Pollution
When people think about air
pollution, they usually think
about smog, acid rain and
other forms of outdoor air
pollution.
But did you know that air
pollution also can exist inside
homes and other buildings?
Every year, the health of many
people is affected by chemical
substances present in the air
within buildings.
Outdoor Air
Pollution
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.
For each city, 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 carbon monoxide pollution. Summer
inversions are more likely to create smog.
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. It damages plants by destroying
their leaves, it poisons the soil, and 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, 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. (One of the consequences of
polar ice cap melting would be a rise in global sea level,
resulting in widespread coastal flooding.)
Ozone depletion is another result of pollution.
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
Indoor
Pollution
Many people spend large portion of time
indoors - as much as 80-90% of their lives.
We work, study, eat, drink and sleep in
enclosed environments where air
circulation may be restricted. For these
reasons, some experts feel that more
people suffer from the effects of indoor air
pollution than outdoor pollution.
There are many sources of indoor air pollution.
Tobacco smoke, cooking, heating appliances,
and vapors cause pollution inside buildings.
Pollution exposure at home and work is often
greater than outdoors. Both indoor and outdoor
pollution need to be controlled and/or prevented.
But how can we prevent the damaging effects of
air pollution?
How can air
pollution hurt my
health?
Air pollution can affect our health in 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, that is, the duration of exposure and the
concentration of the chemicals must be taken into
account.
Examples of 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. 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. It is estimated that half a million
people die prematurely every year in the United
States as a result of smoking cigarettes.
• Research into the health effects of air pollution is
ongoing. Medical conditions arising from air
pollution can be very expensive. Healthcare
costs, lost productivity in the workplace, and
human welfare impacts cost billions of dollars
each year.
• Additional information on the health effects of air
pollution is available from the Natural Resources
Defense Council. A short article on the health
effects of ozone (a major component of smog) is
available from the B.A.A.Q.M.D.