Beijing authorities said they had met their target of "blue sky" days for 2011, amid growing public criticism that officials are underplaying the pollution problem in the Chinese capital.
Japanese workers tackling the Herculean task of clearing millions of tonnes of debris from last month's earthquake and tsunami also face health risks from asbestos and dioxins.
Millions of Chinese went online Tuesday to vent their anger over the thick smog that has blanketed Beijing in recent days, raising health fears and causing hundreds of flights to be cancelled.
Beijing's government on Friday bowed to a vocal online campaign for a change in the way air quality is measured in the Chinese capital, one of the world's most polluted cities.
Every two minutes on the bus ride through the ghost towns surrounding Japan's Fukushima Daiichi nuclear plant, a company guide in a white protective suit holds up a display showing the radiation level. And it is rising.
China has cleaned up its air before but experts say that if it wants to avoid the kind of smog that choked the country this week, it must overhaul an economy fuelled by heavily polluting coal and car use.
Two-thirds of high-street garments tested in a study by Greenpeace contained potentially harmful chemicals, the group said Tuesday, highlighting the findings with a "toxic" fashion show in Beijing.
China is considering a ban on barbecues to help reduce air pollution in built-up areas after heavy smog recently choked large swathes of the country, state media reported Wednesday.
Schools in the Chinese capital kept students indoors and parents brought their kids to hospitals with breathing ailments Tuesday as Beijing grappled with extremely severe air pollution for the fifth straight day.
Shares in a Chinese facemask manufacturer soared on Tuesday as investors looked for opportunities to profit from the severe air pollution that has blanketed large swathes of China.