Everyone knows that Chinese cities have a pollution problem, but as pollution gets worse and the outside world begins to learn the extent of the situation, it has become an increasingly hot topic both inside and outside China’s borders.
What is it, and how bad is it?
Air pollution is far and away China’s most visible environmental problem, because when it’s bad there is absolutely no avoiding it. China’s most polluted cities reach AQI levels that exceed 500, and have even broken 1,000 (for comparison, the United States considers any AQI higher than 150 to be unhealthy, and any exceeding 300 to be hazardous).
China’s air pollution is caused in part by its traffic and its heavy industry, but it is worst in the winters, when cities are heated in large part with power generated by the burning of coal. This generates large quantities of airbourne particles, and when winds and precipitation are low, these particles can remain in the air over cities for extended periods of time. This situation can be exacerbated if, like Beijing, a city is surrounded on several sides by mountains that serve to “trap” the air pollution inside.
What is PM 2.5?
One of the most dangerous parts of air pollution is called PM 2.5; PM 2.5 particles are small enough that they can penetrate the gas exchange regions of the lungs. For a long time, China’s government refused to publish any city’s PM 2.5 readings in real-time, meaning that most Chinese citizens had no effective way of assessing how hazardous the air was on any given day. China’s public pollution assessments also didn’t incorporate PM 2.5 data, meaning that the air was sometimes being classified as safe when it actually contained potentially harmful levels of PM 2.5. The issue came to a head when the United States Embassy in Beijing set up a Twitter feed that reported Beijing’s PM 2.5 levels by the hour, and in doing so caused some diplomatic friction with the Chinese government. But after a spell of particularly bad pollution in the capital a few years ago led to public outcry, China’s government relented and started publishing real-time PM 2.5 data in addition to other pollution data.
What impact does air pollution have?
People deal with the pollution by avoiding it and staying indoors, by wearing protective masks (that may also double as protection from airborne illnesses), and often by equipping their homes and offices with expensive air filters to keep the air clean. But lung cancer is still the most common and most deadly cancer in urban China, and cancer rates in Beijing and other highly polluted cities are rising. Part of the problem may be that many Chinese people simply ignore the pollution, and others wear masks that are aesthetically pleasing but not particularly effective in filtering out particulate matter. The cloth breath masks sold in many Chinese shops do virtually nothing to protect against PM 2.5 particles.
Air pollution also impacts China’s economy, delaying or canceling flights and preventing shipments. In the most extreme cases, it can shut entire cities down. A particularly brutal streak of pollution in the northeastern city of Harbin in October 2013, for example, shut down the city’s airport and many of its businesses and schools because the air was simply too hazardous -- and visibility was too low -- to continue with business as usual.
China’s authorities are often quite frank about the severity of the problem, but in addition to being a health risk, pollution is also becoming a political one. The reaction inside China (and the pressure from outside it) is becoming more severe as incidences of extremely thick air pollution seemingly become more frequent.