Adulterated Air

How air quality issues such as wildfire smoke and pollution can affect equine respiratory health

Catastrophic environmental events such as wildfires that diminish air quality and affect horses’ breathing might seem beyond human influence. We do have control, however, over the equine management choices we make daily about feed, bedding, ventilation, exercise, and veterinary care. Many of these decisions and strategies can help horses breathe easier during times of both crisis and calm. Here’s what you should know about protecting your horse’s respiratory health.

A Hidden Danger

The National Interagency Fire Center reports that in 2021 alone 48,725 wildfires burned more than 6.5 million acres, making it one of the worst fire seasons in history. Fires represent an apparent threat to people, property, and animals. The insidious secondary threat of smoke poses hazardous risks, too, of course. But we might not consider the dangers we can’t detect by sight or smell.

Natural and artificial combustibles, including wood, vegetation, and plastics, produce toxic chemicals when ignited. The components of smoke—carbon monoxide and dioxide, hydrogen cyanide, soot, hydrocarbons, nitrogen oxides, and formaldehyde—can be fatal in high doses when inhaled over long periods.

Even the smoke particulates ­themselves—a combination of solid particles and liquid droplets, each less than 1 micron in diameter—can trigger asthma episodes, infections, and respiratory illness, reducing the lungs’ ability to expel common irritants like pollen.

Smoke inhalation at a very high level can create all sorts of issues,” says Kent E. Pinkerton, PhD, professor of anatomy, physiology, and cell biology at the University of California, Davis, (UC Davis) School of Veterinary Medicine. “Searing heat can damage a horse’s respiratory system and its delicate set of cells that line the airways and the gas exchange regions. The particles you can’t see not only reach the upper respiratory tract but go all the way down into the deep respiratory tract, where they can cause considerable amounts of damage.”

He says horses might be sentinels for the effects of wildfire and air pollution due to their respiratory sensitivity. The equine airways’ cleanup mechanisms expel pollutants like pollen and dust daily.

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