(a) The most straight forward way to reduce or prevent the formation of photochemical smog is to minimise the release of oxides of nitrogen and hydrocarbons to the atmosphere.
The following methods can be applied to minimise the oxides of nitrogen and hydrocarbons.
(i) By fitting efficient catalytic converters in automobiles, the harmful gases are converted catalytically into harmless gases.
(ii) By spraying certain compound into the atmosphere which generate free radicals that readily combine with the free radicals that initiate the reactions forming toxic compounds of the photochemical smog.
The compound diethyl hydroxylamine has been found to posses smog inhibiting property.
(iii) Certain plants such as pinus, juniparus, pyrus, irtis etc., can metabolise oxides of nitrogen.
(b) Solvents used to dryclean clothes are usually chlorinated compounds which are carcinogen. Suitable detergents which work in liquid carbon dioxide have been discovered to replace the chlorinated compounds.
For bleaching of clothes in laundry, H2O2 and not Cl2 is used which gives better results and is not harmful. Earlier, Cl2 gas was used for bleaching paper. Chlorine is highly toxic in nature. Its use has been replaced by H2O2 in presence of a suitable catalyst.
(c) To reduce the use of synthetic detergents as cleaning agent, emphasis should be made on the use of soaps prepared of vegetable oils. The vegetable oils are biodegradable while detergents do not undergo biodegradation.
(d) Instead of petrol and diesel, the use of CNG (Condensed Natural Gas) and LNG (Liquified Natural Gas) has been preferred as they are pollution free fuels.
The other sources such as hydrogen, ethyl alcohol, etc., can be tried in place of petrol and diesel.
