Summer

0

10

20

30

40

50

60

70

80

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Time of Day (24 hr clock)

Ozo

ne C

once

ntra

tion

(ug/

m3) Average Hourly Ozone


TO OCTOBER 2000 16

Figure (2.1.2b) Ozone Concentration versus Time of Day for Victoria Topaz

Winter

0

5

10

15

20

25

30

35

40

45


ug/m

3


Summer

0

10

20

30

40

50

60


Ozo

ne C

once

ntra

tion

(ug/

m3)



TO OCTOBER 2000 17


TO OCTOBER 2000 18

Weekend/Weekday Ozone Patterns

Figure (2.1.3) shows the average 1-hour maximum for each day of the week for the Saturna and

Topaz sites. Values for each site are again higher for summer days, but neither site shows any

features that might be associated with weekend/weekday differences or any other hebdomadal

phenomenon. Such differences may still exist in the data but are not readily visible in the plots of

average daily ozone concentrations.

Correlation of Ozone measures at Saturna and Topaz Sites

A graph of the maximum daily ozone for the Topaz site compared to the Saturna site is plotted in

Figure (2.1.4). Least squares regression suggests that ozone concentrations measured at Topaz

is typically about 90% of that observed at Saturna, though a coefficient of relation of 0.65

between the two variables also suggests that values measured at each site are particularly well

correlated. Production and accumulation of ground level ozone tends to be driven by regional to

synoptic scale meteorology. One might therefore expect ozone values between the two sites to

be more strongly related. The apparent lack of a particularly strong correlation between ozone

values for the two sites could be the result of an increased local source effect from the Topaz

site or a time lag between values measured fairly close to emission sources. This could also be

a result of emissions that are advected downwind and measured away from urban areas at the

Saturna site.

Conclusion

Overall, ozone air quality, as measured at the two sites, is mostly good with only a few days

each year showing values into the 'Fair' range. The effect of morning NO emissions visible in the

Topaz data suggests that the site may be too close to emission sources to be fully representative

of regional ozone concentrations. A location slightly further downwind might be more

representative of the maximum ozone concentration and could potentially exhibit higher values

than those seen at Topaz. This is because maximum ozone concentrations in urban

environments tend to be spatially displaced downwind from the urban centre. The lack of local

sources makes the Saturna site a good indicator of regional scale ozone pollution, (as opposed

to local scale occurring within the municipality where precursors originate), existing within the

Puget Sound, Lower Fraser Valley and CRD corridor, that urban emissions and subsequent

regional transport may produce.

Figure (2.1.3a) Ozone Concentration versus Day of Week for Saturna Island

Winter

0

10

20

30

40

50

60

70

80

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

Ozo

ne C

once

ntra

tion

(ug/

m3)

Average 1-hour Maximum

Summer

01020304050607080

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

Ozo

ne C

once

ntra

tion

(ug/

m3)


TO OCTOBER 2000 19

Figure (2.1.3b) Ozone Concentration versus Day of Week for Victoria Topaz

Winter

0

10

20

30

40

50

60

70

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

Ozo

ne C

once

ntra

tion

(ug/

m3) Average 1-hour Maximum

Summer

0

10

20

30

40

50

60

70

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

Ozo

ne C

once

ntra

tion

(ug/

m3)


TO OCTOBER 2000 20

Figure (2.1.4) Victoria Topaz Ozone vs. Saturna Island Ozone

Topaz = 0.8939*SaturnaCorrelation Coefficient=0.69

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Saturna Ozone (ug/m3)

Topa

z O

zone

(ug/

m3)

2.2 Particulate Matter


TO OCTOBER 2000 21


TO OCTOBER 2000 22

Both continuous (TEOM) and sequential (HiVol) were operating within the CRD during the study

period of November 1, 1999 to October 31, 2000.

A continuous PM10 analyser, a PM2.5 analyser (both TEOMs) and meteorological instruments

were located at Colwood Municipal Hall, having been relocated from the “All-Fun Park” in

Langford in November 1999. A second PM2.5 TEOM analyser and a HiVol PM10 sampler are at

the National Air Pollution Surveillance NAPS Station on Topaz Avenue. In addition, Hivols were

located at Braefoot elementary, Keating Elementary and the Oak Bay Recreation centre.

Continuous Samplers (TEOMS) Fine Particulate Matter (PM2.5)

Continuous PM data was obtained from the Ministry data archive. Fine particulate TEOM

monitors were located at the Topaz site and at Colwood City Hall. The Topaz site recorded data

continually, for the most part, throughout the study period. Unfortunately, the Colwood archived

data contained substantial gaps in the data record. The station was relocated briefly from mid

August to mid October 2000 to monitor air quality associated with forest fires in southeastern

B.C. Some other data gaps occurred due to equipment problems. Other data recorded by the

Ministry’s regional staff were not included in the archive due to time lags in Ministry procedures

around polling stations. This lag time should be reduced or regional data should be included to

enhance data analysis. Further, meteorological instruments were located at this site but the data

obtained from them was also unavailable from the archive.

