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Atmospheric Particulate Matter: Chemical Composition and Basics of Concentration Estimation

Atmospheric Particulate Matter: Chemical Composition and Basics of Concentration Estimation. Mike Bergin, Ted Russell, Jim Mullholland, Sangil Lee. CEE 6319: Air Module. Overview. Week 1 (April 8) Lecture (Bergin) Background (effects, extent of problem, PM characteristics, etc.)

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Atmospheric Particulate Matter: Chemical Composition and Basics of Concentration Estimation

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  1. Atmospheric Particulate Matter: Chemical Composition and Basics of Concentration Estimation Mike Bergin, Ted Russell, Jim Mullholland, Sangil Lee CEE 6319: Air Module

  2. Overview • Week 1 (April 8) • Lecture (Bergin) • Background (effects, extent of problem, PM characteristics, etc.) • An overview of filter based sampling • Week 2 (April 11 -15) • Lecture (Bergin) • Nut and bolts of atmospheric particulate measurements • Detection limit determination • Lab (Lee) • Begin sampling ambient particulate matter on EST roof • Week 3 (April 17-22) • Lab (Lee) • Finish sampling • Laboratory analyses (mass, ions, carbon, select elements) • Week 4 (April 29) • Lab due on last day of classes

  3. Potential Gas/Particle Interactions at a Filter Surface DP

  4. PM2.5 Mass from Teflon Filter Gravimetry Equilibration of Teflon filter samples in Class 1000 Clean Room [PM] < 1000/scf, T = 21 +-0.5 oC, RH = 33 +-3 % Mettler Toledo MT5 Electronic Micro-Balance Exp. DL = 1.2 +-0.02 mg; P = +- 0.4 % @ 1 mg; A = +-0.001 % {1-500 mg}

  5. PM2.5 NAAQS will also impact many smaller cities Monitors at which the 1999 annual average [PM2.5] exceeds (yellow and red) the 15 g/m3 annual average PM2.5 NAAQS.

  6. Annual Average PM2.5 in Urban Areas, 2002

  7. PM2.5 Concentrations Across the PRD • Concentrations at all sites above annual U.S NAAQS • Organic carbon and sulfate are the dominant species • Guangzhou appears to be major source of PM

  8. Aerosol Chemical Composition Measured in Yulin, China Anthropogenic Pollution Dust

  9. Emissions/AQ Trends:Primary PM2.5 Sources (2001) Emissions AQ • Potential Risks andEffects • Heart (arrhythmias, attacks) • Respiratory (asthma, bronchitis) • Among elderly and young • Vegetation (ecosystem) • Buildings, Materials • Visibility

  10. Other (Inorganic) Secondary PM Formation Secondary formation is a function of many factors including: concentrations of precursors, other gaseous reactive species (e.g., O3, OH), atmospheric conditions, and cloud or fog droplet interactions. Gas-to-particle conversion (oxidation) SO2(g) HOSO3 H2SO4 + 2NH3 (NH4)2SO4 NOx(g) HNO3 + NH3 NH4NO3 Heterogeneous reactions

  11. Emissions/AQ Trends: SO2 Emissions Sources (2001) AQ • Potential Risks andEffects • Breathing impairment • Respiratory, cardiovascular {PM} • Precursor for PM • Acidification (soils, waters) • Corrosion (bldgs, monuments) • Visibility

  12. SO2SO4= in Greater Atlanta for July 2001

  13. Emissions/AQ Trends: CO Sources (2001) Emissions • Potential Risks andEffects • Blood-O2 deficiency • Cardiovascular (angina pectoris) • Visual, neurological impairment • Role in P(O3) via HOx cycle (slow) AQ

  14. Emissions/AQ Trends: NOx (NO+NO2) Sources (2001) Emissions • Potential Risks andEffects • Airway, lung function • Respiratory illness, infection • Precursor for O3 and PM • Acid deposition (nutrient loss) • Eutrophication (algae bloom) • Visibility AQ

  15. Measuring ions using ion chromatography

  16. An example Chromatogram (Anions)

  17. An example Chromatogram (Cations)

  18. Measuring Elemental and Organic Carbon (EC/OC)

  19. The Sunset Lab Instrument

  20. Thermal Evolution Thermalgram

  21. Estimating Mass Closure To estimate the mass concentration based on chemical composition: MT = ∑ions + ∑elements + ∑crustal + ∑carbon = ∑ions measured + ∑Al*1.9 (Al2O3) + Si*2.1 (SiO2) +Fe*1.4 (Fe2O3) + Elemental Carbon (EC) +Organic Carbon (OC)*1.4 Mass Closure = ΔM = Measured Mass- Estimated Mass

  22. Uncertainty Estimation Root Sum Square Method:For Example Function: X=ABm/Cn

  23. A Simple Example Mass Concentration = Mass on Filter (ΔM) / Air Volume (V) M = ΔM / V ΔM = 100 ug ± 10 ug; V = 1.0 m3 ± 0.1 m3

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