What is Air Pollution?
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The presence in the atmosphere of one or more contaminants in such quality and for such duration as is injurious, or tends to be injurious, to human health or welfare, animal or plant life.' Air pollution is aggravated because of four developments: increasing traffic, growing cities, rapid economic development, and industrialization. Air pollution can cause health problems and it can also damage the environment and property.
Economic Losses Due to Air Pollution |
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Direct medical losses
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Lost income resulting from absenteeism from work
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Decreased productivity
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Increased cost of cleaning
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Losses due to damage to crops and ornamental vegetation
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Decrease of property values
There are four important factor is causes for air pollution. They are,
- Increaing traffic and vehicle population
- Rapid growth of Population
- Industrialization
- Urbanization
Major air pollutants and their sources
Carbon monoxide (CO) is a colourless, odorless gas that is produced by the incomplete burning of carbon-based fuels including petrol, diesel, and wood.
Carbon dioxide (CO2) is the principle greenhouse gas emitted as a result of human activities such as the burning of coal, oil, and natural gases.
Chloro floro carbons (CFC) are gases that are released mainly from air-conditioning systems and refrigeration. When released into the air, CFCs rise to the stratosphere, where they come in contact with few other gases, which leads to a reduction of the ozone layer that protects the earth from the harmful ultraviolet rays of the sun.
Lead is present in petrol, diesel, lead batteries, paints, hair dye products, etc. Lead affects children in particular. It can cause nervous system damage and digestive problems and, in some cases, cause cancer.
Ozone occur naturally in the upper layers of the atmosphere. This important gas shields the earth from the harmful ultraviolet rays of the sun.
Nitrogen oxide (Nox) causes smog and acid rain. It is produced from burning fuels including petrol, diesel, and coal. Nitrogen oxides can make children susceptible to respiratory diseases in winters.
Suspended particulate matter (SPM) consists of solids in the air in the form of smoke, dust, and vapour that can remain suspended for extended periods and is also the main source of haze which reduces visibility.
Sulphur dioxide (SO2) is a gas produced from burning coal, mainly in thermal power plants. Some industrial processes, such as production of paper and smelting of metals, produce sulphur dioxide
Sources of air pollution
Air pollutants consist of gaseous pollutants, odours, and SPM, (suspended particulate matter) such as dust, fumes, mist, and smoke. The concentration of these in and near the urban areas causes severe pollution to the surroundings. The largest sources of human-created air pollution are energy generation, transportation, and industries that use a great deal of energy sources.
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Common atmospheric pollution sources and their pollutants
| Category |
Source |
Emitting
Pollutants |
| Agriculture |
Open burning |
Suspended particulate matter, carbon monoxide, volatile organic compounds |
| Mining and quarrying |
Coal mining; crude oil and gas production; stone quarrying |
Suspended particulate matter, sulphur dioxide, oxides of nitrogen, volatile organic compounds |
| Power generation |
Electricity; gas; steam |
Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, sulphur trioxide, lead |
| Transport |
Combustion engines |
Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead |
| Community service |
Municipal incinerators |
Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead |
Health impact of specific air pollutants
Some of these gases can seriously and adversely affect the health of the population and should be given due attention by the concerned authority. The gases mentioned below are mainly outdoor air pollutants but some of them can and do occur indoor depending on the source and the circumstances.
| Pollutant |
Health Impact |
| Tobacco
smoke. |
Tobacco smoke generates a
wide range of harmful chemicals and is a major cause of ill
health, as it is known to cause cancer, not only to the smoker
but affecting passive smokers too. It is well-known that
smoking affects the passive smoker (the person who is in the
vicinity of a smoker and is not himself/herself a smoker)
ranging from burning sensation in the eyes or nose, and throat
irritation, to cancer, bronchitis, severe asthma, and a
decrease in lung function. |
|
Biological pollutants |
These are mostly allergens that can cause
asthma, hay fever, and other allergic diseases. |
|
Volatile organic compounds |
Volatile compounds can cause irritation
of the eye, nose and throat. In severe cases there may be headaches,
nausea, and loss of coordination. In the longer run, some of them
are suspected to cause damage to the liver and other parts of the
body. |
| Formaldehyde |
Exposure causes irritation to the eyes, nose and may
cause allergies in some people |
| Lead |
Prolonged exposure can cause damage to the nervous system,
digestive problems, and in some cases cause cancer. It is especially
hazardous to small children. |
| Radon |
A radioactive gas that can accumulate inside the house, it
originates from the rocks and soil under the house and its level is
dominated by the outdoor air and also to some extent the other gases
being emitted indoors. Exposure to this gas increases the risk of
lung cancer. |
| Ozone |
Exposure to this gas makes our eyes itch, burn, and water and
it has also been associated with increase in respiratory disorders
such as asthma. It lowers our resistance to colds and pneumonia. |
|
Oxides of nitrogen |
This gas can make children susceptible to
respiratory diseases in the winters. |
|
Carbon monoxide (CO) |
CO (carbon monoxide) combines with haemoglobin to
lessen the amount of oxygen that enters our blood through our lungs.
