Beijing has opted to include unhealthy "haze" levels in daily weather forecasts from Thursday to warn people about air pollution, according to an official with the Beijing Municipal Meteorological Station (BMMS).
Haze refers to weather with air humidity of 80 percent or below, noted Guo Hu, head of BMMS, and should not be confused with fog, which occurs when humidity in the air is above 90 percent.
Haze forms when concentrations of dust and smog in the air are high.
Haze will be classified light, moderate and heavy in the forecasts. Light haze means that outdoor visibility is between five and ten kilometers; with moderate haze visibility is between two and five kilometers; and heavy haze means visibility is less than two kilometers, said Guo.
Experts said that haze contains substances harmful to the respiratory tract and lungs so that people should stay indoors during moderate and heavy haze days. Long exposure to haze will lead to coryza, bronchitis and even lung cancer. Besides, gloomy hazy days could make people depressed and affect their mental health.
Beijing reported 10 hazy days last December, or one-third of the total recorded in the capital last year.
Shi Hanmin, head of the Beijing Municipal Environmental Protection Bureau, said local environmental authorities would take further steps to control air pollution and had set an ambitious target of 245 "blue sky" days this year after beating the 2006 goal of 238 days with fairly good air quality.
Beijing reported 20 days with "blue sky" in January, up 82 percent over the same period last year, but sulfur dioxide days also tripled to 9 days, according to Bureau statistics.
Beijing launched its "Defending the Blue Sky" program in 1998, when the city had only about 100 days of "blue sky" a year.
(Xinhua News Agency February 2, 2007)