Natural World
Last updated
June 24, 2026

Mammals

Early research suggests that air pollution affects mammalian health and performance. Studies have found that increases in PM2.5 concentration measurably reduce thoroughbred racehorse speed, highlighting how even moderate air pollution levels can impair respiratory performance in mammals.

Horses

  • For PM2.5 between 4 and 23.6 μg/m3, Thoroughbred racehorse speed decreased 0.0008 m/s for every 1 μg/m3 increase of PM2.5 (Kim et al., 2024)
    • A horse’s lung capacity is almost 3x the size of a human’s