Air Pollution by wanghonghx


									      Air Pollution

Causes, Effects, and Solutions
        Terms to be familiar with…

   CAA – Clean Air Act
   CO – carbon monoxide
   NOx – nitrogen dioxide and nitrogen oxides
   PM – Particulate Matter
   SOx – Sulfur dioxide and sulfur oxides
   VOC’s – Volatile Organic Compounds
       Our Atmospheric Composition
                                   Composition of
                               dry atmosphere, by volume
ppmv: parts per million by volume
Gas                                            Volume
Nitrogen (N2)                                  78.084% (780,840 ppmv)
Oxygen (O2)                                    20.946% (209,460 ppmv)
Argon (Ar)                                     0.9340% (9,340 ppmv)
Carbon dioxide (CO2)                           375 ppmv
Neon (Ne)                                      18.18 ppmv
Helium (He)                                    5.24 ppmv
Methane (CH4)                                  1.745 ppmv
Krypton (Kr)                                   1.14 ppmv
Hydrogen (H2)                                  0.55 ppmv
Not included in above dry atmosphere:
Water vapor (highly variable)                typically 1%
Chemical and Transport Processes Related to Atmospheric Composition.
These processes link the atmosphere with other components of the Earth system,
including the oceans, land, and terrestrial and marine plants and animals. Credit:
CCSP Strategic Plan (illustrated by P. Rekacewicz).
              Air Pollution
Air Pollution Control Act of 1955
 1st federal air pollution law
1960s - Clean Air Act of 1963
– (Emissions standards set for stationary
   sources such as power plants and steel mills)
 1970 – The Clean Air Act (CAA) of 1970
– EPA was formed to enforce air pollution laws
   (change in national policy from advisor to
   enforcer) – Six major air pollutant types
 1990 – The Clean Air Act of 1990
– Clean Air Act of 1970 is re-written and new
   titles established
      Six Common Air Pollutants
 Particulate Matter
 Carbon monoxide
 Nitrogen dioxide
 Lower Troposphere OZONE producing activities
 Sulfur dioxide
 Lead
The EPA asked to Obama Administration to
  consider Carbon dioxide as a new common air

Source: U.S. Environmental Protection Agency- March 2008
       Particulate Matter (PM)
 It is known as “Particle Pollution” and can
  range in sizes and effects on humans
 Particle sizes of 10 um (diameter) or smaller
  poses a greater health risk
“Course particles” found near roadways and in
  mining and concrete industries are from 2.5
  – 10 um
“Fine particles” found in smoke and haze can
  have diameters smaller than 2.5 um
       Carbon monoxide (CO)
 CO is a colorless-odorless gas produced by
  the incomplete combustion of fossil fuels.

 Motor vehicle exhaust contributes to 56% of
  the CO produced in the U.S.

 Over 20% comes from other engines, boats
  and equipment not on-road.

 Could be worse in the colder months due to
  more dense air masses.
           CO Pollution

EPA : 1999 Data
Numbers of cases of carbon monoxide poisoning by age group. ........ Data for
1996 and 1997 from the Annual Report of the Am. Assoc. of Poison Control Centers,
Toxic Exposure Surveillance System (published in the American J. Emergency
Medicine). Statistics reported to 67 reporting centers for the two years. The total
number of poisonings in 1996 were 22,154, and in 1997, 20,930. For children less than
age 6 the numbers were 3,029 and 3,116; for children age 6-19 the numbers were
3,814 and 3,530; and for adults (>19 years), the numbers were 12,220 and 11,869.
       Nitrogen dioxide (NOx)
 Generic term for multiple combinations of
  nitrogen and oxygen
 Like CO, colorless and odorless
 NO2 can be seen as a brown-red gas
 Is mostly produced after combustion of fossil
  fuels at high temperatures
 Sources include motor vehicles, electric
  utilities, industry, and commercial and
  residential fossil fuel usages.
“Well We’re Living Here in Allentown…”
            NOx is Alarming
 Contributes to the formation of acid rain

 Can contribute to nutrient load that affects
  water quality

 Reacts to form toxic chemicals

 Contributes to Global Warming (traps long
  wave radiation on Earth) which becomes
  Thermal Radiation.
Los Angeles California: the smog is the brown layer in the
New York city picture: This 1963 photo shows a massive smog episode in
New York City. (Photo: AP/Wide World Photo, EPA Journal Jan/Feb 1990.

