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					Air Pollution
   APES – Period 5
                       Jane Kim
                     Janet Hong
                        Lynn Yi
Exosphere
Thermosphere
Mesosphere
Stratosphere
Troposphere
Primary pollutants: are mixed vertically and horizontally and are
dispersed and diluted by the churning air in the troposphere.
Ex: CO, CO2, SO2, NO, NO2, most hydrocarbons, and most
suspended particles


Secondary pollutants: while in the troposphere, some of the
primary pollutants may react with one another or with the basic
compounds of air.
Ex: SO3, HNO3, H2SO4, H2O2, O3, and PANs
        Six Principal Pollutants

- Carbon Monoxide (CO)
- Lead (Pb)
- Nitrogen Dioxide (NO2)
- Ozone (O3)
- Particulate Matter (PM-10)
- Sulfur Dioxide (SO2)
                        Ozone
Ozone is formed by the action of sunlight on carbon-based
chemicals known as hydrocarbons, acting in combination
with a group of air pollutants called oxides of nitrogen.

Ozone reacts chemically ("oxidizes") with internal body
tissues that it comes in contact with, such as those in the
lung. Ozone (O3) in the troposphere causes more damage
to plants than all other air pollutants combined.
                          SO2
Sulfur dioxide belongs to the family of gases called sulfur
oxides (SOx ). These gases are formed when fuel
containing sulfur (mainly coal and oil) is burned, and
during metal smelting and other industrial processes.
The major health concerns associated with exposure to
high concentrations of SO2 include effects on breathing,
respiratory illness, alterations in pulmonary defenses, and
aggravation of existing cardiovascular disease.
SO2 Emissions
                         Lead
               In the past, motor vehicles were the biggest
         source of lead. But since leaded gasoline has
been phased out, lead emissions have decreased by about
98 percent. Today, metal processing is the biggest source of
atmospheric lead.

Lead can harm the kidneys, liver, nervous system and other
organs. It may cause neurological impairments such as
seizures, mental retardation and behavioral disorders. Even
at low doses, lead is associated with damage to the nervous
systems of fetuses and young children, resulting in lowered
IQ and learning problems.
                  Particulates
Particulates is a general term used to describe tiny bits of
matter floating around in the atmosphere, such as certain
types of smoke (like diesel smoke), fine ash and dust. Larger
particles are caught by the hairs in your nose and your
breathing tubes, but smaller particles can get past these
defenses and cause lots of trouble.
                          NO2
Nitrogen dioxide belongs to a family of highly reactive
gases called nitrogen oxides (NOx). These gases form
when fuel is burned at high temperatures, and come
principally from motor vehicle exhaust and stationary
sources such as electric utilities and industrial boilers.
Nitrogen dioxide can irritate the lungs and lower resistance
to respiratory infections such as influenza.
                Carbon Monoxide
                       Carbon Monoxide is produced by the
                    incomplete combustion of the fossil fuels
                    – gas, oil, coal and wood used in boilers,
               engines, oil burners, gas fires, water heaters,
solid fuel appliances and open fires.
When carbon monoxide is present in the air you breath into
your lungs, it attaches itself to the hemoglobin.
The bond between hemoglobin and carbon monoxide is 250
times stronger than oxygen.
In the lungs carbon monoxide attaches to red blood cells in
place of oxygen.
Smog (smoke+fog)
              The Four Most Dangerous
                 Indoor Air Pollutants
1. cigarette smoke
2. Formaldehyde
3. Asbestos
4. radioactive radon-222 gas
               Formaldehyde
Formaldehyde is a colorless liquid or gas with a strong,
distinctive odor. It is found in furniture, new carpets,
particle board, plywood, rubber cement and adhesives.

Low levels of exposure can irritate the eyes, nose and
throat, cause skin problems, serious breathing problems
and can increase your risk of certain kinds of cancer.
                  ASBESTOS
Sources: Deteriorating of damaged insulation, fire-proofing,
or acoustical materials.

