Tag Archives: pollution

Now you can compare Beijing PM 2.5 air quality readings on your phone

It just so happens that today is not one of the more beautiful days in Beijing. After a week of generally glorious fall weather, with exceedingly clear air (except once or twice), the national holiday is over and whatever process churns up the smog has resumed.

I’m not complaining. I haven’t been here long enough to get worked up about air quality. But it did lead me to check the China Air iPhone app that delivers official Chinese government pollution readings alongside the point-source reading from the U.S. embassy. And I noticed something new.

Before*, you would see only PM 2.5 (particle matter under 2.5 micrometers in diameter) for the U.S. embassy reading, and only PM 10 (10 micrometers), sulfur dioxide, and nitrogen dioxide. The app gives indicies derived from each source’s standards, but the data weren’t directly comparable. These pollutants don’t necessarily come in tandem or in proportion.

Now, however, you can compare PM 2.5 readings from both sources. In the case of a few minutes ago, the U.S. was reading more PM 2.5 than the local government. These still aren’t comparable measures: Beijing creates a number based on many sampling stations, whereas the U.S. has one location. But there’s something to compare. If you trust the measurements from the government, which seems fairly reasonable to me in this case, you could learn that the U.S. embassy is in an unusually polluted part of town right now.

One superficial reason to take the new Chinese data seriously is that a government official has said we should not expect air to be super clean for quite some time. According to a Xinhua article (in Chinese), the city’s 20 new PM 2.5 sensors are expected to find particulate content over their standard of 150 mg/m^3 quite regularly for the foreseeable future. (“从北京整体空气质量水平看,PM2.5浓度值超标在很长一段时间内会经常出现.”)

Seems to me this new data has been around in some forms for some months, but this is the first direct comparison I saw.

*I note that the app’s iTunes page shows data for PM 2.5, but it had been “–” since I installed the app.

Polluting in the new year!

First, of course, happy new year to all those greeting the year of the dragon this week. I, for one, am suitably stuffed.

Second, via Angel Hsu, this image depicting what is most likely a huge cloud of noxious firecracker emissions as Beijing celebrated the new year (which, being lunar, coincided with the new moon). Beijing has promised to provide real-time data on PM-2.5 (particle matter under 2.5 microns), thought to be a category of pollution that acutely threatens human health.

The U.S. embassy in Beijing has for years offered live data from a sensor in its compound, and the addition of the Chinese data is welcomed. Just look at that spike!

Click for full size.

(To see for yourself, visit http://zx.bjmemc.com.cn/ and click on the PM2.5 tab.)

Pollution from space, and human geography

A remarkable photograph published by NASA shows, as Angel Hsu notes, the pollution in the air during the climate talks in Tianjin earlier this month. The high-resolution image is striking, and will live on the desktop of my external monitor for some time.

NASA notes that this image captures an event that resulted from increased emissions and stagnant air due to weather systems. But it also captures, in my amateur opinion, the population centers of China. The first thing I noticed after my habitual task of locating Beijing and drawing some borders in my head (as the political geographer must) was the lonely cloud and its vivid shadow, in the orange-cream yoghurt desert which I’m pretty sure is in Inner Mongolia, next to Gansu. The air, it appears, is glorious when you get far, far from population centers.

As we glance eastward into the eastern Ordos region, across the north-south section of the Yellow River, and into the heavily populated coastal and central plains provinces, we see air thick with particulates and fog. According to NASA, regular clouds look like the brilliant white at right and left.