People will be out this weekend enjoying the holiday, and they literally can breathe easier. New satellite images from NASA show a drastic decrease in air pollution across the United States over the last decade.
Popular Science published the images last week. They focus on a pollutant called nitrogen dioxide that can cause respiratory problems and help form more ozone, “which is an irritant and pollutant at ground level.”
According to the images from NASA, it’s believed the improvement in air quality is from the improvement of fuel efficiency in cars and the scaling back of pollutants from coal power plants. Popular Science writes the reduction in pollutions goes all the way back to the 1990s after the Clean Air Act Amendment, but since 2000 there has been a roughly 50 percent decrease in levels of nitrogen dioxide.
The harshest levels of nitrogen dioxide are still centered over the major metropolitan areas of the country, where roughly 142 million people in U.S. live, according to Popular Science.