AIr pollution by suchenfz

VIEWS: 5 PAGES: 48

									Air Pollution
              Intro
• Air is the ocean we breathe.
• Air supplies us with oxygen which is
  essential for our bodies to live. Air is
  99.9% nitrogen, oxygen, water vapor
  and inert gases.
• Human activities can release
  substances into the air, some of which
  can cause problems for humans,
  plants, and animals.
    Atmosphere structure and
          composition
A. What is the atmosphere?
1. Outermost layer of the Earth
2.Comprised of gas, turbulently flowing,
   held in by gravity
3.Formed by out gassing of the Earth’s
   interior, since modified by many
   Earth system processes
4. Compared to the lithosphere and
   hydrosphere, the atmosphere is more
   rapidly changing and dynamic
5. Basic atmospheric variables
  a. Solar energy – sunshine is the major energy
     source for atmospheric and Earth surface
     processes
  b. Humidity and precipitation (moisture)
  c. Winds – governed by atmospheric pressure
     differences
Composition
          Types of Pollution
•   Smog
•   acid rain
•   the greenhouse effect
•   "holes" in the ozone layer
•   Each of these problems has serious
    implications for our health and well-
    being as well as for the whole
    environment.
     Effects of Pollution
• Pollutants which have an immediate
  effect are primary air pollutants
• Those that become a problem when
  converted to other forms are
  secondary air pollutants.
• Primary pollutants include carbon
  monoxide, radioactive wastes and
  highly toxic compounds such as
  xylenes, cyantes, and atmospheric
  metals.
• Secondary pollutants include low level
  ozone which is produced by sunlight
  reacting with the exhaust from
  combustion engines.
• Some pollutants are natural components
  of the atmosphere and become pollutants
  when they reach critical levels that
  affect life. These natural pollutants
  include such things as volcanic eruptions,
  violent storms, forest fires, wind erosion,
  natural gases from the decay of dead
  organisms, and pollen and spores.
       Threats to humans
• The Environmental Protection
  Agency (EPA) has identified six
  primary pollutants that present a
  threat to human health: carbon
  monoxide, low level ozone, lead,
  the sulfur oxides, the nitrogen
  oxides, and particulate matter.
        Carbon Monoxide
• Carbon Monoxide: A colorless, odorless,
  poisonous gas, produced by incomplete
  burning of carbon-based fuels including
  gasoline, oil and wood as well as
  combustion of many natural and synthetic
  products such as cigarettes.
• When carbon monoxide gets into the
  body, it combines with chemicals in the
  blood and prevents the blood from
  transporting oxygen to the cells of the
  body.
        Low Level Ozone
• Low Level Ozone: A variation of oxygen
  which contains three atoms of oxygen
  instead of two.
• Ozone occurs in nature; it is the cause of
  the sharp smell you notice near a lightning
  strike.
• Ozone is found in large concentrations in
  the stratosphere where it protects the
  earth from ultraviolet radiation.
• Ground level ozone is the main component
  of smog, and is a product of reactions
  during combustion of coal, gasoline and
  other fuels, and also chemicals found in
  products including solvents, paints and
  hairspray.
• In humans, it can cause lung tissue damage,
  and create high incidences of asthma and
  allergenic reactions.
• Plants exposed to high ozone
  concentrations lose their chlorophyll and
  their food manufacturing abilities.
              Lead
• Lead: There has been a dramatic
  decrease of lead in human blood
  levels since the element has been
  removed from gasoline and paints.
  Sources for lead in our
  environment, are large furnaces,
  incinerators, and battery plants.
• Lead in the atmosphere can deposit
  into lakes and streams where it may
  be ingested by fish and eventually by
  humans.
• The physical effects of lead poisoning
  are mental impairment, central
  nervous system damage and high
  blood pressure.
      Sulfur Dioxide
• Sulfur Dioxide: A gas produced by burning
  coal, most notably in power plants, as well
  as some industrial processes such as paper
  production and the smelting of metals.
• Sulfur dioxide plays an important role in
  the production of acid rain. Sulfur dioxide
  can cause nose and throat irritation and
  lung problems such as bronchitis.
        Nitrogen Oxide
• Nitrogen Oxide: Nitrogen Oxides
  (NOx) are produced from burning
  fuels including gasoline and coal.
• The major sources of NOx are power
  plants and transportation--vehicles
  that burn gasoline and diesel.
• Nitrogen Oxides react with organic
  compounds to form smog, and are also
  major components of acid rain.
