Across
- 5. carbon, oxygen, and nitrogen
- 7. produced by burning fossil fuels
- 9. a pollutant created by substances of natural origin
- 10. when tail pipes of cars burn gasoline
Down
- 1. carbon dioxide traps heat through the sun
- 2. when pollutants is emitted by cars,poor plants,industrial boilers,etc.
- 3. the state of the air around us
- 4. describes two distinct but related phenomena observed since the late 1970's
- 6. an agency whose mission is to protect human and environmental health
- 8. a gradual increase in the overall temperature of the earth's atmosphere