Air pollutants and their sources
Carbon monoxide (CO), sulphur dioxide (SO2), oxides of nitrogen (NO and NO2), chlorofluorocarbons (CFCs), etc. Are the main air pollutants. Poisonous gases produced during the decay of dead organic matter and particulate matter like soot, dust particles, pollen’s, metallic compounds (e.g., compounds of lead), etc., also pollute the air.
Carbon monoxide is produced by the incomplete combustion of coal and other fossil fuels (natural gas, petrol, oil, etc.). smoke released from motor vehicles and industries is the main source of carbon monoxide.
Sulphur dioxide is produced by burning of coal or oil in factories. Smoke released from thermal power stations usually contain sulphur dioxide. Oxides of nitrogen are produced by burning of coal and oil at high temperature in industries and vehicle engines. Chlorofluorocarbons (CFCs) are the compounds which contain chlorine, fluorine and carbon atoms. CFCs are used in aerosol sprays, refrigerators and air conditioning system. On leakages from these appliances, chlorofluorocarbons enter the air. Fossil fuel (coal, natural gas, oeil, petrol, etc.) and aerosols are the main sources of air pollutants.
 vehicles’ smoke |  industial smoke |
|  CFCs in aerosol spray |
|  Volcanic eruption |
Properties and effects of air pollutants on human organ systems
Carbon monoxide is a colorless, odorless and poisonous gas. It affects the human organ systems badly and causes headache, brain damage and respiratory problems.when carbon monoxide reaches our blood, it gets bonded with hemoglobin and reduces its oxygen-carrying capacity.
Sulphur dioxide
It is a colorless gas with irritating smell. It dissolves in rain water and causes acid rain. Exposure to sulphur dioxide causes breathing difficulties, pneumonia, lung cancer, etc.
Sulpher dioxide causes:
- Severe respiratory problems such as asthma,
- Chronic bronchitis, degraded lung function
- Respiratory failure
- Cardiovascular diseases
- Cancer
Oxides of Nitrogen
Oxides of nitrogen are all toxic gases. They dissolve in rain water to cause acid rain. They have severe effects of lungs and damage them.
- Sulphur dioxide destroys chloroplast in plants. As a result, the photosynthesis and plant growth are affected.
