Role of Atmosphere in Climate Control
The air is a bad conductor of heat. The atmosphere prevents the sudden increase in temperature during the daylight hours. And during the night, it slows down the escape of heat into outer space The atmosphere keeps the average temperature of the Earth fairly steady during the day and even during the course of the whole year. In the moon there is no atmosphere. So there is no steady temperature.
Every life on the earth needs clean air. But air is contaminated with particulate pollutants (tiny particles of solid and liquid matter) and harmful gases. Air pollution is caused by industries, automobiles, burning of fuels like coal, wood, oil etc.