Effects of Atmospheric Pollution
- Most often SO2 causes respiratory tract diseases in human beings damaging the mucous membrane of the nose and the respiratory tract. If the amount of sulphur dioxide present is 500 ppm., it can also lead to death.
- It bleaches the green colour of the leaf apexes in plants to yellow colour, thus preventing it from performing photosynthesis properly.
- When oxides of nitrogen and sulphur combine with rainwater, they form acids resulting in acid rains.
Chlorofluoro Carbons (C F C' s), Freons
Among the hydrocarbons, methane is present in large quantities around the world. When organic matter and biomass are degraded, methane gas is produced. It undergoes oxidation very easily. The smoke coming out from automobiles contains a mixture of hydrocarbons. Carcinogenic benzopyrene is also released from the emission tubes of diesel engines. All the hydrocarbons are oxidized and converted into free radicals (odd electron molecules). These are harmful to the plants and can damage both the cellulose and tissues present in it. Peroxy acetyl nitrate(PAN) is another harmful substance which damages the plants. Small amounts of PAN (0.02 to 0.05 ppm) is sufficient to cause considerable damage. Peroxy benzoyl nitrate(PBN) also belongs to the same category. It causes irritation to eyes when present in the atmosphere. It also undergoes photochemical oxidation, mixes with ozone, oxides of nitrogen and forms what is called smog(smoke +fog).
The particulate substances such as lead, carbon and metal from the automobile exhausts and from chimneys of various industries, when inhaled along with air causes respiratory disorders. The harmful pesticides, biocides let out into the air by the factories when they are being manufactured, pollute the air and cause minor to major health hazards. Apart from these, accidents that occur in factories also are responsible for the pollution of the air.