Pollutant is a substance that pollutes something, especially water or the atmosphere. It can enter the environment naturally, such as from volcanic eruptions, or through human activities, such as burning coal and gasoline. Here, we are giving the list of Major Pollutant, their sources and their effects on Humans and Environment for general awareness.

List of Major Pollutant, their sources and their effects on Humans and Environment:

1. Oxides of Carbon (COx)
Types: Carbon dioxide (CO2), Carbon monoxide (CO)
Sources of Production: Combustion of coal, oil and other fuels for energy production manufacturing and transport Biomass burning.
Effects on Humans and Environment: C02 has a major role in green-house effect, produces weak carbonic acid adding to acid rains; CO affects human health by binding to hemoglobin, which may result in asphyxia; hemoglobin has 250 times more affinity with CO as compared to that of O2.

2. Oxides of sulphur (SOx)
Types: Sulphur dioxide (SO2); Sulphur trioxide (SO3); Sulphate (SO4)
Sources of Production: Combustion of sulphur containing fuel e.g., coal, petroleum extraction and refining; paper manufacturing; municipal incinerating; ore smelting for metal extraction
Effects on Humans and Environment: SO2 has maximum deleterious effects as it damage to human and other animal lungs and is important precursor to acid rain; adverse effects include corrosion of paint, metals and injury or death to animals and plants.

3. Oxides of Nitrogen (NOx)
Type: Nitrogen oxide (NO); Nitrogen dioxide (N02); Nitrous oxide (N20) ; Nitrate (N03)
Sources of Production: Burning of fuels; biomass burning; by product in the manufacturing of fertilizers
Effects on Humans and Environment: Form the secondary pollutants: peroxy acetyl nitrate (PAN) and nitric acid (HNO3); suppression of plant growth and tissue damage; cause irritation to eyes, viral infections like influenza; nitrate form in atmosphere impairs the visibility whereas in soil promotes the plant growth.

4. Hydrocarbons (HCs) also called Volatile organic compounds (VOCs)
Types: Methane (CH4), Butane (C4H10), Ethylene (C2H4), Benzene (C6H6), Propane (C3H8)
Sources of Production: Evaporation from gasoline tanks, carburettors; burning of fuels; biomass; municipal lard fills; microbial activity of sewage; industrial process involving solvents changes that occur in.
Effects on Humans and Environment: Can have carcinogenic effect on humans; higher concentrations are toxic to plants and animals; can convert into harmful compounds through complex chemical atmosphere; some are more reactive with sunlight and produce photochemical smog.

5. Other organic compounds
Types: Chlorofluoro carbon (CFCs), Formaldehyde (CH20), Methylene chloride (CH2Cl2), Trichloro Ethylene (C2HCl3), Vinyl chloride (C2H3C1), Carbon tetra chloride (CC14), Ethylene Oxide (C2H40)
Sources of Production: Aerosol sprays; foam and plastics for making disposable fast food containers; refrigeration
Effects on Humans and Environment: CFCs cause reduction in stratospheric ozone that allows greater penetration of ultraviolet light at earth surface; intensified UV radiations cause skin cancer and can have lethal effects on various; life forms.

6. Metals and other inorganic Compounds
Types: Lead (Pb), mercury (Hg), Hydrogen sulphide (H2S), Hydrogen Fluoride (HF)
Sources of Production: Oil wells and refineries; transport vehicles; municipal landfills; fertiliser, ceramic, paper, chemical and paint industries pesticides; fungicides; aluminium production; coal gasification
Effects on Humans and Environment: Cause respiratory problems, toxicity and even death to humans and other animals; damage to crops; prove to be carcinogenic.

7. Liquid droplets
Types: Sulphuric acid (H2S04), Nitric acid (HNO3) –Oil, Pesticides e.g. DDT and Malathion
Sources of Production: Agriculture pesticides; fumigation; oil refineries; reactions of pollutants in the atmosphere
Effects on Humans and Environment: Contribute to acid rains; corrosion; damage to various life forms

8. Suspended particulate Matter (SPM-solid Particles)
Types: Dust, soil, sulphate Salts, heavy metal salts, Fire particles of carbon (soot), silica, asbestos, Liquid sprays, mist etc.
Sources of Production: Fuel combustion; building constructions; mining; thermal power stations; stone crushing; industrial processes; forest fires; refuse incineration.
Effects on Humans and Environment: Have chronic effects on respiratory system; deposition on the surface of green leaves thus interfering with absorption of C02 and release of 02; blocking of sunlight; particles size that range between 0.1 to 10um, cause greatest lung damage

9. Photochemical oxidants
Types: Ozone (03), Peroxyacly Nitrates (PANs),
Sources of Production: Photochemical reactions in the atmosphere that involve sunlight, oxides of nitrogen and hydrocarbons.
Effects on Humans and Environment: Produce haze; irritation to eyes, nose and throat; respiratory problems; blocking of sunlight