Lyle Chinkin Sonoma Technology, Inc. Petaluma, CA Presented at the Sierra Ozone Summit Grass Valley, California June 4,

1. Air Quality Primer Lyle Chinkin Sonoma Technology, Inc. Petaluma, CA Presented at the Sierra Ozone Summit Grass Valley, California June 4, 2008 STI-708024

2. Overview • The history of smog • The major air pollutants, formation processes, and emission sources (emphasis on ozone) • The role of weather (meteorology) in ozone transport • Previous transport studies and findings • Conclusions 2

3. History of Smog (1 of 4) • Origin: smoke and fog = Smog • Mixture of chemically reactive compounds in the atmosphere. • The word “smog” coined in early 1900s by Harold A.  Des Veaux to describe conditions of sooty fog in Britain. 3

4. History of Smog (2 of 4) • 1943: First recognized episodes of smog occurred in Los Angeles. Visibility was only three blocks and people suffered from itchy eyes, respiratory discomfort, nausea, and vomiting. The phenomenon was termed a "gas attack" and blamed on a nearby butadiene plant. 4

5. History of Smog (3 of 4) • London, four days in December • Mix of dense fog and sooty black coal smoke • Killed thousands of Londoners "Night at Noon." London's Piccadilly Circus at midday, during another deadly smog episode, this time in the winter of 1955.Source: When Smoke Ran Like Water, Devra Davis, Perseus Books Central London during the killer smog, December 1952. Visibility was less than 30 feet. During the height of the smog, people could not see their own hands or feet, and buses had to be led by policemen walking with flares.Source: When Smoke Ran Like Water, Devra Davis, Perseus Books 5

6. History of Smog (4 of 4) • 1960 Air Pollution Potential – forecasting began • 1963 National Air Pollution Control Agency – started as a research body; not very effective • The Air Quality Act of 1967 • Designation of air quality regions • Regional approach to pollution control • A turning point • Attitudinal change in U.S. society • National Environmental Policy Act (January 1) • Formation of Environmental Protection Agency (July 9) • Clean Air Act of 1970 • National Air Quality Standards • Statutory deadlines for compliance • 1990 Clean Air Act Amendments 6

7. What Makes Up Clean Air ? • What is in our air? • Mixture of invisible gases, particles, and water • Mostly nitrogen (78%) and oxygen (21%) • Other • Argon • Water vapor • Carbon dioxide • Ozone • Particulate matter • and many more 7

8. Major Types of Air Pollutants • Categories of pollutants • Primary– emitted directly from source • Secondary– formed in atmosphere from reaction of primary pollutants • Precursors– primary pollutants (gases) that form secondary pollutants • Pollutants originate from • Combustion - fossil fuels, organic matter • Evaporation - petroleum products, solvents • Natural production - smoke, dust, and emissions from trees and plants 8

9. the remainder of this discussion will focus on ozone Criteria Pollutants • Response to 1970 Clean Air Act • Established the National Ambient Air Quality Standards (NAAQS) for six pollutants: • Nitrogen dioxide (NO2) • Ozone (O3) • Sulfur dioxide (SO2) • Particulate matter (PM10) • Particulate matter (PM2.5)* • Lead (Pb) • Carbon monoxide (CO) * established after 1970 9

10. What is Ozone? (1 of 2) O3 Good Ozone: a naturally-occurring constituent of the upper-atmosphere protecting the earth from the sun’s UV rays. Bad Ozone (ground level): Formed at the Earth’s surface where it causes health problems in humans and damage to many plant species. 10

11. What is Ozone? (2 of 2) • A colorless gas composed of three oxygen atoms • Oxygen molecule (O2) – needed to breathe to sustain life • Ozone (O3) – extra oxygen atom makes ozone very reactive • A secondary pollutant that forms from precursor gases • NOx (nitrous oxides) – combustion product • VOCs (volatile organic compounds) – evaporative and combustion products 11

