Smog warning in Beijing extended

BEIJING -- The city's 20 million people were warned Tuesday to prepare for at least another day of smog, as some factories were closed and government cars were ordered off the road after pollution hit hazardous levels.

Visibility was reduced to a few hundred yards in downtown Beijing and online sellers of face masks reported "overwhelming" demand. A U.S. Embassy pollution monitor showed that air quality reached hazardous levels for the 18th day this month.

Chinese state media have warned that the smog could threaten the country's economic growth and raises questions about policies that sacrifice the environment for the sake of development.

"You used to just open the windows to get fresh air, but now you can't do that since it's even dirtier outside," said a 40-year-old woman who gave only her last name, Zhou. She had bought two air filters for more than $2,000 each.

The concentration of PM2.5, the fine air particulates that pose the greatest human health risk, was 278 micrograms per cubic meter at 6 a.m., the U.S. Embassy said. -- Bloomberg News