Monitoring Citywide Smog

E-mail Melanie Martella

Leading up to the 2008 Olympics, athletes, medical personnel, scientists, and concerned citizens all over the place questioned China's ability to sufficiently decrease the air pollution of the very smog-laden city of Beijing. Put simply, on taking a deep breath, athletes should be breathing mostly air rather than mostly smog, especially for those competing in endurance or distance events. And so the monitoring commenced.

The Chinese government placed pollution monitoring sensors at various locations around the city, alternated the days on which people could drive and work on building projects could occur, and produced a daily average figure of the particulate matter concentration (PM10, the concentration of particulates 10 microns and smaller). The BBC, employer of many enquiring minds, decided to mount its own pollution watch and equipped its Beijing-based reporters with a handheld analyzer (here's a slideshow of its results). The Beeb isn't the only organization deciding to do its own pollution level assessment—so are U.S. diplomats, at least according to an article in The Oregonian. A little independent verification is a good thing, right? I'll add that one of the side benefits to this pre-Olympic smog watch is the likelihood that China will expand its monitoring program ("China likely to broaden anti-pollution monitoring") in 2009.

The reporters aren't the only ones who are busily collecting data. Scientists from the Scripps Institute of Oceanography are using an unmnanned aerial vehicle to measure how the pollution-curbing efforts affect the atmosphere and its meteorology. And it's not just for public health: airborne particulates can diminish the quantity of solar radiation that makes it to the ground, leading to a warmer atmosphere and disrupted cloud formation. In other words, if you've got sufficient air pollution you can change the local weather patterns. For instance, if you're living on the U.S.'s Atlantic coast, and you've ever wondered why it only seems to rain on the weekends, blame the smog.

More Urban Monitoring
Japanese researchers have developed a tiny photochemical sensor to monitor toxic smog. The glass chip's many tiny pores hold chemical compounds that react with oxidants in the air and alter the glass's spectral response. The idea is to allow people to carry the sensor around with them, perhaps in their cell phone, to measure the day's exposure to pollution. The result could be far more detailed maps of pollution exposure and greater insight in how to combat it.

A much larger endeavor is the 100 Cities Project from Arizona State University and NASA, which wants to apply urban remote sensing to questions of urban planning and environmental health.