Winter in Beijing means more time indoors as smog levels rise outside. Turns out, however, that sealing yourself off on high AQI days isn’t entirely the solution. As Jess Lam, co-founder of (the group behind the Laser Egg AQI monitor) explains, indoor air pollutants are a big problem in China, too.
First of all, what level of PM2.5 should I be aiming for inside my home?
Jess Lam: The World Health Organization suggests keeping air under 10 micrograms per cubic metre, which is an AQI of 42 on the US AQI scale. It is worth noting there is a difference between the US and Chinese AQI scales and that 50 US AQI does not equal 50 Chinese AQI.
Besides PM2.5 particles from outside, what are other sources of indoor air pollution Beijingers should be aware of?
In China, indoor pollutants are an enormous problem and often come in the form of gases: volatile organic compounds (VOCs) found in carpets, glues, paints and resins used in wood, which are known carcinogens. Indoor cooking also leads to a build-up of carcinogens and is, in many countries, a major source of lung disease and early mortality.
Finally, if you’re using a humidifier this winter, opt for a steam humidifier – the process of boiling water both kills bacteria and prevents mold and minerals from being released into the air, which ultrasonic, or ‘cool’ humidifiers do not.
Does keeping live plants at home help clean the indoor air?
Unfortunately not against PM2.5, and you would have to live in an overgrown jungle in order for there to be any noticeable reduction in VOCs – and that is if you buy the right ones. Plants do help with the carbon dioxide and oxygen exchange, but the most help plants provide against air pollution is the feeling that they help.
What can be done about leaky windows and doors?
Try 3M silicon sealing tape and draft stoppers, which can be found on Taobao, to help stop PM2.5 from coming into your home. In the winter, this will help keep your home warm and heating bill down, too.
One of the things people often forget about or ignore, even on high AQI days, is that it’s really important to get fresh air! Locking yourself indoors and closing all windows and doors may ensure you have a closed space to purify PM2.5, but there’s often a build-up of other pollutants that originate from indoors. Remember to open the windows every now and then to get some oxygen in the house. After you’ve aired the place out, that’s when it’s time to run the purifiers on max.