Health Effects: No immediate symptoms. Chest and
abdominal cancers and lung diseases. Smokers are at
higher risk of developing asbestos-induced lung cancer.
                    RADON
Sources: Earth, uranium and rock beneath home; well
water; building materials.

Health Effects: No immediate symptoms. Estimated to
cause about 10% of lung cancer deaths. Smokers are at
higher risk of developing radon-induced lung cancer.
                    Radon-222 can enter the house by diffusion
                 from soil and by emanation from building
                 materials, tap water and methane gas.


Characteristics
- an odorless, tasteless, invisible gas that mixes with air
- chemically inert and essentially non-reactive
- heaviest noble gas with highest melting and boiling point
- highly soluble in non-polar solvents
- moderately soluble in cold water
- able to diffuse through rock and soil
- decays by alpha particle emission (T 1/2 = 3.8 days)
The largest source of "indoor air
pollution"- in our homes, our schools or
workplaces- is car and truck pollution.


Electric vehicles are sometimes referred
to as "zero-emission vehicles" because
they produce essentially no pollution
from the tailpipe or through fuel
evaporation. This is important, for it
means that the use of electric vehicles
could greatly reduce emissions of
carbon monoxide and smog-forming
pollutants in cities with dirty air.
                Symptoms (IAP)
As many as 20 million Americans suffer from:
- chronic breathing problems
- dizziness
- rash
- headaches
- sore throat
- sinus
- eye irritation
Acid Deposition: the falling of acids and acid-forming
compounds from the atmosphere to earth’s surface. Acid
deposition is commonly known as acid rain, a term that refers
only to wet deposition of droplets of acids and acid-forming
compounds


Effects of Acid rain
- human respiratory disease (bronchitis and asthma)
- damages statues, buildings, metals, and car finishes
- depletion of calcium and magnesium ions in the soil
- damages trees
How to reduce acid deposition
1. Reduce energy use and thus air pollution by improving
   energy efficiency
2. Switch from coal to cleaner burning natural gas and
   renewable energy resources
3. Remove sulfur from coal before it is burned
4. Burn low-sulfur coal
5. Remove SO2, particulates, and nitrogen oxides from
   smokestack gases
6. Remove nitrogen oxides from motor vehicle exhaust
      Sick Building
        A building is considered “sick” when at
least 20% of its occupants suffer persistent
symptoms that disappear when they go outside
        At least 17% of the 4 million
commercial buildings in the U.S. are considered
“sick”.
       Ozone
Most ozone (about 90%)
exists in the stratosphere,
in a layer between 10 and
50km above the surface of
the earth. This ozone layer
performs the essential task
of filtering out most of the
sun's biologically harmful
ultraviolet (UV-B)
radiation.
                    Ozone Hole
            Over Antarctica (and recently over the Arctic),
        stratospheric ozone has been depleted over the last 15
      years at certain times of the year. This is mainly due to
   the release of manmade chemicals containing chlorine
such as CFC's (ChloroFluoroCarbons), but also compounds
containing bromine, other related halogen compounds and
also nitrogen oxides (NOx).
                       CFC’s
                   CFC's are chemicals that can be used in
                   the refrigerator to help keep food cold.
                   They can also be used in air-
                   conditioning and in products in spray
cans. CFC's rise into the air going into a layer called the
stratosphere. When this happens, the CFC's take part in
chemical reactions that can destroy parts of the ozone
which protects us from the sun's dangerous ultraviolet rays.
       Ozone Hole




1979                1998
       Greenhouse Effect
The Earth is kept warm by it's atmosphere, which
acts rather like a woolly coat - without it, the
average surface temperature would be about -18
degrees Centigrade. Heat from the sun passes
through the atmosphere, warming it up. As the
Earth warms up, it emits heat. Some of this heat is
trapped by the atmosphere, but the rest escapes into
space. The so-called "greenhouse gases" make the
atmosphere trap more of this radiation, so it
gradually warms up more than it should, like a
greenhouse.
Greenhouse
Effect
                             Greenhouse Effect                Ozone Shield

Where in the atmosphere   Troposphere                   Stratosphere
does it occur?

