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.) An overview of filter based sampling Week 2 (April ) –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

PP Potential Gas/Particle Interactions at a Filter Surface

PM 2.5 Mass from Teflon Filter Gravimetry Equilibration of Teflon filter samples in Class 1000 Clean Room [PM] < 1000/scf, T = o C, RH = % Mettler Toledo MT5 Electronic Micro-Balance Exp. DL =  g; P =  g; A = % {1-500 mg}

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.

Annual Average PM 2.5 in Urban Areas, 2002

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

Aerosol Chemical Composition Measured in Yulin, China Dust Anthropogenic Pollution

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

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

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

SO 2 SO 4 = in Greater Atlanta for July 2001

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)

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

Measuring ions using ion chromatography

An example Chromatogram (Anions)

An example Chromatogram (Cations)

Measuring Elemental and Organic Carbon (EC/OC)

The Sunset Lab Instrument

Thermal Evolution Thermalgram

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

Uncertainty Estimation Root Sum Square Method: For Example Function: X=AB m /C n

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