  Particulate Matter
• Particulate Matter: Particulate
  Matter (PM) includes dust, soot and
  other tiny bits of solid materials
  that are released into and move
  around in the air.
• U.S. health standards for air quality
  are based on the concentration of
  particles small enough to be inhaled
  deep into the lungs.
• These are particles with a diameter
  of less than 10 microns. Particulates
  are produced by many sources,
  including burning of diesel fuels,
  incineration of garbage, mixing and
  application of fertilizers and
  pesticides, road construction and
  industrial processes such as
  steelmaking, mining operations or
  agricultural burning.
• Particulate pollution can cause eye,
  nose and throat irritation and other
  health problems.
• Fine-particulate air pollution
  (particles with a diameter of 2.5
  microns or less) tend to deposit in
  the alveoli of the lungs where they
  remain for a long time.
• Fine-particle pollution typically
  contains soot, acid condensates, and
  sulfate and nitrate particles. This
  type of pollution is thought to pose
  greater health risks not only because
  the particles can be breathed more
  deeply into the lungs, but also
  because they are more likely to be
  more toxic than larger particles.
• One type of particulate pollution is the
  release of particles into the air from
  burning fuel for energy. Diesel smoke
  is a good example of this particulate
  matter . The particles are very small
  pieces of matter measuring about 2.5
  microns or about .0001 inches.
• This type of pollution is sometimes
  referred to as "black carbon" pollution.
• The exhaust from burning fuels in
  automobiles, homes, and industries is a
  major source of pollution in the air.
• Another type of particulate pollution
  is the release of noxious gases, such
  as sulfur dioxide, carbon monoxide,
  nitrogen oxides, and chemical vapors.
  These can take part in further
  chemical reactions once they are in
  the atmosphere, forming smog and
  acid rain.
Smog
• Smog is a type of large-scale outdoor
  pollution.
• It is caused by chemical reactions
  between pollutants derived from
  different sources, primarily automobile
  exhaust and industrial emissions.
• Cities are often centers of these types
  of activities, and many suffer from the
  effects of smog, especially during the
  warm months of the year.
• The exact causes of pollution may be
  different. Depending on the
  geographical location, temperature,
  wind and weather factors, pollution is
  dispersed differently. However,
  sometimes this does not happen and
  the pollution can build up to
  dangerous levels.
• A temperature inversion occurs when
  air close to the earth is cooler than
  the air above it. Under these
  conditions the pollution cannot rise
  and be dispersed.
• Cities surrounded by mountains also
  experience trapping of pollution.
• Inversion can happen in any season.
  Winter inversions are likely to cause
  particulate and or inversions are more
  likely to create smog.
            Acid Rain
• Another consequence of outdoor air
  pollution is acid rain. When a
  pollutant, such as sulfuric acid
  combines with droplets of water in
  the air, the water (or snow) can
  become acidified . The effects of acid
  rain on the environment can be very
  serious.
      Acid Rain damage
• Acid rain damages plants by
  destroying their leaves
• it poisons the soil
• it changes the chemistry of lakes
  and streams
• Damage due to acid rain kills
  trees and harms animals, fish,
  and other wildlife.
The Greenhouse effect
• The Greenhouse Effect, also
  referred to as global warming, is
  generally believed to come from
  the build up of carbon dioxide gas
  in the atmosphere.
• Carbon dioxide is produced when
  fuels are burned.
• Plants convert carbon dioxide back to
  oxygen, but the release of carbon
  dioxide from human activities is
  higher than the world's plants can
  process.
• The situation is made worse since
  many of the earth's forests are being
  removed, and plant life is being
  damaged by acid rain.
• Thus, the amount of carbon dioxide in
  the air is continuing to increase. This
  buildup acts like a blanket and traps
  heat close to the surface of our
  earth.
• Changes of even a few degrees will
  affect us all through changes in the
  climate and even the possibility that
  the polar ice caps may melt.
           Ozone
• Chemicals released by our activities
  affect the stratosphere , one of the
  atmospheric layers surrounding earth.
  The ozone layer in the stratosphere
  protects the earth from harmful
  ultraviolet radiation from the sun.
• Release of chlorofluorocarbons
  (CFC's) from aerosol cans, cooling
  systems and refrigerator equipment
  removes some of the ozone, causing
  "holes"; to open up in this layer and
  allowing the radiation to reach the
  earth.
• Ultraviolet radiation is known to
  cause skin cancer and has damaging
  effects on plants and wildlife.
     Indoor Air pollution
• Pollution also needs to be considered
  inside our homes, offices, and
  schools.
