Atmospheric chemist Kenneth Rahn regularly travels to China to consult with scientists there about the country's air pollution problem. Rahn took your questions about pollution in Beijing during the run-up to the Olympic Games.
As the 2008 Olympic Games approach, Chinese officials have issued emergency orders pulling cars off the road and temporarily shutting down factories in an attempt to reduce Beijing's notorious air pollution. But on Monday -- four days before opening ceremonies are set to begin -- smog levels shot up again after a relatively clear weekend.
Atmospheric chemist Kenneth Rahn, an emeritus professor at the Center for Atmospheric Chemistry Studies at the University of Rhode Island, regularly travels to China to work with Chinese scientists studying air pollution. Rahn answered your questions about air pollution in China and Chinese officials' attempts to combat it.
Transcript: Beijing's Pollution a Contentious Foe for Olympic Athletes