The old chestnut about the Great Wall of China being visible from space is just a legend, but something man-made is visible to orbiting satellites: Chinese smog.
NASA’s Terra satellite recently captured an image of the eastern coast of China swathed in a mixture of natural fog and unnatural smog, with the pollution clearly discernible as streaks of white and gray. On the day the image was captured, Dec. 7, pollution monitors operated by the U.S. embassy in Beijing and the U.S. consulate in Shanghai respectively recorded PM 2.5 readings of 480 and355 micrograms per cubic meter of air in the two cities. According to the World Health Organization, PM 2.5 levels below 25 are regarded as safe.
Shanghai experienced one of its worst bouts of air pollution in recent memory earlier this month, leading to road and school closures as well as canceled and delayed flights. “This is a shock,” Robert Theleen, chairman of the American Chamber of Commerce in Shanghai, told Bloomberg News. “There was a perception that Shanghai was doing a better job in controlling pollution than Beijing.” That’s no longer the view from low-earth orbit, it seems.