If the gases did not absorb the Earth's heat, it would be lost in space. Celsius - too cold to sustain life. Some of the sun's rays, especially ultraviolet or UV rays, are harmful to living things. Certain gases in the atmosphere act as a sunscreen, especially ozone gas , and filter our UV rays. The atmosphere acts like a pipeline, carrying air, as well as dust particles and pollution around the globe.
Some particles are natural, like volcanic ash.
Others, like airborne pollutants, can come from human sources. The pipeline is fast and efficient, moving pollutants and particles over long distances. A dust storm in the Prairies can cast a haze clear to Canada's East Coast. Brown smog, known as Arctic Haze, is found over the High Arctic, far from where it was actually produced. It also contains many airborne particles, like dust and contaminants.