E10: Smog

by Katie Leven

1. Formation

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

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

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

1.1.3. Suffering from a temperature inversion.

2. Photochemical Smog

2.1. Most common modern type of smog

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

3. Secondary Pollutants

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

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

3.2.1. Nitric Acid

3.2.2. Peroxides ROOR

3.2.2.1. Extremely reactive

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

3.2.2.2.1. Eye irritants

3.2.2.2.2. Toxic to plants

3.2.3. Aldehydes RCHO

3.2.4. Ketones RCOR

3.2.4.1. Reduce visibility

3.3. Formation of Secondary Pollutants

4. Primary Pollutants

4.1. Nitrogen oxides

4.2. Volatile Organic Compounds (VOCs)

5. New node