Olympic cleanup

Morris was interested in identifying air pollutants that can affect global warming and cause respiratory problems, which had traveled through the jet stream from China to Japan and continued over the North Pacific, some eventually reaching North America. In particular, he wanted to know if the Chinese government’s extensive efforts to improve the air quality in Beijing leading up to the 2008 Olympic Games, which began two days after his August 6th launch, had been successful.

So Morris and his Japanese collaborators launched 10 balloons during August 2008, recording ozone and sulfur dioxide (SO₂) concentrations. The pumps and electrochemical cells rigged to Morris’s balloons are a classic method for measuring ozone, although these pumps are susceptible to interference by SO₂. By adding a filter for SO₂ to one, Morris is able to obtain pure ozone levels; subtracting the unfiltered from the filtered pump yields the levels of SO₂.

Unfortunately, of the 10 balloon launches last year, only two had weather patterns suggesting that the local pollution was influenced by air from Beijing—as determined by meteorological models that predict patterns of air flow—including the very first launch on August 6. That day, surface ozone levels exceeded 60 parts per million (ppm), three times the typical levels in Sapporo of 20 ppm. This year, Morris returned to Japan to launch another 10 balloons.

Over the last decade or so, dramatic economic growth in China has resulted in increasing pollution and growing concern about its worldwide effects. “There [were] a lot of people concerned about how this air quality [would] impact the Olympic Games [and the] performance of athletes,” says atmospheric chemist Renyi Zhang of Texas A&M University, who has been recording air pollutants in Beijing for the last 3 years. As a result, the Chinese government implemented a number of pollution controls, including switching many coal-burning boilers to cleaner fuels, and closing a number of Beijing factories.

Satellite recordings revealed a reduction in primary pollutants over China during the Games, including a 13% reduction in SO₂ compared to the previous 3 years (Geophys. Res. Lett., in press). The problem with satellite readings, however, is that they are looking down at the Earth from above, and thus they can’t measure the altitude of pollutants, says atmospheric scientist Mark Schoeberl of NASA’s Goddard Space Flight Center in Maryland, who has been in charge of the satellite since its launch in 2004. Altitude matters, he says: “if the SO₂ gets lofted, then it has a greater probability of traveling long distances,” which has obvious implications for the global impact of air pollution. Morris’s balloons, on the other hand, measure the altitude of SO₂ concentrations as they travel through the atmosphere.

“Pollution is on the radar screen in China now,” Morris says. “It wasn’t just the Olympics that made that happen, but [they] were certainly a catalyst. We’ll see how things pan out over the next couple of years.”