What causes photochemical smog?
Photochemical smog the smog of cairo image by Elmo Palmer from Fotolia.com Smog is a term evolved from smoke and fog. Smoke emitted from factories, vehicles and domestic ovens that use coal mix up with fog and forms a thick layer in the atmosphere. Smog envelops considerable areas of towns and cities. Photochemical smog is caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust. Smog can occur both during the day and at night but photochemical smog only happens in the presence of sunlight. Photochemical smog is a widespread problem all over the world as industrial and vehicular emissions increase day by day. Conditions of Photochemical Smog Formation Photochemical smog happens when nitrogen oxides and volatile organic compounds react together in the presence of sunlight as a catalyst and form ozone at lower levels. The nitrogen oxides are emitted from vehicle exhausts and volatile organic com
