environment

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Across
  1. 4. a kind of sound that disturbs others
  2. 5. use sth more than once
  3. 7. the gas we need every second
  4. 8. the mass of air surrounding the Earth
Down
  1. 1. the substance that covers the earth's surface
  2. 2. air pollution that reduces visibility
  3. 3. the measurement of the air
  4. 6. prevent sth from destruction