Atmospheric Particulate Matter: Chemical Composition and Basics of Concentration Estimation

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

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Potential Gas/Particle Interactions at a Filter
Surface
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PM2.5 Mass from Teflon Filter Gravimetry
Equilibration of Teflon filter samples in Class
1000 Clean Room PM lt 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 _at_ 1 mg A -0.001 1-500 mg
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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.
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Annual Average PM2.5 in Urban Areas, 2002
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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

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Aerosol Chemical Composition Measured in Yulin,
China
Anthropogenic Pollution
Dust
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Emissions/AQ Trends Primary PM2.5
Sources (2001)
Emissions
AQ

• Potential Risks and Effects
• Heart (arrhythmias, attacks)
• Respiratory (asthma, bronchitis)
• Among elderly and young
• Vegetation (ecosystem)
• Buildings, Materials
• Visibility

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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

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Emissions/AQ Trends SO2
Emissions
Sources (2001)
AQ

• Potential Risks and Effects
• Breathing impairment
• Respiratory, cardiovascular PM
• Precursor for PM
• Acidification (soils, waters)
• Corrosion (bldgs, monuments)
• Visibility

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SO2 SO4 in Greater Atlanta for July 2001
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Emissions/AQ Trends CO
Sources (2001)
Emissions

• Potential Risks and Effects
• Blood-O2 deficiency
• Cardiovascular (angina pectoris)
• Visual, neurological impairment
• Role in P(O3) via HOx cycle (slow)

AQ
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Emissions/AQ Trends NOx (NONO2)
Sources (2001)
Emissions

• Potential Risks and Effects
• Airway, lung function
• Respiratory illness, infection
• Precursor for O3 and PM
• Acid deposition (nutrient loss)
• Eutrophication (algae bloom)
• Visibility

AQ
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Measuring ions using ion chromatography
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An example Chromatogram (Anions)
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An example Chromatogram (Cations)
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Measuring Elemental and Organic Carbon (EC/OC)
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The Sunset Lab Instrument
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Thermal Evolution Thermalgram
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Estimating Mass Closure

• To estimate the mass concentration based on
  chemical composition
• MT ?ions ?elements ?crustal ?carbon
• ?ions measured
• ?Al1.9 (Al2O3) Si2.1 (SiO2) Fe1.4 (Fe2O3)
• Elemental Carbon (EC) Organic Carbon
  (OC)1.4
• Mass Closure ?M Measured Mass- Estimated Mass

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Uncertainty Estimation
Root Sum Square MethodFor Example Function
XABm/Cn
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A Simple Example

• Mass Concentration Mass on Filter (?M) / Air
  Volume (V)
• M ?M / V
• ?M 100 ug 10 ug V 1.0 m3 0.1 m3