2.4 Particulate Matter
2.4.1 particles of different sizes and structures that are released into the atmosphere
2.4.2 present in many sources including fossil fuels, dust, smoke, fog, etc.
3. The causes of pollution in the air
3.1 Natural
3.1.1 Smoke from forest fires
Chemicals caused by burning sometimes to harmful substances and spread out into the air
3.1.2 Volcanic eruptions
The chemicals in the smoke will react get the chemical is toxic spread out into the air.
3.1.3 Dust storm
Will blow harmful substances come together and spread in the air.