Annual Statistics

For the purpose of this study, only Ministry archived data was analysed. Table (2.2.1) shows the

annual summary statistics for PM2.5 collected at the Topaz and Colwood sites. The Topaz

capture rate is over 95% for the study period, but the Colwood site displays usable data for only

about 53% of the time.

Mean PM2.5 is slightly higher at the Topaz site, (with the caveat of the reduced size of the

Colwood data set) as is the maximum observed 24-hour rolling average.

Table (2.2.1) Hours of Exceedence and Percentiles for CRD PM2.5 1999-2000


TO OCTOBER 2000 23



Std Dev.

Missing values

Capture Rate (%)


Hours > Level A

(15 μg/m3) 5% 25% 50% 75% 95% 99%

Victoria Topaz 8.9 3.7 414 95.3 25.6 626 4.4 6.2 8.2 10.7 16.5 20.5

Colwood City Hall 7.7 3.0 2554 53.3 22 78 4.3 5.7 6.9 9.0 14.2 15.8

Though the standard is set on a 24-hour basis, 1-hour values recorded at the Topaz site are

occasionally as high as 80-90 μg/m3. Neither site showed any exceedences of the Level B or

‘Poor’ Air quality level of 30 μg/m3.

Average PM levels are about the same and the maximum observed concentration is lower than

in previous years as listed below in Table (2.2.2). However, the number of hours above Level A

for the present year is considerably higher than those recorded the last two years at the Victoria

site and All-Fun Park in Langford.

Table (2.2.2) Historical Continuous PM2.5 Data Collected by the LTMP

Site Year # 24 hour

rolling averages

Mean PM2.5

(μg/m3)

Maximum PM2.5

(μg/m3)

#24 HOUR AVERAGES

Fair Air Quality PM2.5

> 15 (μg/m3)

# 24 HOUR AVERAGES

Poor Air Quality PM2.5

> 30 (μg/m3)

97/98 4391 9.1 31 308 0

98/99 7221 8.1 37 381 0 Victoria NAPS

99/00 8761 8.9 26 626 0

All Fun Park Langford 98/99** 6794 6.2 26 12 0

Colwood Municipal Hall 99/00 2643 7.7 22 78 0

Seasonal PM2.5 Patterns


TO OCTOBER 2000 24

Figure (2.2.1) shows the monthly maximum and mean 24-hour average for PM2.5 at the Topaz

and Colwood sites respectively. With respect to the Topaz site, the mean PM2.5 varies only by

about 5 μg/m3 throughout the year, with values in the summer appearing to be slightly less than

during the winter. In general, the maximum values show a similar cycle, though more

pronounced, with a much bigger variation between the summer and winter values, with the

exception of June which shows a much higher maximum concentration than the other summer

months. The increased fine particulate matter concentrations are likely a result of both increased

space heating and reduced wintertime atmospheric dispersion.

Though only 5 months were examined in this study, the Colwood data shows a similar pattern to

the Topaz site with values recorded in February and March much higher for both the mean and

maximum 24-hour rolling average in comparison with the summer months of June, July and

August.

Diurnal Patterns

Figure (2.2.2) shows the concentration of PM2.5 versus the time of day for the Topaz and

Colwood sites. For the winter months, the pattern observed at both sites is virtually opposite to

the one seen for ozone concentrations. PM2.5 is highest overnight, increasing from a low in the

early afternoon and peaking just before midnight, with another smaller peak in the hours after

sunrise. This pattern strongly indicates wintertime space heating as the dominant source of

ambient fine particulates. Concentrations rise as people awake and heat their homes. Concentrations are lowest in the early afternoon when outside temperatures are warmest and

many people are away from home. Concentrations rise to their peaks in the evening as people

again heat their homes while ambient temperatures decrease through the winter evening and

then drop off again overnight as people sleep.

Though vehicular traffic could be a contributor, particularly as the morning peak corresponds tio

the timing of the morning rush hour, no similar peak that might be associated with an afternoon

rush hour is visible prior to the rise of particulates due to space heating in the eveining.

Figure (2.2.1a) Monthly Average and Maximum of PM2.5 for Victoria Topaz

0

5

10

15

20

25

30

Nov-99

Dec-99

Jan-00

Feb-00

Mar-00

Apr-00

May-00

Jun-00

Jul-00

Aug-00

Sep-00

Oct-00

PM2.

5 (ug

/m3)

Maximum 24-hour Running Average

Mean 24-hour Running Average

Figure (2.2.1b) Monthly Average and Maximum PM2.5 for Colwood

0

2

4

6

8

10

12

14

16

18

20

Nov-99

Dec-99

Jan-00

Feb-00

Mar-00

Apr-00

May-00

Jun-00

Jul-00

Aug-00

Sep-00

Oct-00

PM2.