What process occurs?      Traps heat near the earth’s   Filters ultraviolet (UV)
                          surface                       radiation from the sun

What natural gases are    Water(H2O), carbon            Oxygen(O2), ozone(O3)
involved?                 dioxide(CO2), methane(CH4)

What are important        Carbon dioxide(CO2),          Chlorofluorocarbons
human inputs?             methane (CH4),                (CFCs), halons, carbon
                          chlorofluorocarbons (CFCs),   tetrachlorine, methyl
                          nitrous oxide(N2O)            choloroform (stable),
                                                        halogen-containing gases

What problems result?     Global warming                Ozone depletion
              Carbon Dioxide
Carbon dioxide is produced when any form of carbon or
almost any carbon compound is burned in an excess of
oxygen. For example, it is released into the atmosphere
during natural forest fires and the man-made combustion of
fossil fuels. Other natural sources of carbon dioxide include
volcanic eruptions, decay of dead plant and animal matter,
evaporation from the oceans and respiration (breathing).
                    Methane
Methane is a greenhouse gas that is creating a serious
problem for global warming. Methane gases are very
potent when trapping infrared heat in the atmosphere,
because one molecule of methane can trap infrared heat
twenty times more than carbon dioxide.

Methane the second most important
greenhouse gas is mostly produced
by the digestive system of cows.
                                      Asthma
                                  Smog and particles certainly
                                trigger attacks in some people
                                who already have asthma. For
                                a long time it was thought that
                                air pollution could not cause
                                asthma to develop in
                 previously healthy people. Some recent
experiments challenge this belief. Scientists have shown
that people exposed to ozone or nitrogen dioxide are more
likely to react to allergens such as grass pollens and
housedust mites than those who are not exposed. Thus a
combination of air pollution and allergens could cause
some cases of asthma.
          Lung Cancer
Lung cancer is more common in cities
than in the country. We know that over
90% of lung cancers are caused by
smoking cigarettes. A radioactive gas
called radon is thought to cause about
7% of lung cancers in North America.
87% of lung cancer cases are caused by smoking. 12
percent of all lung cancer deaths are linked to radon.
Another leading cause of lung cancer is on-the-job
exposure to cancer-causing substances or carcinogens.
Air pollution can make you
sick. It can cause burning eyes
and nose and an itchy, irritated
throat, as well as trouble in
breathing. Some chemicals
found in polluted air cause
cancer, birth defects, brain and
nerve damage and long-term
injury to the lungs and
breathing passages. Some air
pollutants are so dangerous
that accidental releases can
cause serious injury or even
death.
According to the U.S. Environmental Protection Agency's
(EPA) latest Ten-Year Air Quality and Emissions Trends
report, there have been significant reductions in all 6 criteria
pollutants and reductions are expected to continue.
         The 1990 Clean Air Act
Under this law, EPA sets limits on how much of a pollutant
can be in the air anywhere in the United States. This
ensures that all Americans have the same basic health and
environmental protections. The law allows individual states
to have stronger pollution controls, but states are not
allowed to have weaker pollution controls than those set for
the whole country.
Chapter 19: Global Warming
     and Ozone Loss




         Jane S. Kim
         Janet Hong
            Lynn Yi
        Period 5, APES
      The Greenhouse effect
• In the Greenhouse effect,
  certain gases in the atmos
  phere trap heat in the trop
  osphere (lower atmospher
  e).

