2. Sulfur dioxide (SO2), nitrogen oxides (NO and NO2 plus NOx), chlorofluorocarbons (CFCs).
3. Air pollutants move with prevailing wind currents; follow global wind patterns; problems generated in one area move to other areas where effects are felt.
4. Acid rain: sulfur dioxide and nitrogen oxides reacting in the atmosphere to increase acidity of rain. Results: death of trees in forests and fish in lakes.
5. Ozone (O3): in troposphere one of the major components of smog; in stratosphere, forms a radiation shield that blocks UV from reaching the surface.
6. Exposure to UV irradiation is increasing because of damage to the ozone layer -- primarily from stratospheric pollution of chlorine generated by CFCs.
7. Increase in UV irradiation increases the probability of skin cancer, cataract formation, damage to crop plants, damage to domesticated animals, and damage to natural ecosystems.