Runners compete during the 53rd New York City Marathon on Nov. 3, 2024. Selcuk Acar / Anadolu via Getty Images Why you can trust us Planning to tackle a marathon in the new year? While getting in your stretches and miles of practice, you may also want to prepare for air quality when training. According to new research, poor air quality could play a role in slower marathon finish times. Researchers at Brown University School of Public Health have found a link between the amount of fine particulate matter, or pollutants measuring less than 2.5 microns in diameter, in the air on a race day and slower average finish times for marathon runners. Fine particulate matter can come from combustion , such as vehicle exhaust, fossil fuel plants and wildfires, as well as natural sources, like dust and dirt, as explained by Natural Resources Defense Council (NRDC), which was not involved in the study. In a study of 1,506,137 men and 1,058,674 women who finished nine major U.S. marathons, including the Boston Marathon, from 2003 through 2019, researchers evaluated the marathon finishing times and compared them with race-day fine particulate matter levels at various points throughout the race routes. Allan Just, an associate professor of epidemiology and environment and society at Brown University, developed statistical models to determine these PM2.5 levels. “This really sophisticated spatial-temporal model of particulate matter allowed us to plot pollution at every mile of every course,” Elvira Fleury, lead author of the study who earned a master of public health degree at Brown University and is now a doctoral student at Harvard University, said in a statement . “Without a model like this, it wouldn’t have been possible to look at so many different marathons in different states across different years.” Researchers measured concentrations of […]