- Air pollution reduced the visibility.
- Which is conducive to air flow and circulation.
- The developed technique is applied to ambient air and automobile exhaust analysis.
- Elements which influence the urban traffic air, we design a index system and construct the grey decision model to assess the Quality of the air.
- The ambient air over the city is becoming worse.
- The air around him felt dank and airless.
- The air was still as if a whirlwind had just passed.
- Ensure there is a free flow of air around the machine.