Download presentation
Presentation is loading. Please wait.
Published byAshlyn Todd Modified over 9 years ago
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
PP Potential Gas/Particle Interactions at a Filter Surface
4
PM 2.5 Mass from Teflon Filter Gravimetry Equilibration of Teflon filter samples in Class 1000 Clean Room [PM] < 1000/scf, T = 21 +-0.5 o C, RH = 33 +-3 % Mettler Toledo MT5 Electronic Micro-Balance Exp. DL = 1.2 +-0.02 g; P = +- 0.4 % @ 1 g; A = +-0.001 % {1-500 mg}
7
PM 2.5 NAAQS will also impact many smaller cities Monitors at which the 1999 annual average [PM 2.5 ] exceeds (yellow and red) the 15 g/m 3 annual average PM 2.5 NAAQS.
8
Annual Average PM 2.5 in Urban Areas, 2002
9
PM 2.5 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
10
Aerosol Chemical Composition Measured in Yulin, China Dust Anthropogenic Pollution
11
Emissions/AQ Trends: Primary PM 2.5 AQ Emissions Sources (2001) Potential Risks and Effects Heart (arrhythmias, attacks) Respiratory (asthma, bronchitis) Among elderly and young Vegetation (ecosystem) Buildings, Materials Visibility
12
Other (Inorganic) Secondary PM Formation Secondary formation is a function of many factors including: concentrations of precursors, other gaseous reactive species (e.g., O 3, OH), atmospheric conditions, and cloud or fog droplet interactions. Gas-to-particle conversion (oxidation) SO 2 (g) HOSO 3 H 2 SO 4 + 2NH 3 (NH 4 ) 2 SO 4 NOx(g) HNO 3 + NH 3 NH 4 NO 3 Heterogeneous reactions
13
Emissions/AQ Trends: SO 2 AQ Emissions Sources (2001) Potential Risks and Effects Breathing impairment Respiratory, cardiovascular {PM} Precursor for PM Acidification (soils, waters) Corrosion (bldgs, monuments) Visibility
14
SO 2 SO 4 = in Greater Atlanta for July 2001
15
Emissions/AQ Trends: CO AQ Emissions Sources (2001) Potential Risks and Effects Blood-O 2 deficiency Cardiovascular (angina pectoris) Visual, neurological impairment Role in P(O3) via HOx cycle (slow)
16
Emissions/AQ Trends: NOx (NO+NO 2 ) AQ Emissions Sources (2001) Potential Risks and Effects Airway, lung function Respiratory illness, infection Precursor for O3 and PM Acid deposition (nutrient loss) Eutrophication (algae bloom) Visibility
17
Measuring ions using ion chromatography
18
An example Chromatogram (Anions)
19
An example Chromatogram (Cations)
20
Measuring Elemental and Organic Carbon (EC/OC)
21
The Sunset Lab Instrument
22
Thermal Evolution Thermalgram
23
Estimating Mass Closure To estimate the mass concentration based on chemical composition: M T = ∑ions + ∑elements + ∑crustal + ∑carbon = ∑ions measured + ∑Al*1.9 (Al 2 O 3 ) + Si*2.1 (SiO 2 ) +Fe*1.4 (Fe 2 O 3 ) + Elemental Carbon (EC) +Organic Carbon (OC)*1.4 Mass Closure = ΔM = Measured Mass- Estimated Mass
25
Uncertainty Estimation Root Sum Square Method: For Example Function: X=AB m /C n
26
A Simple Example Mass Concentration = Mass on Filter (ΔM) / Air Volume (V) M = ΔM / V ΔM = 100 ug ± 10 ug; V = 1.0 m 3 ± 0.1 m 3
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.