What is photochemical smog?

Question

How is photochemical smog formed?

Answer 1

1. The term ‘smog’ is used to describe a combination of smoke and fog.
2. Thermal inversions (a layer of warm air settling over a layer of cool air) prevent the smoke produced by various sources from escaping into the upper atmosphere.
3. In combination with fog produced by humidity, the air becomes unhealthy and the visibility becomes very poor.
4. Once settled, the smog lasts for many days. The most dangerous constituents of smog is sulphur dioxide (SO₂).
5. It affects the respiratory system of people.
6. Smog also destroys plant life and cause the building material to decay.
7. In human beings, it increases the chances of lung cancer, fatigue, bronchitis and cardiac failure.

Hydrocarbons+ Oxides of nitrogen → Peroxy acetyl nitrate