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Aug. 5, 2008

There is international concern about the air quality in Beijing and how it might impact athletes performing in the Olympics. The city recently enforced measures to mitigate the pollution, pulling millions of cars off the road and closing factories.

Q: How bad is the air pollution in Beijing, and do you think these measures will help?

A: The fairly aggressive measures that have been put into play by Beijing officials are likely to have a beneficial effect. The question is, how much will the levels improve? Certainly it will get better, but whether there are health risks for athletes depends on what levels are attained by these measures. It's difficult to know in advance. I'm cautiously optimistic that air pollution during the Olympics won't turn out to be a big issue because of the precautions the city officials have undertaken.

On the question of how healthy the air should be for any given Olympics, I don't think we should leave this up to local officials, since the concept of clean air varies in different parts of the world. It should be answered in an international context—what is the best standard for athletes to perform in general? The International Olympic Committee should adopt an international standard. There's a need here for an independent judgment about air quality based on global standards of clean air.

Q: Is China's Air Pollution Index a good measure of air quality?

A: The air quality index (API) that China is using includes a composite of three air pollutants that are typically regulated: sulfur dioxide (from coal and power plants), nitrogen dioxide (cars and power plants) and particulate matter measuring less then 10 micrometers, also known as PM10 (coarse particles from dust, and fine particles from engine exhaust, for example). Looking at the concentrations that make up China's API, which ranges from 0 to 300, probably once you get to about 50, you're getting into levels of PM10 that we'd be concerned about. According to China's API, this level is still considered to be "excellent." So looking at their index, I would ideally want to stay between 0-50 for athletes performing in this air.

Q: How does the air in Beijing compare to New York's?

A: Beijing's air pollution is in general much worse than NYC. For instance, on the cleanest day in Beijing last year, PM2.5 (that is, fine particles) averaged 30 micrograms per cubic meter over 24 hours. In NYC, most days are below that level. In fact the average level across NYC over the course of a typical year is about 15. Beijing has a long way to go to achieve air quality that NYC residents take for granted.

Q: What other factors besides auto and factory pollution affect air quality?

A: Beijing's air quality is affected both by emissions of pollutions that occur within Beijing and the regions upwind around the city. In New York City we have our own sources of pollution, mostly from traffic, but our air quality has much or more to do with pollution from areas upwind of the city. A big source of our pollution is power plants spread throughout the coal producing states. The same situation will exist in China, except with a bigger range of industrial sources. China has to cast a wide geographic net to capture all the emissions affecting Beijing's air quality.

I am cautiously optimistic that China will manage to do what is needed to substantially clean the air in Beijing during the Olympics. However, I'm a little concerned because their air pollution index seems skewed to high levels. So it's important to reframe the range of pollutants as more of an international standard. It will be important to check whether the measures are effective in that context and not just on the basis of their Air Pollution Index.

Q: What about the longer-term affects of pollution on people who live in Beijing as well as pollution and climate change?

A: It's interesting how society is suddenly interested in the health effects of air pollution around the Olympics and relatively less concerned about the issue for millions of people who live in China during all the other times of the year. So I hope this is also an opportunity to raise awareness about air pollution, which remains quite severe especially in developing countries like China. At Columbia, we are engaged in research that explores the intimate links between the health effects of pollutants like PM2.5 that are emitted by fossil fuel combustion, and the global climate effects of CO2 and other greenhouse gases that are emitted by the same combustion processes. Climate change is viewed by some as a future problem that that has little relevance to our daily lives, but if we understand that burning of fossil fuels can have serious short-term effects on public health, than we can help raise public awareness and motivation to address the longer-term challenges.

—Interview by Clare Oh

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