Which is always present in photochemical smog?
O3
CO2
SO2
CH4
A.
O3
Photochemical smog occurs at high temperature due to stull air, emission of nitrogen oxides and hydrocarbons. Nitrogen dioxide (NO2) splits into nitric oxide and nascent oxygen.
Nascent oxygen combines with molecular oxygen to form ozone. This further reacts with hydrocarbons to form aldehydes and ketones.
NO2, O2 and ketones combine to form Peroxy Acyl Nitrates (PAN) which is responsible for eye irritation. Therefore, first reported in Los Angeles, so called Los Angeles Smog.
Classical (London) Smog was reported in London. It occurs at low temperature which contains sulphur gases, smoke and dust particles.
