The lights prevent production of a particular type of nitrogen-oxide molecule known as a nitrate radical, which forms from reactions of nitrogen dioxide with ozone.

Changing the type of lighting wouldn't have much impact, the scientists suspect, unless cities would use red lights, which don't interfere with nitrate radical formation.

The only quick solution, says the scientists working at NOAA, would be to swap out all the lamps with red lights, which wouldn't interfere with nitrate radical formation.