A dangerous part of London-type smog is sulfur dioxide, a gas that attacks the lungs and makes breathing difficult. For this reason, London-type smog is sometimes called sulfur smog. Photochemical smog involves the action of sunlight on hydrocarbons and nitrogen oxides in the air. These compounds are chemicals formed by the burning of gasoline and other petroleum products. When activated by sufficient sunlight, the compounds undergo a chemical reaction that produces gases called oxidants.
Ozone forms the most abundant oxidant in photochemical smog.
It can irritate the eyes, nose, and throat and damage the lungs. How to cite this article.