Air Pollution

Presented ByPragna Prathap

Kerala Agricultural University

What is Air pollution ???

Air pollution is the introduction of chemicals,particulates, biological materials, or otherharmful materials into the Earth's atmosphere,possibly causing disease, death to humans,damage to other living organisms such as foodcrops, or the natural or built environment.

Air Pollutants

An air pollutant is a substance in the air that canhave adverse effects on humans and theecosystem.The substance can be solid particles, liquiddroplets, or gases.A pollutant can be of natural origin or man-made.Pollutants are classified as primary or secondary.

Primary P0llutants

Primary pollutants areusually produced from aprocessAsh from a volcaniceruption.carbon monoxide gas frommotor vehicle exhaustsulfur dioxide releasedfrom factories.

Secondary pollutants arenot emitted directly.They form in the air whenprimary pollutants react orinteract.Ground level ozone is aprominent example of asecondary pollutant.

Secondary Pollutants

Major Primary Air Pollutants Are:

Sulphur oxides, esp. sulphur dioxide (SO2)Nitrogen oxidesCarbon monoxide (CO)

Volatile organic compounds classified as methane (CH4) andnon-methane (NMVOCs)

Particulate matter (PM), atmospheric particulate matter, orfine particles - these are tiny particles of solid or liquidsuspended in a gas

Contd..,

Free radicals, radioactive pollutants, odoursToxic metals such as lead and mercury and theircompoundsChlorofluorocarbons (CFCs): these are notorious fordepleting the protective ozone layerAmmonia (NH3)

Secondary Air Pollutants Include-

Smog

"Smog" is a combination of smoke and fog. Photochemicalsmog is the result of chemical reaction of sunlight, nitrogenoxides, and volatile organic compounds in the atmosphere.Smog is a serious threat to human health and is regarded asa problem of modern industrialization.

Ground Level Ozone (O3)

Becomes toxic at high amounts.Human activities including combustion of fossilfuels contribute to high levels of ozone in the air.Ozone is a normal component of the atmosphereand serves as a protective layer (ozone layer).Pollutants such as CFCs deplete the ozone layer.

Peroxyacetyl Nitrate (PAN)

Peroxyacetyl nitrate (pan)is produced fromnitrous oxides and volatile organiccompounds (vocs).

Short Term Effects Of Pollution

Irritation to the eyes, nose and throat.

Respiratory infections.

Headache, nausea, and allergic reactions.

Asthma and emphysema

Long Term Effects Of Pollution

Chronic respiratory diseases.

Lung cancer.

Heart diseases.

Damage to the brain, nerves, liver or kidneys.

Major air pollution disasters

The “GREAT” London smog Melbourne dust storm Malaysian haze Southeast Asian haze

Bhopal Gas Tragedy

In 1984, union carbide plant released massive amounts ofmethyl isocyanate into the air.Because the gas was denser than air, it spread around thesurrounding communities.Over 3,000 people were killed in the 6 hours of leakage,Over 5,00,000 people were exposed.

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