• If the atmospheric concent
  rations of these gases rise
  and arent removed by othe
  r processes, the average t
  emp of the lower atmosph
  ere will gradually increase.
       Greenhouse gases
• The major greenho • These gases remai
  use gases are wate     n in the atmospher
  r vapor (H20), carb    e for 2,000-50,000
  on dioxide (C20), o    years.
  zone (o3), methane
  (CH4), nitrous oxid
                       • The two predomina
  e (N2O), and chlor
                         nt gases are water
  ofluorocarbons (CF
                         vapor (hyrologic cy
  Cs), and a recently
                         cle) and carbon dio
  identified perfluoro
                         xide (global carbon
  carbons (PFCs)
                         cycle)
          Global warming
• Measured atmospheric levels of certain gre
  enhouse gases have risen substantially in r
  ecent decades and are projected to enhan
  ce the earth’s natural greenhouse effect, a
  phenomenon called global warming
• Most of the increased levels of these green
  house gases since 1958 have been caused
  by human activities such as burning fossil f
  uels, agricultue, deforestation, and use of
  CFCs.
• Carbon dioxide (CO2):
  – Responsible for 50-60% of the global warming fr
    om greenhouse gases produced by human activit
    es
  – Main sources are fossil fuel burning (70-75%) an
    d land clearing and burning (20-25%)
  – Remains in atmosphere for 50-200 years
• Chloroflurocarbons (CFCs):
  – Contribute to global warming in the troposphere
    and also deplete ozone in the stratosphere
  – Main sources are leaking ACs and fridges, evap
    oration of industrial solvents, production of plas
    tic foams, and aerosol propellants
  – Trap 1,500- 7,000 times as much heat per mol
    ecule as CO2 while they are in the troposphere.
• Methane (CH4):
  – Accounts for about 20% of the overall warming eff
    ect
  – Produced when anaerobic bacteria break down de
    ad organic matter in moist places that lack oxygen
    .
  – Stays in the troposphere for 9-15 years
  – Each CH4 molecule traps 20 times as much heat a
• Nitrous oxide (N2O):
  – Can trap heat in the troposphere and also deplete oz
    one in the stratosphere
  – Released from nylon production, burning of biomass
    and nitrogen-rich fuels, smog-fighting catalytic con
    verters on motor vehicles, and the breakdown of nitr
    ogen fertilizers in soil, livestock wastes, and nitrate-
    contaminated groundwater.
  – Stays in the troposphere about 120 years.
• According to EPA, emission of green
  house gases by the US rose by 20%
  between 1990 and 1996. Energy rela
  ted activities accounted for about 86
  % of these emissions in 1996, mostly
  through burning fossil fuels.
• The atmospheric concentrations of C
  O2 and other greenhouse gases are p
  rojected to double from preindustrial l
  evels sometimes during the next cent
  ury and then continue to rise
The Earth’s past temperature
             s
• Since 1860, mean global temperature
  after correcting for excess heating ov
  er urban areas has risen 0.3-0.6 degr
  ees Celsius.
• Temperature rose about 0.3 degrees
  between 1846 and 1997
• Since 1860, the thirteen warmest year
  s occurred between 1979 and 1998,
  with 1990, 1995, 1997, and 1998 bein
  g the four hottest years.
Future global warming and its ef
              fects
• According to the la • According to the m
  test climate models   odels, the northern
  , the earth’s mean    hemisphere should
  surface temperatur    warm more and fas
  e should rise 1- 3.
  5 degrees celsius b   ter than the souther
  etween 1990 and 2     n hemisphere beca
  100.                  use the latter has
• Model projects that   more heat- absorbi
  once the climate c    ng ocean than land
  hanges, it will conti and because water
  nue for hundreds o    cools more slowly t
  f years.              han land.
How Earth’s climate is affect
   ed by various factors

