Wildfires have raised concern among horse owners regarding the potential impact of persistent smoke and related air pollution on their equids. And their concern is justified: Smoke can cause serious health problems for horses, as it can in people, notes an equine veterinarian from the University of California, Davis (UC Davis), School of Veterinary Medicine.

Smoke is an unhealthy combination of carbon dioxide, carbon monoxide, soot, hydrocarbons, and other organic substances. Smoke particulates, which are a mixture of solid particles and liquid droplets in the air, can irritate horses’ eyes and respiratory tracts, and hamper their breathing.

“Owners should limit their horses’ activity when smoke is visible,” said UC Davis veterinary professor John Madigan, DVM, MS, Dipl. ACVIM, ACAW.

During California wildfires with persistent smoke several years ago, the Tevis Cup—a 100-mile endurance race—was postponed based on adverse air quality for exercising horses. This is an example of important management decisions that can protect horse health