1. 1.Which gases in Earth’s atmosphere are breathable? 2.How does the ozone layer protect our planet? All the gases in Earth’s atmosphere are breathable. However, some may be harmful to the biosphere (smog, other air pollution). The ozone layer protects our planet by absorbing most of the UV radiation from the sun. However, some UV rays still penetrate through to the surface and are harmful to the biosphere.

2. STRUCTURE & FEATURES OF ATMOSPHERE

6. Why do we still get sunburns?

7. Sunscreens block UVA/UVB rays (check labels for SPF 50)

8. Ozone layer amounts over Antarctica

9. Propellants with chlorofluorocarbons (CFCs)

10. Liquid used in refrigerators, cars, AC systems (freon)

12. Los Angeles, CA Beijing, China Athens, Greece