• In the United States, we spend about
  80-90% of our time inside buildings,
  and so our exposure to harmful indoor
  pollutants can be serious.
Sources of indoor pollution
• There are many sources of indoor air
  pollution. Tobacco smoke, cooking and
  heating appliances, and vapors from
  building materials, paints, furniture,
  etc. cause pollution inside buildings.
• Radon is a natural radioactive gas
  released from the earth, and it can
  be found concentrated in basements
  in some parts of the United States.
• Pollution exposure at home and work
  is often greater than outdoors.
• The California Air Resources Board
  estimates that indoor air pollutant
  levels are 25-62% greater than
  outside levels and can pose serious
  health problems.
                   Radon
• Radon-222 is a radioactive gas released during
  the natural decay of thorium and uranium, which
  are common, naturally occurring elements found
  in varying amounts in rock and soil. Odorless,
  invisible, and without taste, radon cannot be
  detected with the human senses.
• Radon-222 decays into radioactive elements, two
  of which -- polonium-218 and polonium-214 -- emit
  alpha particles, which are highly effective in
  damaging lung tissues. These alpha-emitting radon
  decay products have been implicated in a causal
  relationship with lung cancer in humans.
 Characteristics and Sources
          of Radon
• Outdoors, where it is diluted radon poses
  significantly less risk than indoors.
• In the indoor air environment, the
  magnitude of radon concentration indoors
  depends primarily on a building's
  construction and the amount of radon in
  the underlying soil.
• The soil composition under and around a
  house affects radon levels and the ease
  with which radon migrates toward a
  house.
• Normal pressure differences between the
  house and the soil can create a slight
  vacuum in the home that can draw radon
  gas from the soil into the building.
• Radon gas can enter a home from the soil
  through cracks in concrete floors and
  walls, floor drains, sump pumps,
  construction joints, and tiny cracks or
  pores in hollow-block walls.
• Radon levels are generally highest in
  basements and ground floor rooms that
  are in contact with the soil.
• Factors such as the design, construction,
  and ventilation of the home affect the
  pathways and sources that can draw
  radon indoors.
• Another source of radon indoors may be
  air released by well water during
  showering and other household activities.
Mold
• Molds produce tiny spores to reproduce.
  Mold spores waft through the indoor and
  outdoor air continually.
• When mold spores land on a damp spot
  indoors, they may begin growing and
  digesting whatever they are growing on in
  order to survive.
• There are molds that can grow on wood,
  paper, carpet, and foods.
• The key to mold control is moisture
  control. It is important to dry water
  damaged areas and items within 24-48
  hours to prevent mold growth.
• Clean up the mold and get rid of the
  excess water or moisture. Fix leaky
  plumbing or other sources of water.
  Wash mold off hard surfaces with
  detergent and water, and dry
  completely. Absorbent materials (such
  as ceiling tiles & carpet) that become
  moldy may have to be replaced.
 Noise pollution
• Although noise is a significant environmental
  problem, it is often difficult to quantify associated
  costs. An OECD report on the social costs of land
  transport identified four categories of impact from
  transport noise:
• productivity losses due to poor concentration,
  communication difficulties or fatigue due to
  insufficient rest
• health care costs to rectify loss of sleep, hearing
  problems or stress
• lowered property values
• loss of psychological well-being.
                    effects
   Healthaffect our health in
• Air pollution can
  many ways with both short-term and
  long-term effects.
• Different groups of individuals are
  affected by air pollution in different
  ways.
• Some individuals are much more
  sensitive to pollutants than are others.
  Young children and elderly people often
  suffer more from the effects of air
  pollution.
• People with health problems such as
  asthma, heart and lung disease may
  also suffer more when the air is
  polluted.
• The extent to which an individual is
  harmed by air pollution usually
  depends on the total exposure to the
  damaging chemicals.
• Short-term effects include
  irritation to the eyes, nose and
  throat, and upper respiratory
  infections such as bronchitis and
  pneumonia. Other symptoms can
  include headaches, nausea, and
  allergic reactions.
• Short-term air pollution can
  aggravate the medical conditions of
  individuals with asthma and
  emphysema. In the great "Smog
  Disaster" in London in 1952, four
  thousand people died in a few days
  due to the high concentrations of
  pollution.
• Long-term health effects can include
  chronic respiratory disease, lung
  cancer, heart disease, and even
  damage to the brain, nerves, liver, or
  kidneys. Continual exposure to air
  pollution affects the lungs of growing
  children and may aggravate or
  complicate medical conditions in the
  elderly.

								
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