Question

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

Answer 1

1. Gaseous pollutants: Gaseous pollutants include gases such as Carbon monoxide (CO), Sulphur dioxide (SO₂), and Nitrogen oxides (NO_x). These pollutants are classified into two types based on their origin: primary pollutants, which are emitted directly into the atmosphere, and secondary pollutants, which are formed through chemical reactions within the atmosphere.
2. Particulate Pollutants: Particulate air pollutants consist of tiny particles that can be either solid or liquid in nature.
   1. Solid particulates include substances like smoke, grit, photochemical smog, various biocides, pesticides, heavy metals, and radioactive elements.
   2. Liquid particulates are typically released into the air as sprays or liquid aerosols. Furthermore, gaseous emissions from factories and automobiles often carry particles of heavy metals, such as cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn).

These pollutants affect human health in various ways:

• Air pollutants cause several chronic lung-related diseases, including lung cancer, bronchitis, asthma, and emphysema.
• These pollutants are responsible for causing persistent irritation of the eyes, nose, throat, and the entire respiratory tract.
• Carbon monoxide (CO) is highly hazardous as it reduces the oxygen-carrying capacity of the blood, leading to headaches, fatigue, and heart damage.
• Sulphur dioxide (SO₂) causes swelling and excessive mucus secretion in the respiratory tract, which becomes more severe in the presence of moisture or fog due to acid formation.
• Exposure to hydrogen sulphide (H₂S) can result in headaches, nausea, and irritation, and in extreme cases, it may lead to collapse or respiratory failure.
• Nitrogen oxides and peroxyacetyl nitrate (PAN) are known to damage the lungs and heart while causing significant eye irritation.
• Heavy metals like lead can damage the brain and nervous system, particularly in children, while cadmium leads to respiratory poisoning and mercury damages the liver and nervous system.
• Carcinogenic hydrocarbons, such as benzopyrene, are primarily responsible for causing lung cancer.
• Solid particulates, such as soot, are a major cause of various respiratory diseases and tuberculosis.
• Biological particles like bacterial spores and pollens trigger severe allergic reactions and various bronchial disorders.