Lyle Chinkin

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

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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.

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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.

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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
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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

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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

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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

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

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Ozone Formation

• Recipe for Ozone

UV



Key factors Sunlight (ultraviolet)
needed Relative amount of VOC and NO is
critical Heat speeds up chemical reactions
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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
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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
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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

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Key Weather Factors

• Key factors that influence air quality
• Winds
• Inversions
• Sunlight and clouds

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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/navmenu
0.htm
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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)
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Inversions

• Inversions occur when temperature increases with
  height.
• Inversions are important because they trap
  pollution near the earths surface.

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Inversion Example
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Sunlight and Clouds
Affect on ozone
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Regional Ozone Southerly Winds (1 of 2)
Afternoon Wind
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Regional Ozone Northerly Winds (2 of 2)
Afternoon Wind
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Regional Ozone Characteristics (1 of 3)
Average number of days by month with ozone
concentrations gt than 75 ppb 8-hour average
concentrations 2003 2007
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Regional Ozone Characteristics (2 of 3)
Total number of days by year with ozone
concentrations gt than 75 ppb 8-hour average
concentrations (April-October) 2003 2007
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Regional Ozone Characteristics (3 of 3)
Maximum Concentration (ppb)
8-hour maximum ozone concentrations by month and
year from 2000-2006
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Previous Transport Studies
Note this is not a comprehensive list of
previous studies
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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)
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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

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