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Jason D. Surratt

Trees, Volatile Organic Compounds, and Fine Organic Aerosol Formation: Implications for Air Quality, Climate and Public Health in the Southeastern U.S. Jason D. Surratt Department of Environmental Sciences and Engineering, Gillings School of Global Public Health

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Jason D. Surratt

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  1. Trees, Volatile Organic Compounds, and Fine Organic Aerosol Formation: Implications for Air Quality, Climate and Public Health in the Southeastern U.S. Jason D. Surratt • Department of Environmental Sciences and Engineering, Gillings School of Global Public Health Air Quality Concerns in a Changing Climate: Professional Development Workshop for Teachers Saturday, September 13, 2014

  2. Who is Jason Surratt? • Assistant Professor of Atmospheric and Aerosol Chemistry, began at UNC July 2010 • Born in Memphis, TN, and grew up in NC • Education: • 2010, California Institute of Technology (Caltech), Ph.D., Chemistry • Thesis Title: “Analysis of the Chemical Composition of Atmospheric Organic • Aerosols by Mass Spectrometry” • 2003, North Carolina State University (NCSU), B.A., Chemistry • 2003, North Carolina State University (NCSU), B.S., Meteorology • Teach a graduate course entitled Aerosol Physics & Chemistry (ENVR 416, Fall) • Teach an undergraduate course entitled Environmental Chemistry (ENVR 403, Spring) • Research Focus: Directs a “smog” chamber research group in order to understand the • detailed atmospheric chemical mechanisms that cause organic aerosol formation in the • Earth’s atmosphere; we compare our experimental results with field measurements to • gain insights into adverse impacts on air quality, climate, and human health

  3. What Does “Typical” Smog Look Like? Downtown LA during a Photochemical Smog Event Does anyone know which words “smog” originated from? Ingredients for SMOG: Volatile Organic Compounds (VOCs) + Nitrogen Oxides (NOx = NO + NO2) + Sulfur Dioxide (SO2) + Sunlight (hν) “SMOG” (which contains both “bad” O3 and fine aerosol [PM2.5] particles)

  4. How Do We Study Smog & Thus Aerosol? Same NOx and VOCs Same NOx and VOCs Wet Experiments (RH 90%-50%) Dry Experiments (RH 40%-10%) UNC 274 m3 Dual Outdoor Smog Chamber – Pittsboro, NC Caltech 28 m3 Dual Indoor Smog Chamber UNC 10 m3 Indoor Smog Chamber - Located in MHRC 0016 (Surratt Lab)

  5. Acknowledgements UNC Surratt Group Dr. Ying-Hsuan Lin Dr. Theran Riedel Dr. Matthieu Riva Sri HapsariBudisulistiorini Tianqu Cui WerukaRattanavaraha Xinxin Li UNC Gold Group Prof. Avram Gold Dr. Zhenfa Zhang Towson University Prof. Kathryn Kautzman University of Washington Prof. Joel Thornton Dr. Cassandra Gaston U.S. EPA Dr. HavalaPye Columbia University Prof. Faye McNeill ARA, Inc. Dr. Karsten Baumann Eric Edgerton SOAS Collaborators Russell & Bertram Groups (UCSD) Cappa Group (UCD) McKinney Group (Amherst/Harvard) Aerodyne, Inc. Dr. John Jayne Dr. ManjulaCanagaratna Dr. Philip Croteau Funding TVA Dr. Solomon Bairai Dr. Roger Tanner Dr. Stephen Mueller William Hicks 83540401

  6. What are Atmospheric Aerosol? • Liquid or solid particles suspended in air • Aerosol = Particles = Particulate Matter (PM) • PMx: particles with diameters ≤ x mm PM2.5 : Fine Aerosol Mass Concentrations regulated by EPA PM10 : Coarse Aerosol • Size of Atmospheric Aerosol versus Commonly Known Things: PM10 PM2.5 Kaiser, Science (2005)

  7. Why Study Atmospheric Aerosol? • Component of Photochemical Smog & Visibility Degradation Smoggy Day Clear Day VOCs + h+ NOx+ SO2+ O3 + PM2.5 Charlotte, NC Charlotte, NC http://www.southernenvironment.org/cases/southern_air_smog What is the chemical composition (and thus, source) of this PM2.5?

  8. Why Study Atmospheric Aerosol? • Role in Global Climate Change: [Zahardis et al., 2011, Anal. Chem.] Intergovernmental Panel on Climate Change (IPCC), 2013

  9. Why Study Atmospheric Aerosol? • Health Effects of PM2.5: nasal cavity [Dockery et al.,1993] – Cited 3,477 times alveoli Respiratory system Each 10 g/m3increase in PM2.5 long-term exposure has been associated with ~ a 4%, 6%, and 8% increased risk of all-cause, cardiopulmonary, and lung cancer mortality, respectively. [Pope III et al., 2006, JAMA]

  10. National Ambient Air Quality Standards (NAAQS) NOTE: PM2.5 24 hr is now 35 mg m-3

  11. U.S. Regional Differences in Health Effects Due To Aerosol Exposures Dominici et al. [2006, JAMA] As a Chemist, I ask: What about the chemical compositions might be causing these differences?

