MRPO Data Analysis Update

National RPO Technical Workgroup Meeting

St. Louis, Nov. 4-6, 2003

MRPO Data Analysis Approach

• 3-prong attack– Workgroup: State analysts and

stakeholder members mine AQS data, examine specific issues (narrow focus)

– Contractors: Tackle bigger projects and those requiring specialized expertise

– In-house: Direct workgroup, develop new projects, focus on projects requiring more complex tools or analysis

Current Workgroup Projects

• PM-Coarse: Characterize PM-coarse concentrations across region in terms of annual average, daily peaks, seasonal variation (Sarah Raymond, IDEM)

• Continuous Speciation: Analyze continuous NO3, SO4, EC, OC data for diurnal patterns, weekday/weekend differences, EC/OC ratios, correlations with other criteria pollutants (Bill Adamski, WDNR, Sarah Raymond, IDEM)

• PM2.5-O3 Relationship: Time series analysis of PM2.5 and O3 to explore how closely these 2 pollutants are linked (Mike Rizzo, R5 EPA)

Current Workgroup Projects (cont’d)

• Indicator species: Examine O3 dependence on NOx and VOC with MAPPER (Bill Adamski, WDNR)

• Monthly-Annual Averages: Develop regression model to predict annual average PM from selected monthly averages (Mike Lebeis, DTE)

• Ion balance: Determine if aerosol is neutral, acidic, or basic (Joyce Gentry, MOG)

Contractor Projects• Review of Optical Data (ARS)• Analysis of Aircraft Data (Sonoma Tech) • Seney OC Speciation (Jamie Schauer)• Indicator Species, O3/Nox-VOC dependence, and

sensitivity of PM to SO4 and NO3 reductions with ISORROPIA and SCAPE2 thermodynamic models (Charlie Blanchard)

• Analysis of Recent Haze Data (Betty Pun, AER)• Source Apportionment of IMPROVE Data (DRI/Battelle)

– Phase 1: SA of Eastern and Midwestern IMPROVE sites using PMF and UNMIX. Joint MRPO/Marama project, Battelle, completed 2002

– Phase 2: In-depth analysis of 4 sites using PMF, UNMIX, CMB, more species, more trajectory analysis. Focus on 2o sources, especially OC. DRI draft report 9/03.

Asian dust storm Apr 1998

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Canada Fires, Aug. 12, Canada fires, Aug. 12, 1998

Elevated Concentrations Correspond to PM Events

CMB Modeled Source Attributions for Washington DC - Winter

Geological Dust2%

Motor vehicle emissions

15%

Coal fired power plant6%

Diesel vehicle emissions

2%

Oil combustion1%

Vegetative burning

21%

Marine salt2%

Sec. Ammonium

Nitrate19%

Sec. Ammonium

Sulfate31%

Smelter1%

Measured Mass for PM2.5 = 15.80µg/m3

In-House MRPO Projects

• GIS: Quantification of transboundary transport by back trajectory analysis

• CART: Classification and regression tree analysis for PM forecasting and ozone ‘representativeness’ study

• Spatial characterization of PM2.5 in urban areas

• Ammonia data review

State-by-State Contributions to Class 1 Areas

Illinois Indiana Ohio

Avg. PM2.5 Pct.Mass Avg. PM2.5 Pct. Mass Avg. PM2.5 Pct. Mass

Boundary Waters 9.52 1.66 12.47 0.61 12.80 0.25

Seney 10.98 4.31 8.61 1.49 10.87 1.40

Mammoth Cave 11.28 5.25 12.49 6.30 13.51 3.19

Dolly Sods 8.70 1.63 11.11 3.17 11.54 8.78

Avg. PM2.5 is the average PM2.5 concentration associated with the endpoints in each state of trajectories that originate at the indicated Class 1 area. Percent mass is calculated as

100*)*(AllStates

StateAStateA

EndptsConcn

No.endptsAvg.Concn.

