Air Pollution: Sources, Types, and Global Impact
Sources of Air Pollution
1. Natural Sources
Volcanic eruptions release sulfur compounds, carbon, and particles. Natural forest fires emit CO2 and ash. Windblown sand in eroded areas contributes to particle pollution.
2. Anthropogenic Sources
Human activities are the primary source of air pollution. These activities release pollutants directly or indirectly, such as deforestation, mining, and quarrying, which contribute to particle pollution. Arson also releases gases and ash.
- Transportation: Emits CO2, hydrocarbons, sulfur oxides, and metals.
- Industrial Processes: A major source of various pollutants, including sulfur oxides, carbon oxides, nitrogen oxides, particles, smoke, hydrocarbons, and specific contaminants like ammonia compounds and acid aerosols.
- Domestic Heating: Releases sulfur oxides, nitrogen oxides, and carbon particles.
Pollutants
Pollutants are substances that alter the natural composition of the atmosphere, causing harm to living organisms and ecosystems when present in high concentrations.
Types of Pollutants
- Particles (Aerosols): Dust and smoke particles that remain suspended in the atmosphere for extended periods.
- Metals: Heavy elements found in small concentrations, considered hazardous due to their persistence and accumulation in food chains.
- Gases:
- Sulfur Oxides: Primarily SO2 and SO3, produced by burning fossil fuels in industrial processes and power plants.
- Hydrogen Sulfide (H2S): A toxic gas with an unpleasant odor, emitted from industrial processes and wastewater treatment.
- Nitrogen Oxides: NO and NO2, formed during high-temperature combustion processes.
- Carbon Oxides:
- Carbon Monoxide (CO): Produced by incomplete combustion of organic matter.
- Carbon Dioxide (CO2): Essential for photosynthesis but contributes to the greenhouse effect when emitted in excess.
- Organic Compounds: Volatile organic compounds (VOCs) released from various sources, including evaporation of organic substances.
- Halocarbons: Compounds containing chlorine, fluorine, or bromine, such as Freon.
Photochemical Smog
Formed when hydrocarbons and nitrogen oxides react in the presence of sunlight. Ozone and peroxyacetyl nitrate (PAN) are major components, causing eye and respiratory irritation, and plant damage.
Acid Rain
Caused by emissions of sulfur and nitrogen oxides, which react with water vapor to form sulfuric and nitric acids. Acid rain damages vegetation, animals, and materials.
Noise Pollution
Excessive noise, primarily from transportation and construction, can cause adverse health effects, including hearing loss.
Global Impact: Greenhouse Effect
The greenhouse effect is the warming of the Earth’s surface due to the trapping of heat by greenhouse gases (CO2, CH4, O3). This phenomenon is exacerbated by human activities, leading to climate change.