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. Sources and Formation Issues Characterization Issues
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. How Much is Secondary Organic Aerosol?
Source Apportionment of Organic and Elemental Carbon using PMF in Seattle
Source OC(%) EC(%)
Vegetative Burning
Diesel Vehicles
Gasoline Vehicles
Secondary
Fuel Oil
Road Dust
Marine (Sea Salt)

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
Causative Agents Mechanisms Measurements
Organic Matter
Electrophilic, Oxidative damage, Free-radical
OC/EC, POM, SVOC, Speciated Organics
Inorganic Matter
Acids/Metals
Cell injury
Inflammation
Soluble Metals
Acid aerosol
Ultra fine Particles
Surface effects
Particle #, size, surface area
Bioaerosols
Cytokine induction
Allergic Reactions
Endotoxin

8. Primary Secondary Organic Examples More Toxic Less Toxic
Potential Toxic/Causative Agents
Primary Secondary Organic Examples More Toxic Less Toxic
PAH
Aromatic Hydrocarbons
Nitro-PAH
Diol-Epoxides
Nitro-Lactones
Quinones
OH-PAH
Sulfate products
OHNitro Aromatics
Ketones ?
Aliphatic HC
Aldehydes
Alcohols
Alkenes
Terpenes
Nitro-Alkenes
Aldehydes??? ??
Acids?????

9. Primary Secondary Organic Examples More Toxic Less Toxic
Potential Toxic/Causative Agents
Primary Secondary Organic Examples More Toxic Less Toxic
Alcohols
Aldehydes
Ketones
Hemiacetals
Multi Functional Oxygenated Products ?
Methoxyphenols
Fatty Acids

10. Mechanisms of Action: Lung & Heart
Direct Respiratory Effects
injury & inflammation
increased susceptibility
increased airway reactivity
Systemic Effects (Heart) Secondary to Lung Injury
lowering blood oxygen
lung inflammation, cytokine release
Increased blood coagulation
Direct Effects on the Heart
Decreased Heart Rate Variability
Altered Autonomic Control of Heart
System Circulation of Soluble Substances

11. Mechanisms of Action: Cancer & Reproductive
Cancer & Reproductive Effects
DNA Damage
Covalent DNA Binding
Oxidative DNA Damage
Cytokine Release and Inflammation

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 Toronto
Motor Vehicle Source factor associated with cancer, Cardiovascular (CV), respiratory, and pneumonia deaths
Norris et al Spokane
Combustion factor(s) associated with mortality

14. Epidemiology & Source Apportionment
Laden et al 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. Health Effects Impact Research Needs, Funding, Standards…
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..
(Draft)
NARSTO PM Assessment: (US, Canada, Mexico)
(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