Health Sep 23

Buildings are seen in heavy haze in Beijing's central business district, January 14, 2013. Photo by Jason Lee/REUTERS
U.N. health agency sets higher, tougher bar for air quality

Since the last update, better monitoring and science has cleared up the global picture about the effects of six air pollutants on human health. The agency says 90% of the world's people already live in areas with at least one…