Beijing fog

Before heading out to get lunch today we looked out our window to find a layer of haze so thick outside that we couldn't see past the police station building down the street, maybe 100 yards away. Hockey friends sent screenshots over Weixin showing the US Embassy's air quality index; 799 was the highest I saw. Average in American cities is somewhere between 50 and 100; on a smoggy day, Los Angeles would hit about 120. At 500, international schools tell students to stay inside. My guess would be that 700 could be downright harmful if you were running around too much outside. Needless to say, we ordered lunch in.