air renewal

例句：

1. 1. The air in the city is becoming increasingly polluted due to heavy traffic.
   由于交通拥堵，城市的空气质量变得越来越差。
2. 2.To improve air quality, we need to reduce emissions from factories and vehicles.
   为了改善空气质量，我们需要减少工厂和车辆的排放。
3. 3. Air renewal systems are designed to remove harmful pollutants from the environment.
   空气更新系统旨在从环境中去除有害污染物。