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

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

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

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

How Much is Secondary Organic Aerosol? Source Apportionment of Organic and Elemental Carbon using PMF in Seattle 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

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

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

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?????

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

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

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

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

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

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

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

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??

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)

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