. Photochemical smog formed in congested metropolitan cities mainly consists of
a. ozone, peroxyacetyl nitrate and NOx
b. smoke, peroxyacetyl nitrate and SO2
c. hydrocarbons, SO2 and CO2
d. hydrocarbons, ozone and SOx
Solution ||| Photochemical smog or oxydizing type of pollution is characterized by the presence of large concentration of ozone, oxides of nitrogen and various hydrocarbons. It occurs in Los Angeles. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Oxone reacts with carbohydrates (unsaturated hydrocarbons) to aldehyde and ketone. Nitrogen oxides, oxygen and ketone combine to form Peroxy Acetyl Nitrates (PAN).