SHANGHAI/BEIJING The dark haze of pollution enveloping Beijing is not only a serious health hazard, it also disrupts daily life. "When pollution is really severe, schools close down and I have to ask for leave from work to take care of my 8-year-old daughter," said Zhang Caixia, a 34-year-old mother of two who lives in the Chinese capital. "It's affecting my life a lot."
In Beijing, concentrations of PM2.5 -- fine particles of dust, dirt, soot, smoke and liquid droplets that are suspended in the air and are considered especially hazardous -- briefly exceeded 1,000 micrograms per cubic meter at the end of last year, 40 times the World Health Organization's recommended guidelines for 24-hour average levels. The high concentrations have also affected economic activity, in some cases preventing aircraft from taking off and landing.