The formation and inhibition of photochemical smog.

Photochemical smog is caused by a free-radical chain mechanism which converts NO to NO2. The NO2 further reacts to produce ozone, nitric acid, and peracylnitrates. This chain mechanism can be inhibited by suitable free-radical scavengers. The chemistry and toxicology of one such free-radical scavenger, diethylhydroxylamine, has been studied in depth. It has been shown to be effective, safe, and practical for use in urban atmospheres to prevent photochemical smog formation.