12. Oxides of Nitrogen (NOX) Volatile Organic Compounds (VOC) Gasoline combustion Gasoline evaporation Solvent evaporation Natural – trees and plants Fossil fuel combustion Ozone (O3) Ozone Formation • Recipe for Ozone UV + + = • Key factors: • Sunlight (ultraviolet) needed • Relative amount of VOC and NO is critical • Heat speeds up chemical reactions 12

13. Ozone Characteristics • Clean-air background levels are 35-40 ppb* (sometimes lower) • U.S. concentrations range from 0 to 250+ ppb* • Ozone health concerns • A severe irritant (reactive). • Inflames and irritates the respiratory tract, particularly during physical activity. Breathing ozone can worsen asthma attacks. • Symptoms include breathing difficulty, coughing, and throat irritation. • Medical studies have shown that ozone damages lung tissue; complete recovery may take several days after exposure. *One-hour average 13

14. Concentration (ppb) Ozone Lifecycle – Day/Night (1 of 2) Note: the Northern Sierra Air Quality Management District comprises the northern portion of the Mountain Counties Air Basin 14

15. Ozone Lifecycle – Day/Night (2 of 2) Concentration (ppb) • Ozone is transported from one area to the next • Along the way: • photochemical reactions continue • fresh emissions are infused 15

16. Key Weather Factors • Key factors that influence air quality • Winds • Inversions • Sunlight and clouds 16

17. Winds – Dispersion • How do winds affect pollution? • Disperse pollutants – the spreading of atmospheric constituents. • Introduce dispersion process • Molecular Diffusion (not efficient) • Atmospheric turbulence • Mechanical • Shear • Buoyancy (convective) Resource: meted.ucar.edu/dispersion/basics/navmenu0.htm 17

18. Winds – Transport • How do winds affect pollution? • Pollutant transport –Movement of pollutants from one area to another by the wind • Types • Neighborhood scale: monitor to monitor • Regional scale: city to city and state to state Transport of pollution from the Los Angeles Basin to the Mojave Desert (Courtesy of Don Blumenthal) 18

19. Inversions • Inversions occur when temperature increases with height. • Inversions are important because they trap pollution near the earth’s surface. 19

20. Simplified vertical temperature profile Warm Inversion Cool Inversion – Example 20

21. Sunlight and Clouds Affect on ozone 21

22. Regional Ozone – Southerly Winds (1 of 2) Afternoon Wind 22

23. Regional Ozone – Northerly Winds (2 of 2) Afternoon Wind 23

24. Regional Ozone Characteristics(1 of 3) Average number of days by month with ozone concentrations > than 75 ppb 8-hour average concentrations 2003 – 2007 24

25. Regional Ozone Characteristics(2 of 3) Total number of days by year with ozone concentrations > than 75 ppb 8-hour average concentrations (April-October) 2003 – 2007 25

26. Regional Ozone Characteristics(3 of 3) Maximum Concentration (ppb) 8-hour maximum ozone concentrations by month and year from 2000-2006 26

27. Previous Transport Studies Note: this is not a comprehensive list of previous studies 27

28. Findings from Previous Studies • ARB transport findings (2001) • Ozone violations are caused mainly by transport from the Sacramento Valley, San Joaquin Valley, and San Francisco Bay Area. • Grass Valley, Placerville, Jackson, and San Andreas can receive pollutants from Sacramento, the San Joaquin Valley, the Bay Area or a combination of areas depending on the weather. • In the future, local pollutant emissions may contribute to ozone concentrations in the region as population continues to increase. Source: California Air Resources Board Ozone Transport: 2001 Review (http://www.arb.ca.gov/aqd/transport/summary/transportsummary.doc) 28

29. Conclusions • A literature review should be performed to synthesize the findings of recent transport studies in the Sacramento region to understand the state-of-the-science. • Recommendations should be made for future activities that may include: • Field studies • Data analysis • Photochemical modeling 29