The chemical cycles in the troposphere along with pollutants of human and natural origin can alter the composition of the air and effect local, regional and global environmental quality, according to a Penn State researcher. In the atmosphere, a complex series of chemical reactions can alter some pollutants so that they rain out as aerosol particles or acid rain and clear the air. Other compounds remain in the air, changing, and changing again as other chemicals cause reactions. These compounds can also be transported great distances before descent, possibly influencing the chemistry of remote regions.
Ozone is complicated.
In the stratosphere it serves to protect life from the detrimental effects of the sun's ultraviolet radiation. At ground level, it is a pollutant implicated in respiratory problems and eye irritation. Sunlight breaks ozone apart resulting in the creation of the very reactive hydroxyl radical which begins the process that removes some pollutants from the air. However, when hydroxyl radicals break down some compounds, they produce other hydrogen oxides, which react with other pollutants and form ozone. The sun then breaks down this ozone, creating hydroxl radicals and starting the cycle all over again.