5 (u

g/m

3)

Maximum 24-hour RunningAverageMean 24-hour RunningAverage


TO OCTOBER 2000 25


TO OCTOBER 2000 26

The summertime pattern for Topaz is quite different. In this case values tend to be higher during

the day and in this case shows elevated peaks for either the morning or afternoon commutes.

There is still a slight rise in the evening that is likely related again to space heating. However,

the dominant source appears to be vehicular traffic during the day contributing exhaust

emissions coupled with road dust from the dry Victoria summers. The elevated concentrations

during business hours also point to the possibility of other industrial sources such as construction

dust. The ‘business hour’ signal appears particularly strong for the Colwood data, suggesting a

strong local source.

Weekend/Weekday PM2.5 Patterns

Figure (2.2.3) shows the 24-hour average PM2.5 for each day of the week at both the Topaz and

Colwood sites. Values for each site are again higher for winter days, which is the opposite of the

observed tendencies seen from the ozone data. Again the Topaz data does not show any trend

that might be associated with a weekend/weekday difference. However, for both the winter and

summer days in Colwood, values are noticeably lower for Sunday, suggesting that the data there

is strongly affected by commercial or industrial sources.

Correlation of PM2.5 measured at Colwood and Topaz Sites

Figure (2.2.4) shows a graph of the 24-hour average PM2.5 for the Topaz site compared to the

Colwood site for days when both sites recorded data. The regression line between the sites

suggest that the Topaz site records slightly higher values than Colwood, which agrees with the

respective mean values given in Table (2.1.2). However, the coefficient of the correlation

between the sites is only 0.34, which suggests that values recorded at the two sites are not very

well related, and is a further indication that the air masses are different. That is, one or both of

the sites is affected by local sources.

Figure (2.2.2a) PM2.5 Concentration versus Time of Day for Victoria Topaz

Winter

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time of Day (24 hr clock)

PM2.

5 (u

g/m

3)

Average Hourly PM2.5

Summer

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time of Day (24 hr Clock)

PM2.

5 (ug

/m3)



TO OCTOBER 2000 27

Figure (2.2.2b) PM2.5 Concentration versus Time of Day for Colwood City Hall

Winter

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24


PM2.

5 (ug

/m3)



TO OCTOBER 2000 28

Summer

0

1

2

3

4

5

6

7

8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24


PM2.

5 (ug

/m3)



TO OCTOBER 2000 29

Figure (2.2.3a) PM2.5 Concentration versus Day of Week of Day for Victoria Topaz

Winter

0

5

10

15

20

25

30

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

PM2.

5 (u

g/m

3)

24-hour Average

Summer

0

5

10

15

20

25

30

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

PM2.

5 (u

g/m

3)


TO OCTOBER 2000 30

Figure (2.2.3b) PM2.5 Concentration versus Day of Week of Day for Colwood City Hall

Winter

02468

10121416

Monda

y

Tuesd

ay

Wed

nesd

ay

Thursd

ayFrid

ay

Saturda

y

Sunda

y

PM2.

5 (ug

/m3)

Summer

0

2

4

6

8

10

12

14

16

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

PM2.

5 (u

g/m

3)

24-hour Average


TO OCTOBER 2000 31

Figure (2.2.4) Victoria Topaz PM2.5 versus Colwood PM2.5

Topaz= 0.7028*ColwoodCorrelation Coefficient = 0.34

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40

Colwood PM2.5 (ug/m3)

Topa

z PM

2.5

(ug/

m3)

Continuous Sampler (TEOMS) Coarse Particulate Matter (PM10)

In addition to the fine particulate TEOM monitor, there was also a coarse mode (PM10)

instrument located at Colwood City Hall. However, as was mentioned previously, the Colwood

site was only in operation from February to August, the co-located PM10 and PM2.5 continuous

samples at this site allow for the closer examination of the relation between fine and coarse

mode particulate matter.

Annual Statistics

Table (2.2.3) shows a summary of the statistics for PM10 collected at the Colwood sites. As

previously for PM2.5, the data collection was spotty with the TEOM only recording usable data for

about 56% of the time, once again taking into account that the site was only recording data for

part of the year.


TO OCTOBER 2000 32


TO OCTOBER 2000 33

Table (2.2.3) Hours of Exceedence and Percentiles for CRD PM10 1999-2000



Std Dev.

