Via NASA's Terra satellite comes a staggering view of China's pollution problem.
China suffered another severe bout of air pollution in December 2013. When the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite acquired this image on December 7, 2013, thick haze stretched from Beijing to Shanghai, a distance of about 1,200 kilometers (750 miles). For comparison, that is about the distance between Boston, Massachusetts, and Raleigh, North Carolina. The brightest areas are clouds or fog. Polluted air appears gray. While northeastern China often faces outbreaks of extreme smog, it is less common for pollution to spread so far south.
"The fog has a smooth surface on the top, which distinguishes it from mid- and high-level clouds that are more textured and have distinct shadows on their edge," explained Rudolf Husar, director of the Center for Air Pollution Impact and Trend Analysis at Washington University. "If there is a significant haze layer on top of the fog, it appears brownish. In this case, most of the fog over eastern China is free of elevated haze, and most of the pollution is trapped in the shallow winter boundary layer of a few hundred meters."
At the time this image was captured, the air quality index (AQI) had reached 487 in Beijing and 404 in Shanghai. An AQI above 300 is considered hazardous to humans.