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Air pollution

Air Pollution Slows Down Marathon Runners

Strategic Insights

— 1 min read

Research has consistently shown that runners who compete in marathons in cities with high levels of air pollution tend to finish slower compared to those who run in less polluted areas. Analysts at Brown University studied a dataset of millions of marathon finish times collected from major U.S. marathons over 17 years, between 2003 and 2019. The study revealed that runners who breathed in higher levels of fine particulate matter called PM2.5, which is associated with slower finish times, particularly in cities like New York City, Boston, and Los Angeles.

Key Takeaways:

  • The study analyzed 2.6 million marathon finish times from nine races, including those in New York City, Boston, and Los Angeles, between 2003 and 2019.
  • For every increase of one microgram per cubic meter of PM2.5, men's average finish times were 32 seconds slower and women's were 25 seconds slower.
  • Even short-term exposure to PM2.5 can be harmful, reaching deep into the lungs and entering the bloodstream, causing inflammation, coughing, or tightening in the chest.
  • The study found that elite marathon runners were not immune to the effects of air pollution, rather the slowdown was more pronounced for faster-than-average marathon finishers.
  • A decrease of one microgram per cubic meter of PM2.5 could be the difference between breaking a record or not.

Statistics:

  • Average finish times for men increased by 32 seconds for every microgram per cubic meter of PM2.5.
  • Average finish times for women increased by 25 seconds for every microgram per cubic meter of PM2.5.
  • Los Angeles Marathon had the highest estimated median pollution levels and also the slowest median finish times across runners.
  • Researchers used machine-learning models to estimate PM2.5 levels along the marathon routes on given days, based on readings from monitoring stations.

Sources:

  • [1] Braun, Joseph M. "Air Pollution and Marathon Performance: A Study of the Association Between Fine Particulate Matter and Running Times." Brown University, 2020.

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