Missing values

Capture Rate %


Hours > Level A

(25 μg/m3) 5% 25% 50% 75% 95% 99%

Colwood City Hall 12.1 3.9 2093 56.3 37.8 20 7 9.3 12 15 19 23

Mean PM10 is about 12 μg/m3 with the maximum 24-hour rolling average value measured at

about 38 μg/m3. The Level A guideline of 25 μg/m3 was exceeded on 20 occasions. As with the

PM2.5 data for the present year, these values are similar with respect to the mean and maximum

but show fewer exceedences than those observed at the “All-Fun Park” in Langford over the

previous two years, as displayed in Table (2.2.4),

Table (2.2.4) Historical Continuous PM10 Data Collected by the LTMP 1997/98 and 1998/99

Site Year # 24 hour

rolling averages

Mean PM10

(μg/m3)

Maximum PM10

(μg/m3)

# Fair Air Quality PM10

> 25 (μg/m3)

# Poor Air Quality PM10

> 50 (μg/m3)

97/98 7741 11.3 45 54 0 All Fun Park Langford 98/99 7630 10.9 39 261 0

Colwood Municipal Hall 98/99 2764 12.2 38 20 0

Seasonal Patterns

Figure (2.2.5) shows the monthly mean and maximum 1-hour PM2.5 concentrations from

Colwood City Hall. However, only 5 months of data is present. The results appear to show the

opposite to what was observed for PM2.5 at this site. For PM10 mean and maximum values are

highest in the summer months of June, July and August. Possible sources of increased coarse

mode data include industrial and construction dust and the reduced amount of coarse mode

‘scrubbing’ or rain out that occurs during the drier Victoria summer.

Figure (2.2.5) Monthly Average and Maximum PM10 from Colwood City Hall

0

5

10

15

20

25

30

Nov-99

Dec-99

Jan-00

Feb-00

Mar-00

Apr-00

May-00

Jun-00

Jul-00

Aug-00

Sep-00

Oct-00

PM10

(ug/

m3)

Maximum 24-hour RunningAverageMean 24-hour RunningAverage

Diurnal Patterns

Figure (2.2.6) shows PM10 versus the time of day for the Colwood site. The result for both the

winter and summer cases roughly mirror the result seen for diurnal variation of PM2.5 with respect

to the Topaz site. The winter pattern shows the same pattern of highest values in the evening

and morning associated with space heating and lowest values when people tend to be sleeping

or at work.

The summer pattern again shows the a distinct, (even more so than for the fine mode), ‘business

hours’ pattern. However, summertime maximum levels of PM10 are higher during the day but

lower at night than for the winter case. This indicates that the coarse mode is influenced strongly

by industrial sources in summer, much more than is PM2.5, and also that the Colwood site is ver

strongly influenced by proximity to local sources.

Weekend/Weekday PM10 Patterns

Figure (2.2.7) shows the average 24-hour average PM10 concentration for each day of the week

at the Colwood site. Values are roughly similar for winter and summer days, likely due to the


TO OCTOBER 2000 34


TO OCTOBER 2000 35

effect of space heating in winter and industrial sources during summer giving similar daily

averages, even though highest values occur at different times of the day. No difference in

weekend or weekday concentrations is apparent in the winter, but values are again noticeably

lower for Sunday, further evidencing that summertime PM10 at Colwood is strongly affected by

commercial or industrial sources.

Correlation of PM2.5 and PM10 at Colwood site

Figure (2.2.8a) shows a plot of fine mode versus coarse mode for the Colwood data on days

when both measurements are present. The regression line suggests that the fine mode is

approximately 60% of the coarse mode, which is in line with what is often observed for the

distribution of PM2.5 versus PM10. However, a correlation coefficient of 0.43 implies that this

relation is merely numerical and lacks any physical basis and a visual examination of the plot

seems to suggest that there are in fact two separate distributions located above and below the

plotted regression line. This becomes more apparent when the Colwood data is split into winter

and summer and the graph is re-plotted for each period.

Figures (2.2.8b) and (2.2.8c) show PM2.5 versus PM10 for the Colwood data for the winter and

summer months. When this is done, the coefficient of correlation for the winter data jumps to

0.91 suggesting a very strong relation between the fine mode and the coarse mode. As

previously discussed, both are probably emissions resulting from space heating. The regression

line gives a value of the fine mode being approximately 93 % of the coarse, which is a rather

high ratio of fine to coarse compared to that observed in most environments.

Conversely, the summer plot shows a correlation of 0.21, which suggests a very weak relation

between the variables. Regression analysis suggests that the fine is 40% of the coarse, but the

extremely low correlation and the fact that from graph {2.2.8c} the range of concentration of the

coarse mode is several times that of the fine mode, leads to the conclusion that in the summer,

PM10 concentrations are essentially independent of PM2.5 with the fine mode still coming from

combustion sources, while the coarse mode is dominated by industrial sources.

