Editors' ChoiceCardiovascular

Smog Signals

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Science Translational Medicine  30 May 2012:
Vol. 4, Issue 136, pp. 136ec96
DOI: 10.1126/scitranslmed.3004353

Smoggy days don’t just spoil the view; air pollution has known harmful effects on cardiopulmonary health. Although previous research has suggested that pollution-induced effects on inflammation, endothelial function, and/or coagulation may be important, the mechanisms by which air pollution leads to cardiovascular disease have not been precisely identified. Rich and colleagues capitalized on a natural experiment that occurred during the 2008 Beijing Olympic Games to study the immediate effects of dramatic changes in air quality on biomarkers relevant to cardiovascular disease.

In recent decades, air quality in Beijing has been poor, with high levels of air pollutants considered hazardous to human health. In preparation for the 2008 Olympics, the Chinese government agreed to temporarily restrict industrial and traffic emissions, with the goal of reducing air pollution to levels that were less likely to be dangerous to the elite athletes competing in the Olympic Games. To do so, the government restricted the operation of industrial and commercial combustion facilities, reduced government-owned vehicular traffic, and enforced alternate-day-only travel for other vehicles. Rich and colleagues measured local air quality before and after these changes and found that concentrations of particulate and gaseous pollutants decreased measurably during the Olympics. In addition, they measured plasma biomarkers of endothelial function and thrombosis in healthy medical residents before and after the changes in air quality and found significant declines in biomarkers of endothelial activation (soluble P-selectin and von Willebrand factor) during this time period. When the Chinese government then relaxed the restrictions on air quality after the Olympics ended—and air pollution increased again—soluble P-selectin increased as well, bringing this natural experiment full circle. Although this study did not identify dramatic changes in physiologic markers of cardiovascular health (blood pressure and heart rate), the sample size was relatively small, and the subjects were previously healthy—and therefore perhaps less likely to experience such physiologic effects.

This clever study provides additional important evidence that major improvements in air quality can likely have immediate beneficial effects on cardiovascular health and that these beneficial effects may be mediated by decreased endothelial activation and inflammation.

D. Q. Rich et al., Association between changes in air pollution levels during the Beijing olympics and biomarkers of inflammation and thrombosis in healthy young adults. JAMA 307, 2068–2078 (2012). [Abstract]

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