Acid rain acidifies the soils and waters where it falls, killing plants, fish, and the animals that depend on them. Acid rain also causes property damage through the corrosion of buildings and monuments. VOCs react in the presence of nitrogen oxides and sunlight to form ground-level ozone, a major component of smog. Ozone irritates the eyes, damages the lungs, and aggravates respiratory problems. It is our most widespread and intractable urban air pollution problem.
Ozone also reduces agricultural production and the growth rate of trees.
A number of exhaust VOCs are also toxic, with the potential to cause cancer, nerve damage, and other health effects. Benzene, a known human carcinogen, is an example of a toxic VOC found in vehicle exhaust. People of highest risk of these effects include asthmatics, individuals with chronic heart or lung disease, as well as children and the elderly. Ultrafine PM easily makes its way past the upper airway, and penetrates into the deepest tissues of the lungs, where accumulation can occur. SO 2 also contributes to the formation of acid rain.