acid rain and smog are said to be constituents of air pollution . how are they caused .what are the ill effects of breathing polluted air on human health.

Acid rains are caused by release of SO₂ and NO₂ in air which reacts with water to form acids during rain.
Smog is caused by mixing of smoke in fog during cold temperatures.

Polluted air has many health hazards mainly fatigue, asthma, lung infections and sometimes even cancer.