Clean air stadiums cost $5 million in Beijing

The International School of Beijing spent $5 million building two indoor stadiums with clean air domes to protect their children from pollution. The two extraordinary stadiums cover 8,000-square-meters and are equipped with separate air filtration systems, Beijing Times reported.

Before the fresh air flows into the stadium, it is filtered three times by the clear air system. According to the report, when particulate matter from outside air reaches a density of 0.143 milligrams per cubic centimeter, there is just a density of 0.002 milligrams per cubic centimeter in the stadium.