AdvertisementWhy China's Pollution Could Be Behind Our Cold, Snowy WintersMarch 08, 2015Michaeleen DouclefffacebookEmailA lot of the airborne particles in the Earth's atmosphere come from natural sources, such as desert dust (red-orange) and sea salt (blue). But there's also soot from fires (green and yellow) and sulfur emissions (white) from burning fossil fuel. (NASA/Goddard)