If you go all-out with your Christmas light display, you might be doing more harm than good. According to a recent study presented by the US National Oceanic and Atmospheric Administration (NOAA) at the American Geophysical Union, city lights exacerbate air pollution. At night, nitrate radicals (a form of nitrogen oxide found in the atmosphere) routinely filter and abate the air of airborne pollutants. Nitrate radicals are susceptible to light, however. As a result, researchers have discovered that the glare caused by lights is in fact interfering with the normal nighttime cleansing of the air.
Our first results indicate that city lights can slow down the nighttime cleansing by up to 7% and they can also increase the starting chemicals for ozone pollution the next day by up to 5%. (BBC)
According to Dr. Harald Stark of the US National Oceanic and Atmospheric Administration (NOAA), replacing the lights with other types isn’t really a solution. He did indicate that nitrate radicals are less affected by red lighting, which might make sense this time of the year, but not during the other eleven months. A more practical option, according to Stark, would be to do what is advocated by the International Dark-Sky Association, point the lights toward the ground.
Will this news impact how you use your lights at night? How you decorate your house?