Question

How does classical smog differ from photochemical smog?

Answer 1

• Classical smog:

1. Classical smog is caused by coal smoke and fog.
2. It occurs in cold humid climate.
3. The chemical composition is the mixture of SO₂, SO₃ gases and humidity.
4. Chemically it is reducing in nature because of the high concentration of SO, and so it is also called reducing smog.
5. It is primarily responsible for acid rain.
6. It also causes bronchial irritation.

• Photochemical smog:

1. Photochemical smog is cause by photochemical oxidants.
2. It occurs in warm, dry and sunny climate.
3. The chemical composition is the mixture of NO₂ and O₃ gases.
4. Chemically it is oxidising in nature because of the high concentration of oxidising agents such as NO₂ and O₃
5. and so it is also called oxidizing smog.
6. It causes irritation to eyes, skin and lungs and increases the chances of asthma.
7. It causes corrosion of metals, stones