Air Pollution May Make SARS More Deadly

Death Rate From SARS Twice as High in Polluted Areas

From the WebMD Archives

Nov. 21, 2003 -- People who live in areas of high air pollution may be twice as likely to die from SARS as those from areas with cleaner air.

A new study shows the number of deaths caused by SARS (severe acute respiratory syndrome) in different regions of China increased as air pollution levels increased during the recent outbreak.

Researchers say that the results suggest that exposure to air pollutants may compromise lung function and make people more vulnerable to dying from SARS.

Air Pollution Linked to SARS Deaths

The study, which appears in this week's Environmental Health: A Global Access Service Source, compared SARS death rates and air pollution levels in five different regions of China between April and May 2003, when the majority of SARS cases were diagnosed.

Researchers found that SARS death rates increased as pollution levels increased, ranging from about 4% in regions with low air pollution to 7.5% and 9% in regions with moderate or high air pollution levels, respectively.

Guangdong, the southern region where the outbreak began, had a low level of air pollution with an air pollution index of 75, according to data obtained from the Chinese National Environmental Protection Agency. Tianjin had a high level of air pollution with an air pollution index of more than 100, and Shanxi, Hebei, and Beijing had moderate air pollution levels.

More Study Needed

Researchers say exposure to air pollutants has previously been linked to a variety of respiratory disorders, and air pollution may predispose SARS patients to more severe SARS symptoms.

But researchers say it's too soon to draw firm conclusions about the link between SARS and air pollution. For example, this study did not take other factors into account that might also have contributed to the patients' outcome, such as socioeconomic status, smoking habits, or the treatment the patients were given.

However, the two regions with the highest SARS death rates, Beijing and Tianjin, were more urban, and researchers suspect that patients would have received better medical care in these areas, which lends support to the role of air pollution in increasing death rates.