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Time-Integrated Particle Measurements : Status in Canada

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Presentation on theme: "Time-Integrated Particle Measurements : Status in Canada"— Presentation transcript:

1 Time-Integrated Particle Measurements : Status in Canada
J. R. Brook, T. F. Dann, R. Vet EMEP Workshop on Particulate Matter Measurement & Modeling New Orleans, LA April 2004

2 Background Starting in 1970's mass-based PM measurements focused on TSP Major cities covered with 1-in-6 sampling selected trace elements (e.g., Pb) and sulfate determined in some geographic areas. In ~1980 open face filter pack measurements began Sparked by acid deposition issue Regionally-representative sites PM2.5 and PM10 or PMcoarse began in mid 1980s National Air Pollution Surveillance (NAPS) program dichotomous samplers and Provincial SSI hi-vols Major cities, 1-in-6 sampling, relatively advanced chemical characterization from NAPS

3 Current Status Several Canadian locations have almost a 20 year record of PM2.5 and PMcoarse, plus chemical constituents Chalk River, Ontario, has one of the longest, high-quality daily records of ambient sulfate in North America Periodic special studies have provided additional chemical characterization and more detail on small-scale spatial patterns PM2.5 speciation programs enhanced starting in 2000

4 Long-Term PM Mass Trend in Canadian Major Cities
Victoria, Vancouver, Calgary, Edmonton, Winnipeg, Windsor, Toronto, Ottawa, Montreal, Quebec, Saint John and Halifax

5 Multi-Year Trend in N-Compounds

6 Average Seasonal Patterns
Egbert, Ontario CAPMoN filter pack ( )

7 Average Spatial Patterns
Combined CAPMoN CASTNet (USEPA) filter pack ( )

8 Urban-Rural Differences
Sites are km apart in same regional airmass

9 Characteristics of Air Masses
Sutton, Quebec, CAPMoN site PM10 = 15.6 mg m-3 PM2.5 = 12.0 mg m-3 SO42- = 4.4 mg m-3 PM10 = 10.3 mg m-3 PM2.5 = 6.6 mg m-3 SO42- = 1.8 mg m-3

10 Importance of Sulfate to Summer PM2.5 Episodes
NAPS

11 Main Constituents “Driving” Episodes
Montréal Warm Season Sulphate Montréal Cold Season Nitrate Canadian Acid Aerosol Measurement Program

12 Response to SO2 Emission Reductions during cold season: Nov.-Apr.
Concentration (mg m-3) Longwoods, Ontario, CAPMoN site

13 Main Weaknesses CAPMoN NAPS Special Studies size-cut uncontrolled
total mass not determined no measurement of carbon content NAPS not daily sampling nitrate biased low due to analytical protocol Special Studies limited in time and space few carbon measurements

14 Carbon Fraction Can't be Ignored (especially since health studies tell us fine mass is important!)

15 SHEMP Study (daily 24 hr data)
Vancouver 7.5 mg m-3 Feb June 2002 Toronto mg m-3 Feb March 2003

16 Current PM Speciation Monitoring in Canada
Sequential dichot Partisol (R&P) for PM2.5 and PMcoarse Sequential R&P chemcomb cartridge-based sampler for PM2.5 speciation

17 Seven Filters for Each Integrated Speciation Sample Period
NH3 NH4 Chemcomb cartridge

18 Canadian Locations with Fine and Coarse Mass, Fine Mass Speciation
24 hour integrated samples

19 Status of Speciation Sites

20 Gas-to-Particle Partitioning of OM and +’ve & -’ve Artifacts
16 Summer (July 16 to 21), Winter (March 17 to 24) , 2003 2 4 6 8 10 12 14 Mon-D Mon-N Tue-D Tue-N Wed-D Wed-N Thu-D Thu-N Fri-D Fri-N Sat-D Sat-N Sun-D Sun-N IOGAPS-OCQ IOGAPS-SVOC IOGAPS-OC FP-OC OC Concentration (mgC m-3) Downtown Toronto Best measure of OC What a single quartz filter sees Maximum size of +’ve artifact

21 What is in the OM? Another ~15% could be associated with fungal spores (primary biological organic matter) Concentration (ng m-3)

22 Summary What have we learned about the PM problems from time-integrated measurements? Trends, spatial and temporal patterns What sort of hypothesis testing is being supported by these measurements? Regional scale source-receptor analyses, contributions from chemical components, changes in composition, interrelationship between constituents What are the most serious issues vis a vis representing what is actually in the air? Mass and carbon are operationally defined, carbon artifacts, especially in cities Are critical variables missing that are needed for the support of hypothesis testing/interpretation of mass and species composition measurements? Organic speciation, collocated measurements of particles and precursors, size-resolved chemical composition

23 Evaluation of the FNO3 Estimation Technique


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