The binding with other haeme proteins causes changes in the function
of the affected organs such as the brain and the cardiovascular
system, and also the developing foetus. It can impair our
concentration, slow our reflexes, and make us confused and sleepy. |
|
Sulphur dioxide. (SO2) |
Sulphur
Dioxide in the air is caused due to
the rise in combustion of fossil fuels. It can oxidize and form
sulphuric acid mist. SO2 in the air leads to diseases of the lung
and other lung disorders such as wheezing and shortness of breath.
Long-term effects are more difficult to ascertain as SO2 exposure is
often combined with that of SPM. |
| Suspended
Particulate Matter |
SPM (suspended particulate matter). Suspended matter consists of
dust, fumes, mist and smoke. The main chemical component of SPM that
is of major concern is lead, others being nickel, arsenic, and those
present in diesel exhaust. These particles when breathed in, lodge
in our lung tissues and cause lung damage and respiratory problems.
The importance of SPM as a major pollutant needs special emphasis as
a) it affects more people globally than any other pollutant on a
continuing basis; b) there is more monitoring data available on this
than any other pollutant; and
c) more epidemiological evidence has
been collected on the exposure to this than to any other pollutant. |
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How to reduce to reduce the air pollution ?
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Encourage your family to walk to the neighbourhood market.
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Whenever possible take your bicycle.
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As far as possible use public forms of transport.
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Don't let your father drop you to school, take the school bus.
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Encourage your family to form a car pool to office and back.
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Reduce the use of aerosols in the household.
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Look after the trees in your neighbourhood.
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Begin a tree-watch group to ensure that they are well tended and
cared for.
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Switch-off all the lights and fans when not required.
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If possible share your room with others when the airconditioner,
cooler or fan is on.
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Do not burn leaves in your garden, put them in a compost pit.
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Make sure that the pollution check for your family car is done at
regular intervals
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Cars should, as far as possible, be fitted with catalytic
converters.
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Use only unleaded petrol.
Contents which are related with air pollution
Acid rain
The term 'acid rain' refers to the acidification of rain associated
with the combustion of fossil fuel: coal, oil and natural gas. Acid
rain causes extensive damage to water, forest, soil resources and
even human health. In the early 1980s acid rain become the favourite
cause of doom. By 1986, the United Nations reported that 23 percent
of all trees in Europe were moderated or severely by acid rain.
Ground-level ozone
Ground-level ozone is formed through a complex reaction involving
hydrocarbons, nitrogen oxides, and sunlight. Ground-level ozone is
especially harmful for seniors, children, asthmatics, and people
with heart and lung conditions. It aggravates respiratory symptoms
and further impairs the ability of these individuals to perform
normal activities. It can inflame breathing passages, decreasing the
lung's working capacity, and causing shortness of breath, pain when
inhaling deeply, wheezing, and coughing. It can cause eye and nose
irritation and dry out the protective membranes of the nose and
throat and interfere with the body's ability to fight infection,
increasing susceptibility to illness.
Indoor air pollution
In the developing countries, it is the rural areas that face the
greatest threat from indoor pollution, where some 3.5 billion people
continue to rely on traditional fuels such as firewood, charcoal,
and cowdung for cooking and heating. Concentrations of indoor
pollutants in households that burn traditional fuels are alarming.
Burning such fuels produces large amount of smoke and other air
pollutants in the confined space of the home, resulting in high
exposure. Women and children are the groups most vulnerable as they
spend more time indoors and are exposed to the smoke. In 1992, the
World Bank designated indoor air pollution in the developing
countries as one of the four most critical global environmental
problems. Daily averages of pollutant level emitted indoors often
exceed current WHO guidelines and acceptable levels. Although many
hundreds of separate chemical agents have been identified in the
smoke from biofuels, the four most serious pollutants are
particulates, carbon monoxide, polycyclic organic matter, and
formaldehyde.
In urban areas, exposure to indoor air pollution has increased due
to a variety of reasons, including the construction of more tightly
sealed buildings, reduced ventilation, the use of synthetic
materials for building and furnishing and the use of chemical
products, pesticides, and household care products. Indoor air
pollution can begin within the building or be drawn in from
outdoors. Other than nitrogen dioxide, carbon monoxide, and lead,
there are a number of other pollutants that affect the air quality
in an enclosed space.
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