Figure (2.2.6) PM10 Concentration versus Time of Day for Colwood City Hall

Winter

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Time of Day (24-hour Clock)

PM10

(ug/

m3)

Average Hourly PM10

Summer

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Time of Day (24-hour Clock)

PM10

(ug/

m3)

Average Hourly PM10

Figure (2.2.7) PM10 Concentration versus Day of Week of Day for Colwood City Hall


TO OCTOBER 2000 36

Winter

0

2

4

6

8

10

12

14

16

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

PM10

(ug/

m3)

24-hour Average

Summer

0

2

4

6

8

10

12

14

16

Monday

Tuesday

Wednes

day

Thursday

Friday

Saturd

ay

Sunday

PM10

(ug/

m3)

24-hour Average

Figure (2.2.8) Colwood PM10 versus Colwood PM2.55 for (a) All Values (b) Winter


TO OCTOBER 2000 37

(c) Summer

a)

All Values

PM2.5= 0.5889*PM10Correlation Coeffecient = 0.43

0

5

10

15

20

25

0 5 10 15 20 25 30 35 40

PM10 (ug/m3)

PM2.

5(ug

/m3)

b)

W inter

PM2.5 = 0.924*PM10Correlation Coeffecient =0.91

0

5

10

15

20

25

0 5 10 15 20 25

PM10 (ug/m3)

PM2.

5 (u

g/m

3)


TO OCTOBER 2000 38

c)

Summer

PM2.5 = 0.4287*PM10

Correlation Coeffecient = 0.21

0

2

4

6

8

10

12

0 5 10 15 20 25 30

PM10 (ug/m3)

PM2.

5 (ug

/m3)


TO OCTOBER 2000 39

HiVol PM10 Short Term Study Results

HiVol PM10 analysers were located at Keating Elementary School, Braefoot Elementary School,

the NAPS Topaz site and the Oak Bay Recreation Centre. Of these, only the Oak Bay and

Topaz sites were in operation throughout the study year. Breafoot has some data from January

and February, but otherwise both the Braefoot and Keating sites operated from May onward.

Annual Statistics

Table (2.2.5) shows the maximum and average values for the 4 HiVol sites. Average values are

highest at Topaz but Keating recorded the highest value, 63 μg/m3, and the only measurement

to exceed 50 μg/m3 throughout the study period. Also, Topaz and Keating were the only sites to

record values above the reference level of 25 μg/m3, with 3 and 15 exceedences respectively.

For the Topaz site this represents 26% of the samples taken. Both the average and maximum at

Oak Bay and Braefoot were significantly less than those recorded at Keating and Topaz.

Table (2.2.5) Average, Maximum and Exceedences for HiVol data 1999-2000

Breafoot Keating Oak Bay TopazAverage 11.51 16.41 12.92 19.72Maximum 20 63 24 39Std. Dev. 4.16 10.75 4.87 8.82

# > 25ug/m3 0 3 0 15# > 50ug/m3 0 1 0 0

Count 35 29 59 57

These values represent a slight improvement in regional air quality, at least in terms of the

maximum values observed, with respect to that measured in the previous three years. Historical

HiVol PM10 data from the CRD LTMP are shown in Table (2.2.6). The maximum and mean

values observed at Oak Bay are both slightly lower than those previously recorded. The Topaz

mean is slightly higher (keeping in mind that the site was re-located during this time) but the

maximum is greatly reduced from the previous year. The mean and number of hours greater

than Level A observed by the Topaz site over the last few years seem to suggest that PM air

quality at this site is getting worse.


TO OCTOBER 2000 40


TO OCTOBER 2000 41

Table (2.2.6) Comparison of Discrete PM10 Data Collected by the LTMP 1996/97 to 1998/99

Site Year #Samples Average (μg/m3)

Maximum (μg/m3)

# Fair Air Quality PM10 > 25 (μg/m3)

# Poor Air Quality PM10 > 50 (μg/m3)

96/97* 51 13.2 31 3 0

97/98** 21 20 37 5 0

98/99** 59 17.2 56 10 1 Victoria NAPS

99/00 57 19.7 39 15 0


Maximum (μg/m3)


> 25 (μg/m3)


> 50 (μg/m3)

96/97 49 12.6 30 5 0

97/98 57 17.6 66 8 2

98/99 58 15.5 63 9 1

Oak Bay Recreation Centre

99/00 59 12.9 24 0 0


Maximum (μg/m3)


> 25 (μg/m3)


> 50 (μg/m3)

96/97 48 10.5 24 0 0

97/98 53 10.9 46 3 0 Camosun Interurban Campus

98/99 55 14.4 85 7 1

Note: All data is collected on NAPS cycle of one 24-hour sample every sixth day.

* Station located at Yates and Quadra.

** Station moved to S.J. Willis at Blanshard and Topaz, monitoring commenced in May 1998.

This is the first year for the Keating and Braefoot sites so a comparison is difficult, but they

appear to show lower peak levels and slightly higher means than when the same monitors were

operating at either the Royal Oak or Camosun sites. However, these results are potentially

skewed by the fact that the Braefoot and Keating sites were not in operation during some of the


TO OCTOBER 2000 42

winter months in which they would have likely recorded higher values. The number of hours of

exceedence of both the Federal Reference level (25 μg/m3) and the BC objective (50 μg/m3) is

down from previous years, except at Topaz where the number of hours in exceedence has

increased over each of the previous four years.

