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Atmospheric Pollution

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					Chapter 21

ATMOSPHERIC POLLUTION
Donora Pennsylvania
 Tuesday, October 28, 1948
 Dense fog
     Usually fogs cleared by noon
     This fog lasted 5 days
     Air began to smell of sulfur
     Complaints of stomach pain, headaches, nausea, and
      choking
     First deaths by Saturday
     Sunday morning mills were shut down, rain came and
      cleared away fog.
     6,000 people were stricken, 20 elderly dead, during the
      next month, 50 more died
     Culminated the Clean Air Act of 1970 and its amendments
 Sulfur and the lungs

Sulfur dioxide + H2O (in the lungs)  sulfuric acid

                                  OUCH!!
Air Pollution Essentials
Lesson 21.1
Major Constituents of the atmosphere

     Nitrogen- 78.08%
     Oxygen- 20.95%
     Argon- 0.93%
     Carbon dioxide- 0.04%
     Water vapor- ranging from 0-4%
Aerosols

 Microscopic liquid and solid particles such as
  dust, carbon particles, pollen, sea salts, and
  microorganisms.
Determining air pollution

 Three factors determine the amount of air
  pollution:
   Amount of pollutants entering the air
   The amount of space into which the pollutants are
    dispersed
   The mechanisms that remove pollutants from the
    air
Natural mechanisms for
cleaning:
 There are mechanisms in the biosphere that
  remove, assimilate and recycle natural
  pollutants:
   Hydroxyl radical (OH)2
     Oxidizes many gaseous pollutants to products that
      are harmless or that can be brought down to the
      ground or water by precipitants
   Sea salts
     Act as nuclei for the formation of raindrops
   Sunlight
     Breaks organic molecules apart
Hydroxyl Radical

 Plays a key role in removing anthropogenic
  pollutants
 “cleansing power” can be used up when high
  concentrations of pollutants are oxidized and
  the pollutants are able to build up to
  damaging levels
 Photochemical breakdown of ozone is the
  major source of the hydroxyl radical
Industrial Smog

 Smoke and fog
 Irritating, grayish mixture of soot, sulfurous
  compounds, and water vapor
  Photochemical Smog
 Brownish, irritating haze that
  was different from the more
  familiar industrial smog
 Came about as other fossil
  fuels were being used
 Produced when several
  pollutants from automobile
  exhausts (nitrogen oxides and
  volatile organic compounds)
  are acted on by sunlight
  Temperature inversions
 Condition of cooler air
  below and warmer air
  above.
 Traps pollutants in the
  denser cooler air close to
  Earth.
 Topography can intensify
  smog as cool ocean air
  flows into valleys and is
  trapped there by a nearby
  mountain range.
Smog effects

 Headaches, nausea, eye irritation, throat
  irritation
   In extreme cases it has caused death (Donora)
 Not limited to humans
   Many species of tree and other vegetation in and
    near cities has begun to die back.
   Acceleration in the rate of corrosion of metals,
    deterioration of rubber, fabrics, and other
    materials.
Major Air Pollutants and their
sources
                            Lesson 21.2
Complete combustion

 The by-products of burning are carbon
  dioxide and water vapor.
     CH4 + 2O2  CO2 + 2H2O
 Oxidation however is seldom complete.
   Substances far more complex than methane are
    also involved.
 Other processes that cause air pollution:
   Evaporation (of volatile substances)
   Strong winds that pick up dust and other solid
    particles
Primary and Secondary pollutants
                 Table 21.1 page 547
 Primary                     Secondary
  Particulate matter (PM)    Ozone (O3)
  Volatile organic           Peroxyacetyl nitrates
     compounds (VOC)           (PAN)
    Carbon monoxide (CO)
    Nitrogen oxides (NOx)
    Sulfur oxides (SOx)      *Strategies for
    Lead (Pb)                containing pollutants
    Air toxics (various)     are dependant upon
    Radon (Rn)
                              the type of pollutant
NOx

 Because nitrogen and oxygen can bond
  together in many ways, they are collectively
  referred to as NOx
 NO
 NO2
 N2O4
Coal and refuse burning

Coal                    Refuse
 Heavy metals           Endless array of impurities
   Mecury




          Patented
       refuse burning
          container
EPA tracking

 The EPA has tracked many sets of data with
  respect to the first five primary pollutant
  National emissions:
   2005=141 million tons/1970 (when CAA was
    adopted the levels were at 301 million tons (47%)
   Reflects the effectiveness of the CAA 1970
   These impressive numbers come despite the
    economic increase of 195% and an increase in
    vehicular miles by 178%
   The 6th primary pollutant (Pb) fell 98%!!
Ozone formation

 Formed as a result of chemical reactions
  between nitrogen oxides and VOC.
   Sunlight provides the energy necessary to propel
    the reactions, these products are collectively
    known as photochemical oxidants.
Acid Rain

 Technically referred to as acid deposition
   Made from sulfuric acid and nitric acid
 Acid precipitation refers to any precipitation-
  rain, fog, mist, or snow…that is more acidic
  than normal
 Acid deposition- is the combination of
  precipitation and dry-particle fallout.
Properties of acids and bases

