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