• Solar output: ups and downs in solar
  output can temporarily warm or cool t
  he earth and thus affect the projectio
  ns of climate models.
  – Two studies showed that the projected
    warming power of greenhouse gases sh
    ould outweigh the climatic influence of t
    he sun over at least the next 50 years.
• Oceans: the oceans might amplify gl
  obal warming by releasing more CO2
  into the atmosphere or might dampen
  it by absorbing more heat. The ocea
  ns currently help moderate troposphe
  ric temperature by removing about 29
  % of the excess CO2 pumped into th
  e atmosphere
• Water vapor content and clouds: cha
  nges in the atmosphere’s water vapor
  content and the amount and types of
  cloud cover also affect climate. Warm
  er temperatures would increase evap
  oration and the water-holding capacit
  y of the air and create more clouds.
  Significant increase in the water vapo
  r, a potent greenhouse gas, could en
  hance warming (positive feedback).
• Polar ice: the ability of the earth’s surface
  to reflect light is called its albedo. Becaus
  e of their albedo, light-colored Greenland
  and Antarctic ice sheets act like enormous
  mirrors, reflecting sunlight back into space
  . If warmer temperatures melted some of t
  his ice and exposed darker ground or ocea
  n, more sunlight would be absorbed and w
  arming would be accelerated.
• Air pollution: pollutants in the lower tropos
  phere can either warm or cool the air depe
  nding on the reflectivity of the underlying s
  urface.
• It is hypothesized that SO2 and tiny particl
  es in the troposphere attract enough water
  molecules to form condensation nuclei, wh
  ich leads to increased cloud formation
Some possible effects of a warmer
             world
• Food production: a warmer global climat
  e could increase food production in some
  areas and lower it in others, depending o
  n crop- growing capacity and climate bel
  ts.
• Water supply: global warming would redu
  ce water supply, shrinking or completely
  drying up lakes, streams, and aquifers.
• Forests and biodiversity: global warming
  would change the makeup and location o
  f many of the worlds forests
            Continued…
• Sea levels: in a warmer world, sea levels a
  re expected to rise, primarily because ocea
  n water expands when heated and becaus
  e some land-based glacial ice will melt
• Weather extremes: as more heat is retaine
  d in the earth’s climate system, more air wi
  ll move across the earth’s surface.
• Human health: global warming would bring
  more heat waves, which would double or tr
  iple heat-related deaths among the elderly
  and people with heart disease; it would als
  o increase suffering from respiratory ailme
  nts such as asthma and bronchitis.
Solutions: dealing with global warm
                 ing
• Stabilizing the Co2 levels at the curre
  ct level would require reducing curren
  t global CO2 emissions by 66-83%.
• Increased use of nuclear power to re
  duce the amount of CO2 per unit of e
  lectricity as coal
• Using natural gas could help make th
  e 40 to 50 year transition to an age of
  energy efficiency and renewable ener
  gy.
            Ozone depletion
• In a band of the stratosphere 17- 26 kms abov
  e the earth’s surface, oxygen is continually con
  verted to ozone and back to oxygen by a seque
  nce of reactions initiated by UV radiation from t
  he sun.
• UV radiation reaching the stratosphere consists
  of three bands: A, B, and C. The ozone layer b
  locks out nearly all of the highest- energy and
  biologically damaging UV-B band.
• Ozone depletion by certain chlorine- and bromi
  ne- containing chemicals emitted into the atmo
  sphere by human activities is a serious long-ter
  m threat to human health, animal life, and the s
  unlight drive promary producers that support th
• CFCs released into the air rise slowly into the st
  ratosphere. There, under the influence of high
  energy UV radiation, they break down and relea
  se highly reactive chlorine atoms, which speed
  up the breakdown of highly reactive ozone into
  O2 and O. This causes ozone to be destroyed f
  aster than it is formed.
  Solutions: protecting the ozo
             ne layer
• It will take another 50-60 years for the ozo
  ne layer to return to 1975 levels and anoth
  er 100- 200 years to return to pre- 1950 r
  ecovery levels.
• Substitutes are already available for most
  uses of CFCs.
  – Hydochlorofluorocarbons (HCFCs) contain fe
    wer chlorine atoms per molecule than CFCs
    • Because of their shorter lifetimes in the stratospher
      e, these compounds should have only about 2.5%
      of the ozone depleting potential of CFCs.

				
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