This topic will cover the definition of air pollution, its sources, types, and the impact it has on human health and the environment.
Introduction to Air Pollution
Key concepts, sources, impacts, and mitigation strategies
| Definition | Air pollution is the presence of substances in the atmosphere that are harmful to human health, ecosystems, or the climate. |
|---|---|
| Primary vs. Secondary | Primary pollutants are emitted directly from a source (e.g., CO₂ from a factory). Secondary pollutants form in the atmosphere through chemical reactions (e.g., ozone O₃ formed from NOₓ and VOCs). |
| Units of Measurement | Concentrations are usually expressed as µg m⁻³ (micrograms per cubic meter) or ppm (parts per million). |
| Category | Common Examples | Typical Sources | Main Health/Environmental Effects |
|---|---|---|---|
| Particulate Matter (PM) | PM₂.₅ (≤2.5 µm), PM₁₀ (≤10 µm) | Combustion (vehicles, power plants), dust, construction | Respiratory & cardiovascular disease, reduced visibility |
| Gaseous Pollutants | • Sulfur dioxide (SO₂) • Nitrogen oxides (NOₓ) • Carbon monoxide (CO) • Ozone (O₃) • Volatile organic compounds (VOCs) |
Fossil‑fuel combustion, industrial processes, vehicle exhaust, solvent use | Acid rain (SO₂, NOₓ), smog (O₃, VOCs), impaired oxygen transport (CO) |
| Heavy Metals | Lead (Pb), Mercury (Hg), Arsenic (As) | Mining, smelting, waste incineration, coal combustion | Neurological damage, kidney dysfunction, bioaccumulation |
| Greenhouse Gases (GHGs) | Carbon dioxide (CO₂), Methane (CH₄), Nitrous oxide (N₂O) | Fossil‑fuel use, agriculture, waste | Global warming, climate change impacts |
| Sector | Typical Emissions | Representative Activities |
|---|---|---|
| Energy production | SO₂, NOₓ, CO₂, PM | Coal‑fired power plants, natural‑gas turbines |
| Transportation | CO, NOₓ, VOC, PM₂.₅ | Cars, trucks, ships, aircraft |
| Industry & Manufacturing | VOC, heavy metals, PM | Steel mills, chemical plants, cement factories |
| Agriculture | NH₃, CH₄, N₂O | Livestock, fertilizer application, rice paddies |
| Residential | CO, PM, VOC | Cooking, heating with solid fuels, biomass burning |