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Scientific Issues: Organic Aerosols

Scientific Issues: Organic Aerosols. Primary and Secondary Organic Aerosols. Joellen Lewtas, Ph.D Human Exposure & Atmospheric Sciences Div. National Exposure Research Laboratory Office of Research & Development. Secondary Organics: Scientific Issues. Sources and Formation Issues

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Scientific Issues: Organic Aerosols

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  1. Scientific Issues: Organic Aerosols Primary and Secondary Organic Aerosols Joellen Lewtas, Ph.D Human Exposure & Atmospheric Sciences Div. National Exposure Research Laboratory Office of Research & Development

  2. Secondary Organics: Scientific Issues • Sources and Formation Issues • Characterization Issues • Measurement Issues • Effects Issues: Health and Welfare • Climate Change & Visibility Effects • Health and Ecosystem Effects

  3. PM Characteristics of Concern to Health • Organic Carbon & Elemental Carbon Total, OC/EC, thermal fractions Functional Groups and Speciated Organics Semivolatile organic carbon and species Specific toxic organic compounds • Inorganic Ions, Acidity, Transition Metals • Particle # , surface area, size distribution • Bioaerosols

  4. How Much Organic Carbon is in PM2.5? Denuder Experiments in Seattle, WA

  5. Source Apportionment of Organic and Elemental Carbon using PMF in Seattle How Much is Secondary Organic Aerosol? Source OC(%) EC(%) Vegetative Burning 57 47 Diesel Vehicles 19 36 Gasoline Vehicles 5 1 Secondary 12 9 Fuel Oil 3 4 Road Dust 2 2 Marine (Sea Salt) 2 0

  6. Biological Plausibility • What Component (s) of PM Cause Health Effects? • Are Statistical Associations between PM and • Health Effects Biologically Plausible? • Critical Need To: • Identify Toxic Component(s) of PM • Identify the Mechanisms of Action

  7. Causative Agents Mechanisms Measurements Potential Toxic/Causative Agents

  8. Primary Secondary Organic Examples More Toxic Less Toxic Potential Toxic/Causative Agents

  9. Primary Secondary Organic Examples More Toxic Less Toxic Potential Toxic/Causative Agents

  10. Mechanisms of Action: Lung & Heart

  11. Mechanisms of Action: Cancer & Reproductive

  12. Role of Organics • Organics are a major component of primary and secondary aerosols • Many are electrophilic and reactive in biological systems • Can cause oxidative damage and induce inflammation • Recent epidemiological studies found associations between combustion sources and mortality/morbidity

  13. Epidemiologist & Source Apportionment Recent epidemiological studies found associations between combustion sources and mortality/morbidity • Ozkaynak et al 1996- Toronto • Motor Vehicle Source factor associated with cancer, Cardiovascular (CV), respiratory, and pneumonia deaths • Norris et al 1996-8 Spokane • Combustion factor(s) associated with mortality

  14. Epidemiology & Source Apportionment • Laden et al. 2000---Harvard 6 Cities • Mobile Source factor strongest association with mortality, Coal Combustion also + • Mar et al. 2000—Phoenix • Motor Vehicle, Vegetative Burning, & Regional Sulfate (associated secondary organics not measured) significantly associated with CV Mortality

  15. Epidemiology & Source Apportionment • Tsai et al 2000—Newark, Elizabeth and Camden, NJ • Oil burning, Industry, Secondary aerosol and Motor Vehicle factors associated with Mortality

  16. Why is this Important? • Health Effects Impact Research Needs, Funding, Standards… • Critical Need To: • Identify Toxic Component(s) of PM: Organics? SOA? • Identify the Mechanisms of Action • Identify the Sources of the Toxic Components? • Primary Combustion Sources, Biogenic, SOA??

  17. Strategic Research Planning • NAS/NRC Panels Recommendations • EPA PM Research Strategy • CENR Air Quality Research Subcommittee Strategic Research Plan for PM across Federal Agencies: NSF, EPA, USFS, NOAA, DOE, DOD.. • www.nnic.noaa.gov/CENR/AQRS (Draft) • NARSTO PM Assessment: (US, Canada, Mexico) • www.cgenv.com/NARSTO (Draft)

  18. Science & Regulatory Issues: • State Implementation Plans for PM2.5 • Apportionment of Secondary Organics • Health Effects based PM2.5 Standards • Understanding the Health Risks of Secondary Organics • Visibility • Secondary Organics Contribution to Visibility Impairment Need for Sound Scientific Information on Secondary Organic Aerosols

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