Beijing is famous for its filthy air. Even more so than sky-high house prices or terrible traffic, it’s the most complained-about thing in the city among both locals and outsiders alike. Anyone who has never experienced this kind of air before takes some time to adjust. Using indoor air purifiers and wearing facemasks when outdoors makes life here much more pleasant, and many of my classmates who didn’t take the proper precautions reported headaches, blocked noses and breathing difficulties in their first few months here.
A major cause of the air problems is coal-burning, especially during the winter months when this part of north China gets very cold and every inhabited building is slurping electricity to power its central heating system. In more remote areas, some people burn coal directly for heating, and factories in Beijing and neighbouring provinces also emit copious amounts of soot. China’s biggest coal-mining province, Shanxi, is nearby and upwind of here. Combined with emissions from diesel trucks, passenger vehicles, cigarettes, barbecues, and other good things, the air can become an unpleasant soup of chemicals that lingers for days until the wind blows it away and makes it someone else’s problem.
A household name in China is “PM 2.5”, which refers to particulate matter with a diameter less than 2.5 micrometres. These are very fine particles, like soot, that can penetrate deep into the lungs and get lodged there, potentially causing serious health issues even many years down the line. Very small particles are considered more dangerous than larger ones, and are also more difficult to filter out using facemasks or air purifiers.
The other major outdoor air quality problem is ground-level ozone, which is formed by UV rays interacting with vehicle emissions, methane, and other VOCs (volatile organic compounds) in the air. This ozone is called a secondary pollutant, because it is not directly emitted by a factory or vehicle, and it can irritate the lungs, bringing about asthma attacks, bronchitis, heart attacks, and the like. Fortunately, ground-level ozone is not a serious problem outside the summer months or at night-time when there isn’t enough sunlight to form it, but facemasks do not offer effective protection.
When I first arrived, I looked online for recommendations about which facemasks to buy. Although there are several good manufacturers, the best-known is 3M, who make not exactly fashionable but very reputable protective equipment for people who work on construction sites and other environments with poor air.
The 3M 6200 costs around 90 RMB (£9.60) on Tmall.com. It’s a bit too much for everyday use, but is good when cycling, since it works against car fumes and nobody really has time to stare at you as you speed by.
The white, foam-like PM 2.5 filters cost 53 RMB (£5.60) for a pack of 10, which is enough for five changes. Even if you use the mask every day, you only need to change the filters about once a week. The activated carbon cartridges cost around 37 RMB (£3.90) for a pack of two.
Another model is the 3M 9332, which is a disposable facemask and much more convenient to wear and carry. One seller on Tmall lists a box of 10 for 228 RMB (£24.30). It’s not completely effective against car fumes, cigarette smoke and the like, but filters out dangerous PM 2.5 and heavy metal particles.
The straps on this mask go around the head and feel very light, which is not the case for some of the cheaper masks that loop around the ears and tug very hard on them. It folds neatly and can be carried in a pocket or bag. The noseclip can be moulded to suit different nose shapes and sizes, and the breathing valve stops the mask from becoming too hot or moist. The grey foam around the nose also makes it more comfortable to wear.
There are also some air quality issues specific to indoor environments, like mould and formaldehyde, but cleaning the house is a more effective remedy than wearing a mask all the time when inside.