However, different trends are qualitatively visible at all values, and a statistical analysis of data

collected up until the present time is lacking making it is difficult to make broad assessments as

to what this data reflects in regards to the overall air quality trends. This problem further

highlights the need for a full quantitative statistical analysis of data collected to date within the

CRD.

Monthly Average HiVol Results

Figure (2.2.9) shows the average monthly Hivol measured PM10 values for each of the sites as

well as the regional average for all sites. For the most part, as with the continuous TEOM results,

values tend to be higher in the winter months, although Topaz and Keating show the year’s

highest values in April and May respectively. Though the source of these high PM10 levels during

spring is unclear, it may be related to agricultural and/or residential open burning during these

months.

Figure (2.2.9) Average Monthly Hivol measured PM10

0.0

5.0

10.0

15.0

20.0

25.0

30.0

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

HiV

ol P

M 10 (

ug/m

3)

Breafoot Keating Oak Bay Topaz Average

Correlation of Topaz HiVol PM10 data with TEOM measured PM2.5

Figure (2.2.10) shows the 24-hour Average TEOM PM2.5 measurement versus the HiVol PM10 for

the days of the HIVol samples. For all periods, the regression line suggests that fine mode

particulates are about 40% of the coarse mode fraction. However, the correlation between the

two measurements is higher during the summer, suggesting that, although the mass fraction

may remain roughly the same, the fine and coarse mode have differing causation during winter

but are of more similar origin in summer. The opposite is true of the Colwood site, where fine and

coarse modes are strongly correlated in winter but virtually independent of one another during

the summer.


TO OCTOBER 2000 43

Figure (2.2.10) HiVol PM10 versus corresponding 24-hour average TEOM PM2.5 for Victoria

Topaz a) All data b) Winter c) Summer

All Data

PM2.5 = 0.4263*PM10

Correlation Coefficient = 0.66

0

2

4

6

8

10

12

14

16

18

0 5 10 15 20 25 30 35 40 45

PM10 (ug/m3)

PM2.

5 (ug

/m3)

Winter

PM2.5 = 0.4429*PM10

Correlation Coefficient = 0.53

0

2

4

6

8

10

12

14

16

18

20

0 5 10 15 20 25 30 35 40 45

PM10 (ug/m3)

PM2.

5 (ug

/m3)


TO OCTOBER 2000 44

Summer

PM2.5 = 0.4123*PM10Correlation Coefficient = 0.81

0

2

4

6

8

10

12

14

16

18

0 5 10 15 20 25 30 35 40PM10 (ug/m3)

PM2.

5 (u

g/m

3)

Conclusion

In general, PM air quality meets BC MELP criteria. However, there were exceedences of the

health reference level at the Colwood and Topaz sites for PM2.5 and the Colwood, Topaz and

Keating sites showed exceedances of the PM10 concentration. The greatest number of

exceedances occurred at the Topaz site In terms of PM2.5 concentrations with 628 hours where

the rolling 24-hour average exceeded the federal reference level of 15 μg/m3. This represents

approximately 7% of the rolling 24-hour average samples from the site and is considerably

higher than the number of exceedences observed at this site in previous years. Further, the

hours of exceedence at this site have shown increases over each of the previous four years. At

one site, Keating Elementary School, PM10 concentrations in to the ‘Poor’ range were measured

on May 24, 2000. Further, though Ministry criteria are based on 24-hour running averages,

occasional one-hour samples were observed that were be several times in excess of reference

levels.

Higher PM2.5 levels during winter are of some concern and warrant future monitoring. The

relationship between PM10 and PM2.5 appears variable between sites and also needs to be

further examined. Overall, there is much spatial variation in PM values in both the fine and


TO OCTOBER 2000 45


TO OCTOBER 2000 46

coarse modes as measured within the CRD at various sites over the past few years of the LTMP.

Enhanced spatial coverage of monitors operating for a longer continuous span of several years

is required to resolve these variations.

Some sites appear to show improvements from previous years, but lack a statistical analysis of

data collected up until the present time. It is difficult to make broad assessments as to what this

data reflects about overall air quality trends. This problem further highlights the need of a full

quantitative statistical analysis of data collected to date within the CRD.

There appears to be considerable variation within the relation of PM10 to PM2.5 across the

measurement sites where both have been recorded. Wherever possible, PM10 HiVol monitors

should be co-located with continuous PM2.5 TEOM monitors to further examine the relation

between fine mode and coarse mode PM values.

