Looking up at the night sky in the city, even if the sky is clear, there are fewer and fewer stars to be seen, mainly due to the light pollution from the bright lights of the city at night. However, scientists have recently discovered that light pollution is not only causing problems for astronomers, but may even make air pollution worse and worse around the world.

According to a study by the National Oceanic and Atmospheric Administration of United States, a chemical called nitrate (commonly referred to as the anion of nitrate) is limited and hindered by street lights, which can break down harmful gases emitted by cars and factories.

United States research tests conducted in Los Angeles by Harald ·Stark, a scientist at the National Oceanic and Atmospheric Administration, have shown that light from buildings, streetlights, and car lights can have an inhibitory effect on nitrates. "Our preliminary findings prove that city lights can slow down cleaning at night by 7% and increase the starting chemicals that cause ozone pollution by 5% the next day." "The next step for us is to quantify more accurately the impact, which is how much ozone our city actually produces the next day," Stark said. It is important to carry out this work because many cities are already approaching the limit of ozone control levels, so even a very small reaction like this can have a huge impact. ”

Although the light is much dimmer than the sun's, it can still have undesirable effects that are hard to ignore. To this end, Stark suggested a possible solution by changing the color of the light to a less impactful red, but this may not be practical. Stark had an easier remedy, changing the direction of the light to downwards. Because the fewer lights facing upwards, the less impact there is on nitrate in the atmosphere. Li Zhongdong