Website: AMFIC – Air Quality Bulletin – 空气质量公告.

Beijing’s air pollution has definitely improved over the past year, but there is still a long way to go before they meet WHO criteria for healthy air. The usual standard is to measure particulates in the air; China usually reports the larger size PM10 numbers, while the international standard is more focused on the smaller and more dangerous PM2.5 particles. These can get into the lungs deeper and cause more damage.

In either case, the link above, from the Air Quality Monitoring and Forecasting in China group, has an excellent daily pollution forecast. The image above shows the last 24 hours of PM10 — note how the pollution rises after evening rush hour and peaks at midnight. This is from the diesel trucks which are allowed to enter Beijing only  at night to assist the construction sites. That’s why you should not leave your windows open overnight.

The best time in Beijing to open your windows and clear out your household air is in the mornings. And it is important to clean out your indoor air regularly, as there are many dangerous indoor pollutants which can build up. A good habit is to open your windows when you wake up and close them before you leave for work or school.