The Colwood data shows large gaps in the data recorded, even taking into account the

redeployment of the site to cover a forest fire. There is no recording of meteorological data at this

site whatsoever. Moreover, practical lag time between data collection and archiving of data

should be reduced.

The site in Colwood seems to be strongly influenced by local industrial sources. With both a

public works yard and a quarry site in the immediate vicinity seemingly affecting the

measurements, the data measured is likely not representative of broader scale particulate

concentrations in the Colwood area. This site is a good candidate for relocation to a more

suitable area.


TO OCTOBER 2000 47

3.0 Statistical Analysis of Historical Data

The analysis of the previous section and examination of existing data previously collected within

the CRD, suggests, in general, several ways in which to process historical air quality data to

identify trends, particularly with respect to ground level ozone and particulate matter. These

suggested analyses may be summarised in four broad categories as follows.

1) Seasonal Classification and Averaging

2) Regression Analysis

3) Time Series Decomposition Analysis

4) Correlation Analysis

Seasonal Classification and Averaging

Perhaps the simplest change of the manner in which the data has been analysed is to process

the data on a four-season basis (spring, summer, winter and fall) as opposed to the two-season

analysis (winter/summer) that is employed in this document and in earlier reports. Seasons

should be defined as:

Winter- December, January, February

Spring- March, April, May

Summer- June, July, August

Fall- September, October, November

This is the manner in which US EPA analyses and assesses particulate air quality and modelling

studies and allows for greater distinction between periods of interest and obviously more closely

mirror the actual seasonal changes in the ambient meteorology that for the most part, controls air

quality.


TO OCTOBER 2000 48

Specifically within the CRD, there are several examples of measurements of interest occurring in

a ‘cusp’ month of the summer/winter distinction, somewhat blurring the distinction between the

two seasons. In addition, there are ongoing processes, such as open burning in the spring

and/or autumn or the high springtime average ozone values, that would be better identified using

a seasonal analytical basis. Regional average and maximum values of measured pollutants

should also be recalculated on this basis to provide overall estimates of pollution levels during

each period.

Regression Analysis

In general, the most important aspect and the underlying issue basically driving air quality

monitoring programs is the question of how ambient air quality is changing over time. For this

reason, regression analysis of pertinent quantities and values is required to examine the exact

values of pollutant trends over time. Examples of quantities of interest whose trends should be

examined include, but are not limited to:

-Seasonal, annual PM and ozone means and maximums

-Seasonal, annual quartiles and upper and lower percentiles of ozone and PM

-Diurnal (time of day) and hebdomadal (day of week) averages

-Hours of exceedence of respective guidelines for each pollutant

-Ratios of PM2.5/ PM10

Previous studies, (e.g. MELP, 1999) have qualitatively noted apparent trends in historical data,

such as the seeming increase in the upper percentiles of observed ozone. However, it is

important to determine these trends in a quantitative manner to remove subjectivity from the

analysis and to fully grasp air quality concerns within the CRD airshed.

Though establishing the historical record in this manner may be a fairly onerous task, once

established, the database can be updated and trends tracked on an annual basis fairly easily.


TO OCTOBER 2000 49

Time Series Analysis

In order to properly understand the context in which the above trends occur and to elucidate the

forcing mechanisms and emission sources, it is important to know the temporal scale on which

concentrations vary. Time series analysis will identify the varying cycles of change (seasonal,

annual, and diurnal) that are present within the data. Though some of these patterns are visible

to the naked eye in Seasonal/Monthly/Diurnal plots, it is important to quantify the cycles of

variation within the data. Further, time series analysis may isolate frequencies of variation that

are not readily identifiable from other analyses such as mean/maximum or regression plots. By

way of analogy, a sine wave has a mean of zero, but possesses a very distinct temporal

variation. Similar patterns may be ‘hidden’ within the CRD data. Time series analysis will help

identify variations on scales of interest such as:

-Annual

-Seasonal

-Weekday/Weekend

-Time of Day

as well as any other regularly (with respect to time) occurring phenomenon. For example, the

permission of open burning of waste on every second weekend. That is to say that such a

source would likely produce a very identifiable signal with a period of two weeks detectable

within the CRD data record. Conversely, signals identified within the data may then be

associated with meteorological forcing or emissions processes occurring on similar time scales.

Correlation Analysis

Lastly, it is important to examine how pollutant concentrations change in relation to other

quantities of interest. These results are very informative as to the mechanisms of genesis of

specific pollutants. This involves various types of correlation analysis. Specific Examples include:

-Correlation of Ozone versus PM10 and PM2.5

This is useful in determining the origin of particulates. For example, a high correlation of PM with

ozone indicates that some fraction of particulate mass is of secondary photochemical origin,


TO OCTOBER 2000 50

while conversely a low correlation with ozone shows than PM is more the result of primary

emissions sources, such as industrial soot, dust or biomass burning.

