美国把中国雾霾当教材拿到课堂，说出了雾霾的真正源头

空气质量：三城记

即便生活在霾的国度，我们仍然不了解霾。

NASA科学家Dr. Bryan N. Duncan 从太空的角度，告诉大家什么是雾霾？为什么中国雾霾如此严重？以及美国的污染历史、解决办法、现状等等。

Air Quality: A Tale of Three Cities

Dr. Bryan N. Duncan is a deputy project scientist for the Aura Mission at NASA's Goddard Space Flight Center in Greenbelt, Maryland. In this video, Duncan talks about the dynamic nature of air quality, what causes ozone, sulfur dioxide, and nitrogen dioxide, and why reducing volatile organic carbon pollution worked to reduce ozone in Los Angeles, but not in Atlanta.

https://v.qq.com/txp/iframe/player.html?vid=a03425p76p3&width=500&height=375&auto=0