Schools in Beijing have started to monitor air quality on campus and issue warnings if necessary to minimize risks to students posed by hazardous gases and particles such as PM2.5, which has become a major air pollutant in the city.

The pilot program, which was put into operation in September and covers two schools, will be applied to all schools in Beijing if the one-year trial period is successful, according to the Beijing Health Inspection Institute.

The monitoring includes carbon dioxide, carbon monoxide, methanol, PM10, and PM2.5, which is particulate matter smaller than 2.5 micrometers in diameter.