You Can See China’s Smog from Space
The air quality in portions of China is so poor that the resulting smog is actually visible from outer space. Images have been captured by passing satellites that show the severity of the situation, including one period where the PM measurement was 666 micro grams per cubic meter of air.
According to the WHO, the air is only safe to breath when that measurement is below 25. That means China’s PM measurement was 25 times above the safety level at the time.