 It is not usually emitted directly into the air,
  but at ground level is created by a chemical
  reaction between oxides of nitrogen (NOx)
  and volatile organic compounds (VOC) in
  the presence of sunlight.

 Sunlight and hot weather cause ground-
  level ozone to form in harmful
  concentrations in the air.
Good                  Good

Ozone is “Bad” Here

There are two forms of Ozone. The Ozone
that limits UV rays from reaching the Earth is
in the Stratosphere (10 – 30 miles above the
Earth’s surface. The “Bad” Ozone is in the
lower Troposphere.

                                         Ground-level Ozone can be measured
                                         using remote monitoring devices

      Crops affected by
     ground-level ozone

Source: Forsyth County Environmental Affairs Department, 537 N. Spruce Street,
Winston-Salem, NC 27101-1362.
           Sulfur dioxide (SOx)
 Common in raw materials like coal, ore, and
  crude oil.

 Processing and burning of raw materials
  emits SOx.

 Over 65% of SO2 released to the air, or
  more than 13 million tons per year, comes
  from electric utilities, especially those that
  burn coal.
           SOx emission

Trends in Sulfur Dioxide Emissions Following
Implementation of Phase I of the Acid Rain Program: Total
State-level Utility SO2 (1980, 1990, 1999) EPA

A steel factory in Homestead, Pennsylvania, 1907, pictured on a stereopticon card.
Library of Congress, Prints and Photographs Division,
Detroit Publishing Company Collection.
Normal Lung Aveoli (Left) versus Emphysema (Right)
      SOx Environmental Impacts
 Acid Rain
  SO2 and nitrogen oxides react with other
  substances in the air to form acids, which fall to
  earth as rain, fog, snow, or dry particles.

 Plant and Water Damage
  Acid rain damages forests and crops, changes the
  makeup of soil, and makes lakes and streams
  acidic and unsuitable for fish. Exposure over a
  long time changes the natural variety of plants and
  animals in an ecosystem.

 Aesthetic Damage
  SO2 accelerates the decay of building materials
  and paints, including irreplaceable monuments,
  statues, and sculptures.
 Acadia, ME

 Big Bend, TX

Bryce Canyon, UT
 The major sources of lead emissions have
  historically been motor vehicles (such as
  cars and trucks) and industrial sources.

 These emissions have been phased out in
  the U.S., but NOT globally.

 The major sources TODAY are smelters,
  waste incinerators, utilities and lead-acid
  battery manufacturers.
         Notice the
         change in lead
         emission sources
         since the
         banning of lead
         fuel use in the
         early 1980’s in
         the U.S.

             Lead Concerns
 Particularly affects young children and
 Is still found at high levels in urban and
  industrial areas
 Deposits on soil and water and harms
  animals and fish
 In 1999, ten areas of the country did not
  meet the national health-based air quality
  standards for lead.
Solutions to Industrial Emissions
 Wet Scrubbers

 Baghouse (Venturi) Filters

 Electrostatic Precipitators

 Cyclone Separators
                  Wet Scrubbers
 The purge stream, which
  contains the particulate and
  sulfur oxides removed from
  the flue gas, may either be
  treated in the refinery's
  existing wastewater treatment
  system or may be treated in a
  dedicated PTU (Purge
  Treatment Unit).
          Cyclone Separators

 Cyclone dust collectors
  have been used as a
  pre-filter before a
  cartridge or baghouse
  collector, to weed out
  the larger, more
  abrasive dust particles
  that can easily damage
  standard media filters.
                  Baghouse filter
 "Baghouse" is an
  example of surface
 "Filter" is a membrane
  (sheet steel, cloth, wine
  mesh, or filter paper)
  with holes smaller than
  the dimension of the
  particles to be retained.
 It is not the cloth/fabric
  that does the filtering, it
  is usually the cake on
  the filter that stops
  particles from flowing
     Electrostatic Precipitators
 Electrostatic precipitators have collection
  efficiency of 99%, but do not work well for flyash
  with a high electrical resistivity (as commonly
  results from combustion of low-sulfur coal). Flyash
  is a common emission from the burning of fossil
                   Indoor Pollutants

