Air pollution slows marathon finishing times, study finds

A study by researchers at the University of Leicester has found that air pollution significantly impacts marathon finishing times. Analyzing over 2.7 million performances from the World Marathon Majors between 2010 and 2024, the research focused on six major cities: Berlin, Boston, Chicago, London, New York City, and Tokyo.

The study identified a strong association between nitrogen dioxide levels and slower race times. For every microgram-per-cubic-metre (µg/m3) increase in nitrogen dioxide, men's finishing times increased by 1.43 minutes and women's by 1.56 minutes. On days with high pollution (10.3 µg/m3) compared to low pollution (5.2 µg/m3), runners were approximately seven to eight minutes slower.

The impact was notably more pronounced among recreational runners, who saw time increases of 2.12 minutes per 1 µg/m3, compared to just 0.34 minutes for elite athletes. While fine particulate matter (PM2.5) was also studied, no statistically significant association with finishing times was found. London recorded the highest median nitrogen dioxide concentration at 10.9 µg/m3, while Berlin recorded the lowest at 6.1 µg/m3.