Students at Western Academy of Beijing play soccer near the international school’s dome, which is inflated with purified air. The dome was set up in November so that students can exercise on smoggy days. ZHANG WEI / CHINA DAILY

With Beijing education authorities urging schools to cancel outdoor activities when pollution level alerts hit orange, some international schools in the capital are building facilities to ensure children can exercise in cleaner air.

The color-coded alert system, in order of increasing severity, is blue, yellow, orange and red.

Special: Fight air pollution

In order to ensure children do not have to cut down their outdoor activities due to air quality, international schools in Beijing are spending tens of millions of yuan building air domes - large enclosed areas with filtered air.

The Western Academy of Beijing, an international school in Chaoyang district, constructed a campus dome in January that covers 1,000 square meters.

"The design and construction of the dome took about six months; three waiting for the required materials to be transported here from the US and three constructing it," said Johnny Whang, the school's property manager.

The dome, named Tiger L'Air, was built on the school's tennis court, and has an air purifier on one side, said Gordon Gao, general manager of ASATI (Beijing) Air Dome Co. Ltd, a US company in charge of designing and constructing the dome.

About half of the dome's materials were purchased from the United States, Gao said.

The company entered the Chinese market in 2000.

"Most of our clients in the beginning wanted them for sports teams," Gao said.

The International School of Beijing in Shunyi district was the first school to approach ASATI in 2012. The ISB dome cost about 30 million yuan ($4.9 million), CNN reported.

Fei Cong, WAB school affairs director, said, "We built the dome to protect children during hazardous weather in Beijing as some sports activities, such as soccer, had to be canceled."

WAB students have about three PE classes every week, not including organized outdoor activities, which usually take place at 3:30 pm.

Fei said WAB staff paid several visits to IBS to learn how the dome is best utilized.

Students and parents appreciated the options the new facility provides.

On Feb 25, when the AQI in Beijing exceeded 300 for most of the day, the air quality monitor inside the dome showed the AQI was just 4, Fei said.

zhangyue@chinadaily.com.cn