E10: Smog

1. Photochemical Smog

1.1. Most common modern type of smog

1.2. Note characteristic yellow/red colour, caused by VOCs

2. Primary Pollutants

2.1. Nitrogen oxides

2.2. Volatile Organic Compounds (VOCs)

3. New node

4. Formation

4.1. Usually in large cities, especially ones that are:

4.1.1. Bowl-shaped, as this traps air/chemicals,

4.1.2. Large, with many tall buildings, as this again traps air/chemicals,

4.1.3. Suffering from a temperature inversion.

5. Secondary Pollutants

5.1. Formed by reaction of oxygen radicals with oxygen and water to form ozone and hydroxyl radicals.

5.2. These then react with a variety of molecules to form...

5.2.1. Nitric Acid

5.2.2. Peroxides ROOR

5.2.2.1. Extremely reactive

5.2.2.2. Can react with nitrogen dioxide in a Chain Reaction to form peroxyacylnitrates (PANs)

5.2.2.2.1. Eye irritants

5.2.2.2.2. Toxic to plants

5.2.3. Aldehydes RCHO

5.2.4. Ketones RCOR

5.2.4.1. Reduce visibility

5.3. Formation of Secondary Pollutants