Across
- 3. measure of how acidic water is
- 4. Environmental Protection Agency
- 5. become progressively worse
- 6. invention and application of machinery
- 7. a natural gas like coal, gas and oil
- 9. possesses elevated levels of hydrogen ions
- 11. federal law that regulates air emissions
- 13. harmful substances or products
- 14. height above a given level
Down
- 1. chemical element with symbol N
- 2. removal from an office or position
- 3. a casting down or falling headlong
- 8. a chemical element with symbol S
- 10. a community of living organisms
- 12. harm caused to something