Across
- 5. measure
- 9. cushion
- 10. approximately
- 11. carbon
- 12. sneeze
- 13. pollution
- 15. humid
- 17. contributor
- 18. protect
- 20. pollen
Down
- 1. exhaust
- 2. gasoline
- 3. meteoroid
- 4. victim
- 6. photosynthesis
- 7. coal
- 8. soot
- 14. contact
- 16. particle
- 19. smog