  12. Typical Fine Particulate Matter (PM2.5) Composition Inorganics complex mixture of thousands of individual organic compounds Aerosol composition from Duke Forest, NC. (9/13/2004-9/21/2004) [Zhang et al., GRL, 2007]

  13. Organic Material Contributes Significantly to PM2.5 Mass Across the Globe! [Zhang et al., 2007, GRL] Organic Sources = Primary+ SECONDARY Most of Organic Mass!

  14. Types of Organic Aerosol (OA) • Primary organic aerosols (POA) • Directly emitted from the sources • Examples: Diesel soot, wild fire, cooking particles • Secondary organic aerosols (SOA) • Formed as a result of atmospheric reactions • SOA precursors: volatile organic compounds (VOCs) • Biogenic emissions • Examples: • Anthropogenic emissions • Examples: isoprene a-pinene toluene naphthalene

  15. “Traditional” View of Secondary Organic Aerosol (SOA) Formation (VOCs) VOCs Known to Yield SOA: Isoprene Monterpenes (C10H16) Sesquiterpenes (C15H24) -pinene -caryophyllene This Process is Parameterized by Laboratory Chamber Experiments SOA Yield = Mo/VOC Mo= organic mass produced (g/m) VOC = mass of reacted VOC (g/m3)

  16. What is the Current Motivation For Studying Secondary Organic Aerosol? • Field Studies Indicate HIGHER SOA Formation in the Atmosphere than Models Predict SOAmeas /SOAmod >> 1 Volkamer et al., GRL (2006) • Possible Explanations For Discrepancy: • Other Unidentified SOA Precursors • Chemical Formation Mechanisms Not Fully Established or Identified • Role of Aerosol Acidity & Heterogeneous Chemistry • Chemical Conditions in Laboratory Chambers Not Same as in Troposphere IMPACT of Aerosols on Climate & Health Cannot be Fully Assessed!

  17. Global Isoprene Emissions • Isoprene is the most abundant • non-methane hydrocarbon in the atmosphere • Observe global distribution of isoprene in January and July • What factor(s) might be responsible for varying distribution of isoprene over space and time? • Why do you think the Southeastern US has elevated isoprene levels in July? Guenther et al., ACP (2006)

  18. Global Isoprene Emissions Guenther et al., ACP (2006) The yearly production of isoprene emissions by vegetation is around 600 million tons! • Previously thought not to yield SOA due to high volatility of its known oxidation products • [Pandis et al., 1991, Atmospheric Environment] • Question of how isoprene oxidation yields SOA re-opened by detection of molecular tracers in • Amazonian PM2.5 [Claeys et al., 2004, Science]

  19. My Current Work: Do the Interactions Between Human Activities and Natural VOC Emissions Enhance Secondary Organic Aerosol Formation in S.E. USA? Total emissions (biogenic + anthropogenic) Biogenic emissions only Modeled biogenic SOA When all anthropogenic emissions were removed, secondary organic aerosol (SOA) formation from natural emissions is reduced by more than 50% or ∼1 µg m-3 in the eastern U.S. [Carlton et al., 2010, ES&T] Notably, this interaction could be more pronounced than currently understood since models currently under predict PM2.5 mass concentrations in eastern USA

  20. Isoprene-Derived Epoxides Are Critical in SOA Formation from Isoprene Oxidation [Paulot et al., 2009, Science; Surratt et al., 2010, PNAS; Lin et al., 2012, ES&T; Zhang et al., 2012, ACP; Lin et al., 2013, ACP; Lin et al., 2013, PNAS; Nguyen et al., 2014, ACP; Jacobs et al., 2014, ACP]

  21. Implications & Conclusions • IEPOX-derived epoxides appears to be major source (~1/3) of fine organic • aerosol mass in both rural and urban areas of S.E. U.S. during summer • Brown carbon from IEPOX occurs in the laboratory due to light-absorbing • oligomer formation; results from field suggest some could be there but • further work is needed to determine how important (abundant) in order to fully • assess impact on radiative budgets. • IEPOX-derived SOA appears to yield potential inflammation and oxidative • stress in human bronchial epithelial cells; more work is underway • systematically examining gene arrays and investigating individual SOA • components • Importantly, further reductions in sulfate (SO2) emissions will likely decrease • the amount of fine organic aerosol from isoprene in the S.E. USA region

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