Midwest RPO Monitoring and Data Analysis Activities

St. Louis SupersiteContinuation of St. Louis Supersite (cofunding by EPA) through June 2004. Comprehensive suite of measurements including criteria gases; continuous SO4, EC/OC, NO3, met; 1/6 day PM10, PM2.5, speciated PM2.5.

Organic Carbon Speciation at Seney

Seney National Wildlife Refuge, one of two Class 1 areas in Midwest RPO

• Organic carbon makes up about one-third of PM2.5 mass at Seney NWR.

• OC on monthly composited filters analyzed for markers of various sources of organic carbon (gasoline- and diesel-fueled vehicles, wood burning, meat cooking, other combustion)

•Source apportionment will examine relative importance of anthropogenic and biogenic sources to visibility impairment in this scenic wilderness

•Isotope analysis on select species

Nitrogen Speciation at Bondville, IL

• Continuous (15-minute) measurements of particle nitrate, particle sulfate, ammonium, and gaseous nitric acid, sulfur dioxide, nitrous acid, and ammonia

• Operating in central, rural Illinois in agricultural area

• Supplemented with denuder measurements, IMPROVE, meteorology, photolytic NO2, ozone

• Will support thermodynamic models of particle formation and help determine when conditions for particle formation are limited by nitric acid and ammonia. 

Particle humidification and collection chamber

New Monitoring Projects

• Rural ammonia monitoring (with CENRAP)– 1/6 day denuder sampling at 8 sites for one

year – Continuous ammonia at Bondville, plus 1

‘roving’ monitor – Intercomparison of denuder, IC, and

photoacoustic NH3 measurements– Denuder measurements include HNO3, SO2,

particle NO3, SO4, and NH4

Equipment installation completed and sampling started Oct. 2003

New Monitoring Projects (cont’d)

• Urban organic speciation– 1/6 day or more frequent sampling and

analysis at 3 urban sites (Indianapolis, Detroit, Cincinnati) and 1 rural site (Bondville)

– Includes drum sampling – Source apportionment of organic species will

quantify contribution of vehicles, diesels, and wood-burning to urban and rural OC

Spatial and Seasonal Patterns of PM2.5 in Detroit

Goals

• For both total mass and individual components of PM2.5:– Summarize annual average concentrations and

show sites relative to each other; characterize background, upwind, central, and downwind sites.

– In the same way, summarize seasonal variations

• Determine whether an ‘urban excess’ exists, what species contribute to it, and whether it varies seasonally

Data Available• FRM data from 1999-2002 (note that most sites do

not meet completeness criteria in early years)– 12 sites total in metro area– Only POC 1 data used

• Speciation data from 2001-2003– 5 sites, 2 shut down and 3 currently operating– Reconstructed mass calculating using IMPROVE

algorithm

• IMPROVE data for Bondville IL and Livonia IN were averaged for 2001-2002 to represent regional background concentrations. – Note slightly different analytical methods for OC/EC

Preliminary Conclusions—FRM Analysis

• PM2.5 mass concentrations increase on a gradient from SW to NE through downtown Detroit, then decrease moving away from the city. All sites between Luna Pier (farthest upwind) and Linwood are above the NAAQS.

• An ‘outer ring’ of suburban sites (Ann Arbor, Ypsilanti, Oak Park) have lower concentrations, just below the NAAQS.

• Dearborn is the highest site, in keeping with its highly industrial location.

• All FRM sites exhibit the same seasonal pattern of winter and summer peaks, spring and fall lows. Seasonal differences are generally only about 2 ug/m3.

• Year-to-year changes are quite small (about 1 ug) and the relative differences among sites remain the same over the three years of data

Preliminary Conclusions—Speciation Data

• Organic carbon makes up the biggest fraction of PM2.5 in Detroit (36%), followed closely by sulfate (31%) and nitrate (23%). EC and soil are 4% and 5%, respectively.

• Organic carbon, elemental carbon, and soil show the largest changes from site to site.

• Each species shows the same SW-NE gradient changes in concentration as does total PM2.5, increasing as you approach the center city, peaking at Dearborn, and decreasing as you move away from the city.

