GENERAL AIR POLLUTANTS

PRERNA FOR IAS

GENERAL AIR POLLUTANTS

(ECOLOGY AND ENVIRONMENT)

1. Primary Pollutants

Primary pollutants are harmful substances released directly into the atmosphere from natural or human-made sources. Common examples include carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen oxides (NOₓ), particulate matter, and hydrocarbons. Major sources are vehicle exhausts, industries, power plants, forest fires, and volcanic eruptions. These pollutants can immediately affect air quality and human health. Carbon monoxide reduces oxygen transport in blood, while sulfur dioxide irritates the respiratory system. Primary pollutants may also react with other atmospheric substances to form secondary pollutants. Controlling emissions at the source is the most effective strategy for reducing primary air pollution.

2. Secondary Pollutants

Secondary pollutants are not emitted directly into the atmosphere but form through chemical reactions involving primary pollutants. Sunlight often drives these reactions. Examples include ground-level ozone, photochemical smog, and certain acids responsible for acid rain. Nitrogen oxides and volatile organic compounds react in sunlight to produce ozone near the Earth’s surface. Secondary pollutants can spread over large areas and have serious environmental and health impacts. They may damage crops, forests, buildings, and aquatic ecosystems while causing respiratory problems in humans. Reducing secondary pollutants requires controlling the primary pollutants that act as their precursors.

3. Common Causes of Air Pollution

Air pollution originates from both natural and human activities. Human causes include vehicle emissions, industrial smoke, power plants, construction activities, agricultural practices, and household fuel burning. Natural causes include volcanic eruptions, forest fires, dust storms, and pollen release. Urbanization and industrialization have greatly increased pollution levels worldwide. Burning fossil fuels releases gases and particulate matter that degrade air quality. Agricultural activities contribute methane and ammonia emissions. Indoor sources such as cooking fuels, paints, and cleaning chemicals also affect health. Understanding pollution sources helps governments and communities design effective measures to reduce emissions and improve environmental quality.

4. Carbon Monoxide (CO) Pollution