The AQI may be high outside, but when you come home and shut the door, you can take your mask off and relax, right?
Unfortunately, it’s not that simple. No building, however modern and well-designed, can keep out all the pollutants. And dangers may lurk in your home which you had never even considered.
We talked about the problem of indoor pollution with Alex Gao, General Manager at Pure Living, Beijing. For the last six years Pure Living have been advising on air safety and providing solutions to international businesses and schools. Their clients have included Yew Chung International School of Beijing, the British School of Beijing, Western Academy of Beijing, Dulwich College Beijing, and the Canadian International School of Beijing.
Although all buildings offer some level of protection, Gao told us, if levels of PM2.5 outside are high, the quality of air in the average home without purifiers is usually poor.
What is PM2.5?
The most dangerous air pollutants are the smallest particles, those measuring below 2.5 micrometers in diameter – finer than a human hair, and small enough to enter the lungs or bloodstream. PM2.5 concentration is measured by micrograms of particles per cubic meter of air (µg/m3). The United States Environmental Protection Agency (EPA) considers a level above 35µg/m3 as potentially hazardous. The World Health Organization’s standard is even lower, at 25µg/m3 , equivalent to an AQI of 78.
“Depending on the age and construction quality of the building, it will keep out typically one fifth to a half of PM2.5. So if the AQI is 175, meaning the air outside has 100 micrograms of particulates per cubic meter (µg/m3), even the most well-sealed homes will have 50µg/m3 – double the World Health Organization’s recommended safe limit,” says Gao.
Gao recommends having an air purifier in the living room, and one in each bedroom. “Maintenance is important too,” he says. “An air purifier with a dirty filter actually makes the air dirtier!”
Manufacturers will recommend how frequently you should change the filter. It’s worth bearing in mind though that if you brought your purifier with you, you will need to allow for dirtier Beijing air! A filter which in the US would last for five years might only last two in China. Gao suggests you check your filters every couple of months. You can use a particle meter at the outlet, but a visual check will often suffice. “If it looks dirty and dark, change it!” he says.
Tips on buying air purifiers
• You don’t necessarily have to buy the most expensive… Some brands spend a lot of money on marketing, and then pass those costs on to the customer.
• But don’t buy the cheapest either! You can get units very cheaply from Taobao and other online retailers, but they may not be as effective. Go for a reputable name.
• Make sure you’re getting the right size for the room you’ll be using it in. Smaller units are generally suitable for rooms around 20m2, larger units may cover up to 60m2. Ask your supplier, or check the manufacturer’s manual or website.
• Don’t forget to budget for consumables. As with computer printers, some manufacturers will sell their units cheaply, and make their profits from consumables. Check the cost of filters, and how often you’ll need to replace them.
However PM2.5 are not the only pollutants your family may be breathing in your home. “Chinese safety standards are not as stringent as those in the west,” Gao told us. “So new paint and furniture often give off volatile organic compounds (VOCs).” The term VOCs covers a huge range of chemical compounds, many of them naturally occurring and harmless; most smells are caused by VOCs. However man-made VOCs can be very dangerous: formaldehyde, for example, is often used in paints, and is highly toxic. Regularly inhaling VOCs can lead to discomfort, respiratory tract irritation, and over the long term, serious health problems.
When moving into a new home, many Chinese people will leave it vacant for three to six months, to allow the VOCs to disperse. However this is not an option for most international families! Photocatalytic oxidation (PCO) can clean up VOCs quickly, but as a new technology it can be expensive. If you’re concerned, Gao recommends having your air tested, or make sure the landlord tests it before you move in. A test can help identify the source of the problem, or give you peace of mind if the results are negative.
Lead is another substance now strictly controlled in the west, due to the dangers it presents to growing children in particular. Some scientists believe there is a link between the ban on lead in petrol, and the subsequent fall in violent crime across the western world. Air purifiers help, but if possible you should identify and remove the source: often toys or building materials.
Mold can also be a problem. Like all fungi, mold reproduces by releasing invisible spores into the air. Some spores are harmless, but others can trigger allergic reactions, or contain mycotoxins (toxic chemicals produced by the fungi which can cause weakened immune system, disease, and death). As with all pollutants, long term exposure increases the risks. Again, finding the source is key to tackling mold. Often household cleaning materials will be sufficient to eliminate the problem, but in other cases specialist chemicals will be needed.
It’s easy to become paranoid about air quality, and seal yourself up in your home. However Gao reminds us that fresh air is important too. “If you have several people all breathing the same air, then the oxygen levels become depleted, carbon dioxide builds up, and that’s unhealthy.” You can buy ventilators, and some homes will have them already built in. You need to make sure though that they have a filter installed, to screen out particulates. Of course there’s nothing wrong with the old-fashioned method: opening your windows and doors! On low AQI days you should make sure to give your home a good airing. Gao recommends that even when the AQI is high you should open the windows for 20-30 minutes, at least twice a day. After that turn on your purifiers at maximum setting to clear the air.
There’s a growing awareness in China of the problem of air pollution. Gao points to the reliable, easily understood information produced by the US Embassy as having had an impact beyond the international community. Officials from Beijing, Tianjin and Hebei have pledged to work together to clean up the air. In the meantime though, it’s worth taking a few simple steps to ensure your family’s health is protected in the place they should be safest: the home.
This article originally appeared on pages 52-53 of the beijingkids March 2016 issue. Click here to read the issue for free on Issuu.com. To find out how you can get your own copy, email firstname.lastname@example.org.
Photo: Thomas Leuthard (Flickr)