Question

How are pollutants classified?

Answer 1

1. By degradability: Biodegradable pollutants, e.g., sewage, domestic waste, and Non‑biodegradable pollutants, e.g., plastics, pesticides, heavy metals.
2. By origin/formation: Primary pollutants emitted directly from sources e.g., smoke, SO₂, CO) and Secondary pollutants formed in the environment by reactions of primary pollutants e.g., ozone, PAN.
3. By existence in nature: Quantitative pollutants (natural components that become harmful at high concentrations, e.g., CO₂ and Qualitative pollutants substances not normally present, introduced by humans, e.g., industrial effluents.
4. By physical/state: Gaseous (CO₂, NOx, SOx), particulate dust, soot, fly ash, liquid/effluent, thermal, noise, and radioactive pollutants.
5. By source: Natural volcanic eruptions, forest fires, dust storms vs. man‑made/anthropogenic vehicles, industries, agriculture.
6. By environmental medium affected: Air pollution, water pollution, soil (land) pollution, radiation pollution, and noise pollution.