Bright city lights exacerbate air pollution

BBC : At night, ozone, carbon monoxide, and other pollutants emitted by cars and factories are broken down by highly reactive nitrate radicals. That cleanup operation would be more effective if upward-pointing street lights didn’t destroy nitrate radicals, argued Harald Stark of the US National Oceanic and Atmospheric Administration in a talk he gave at this week’s meeting of the American Geophysical Union. Stark and his colleagues reached that conclusion after analyzing data gathered from aircraft flying over Los Angeles.