Herald Stark from the US National Oceanic and Atmospheric Administration (Noaa) reported this week from American Geophysical Union meeting in San Francisco that light pollution is making air pollution worse.
Clear evening skies contain a special form of nitrogen oxide, called the nitrate radical, which break down chemicals that would otherwise go on to form smog and ozone. The cleansing normally occurs in the hours of darkness because the radical is destroyed by sunlight. City lights that point upward also destroy these nitrate radicals.
"Our first results indicate that city lights can slow down the night-time cleansing by up to 7% and they can also increase the starting chemicals for ozone pollution the next day by up to 5%," said Harald Stark from the US (Noaa).
The Dark Sky Association has long advocated that lights be pointed toward the ground rather than upward. Their rationale to campaign for dark skies has related issues including: stolen sky (we can’t see our stars), carbon emission from lights, and disrupted bird migrations. Scientists just gave their campaign more evidence and authority.
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