Chapter 14: Resource Issues Key Issue 2: Why are resources being polluted? Rubenstein, pp. 451-459 AIR POLLUTION 1. Earth?s average atmosphere comprises _____________% nitrogen, _________% oxygen and less than ____% argon. The remaining _____% includes several ____________________, some of which are critical. 2. What are the most common air pollutants are: 3. Explain the three human activities that generate the most air pollution. 4. How does Global Warming occur? Explain the process. 5. Why is the term ?greenhouse effect? somewhat misleading? 6. Explain the impact of global warming to polar ice caps and precipitation. 7. Define chlorofluorocarbons (CFC?s):