Major air pollutants include nitrogen oxide, which is created through combustion, carbon monoxide, which is a byproduct incomplete combustion, and sulfur dioxide, which comes from the sulfur contained in coal and oil.
The benefits of clean air are fewer illnesses, a healthier respiratory system, and reduced exposure to dust, smoke and other contaminated particles.
Photochemical smog accumulates in the troposphere in the presence of sunlight when nitrogen oxides and volatile organic compounds are present.
The gray smog of older industrial cities like London and New York derives from the massive combustion of coal and fuel oil in or near the city, releasing tons of ashes, soot, and sulfur compounds into the air.
The characteristic brown smog of Los Angeles and Denver in the late 20th century is caused by automobiles. Nitric oxide from automobile exhaust combines with oxygen in the air to form the brown gas, nitrogen dioxide.
Innovative Pollution Control
Hydrogen powered engines for cars, choosing fuels that contain fewer impurities, and allow pollution permits to be bought and sold on free markets to bring down emissions in a cost-efficient way are a few examples of innovative pollution control.