• Dearborn has uncharacteristically high soil (2.5x other sites, unusual for PM2.5) and also significantly more OC than other sites

Preliminary Conclusions—Speciation Data

• Strong seasonal behavior by sulfate (summer peak) and nitrate (winter peak).

• Moderate seasonality (summer peak) by OC. • EC and soil show little seasonality. • Use caution comparing IMPROVE data with

STN data, especially carbon (but this analysis is based on multiyear averages so differences have less effect)

Urban Excess

• Annually, urban area contributes no sulfate, 1.6 ug/m3 nitrate, and 4.9 ug/m3 of OC to PM2.5, above regional background concentrations

• Seasonally, the excess varies with the mass of the component, except for sulfate and soil.– OC excess is higher in summer and winter, nitrate

excess is higher in winter, EC exhibits little seasonal difference

– Sulfate excess is actually negative in the summer when sulfate is highest (i.e., the city is acting as a sink for sulfate). Likewise, soil excess is also negative in summer when soil is typically higher than other seasons.

Ambient Ammonia Measurements

Review of Available Data

Acknowledgements: Data provided by Purnendu Dasgupta, Texas Tech; Rick Strassman, Minnesota Pollution Control

Agency, Sean Fitzsimmons, Iowa Dept. of Natural Resources

LADCO/Cenrap Ammonia Monitoring Project

• Rural ammonia monitoring – 1/6 day denuder sampling at 8 sites for one

year – Continuous ammonia at Bondville, plus 1

‘roving’ monitor – Intercomparison of denuder, IC, and

photoacoustic NH3 measurements– Denuder measurements include HNO3,

SO2, particle NO3, SO4, and NH4

Equipment installation to begin late Sept/early Oct.

Data summary

• Data presented here include:– All NH3 hourly data from AIRS (14 sites, mostly

source-oriented)– Continuous NH3 data from 3 urban sites collected

by Sandy Dasgupta: Houston, Philadelphia, and Tampa (4-6 weeks at each site).

– 24-hour denuder data from Bondville (3 years of 1/6-day samples)

– Continuous hourly data from Hancock, MN (source site)

– 24-hour denuder data from MARCH-Midwest study (5 urban, 1 rural site, 6 weeks of summer and winter data

Analysis

• Data were examined for evidence of – Seasonal patterns– Diurnal patterns– Weekday/weekend differences– Urban/rural differences– Source/background differences

• Insufficient data for trends or long-term patterns

Seasonal Patterns

• Both source and background monitors show higher concentrations in summer, lower in winter.

• Summer concentrations are higher by a factor of 2 to 10; higher-concentration sites exhibit higher variability

• Not enough urban data to see a seasonal pattern

Diurnal Patterns

• Two different (and opposite) diurnal patterns– Midwest rural sites show midday low concentrations

and late-night high concentrations during warm weather, and relatively constant concentrations at all times during cold weather

– North Carolina source sites show midday peak and late-night low concentrations

• Urban sites generally show daytime peaks; Houston and Tampa at 6-9 am and Philadelphia slightly later at 10-12 am. Philadelphia and Tampa have secondary peaks at 5-6 pm (possibly indicating vehicle source?)

Day-of-Week Variability at Rural Monitors

--No strong evidence of distinct weekday differences

Urban Weekday/Weekend Differences in Hourly Ammonia Concentration

Within each city, diurnal pattern is generally similar.

Not clear why Houston and Tampa have higher weekend concentrations and Philadelphia has lower weekend concentrations

Conclusions• Seasonal patterns are evident at all sites where sufficient

data were collected • Daily patterns also evident, but not consistent from site to

site; these also vary seasonally• No strong day-of-week or weekday/weekend differences,

especially at rural sites. (Cities vary, possibly because of different source influences?)

• Background sites have lower average concentrations than urban sites (but urban data are limited in temporal scope)

• Meteorological variables very weakly correlated with NH3 (RH, dew point, WS, WD, pressure)

• LADCO/Cenrap rural monitoring project will provide more spatially consistent data to examine temporal and spatial variation with more rigor.