An expert from the Chinese Academy of Sciences (CAS) said on Tuesday that if the weather does not change dramatically in the next three days, Beijing will have a "fairly good" level of air quality on Friday, the opening day of the Olympics.

The photo taken on Aug. 1, 2008 shows the white cloud floating above the No.1 court of the Beijing Olympic Green Tennis Court in Beijing, capital of China. (Xinhua Photo)

It might rain on Wednesday and Thursday, said Wang Zifa, a researcher with the Institute of Atmospheric Physics of CAS, a government research organization.

Using a multi-model system, Wang said he was able to forecast Beijing's air quality 72 hours ahead.

He said that even if the air is humid and still on Friday, the city is unlikely to have heavy pollution. "I think the city's comprehensive and strict measures to control pollution have paid off," he said

The capital's air quality on Tuesday was categorized as "fairly good" with an average pollution index from 27 monitoring stations standing at 88, slightly higher than the 83 recorded on Monday.

A pollution reading below 50 is classed as "excellent," 51 to 100 "fairly good," 101 to 200 "slightly polluted," 201 to 300 "poor" and over 301 is "hazardous," according to the Beijing Municipal Bureau of Environmental Protection.

The deputy director of the bureau, Du Shaozhong, said that Beijing had three days with "excellent" air quality and two days with "fairly good" air quality so far this month.

The photo taken on Aug. 1, 2008 shows the National Stadium, namely the Bird's Nest, standing with its reflection image under the blue sky in Beijing, capital of China. (Xinhua Photo)

He said the Ministry of Environmental Protection has issued emergency plans for "extremely adverse weather conditions". However, the ministry did not see any need to activate this plan since the weather has not been "extremely adverse" so far.

Environmental experts said in the next few days, Beijing will have wind coming from the south. They suggested that southern neighboring areas including Baoding and Langfang in Hebei Province and Tianjin should strengthen pollution controls.

As of Tuesday, Beijing had 154 days with fairly good or excellent air quality, accounting for 70.6 percent of the days in 2008.

Editor: Yan