Question

Illustrate various types of pollutants that cause air pollution. How do they affect the health of man?

Answer 1

1. Gaseous Air Pollutants:
   • Carbon monoxide (CO)
   • Oxides of sulphur (SO₂) and hydrogen sulphide (H₂S)
   • Hydrocarbons (mainly from motor vehicles and burning natural gas)
   • Aldehydes and organic acids (from incomplete combustion of fuels)
   • Oxides of nitrogen (NO_x)
   • Ozone (O₃) formed as a secondary pollutant through photochemical reactions in presence of sunlight
   • Other inorganic gases such as ammonia, chlorine, and phosgene
2. Particulate Pollutants:
   • Solid particulates like smoke, grit, heavy metal particles (cadmium, copper, lead, zinc), radioactive elements, asbestos, silica, soot
   • Liquid particulates like sprays and liquid aerosols

These pollutants affect human health in various ways:

1. Lung-related chronic diseases such as lung cancer, bronchitis, asthma, emphysema
2. Irritation of eyes, nose, throat, and respiratory tract
3. Carbon monoxide reduces oxygen carrying capacity of blood leading to headache, fatigue, and heart damage
4. Sulphur dioxide causes swelling and mucus secretion in respiratory tract, intensified by moisture and fog due to acid formation
5. Hydrogen sulphide causes headache, nausea, irritation, collapse, and respiratory failure
6. Nitrogen oxides and peroxy acetyl nitrate damage lungs and heart and cause eye irritation
7. Heavy metals like lead can damage the brain, especially in children, and affect the nervous system; cadmium leads to respiratory poisoning and heart diseases; mercury damages nervous system and liver
8. Carcinogenic hydrocarbons like benzopyrene cause lung cancer
9. Particulates such as soot cause respiratory diseases and tuberculosis
10. Biological particles like bacterial spores and pollens cause allergies and bronchial disorders