                    Acidic
Acids                        Bases
 Any chemical                Any chemical
  that releases                that releases
  hydrogen ions                hydroxide ions
  when                         when
  dissolved in     Neutral
                               dissolved in
  water                        water
 Sour,                       Bitter, caustic
  corrosive                   Presence of
 Presence of H+               OH- ions
  ions
                     Basic
pH

 From a pH of 4 to 5 the concentration of H+
  ions decrease 10 fold
   (10-4 to 10-5) = (0.0001 to 0.00001)
 Rainfall is normally somewhat acidic, with a
  pH of 5.6
   Acid precipitation is any precipitation with a pH
     <5.5
Sources of Pollutants

Natural                          Anthropogenic
 50-70 million tons per year     100-130 million tons per
  of Sulfur dioxide                tear of sulfur dioxides
    Volcanoes, sea spray, and    60-70 million tons per year
     microbes
                                   of nitrogen dioxides
 30-40 million tons per year
                                  Strongly concentrated
  of nitrogen oxides               around industrialized
    Lightning, the burning of
                                   regions
     biomass, and microbes
                                  Increased 4 fold since 1900
 Remained relatively
  constant since 1900
Impacts of Air Pollutants
Lesson 21.3
Make-up of pollutants

 The make-up of pollutants can vary from day-
  to-day, hour-to-hour and from place-to-
  place.
 The effects we feel and observe are rarely
  from a single pollutant.
   Instead they are a combined impact of a whole
    mixture of pollutants leading to a synergistic
    (things combining to for a greater effect than
    either would on their own) effect.
Environmental effects of
Pollutants
 Experiments show that
 plants are considerably
 more sensitive to gaseous
 pollutants than humans
   Costing $2 billion to $6
    billion per year in crop
    damage caused by exposure
    to ozone and other
    photochemical oxidants.
Regional Haze

 Particulates
  originating hundreds
  of miles away which
  decreases visibility
 Mt Rainier with and
  without regional haze
Regional Haze Rule
 EPA and other Agencies have been
  monitoring visibility in national parks and
  wilderness areas since 1988. In 1999, the U.S.
  Environmental Protection Agency announced
  a major effort to improve air quality in
  national parks and wilderness areas. The
  Regional Haze Rule calls for state and federal
  agencies to work together to improve
  visibility in 156 national parks and wilderness
  areas such as the Grand Canyon, Yosemite,
  the Great Smokies and Shenandoah.
Bringing Air Pollution Under
Control                    Lesson 21.4
   CAA and CAAA
 Clean Air Act (CAA-1970) and
  its amendments (CAAA-
  1977/1990). Administered by
  the EPA
 Identify the most wide
  spread pollutants, set
  ambient standards (levels
  that need to be set to
  protect envir. And human
  health), and establishing      Bush signing CAAA -1990
  control methods and
  timetables to meet the
  standards.
NESHAPS

 National Emissions Standards for Hazardous
  Air Pollutants
 CAAA 1990 extended this section of the EPA’s
  regulatory work by specifically naming 188
  toxic air pollutants for the agency to track
  and regulate. Tracks them in a database
  called The National Emissions Inventory
5 criteria pollutants

 Particulates
 Sulfur dioxides
 Carbon monoxide
 Nitrogen dioxide
 Lead
Command and control

 Basic strategy of the CAA 1970 to regulate the
  emissions of air pollutants so that the
  ambient criteria pollutants would remain
  below the primary standards levels.
SIP

 State Implementation Plan
 State determine their route to reducing their
  use of pollutants. The plans are then
  submitted to the EPA for approval.
Particulate Matter (PM)

 PM2.5 vs. PM10: refers to the size of the
  particle.
   2.5= 2.5 micrometers in diameter
 2.5 and less are more closely monitored
  because they have a greater effect on health.
Changes in automobiles

 A car in the year 2000 emitted 75% less
  pollution than did a car in 1970.
   Number of vehicle miles increased from 1 trillion
    to 2.75 trillion
   Pollution control devices such as the catalytic
    converter.
 The CAA mandated a 90% reduction in these
  emissions by 1975
Highlights of the CAAA

 #1-3 on page 563
Café standards

 Under the authority of
  the Energy Policy and
  Conservation Act of
  1975
 Corporate Average
  Fuel Economy (café)
 Conserve oil and
  promote energy
  security.
Ozone Standards

 Revised in 1997
 0.12-0.08 ppm
 Industry objected and sued in 1999
   US supreme court upheld the EPA standards
 Delays put the implementation off until 2004
Tier 2 standards

 Being phased in gradually between 2004 and
  2009.
 Emissions for all SUV’s, light trucks, and
  passenger vans will be held to the same
  standards as passenger vehicles.
   NOx=0.07 grams per mile
  Title IV of CAAA
 2010-total SO2 must be reduced 10 million tons
  below 1980 levels
   50% reduction
 Free-market approach to regulation (goes against
  command and control). Each plant is granted
  emissions allowances based on formulas
 New utilities will not receive allowances.
   Must purchase existing allowances
 Nitrogen oxides from power plants to be reduced
  by 2 million tons by 2001

				
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