辛达雅思代报考位 ：直到2017年12月20日上午雅思官网没有释放考位，在此提醒广大考生抓紧时间报名，注意自己的考试时间，如对雅思报名有任何疑问，欢迎咨询在线客服。 

近日的塘沽爆炸让大家心有余悸，空气污染的危机始终在头顶盘旋。天气预报也一直徘徊在雷阵雨将来未来之间，雅思小编为大家带来雅思阅读精选：北京空气污染——最黑暗的一天，后附参考译文。

　　Blackest day

　　ON January 12th of last year, in an article in the print edition of TheEconomist, we reported that the public outcry over Beijing’s atrocious airquality was putting pressure on officials to release more data about more kindsof pollutants. We also noted that Chinese authorities had already embarked on awide range of strategies to improve air quality, and that they probably deservemore credit than either foreign or domestic critics tend to give them. But weconcluded with the sad reality that such work takes decades, and that “Beijingresidents will need to wait before seeing improvements.”

　　On January 12th of this year, Beijing residents got an acrid taste of whatthat wait might be like, as they suffered a day of astonishingly bad air.Pollution readings went, quite literally, off the charts. Saturday evening saw areading of 755 on the Air Quality Index (AQI). That index is based on therecently revised standards of the American Environmental Protection Agency (theEPA), which nominally maxes out at 500. For more perspective, consider that anyreading above 100 is deemed “unhealthy for sensitive groups” and that anythingabove 400 is rated “hazardous” for all.

　　Like many Beijing residents, your correspondent has mobile-phone apps thatkeep up with the pollution readings. At an otherwise pleasant Saturday-eveningmeal with friends, he joined his companions in compulsively checking forupdates.

Those previously unseen numbers were hard to believe, but they did seem tomatch up well enough with the noxious soup we could see, smell and tasteoutside. We are all far more familiar with the specifics of air-qualitymeasurement than we would like to be. Apart from the AQI readings above 700, wewere quite struck to see the readings for the smallest and most dangerous sortof particulate matter, called PM 2.5, which can enter deep into the respiratorysystem. These are named for the size, in microns, of the particles. A reading ata controversial monitoring station run by the American embassy showed a PM 2.5level of 886 micrograms per cubic metre; Beijing’s own municipal monitoringcentre acknowledged readings in excess of 700 micrograms.

　　For perspective on that set of figures, consider that the guideline valuesset by the World Health Organisation regard any air with more than 25 microgramsof PM 2.5 per cubic metre as being of unacceptable quality.

　　Chinese authorities have complained about the American embassy's insistenceon independently monitoring—and publicly reporting—Beijing’s air quality. Andsometimes much is made of the vast differences between those readings andChina’s own official ones, which are often less dire. Indeed, a key feature ofone of those mobile-phone apps is the side-by-side comparison of those competingdata-sets. (It is of course a bad sign that people here need more than one appto keep up with all this.)

　　But on a day like Saturday, the discrepancy between official readings andindependent ones hardly seemed to matter; you didn't need a weatherman to knowwhich way the ill wind blew. Or failed to blow, as the case may have been. Oneexpert quoted by Chinese media attributed this spike in pollution to a series ofwindless days that allowed pollutants to accumulate.