Write short notes on Photochemical smog.
Answers
Photochemical smog is type of smog produced by ultraviolet light from sun which reacts with nitrogen oxides in atmosphere.
Its visible as brown haze and is prominent during morning and afternoon specially in densely populated and warm cities.
Cities experience this smog daily which includes Los Angeles, Sydney, Mexico City, Beijing.
Photochemical smog forms complex process however source is quite apparent.
Largest contributor is automobiles but coal-fired power plants and other power plants produces necessary pollutants to facilitate its production.
Smog abundance in warmer temperatures whereas photochemical smog is common in summer.
It occurs in morning when tremendous number people are driving their vehicles to work.
Nitrogen oxides emitted by car engine are introduced into atmosphere which combines with water forming nitric acid or reacts with sunlight forming oxygen atoms.
Nitric acid precipitates to Earth resulting in acid rain or stays inside smog.
Direct production of it by vehicles smog forms over cities where peoples encounters adverse health effects.