News Earth New Recipe for Pollution Stew: Another chemical culprit adds to ozone By Sid Perkins March 19, 2008 at 12:46 pm - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print A chemical reaction long assumed to be unimportant in urban air quality may be a significant source of ozone, the major component of smog. Hydroxyl (OH) radicals, among the most reactive natural chemicals in the atmosphere, help cleanse the air of some noxious pollutants.