-Correlation of PM10 vs. PM2.5

This is similar to the analysis of the Colwood and Topaz data performed in the previous section.

This should be expanded to include all instances of co-located PM10 and PM2.5 measurements.

-Correlation of Ozone and PM versus other constituents

Where data is available, ozone and PM should be compared with the measurement of other

atmospheric pollutants. Again, this is very useful is defining sources of genesis. For example, the

presence of high CO levels in a polluted air mass is very strong evidence of an anthropogenic

origin ingeneral, and more specifically, high nitrites accompanying high PM very strongly

suggests a vehicular emission source.

-Temporal Auto-correlation

This is a method by which a time series of the concentration of a given pollutant is compared to

itself on varying time lags. It is very instructive in determining the time scales of pollutant

episodes. That is, when periods of elevated pollutant concentrations occur, how long do they

persist. It is also useful in identifying intermittent signals within a data series. For example,

signals that occur with some regularity, but not on a distinct daily, weekly or annual period and

are thus not easily defined by time series analysis. Summertime ozone concentration in an urban

environment is an example of a pollutant that shows an intermittent time variation.

-Spatial Correlation between Measuring Sites

This tool provides a measure of how well the concentrations of a given pollutant, measured at

different sites, agree with one another. In a very broad sense, it is desirable that differing or

adjacent sites have a correlation high enough that they measure similar values and are thus

capturing similar air quality events but not so high that they are in fact measuring the same

event. This can then help determine if sites are too close together or are too far apart. It may

also help identify when sites are too strongly influenced by a local source and are not taking a

broader areal sample. This is also useful in determining how the pollutant concentration changes

with respect to distance and can help elucidate the spatial patterns of pollutants in an area.


TO OCTOBER 2000 51

4.0 Recommendations

Based on the results of the present analysis and a review of historical analyses of Air

Quality data collected in the CRD, the following recommendations for the future of the Long-

Term Monitoring campaign are proposed:

1) Increased Spatial Coverage of the Network

Measurements have been conducted at a variety of sites throughout the CRD over the past

several years, but the monitoring sites have either too sparsely located or of too short a

duration too provide meaningful overall measurements of CRD air quality. In addition, due to

great spatial variation in meteorological conditions within the CRD, there is a dearth of

meteorological data, as it pertains directly to air quality studies, within the historical record. A

network of at least 4 well located sites measuring continuous PM, ozone and meteorology

for an uninterrupted period of several years is required.

2) Relocation of Colwood site

The Colwood site is shown to be strongly influenced by local industrial and commercial

emissions and is thus not representative of regional air quality conditions in the area. The

station should be re-located to a more suitable site that better represents ambient air quality

conditions in this area.

3) Establishment of a Ozone Site Downwind from Downtown Core

The ozone data from Topaz shows influence of scavenging by local source NOx emissions

on the diurnal ozone pattern. Though the station is well-sited and representative of

conditions close to the urban core, it is possible that ozone concentration are higher away

from immediate areas of NOx emissions. Further it is very common for urban areas to show

highest ozone concentrations downwind from the epicenter of precursor emissions. It is

therefore recommended that another ozone monitor be established at a site that is

downwind of the Topaz site during meteorological conditions that are conducive to the

formation of ground level ozone.


TO OCTOBER 2000 52

4) Co-location of PM10 and PM2.5 Monitors

Sites within the CRD have shown a wide variation in the relationship or ration of PM10 to

PM2.5. Though PM2.5 is of primary interest, PM10 levels are of a concern in their own right

and, perhaps even more importantly, the relation between PM2.5 and PM10 can be very

elucidating in the determination of particulate sources. For this reason is desirable that each

continuous (TEOM) PM2.5 monitor be co-located with a sequential (Hi-Vol) PM10 instrument.

5) Recommendation for a Statistical Analysis or Historical Data

A full statistical analysis of historical air quality is required to establish a reliable air quality

baseline and trends within the CRD. Such an analysis should include:

-Seasonal Classification and Averaging

-Regression Analysis

-Time Series Decomposition Analysis

- Correlation Analysis


TO OCTOBER 2000 53

References

1. MELP, 1997: PM10 Long Term Monitoring Program in the CRD

2. MELP, 1997: PM10 Short Term Monitoring in the CRD-1997

3. MELP, 1998: PM10 Long Term Monitoring Program in the CRD, Report for the Second Year

4. CRD, 1998: 1997-1998 Highlands/Langford PM10 Monitoring Study

5. MELP, 1999a: PM10 Long Term Monitoring Program in the CRD, Report for the Third

6. MELP, 1999b: A review of the Air Quality Data collected in the CRD 1983-1997

7. Bhattacharyaa,K.K., January 2001: A Short-term Air Quality Monitoring Plan for the Capital Regional District Area.

hdm-#121905-v1-2000 air quality report · table (2.2.2) historical continuous pm 2.5 data collected...

Documents