VOC’s (emitted from dishwashers)   Solvents (common) from paints, etc

 Over-insulated homes can cause
 pollutants to be held indoors     Poorly maintained heating systems
               PM Health Effects
Particle pollution - especially fine particles - contains
  microscopic solids or liquid droplets that are so
  small that they can get deep into the lungs and
  cause serious health problems. Numerous
  scientific studies have linked particle pollution
  exposure to a variety of problems, including:
 increased respiratory symptoms, such as irritation of the
  airways, coughing, or difficulty breathing, for example;
 decreased lung function;
 aggravated asthma;
 development of chronic bronchitis;
 irregular heartbeat;
 nonfatal heart attacks; and
 premature death in people with heart or lung disease.
          CO Health Effects
 Cardiovascular Effects – People with heart
  disease can feel effects from exposure to
  CO (chest pains and trouble breathing)
 Central Nervous System – People who are
  exposed to high levels of CO can
  experience poor vision, reduced dexterity,
  and tiredness.
 High levels of CO are fatal
           NOx Health Effects
 NOx and VOC’s reacted with sunlight (UV)
  to form ground level Ozone
 Acid rain lowers pH on terrestrial and water
  bodies and affects many species
 Reacts with ammonia to form nitric acid
  which can cause respiratory distress and
  damage to lung tissue
 Can react with Ozone to produce mutagenic
  compounds. Examples of these chemicals
  include the nitrate radical, nitroarenes, and
        OZONE Health Effects
 Can irritate respiratory passageways
 Can cause wheezing, coughing, and
  breathing difficulties
 Permanent exposure can cause lung
 Chronic exposure can also cause asthma,
  reduces lung capacity, and bronchitis
 Plants too can become more susceptible to
 Can reduce crop forest yields
             SOx Concerns
 SO2 and the pollutants formed from SO2,
  such as sulfate particles, can be transported
  over long distances and deposited far from
  the point of origin. This means that
  problems with SO2 are not confined to areas
  where it is emitted.
 SO2contributes to the formation of acid rain,
     -damages trees, crops, historic buildings,
      and monuments; and
     -makes soils, lakes, and streams acidic.
            SOx Health Effects
 Respiratory Effects from Gaseous SO2
  Peak levels of SO2 in the air can cause temporary
  breathing difficulty for people with asthma who are
  active outdoors. Longer-term exposures to high
  levels of SO2 gas and particles cause respiratory
  illness and aggravate existing heart disease.

  Respiratory Effects from Sulfate Particles
  SO2 reacts with other chemicals in the air to form
  tiny sulfate particles. When these are breathed,
  they gather in the lungs and are associated with
  increased respiratory symptoms and disease,
  difficulty in breathing, and premature death.
          Lead Health Effects
 Damages organs - Lead causes damage to
  the kidneys, liver, brain and nerves, and
  other organs. Exposure to lead may also
  lead to osteoporosis (brittle bone disease)
  and reproductive disorders.
 Affects the brain and nerves - Excessive
  exposure to lead causes seizures, mental
  retardation, behavioral disorders, memory
  problems, and mood changes. Low levels of
  lead damage the brain and nerves in fetuses
  and young children, resulting in learning
  deficits and lowered IQ
    Lead Environmental Effects
 Affects animals and plants - Wild and domestic
  animals can ingest lead while grazing. They
  experience the same kind of effects as people who
  are exposed to lead. Low concentrations of lead
  can slow down vegetation growth near industrial
 Affects fish - Lead can enter water systems
  through runoff and from sewage and industrial
  waste streams. Elevated levels of lead in the water
  can cause reproductive damage in some aquatic
  life and cause blood and neurological changes in
  fish and other animals that live there.

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