SHANGHAI residents suffered poor air quality yesterday, as the fallout from a sandstorm that hit northern China this week reached the city.

The situation is expected to improve lightly" target="_blank" title="ad.轻微地；细长的">slightly over the weekend, the city's Environmental Protection Bureau said.

Air quality in Shanghai and other cities in the Yangtze River Delta was moderately polluted, the fourth in a five-level scale.

The sandstorm, which first hit areas such as Xinjiang Uygur Autonomous Region in northwest China, spread eastward to Shaanxi, Shanxi, Hebei, Shandong and Henan provinces on Thursday.

Beijing was also affected, with the sky tinged yellow. This was the first time that the capital had been affected by dust and sand-weather pollution since July.

But Shanghai will not experience sand and dust pollution as bad as Beijing, as the cold front which brought the sandstorm is moving east and will not hit the city directly, weather forecasters said.

Today is forecast to be clear, with temperatures expected to climb to 22 degrees Celsius. But, due to the cold front, they will plummet tomorrow to a high of 15 degrees, accompanied by drizzle.

From early yesterday morning, air pollution began to rise significantly, and the city seemed in a haze of dust.

Visibility in downtown Luwan and Jing'an districts and the Pudong New Area, where the air quality was rated heavily polluted, was only 3 kilometers. The index usually stays around 10 to 22 kilometers.

This week in general, air quality in Shanghai, influenced by fogs, worsened from levels recorded during the World Expo. Tuesday through to Thursday were classified as lightly polluted.

Last Sunday morning, dense fog shrouded the city, grounding many flights and forcing expressways to close and ferry services to be suspended.

It's normal for Shanghai to experience poor air quality in November due to the frequentarrival of cold fronts, the environmental bureau said.

Stubble burning, which was banned during the Expo, has resumed in some areas, contributing to poor air quality.

And dust produced by construction sites across the city, now back in operation following breaks during the Expo, also helps explain the problem.

The environmental bureau advised the elderly and people with cardio and lung diseases to stay indoorswhenever possible over the weekend and curtailstrenuous activities.

For the first three months of the Expo, Shanghai reported 121 days, or 98.4 percent of the total from May 1 to August 31, of excellent or good air quality - the top two in the air quality scale.

City environment officials hope that at least 90 percent of days in November and December can meet the standard of excellent or good air quality.

• yesterday [´jestədi] n.&ad.昨天；前不久 (初中英语单词)
• slightly [´slaitli] ad.轻微地；细长的 (初中英语单词)
• protection [prə´tekʃən] n.警戒；护照；通行证 (初中英语单词)
• bureau [´bjuərəu] n.局；编辑部；事务所 (初中英语单词)
• lightly [´laitli] ad.轻微地，稍微 (初中英语单词)
• normal [´nɔ:məl] a.正规的 n.正常状态 (初中英语单词)
• frequent [´fri:kwənt] a.常见的，频繁的 (初中英语单词)
• arrival [ə´raivəl] n.到达；到达的人(物) (初中英语单词)
• construction [kən´strʌkʃən] n.建设；修建；结构 (初中英语单词)
• whenever [wen´evə] conj.&ad.无论何时 (初中英语单词)
• northwest [,nɔ:θ´west] n.&ad.西北(部) (高中英语单词)
• indoors [,in´dɔ:z] ad.在屋里 (高中英语单词)
• environment [in´vaiərənmənt] n.郊区；周围；条件 (高中英语单词)
• weekend [´wi:kend, ,wi:k´end] n.周末休假 (英语四级单词)
• yangtze [´jæŋtsi:] n.长江 (英语四级单词)
• moderately [´mɔdəritli] ad.适度；适中；普通 (英语四级单词)
• eastward [´i:stwəd] a.&ad.向东(的) (英语四级单词)
• downtown [,daun´taun] ad.&a.在商业区 (英语四级单词)
• elderly [´eldəli] a. 较老的，年长的 (英语四级单词)
• strenuous [´strenjuəs] a.费力的；奋发的 (英语四级单词)
• affected [ə´fektid] a.做作的；假装的 (英语六级单词)
• forecast [´fɔ:kɑ:st] vt.&n.预测；预报 (英语六级单词)
• stubble [´stʌbəl] n.麦茬；短须 (英语六级单词)
• curtail [kə:´teil] vt.缩短；削减 (英语六级单词)
• august [ɔ:´gʌst] a.尊严的；威严的 (英语六级单词)