| __ | 1. | atmosphere | | A. | mass of air surrounding Earth |
| __ | 2. | contaminant | | B. | an element that pollutes |
| __ | 3. | environment | | C. | impurities in the air, water and land |
| __ | 4. | ozone | | D. | all that exists around us |
| __ | 5. | pollution | | E. | a colorless gas that reacts with sunlight |
| __ | 6. | respiratory | | F. | ground level fog mixed with smoke |
| __ | 7. | smog | | G. | second layer of the Earth's atmosphere |
| __ | 8. | stratosphere | | H. | layer of Earth's atmosphere closest to the ground |
| __ | 9. | toxic | | I. | something that is poisonous or deadly |
| __ | 10. | troposphere | | J. | anything that has to do with breathing |