Atmospheric pollutants
Pollutants from burning fuels
Most fuels, including coal, contain carbon and often sulfur. Burning them releases gases and particles into the atmosphere: carbon dioxide, water vapour, , , , and (tiny solid particles such as soot) along with unburned hydrocarbons.
Key terms
Sources and effects
| Pollutant | Source | Effects |
|---|---|---|
| (CO) | of fuels | Toxic: it stops the blood carrying oxygen. It is colourless and odourless, so it is hard to detect |
| (carbon particulates) | Incomplete combustion | (less sunlight reaches the ground) and lung damage |
| (SO₂) | Burning fuels that contain sulfur impurities, such as coal | and breathing problems |
| (NOₓ) | Nitrogen and oxygen from the air reacting at the high temperatures in engines | Acid rain and breathing problems |
Carbon monoxide detectors are fitted near gas boilers because the gas can't be seen or smelled.
Key terms
Acid rain
Sulfur dioxide and oxides of nitrogen dissolve in water droplets in clouds to form acids, which fall as .
Acid rain:
- damages buildings and statues, especially those made of limestone
- kills trees and other plants
- makes lakes and rivers acidic, harming fish and other aquatic life
It can be reduced by removing sulfur from fuels before they are burned, and by fitting to cars to reduce oxides of nitrogen.