China uses PM 2.5 in weather alert system

 　　BEIJING, Jan. 29 (Xinhua) -- China's meteorological authority has introduced a new weather warning system for smog which will use readings of PM 2.5, a particle pollutant¹.

　　The announcement comes as thick haze² chokes many cities.

　　The National Meteorological Center (NMC) has introduced a three-tier color-coded weather warning system to alert the public to the severity of smog. The system uses yellow to imply moderately smoggy weather, orange for severe conditions and red for extremely severe levels of smog.

　　The system not only measures the density³ of PM 2.5, a major pollutant that triggers smog, but also takes into account visibility and relative humidity to better reflect air quality conditions, according to the center.

　　The smog that has blanketed many Chinese cities in recent days has affected⁴ a total area of 1.3 million square kilometers, according to the Ministry⁵ of Environmental Protection.

　　The municipalities of Beijing and Tianjin, together with the provinces of Hebei, Shandong and Henan, will remain the hardest-hit regions on Tuesday evening through Wednesday daytime.

　　However, rain and snow that is expected to fall on Wednesday night will help disperse⁶ the smog in central and eastern regions, the NMC said.

　　Earlier this month, several consecutive⁷ days of smoggy weather choked Beijing and other cities in north and east China, as readings for PM 2.5 far exceeded safe levels.

1 pollutant   

n.污染物质，散布污染物质者

参考例句：

• Coal itself is a heavy pollutant.煤本身就是一种严重的污染物。
• Carbon dioxide may not be a typical air pollutant.二氧化碳可能不是一种典型的污染物。

2 haze   

n.霾，烟雾；懵懂，迷糊；vi.(over)变模糊

参考例句：

• I couldn't see her through the haze of smoke.在烟雾弥漫中，我看不见她。
• He often lives in a haze of whisky.他常常是在威士忌的懵懂醉意中度过的。

3 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

4 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

5 ministry   

n.(政府的)部；牧师

参考例句：

• They sent a deputation to the ministry to complain.他们派了一个代表团到部里投诉。
• We probed the Air Ministry statements.我们调查了空军部的记录。

6 disperse   

vi.使分散；使消失；vt.分散；驱散

参考例句：

• The cattle were swinging their tails to disperse the flies.那些牛甩动着尾巴驱赶苍蝇。
• The children disperse for the holidays.孩子们放假了。

7 consecutive   

adj.连续的，联贯的，始终一贯的

参考例句：

• It has rained for four consecutive days.已连续下了四天雨。
• The policy of our Party is consecutive.我党的政策始终如一。