Supporting Your Horse When Air Quality Is Poor

Respiratory health is very important in our equine partners. Some horses struggle with this during the best of times, like those with heaves or COPD, collectively referred to as equine asthma. During periods of poor air quality, horses with compromised respiratory health are under even greater stress, but horses with healthy respiratory tracts can also be at risk of experiencing complications, as well.

What Causes Air to be Poor Quality for Horses?

Barns are inherently poor environments for respiratory health. Dust from bedding, hay and arena footing are common air pollutants. Hay can also be a major source of airborne mold in the environment.

The impact of a normal environment on a horse’s respiratory health can be further compounded by transient environmental factors. Smoke from wildfires is a major seasonal air pollutant along the west coast of the United States and is a more recent experience for those in the Upper Midwest, Northeast and Mid-Atlantic states.

Smoke is particularly dangerous to respiratory health because it contains small diameter particulate. Particulate is a mixture of solid particles and liquid droplets in the air. The small diameter of particulate in smoke allows it to infiltrate the deepest airways within the lungs.

The Impact of Poor Air Quality On Horses

Horses respond to poor air quality very similarly to people. Horses experience irritation of the eyes and respiratory tract. They can develop a cough, have increased nasal discharge, and experience greater physical effort to breathe. The increased effort to breathe can be observed as an elevated number of breaths per minute and is often combined with a heaving flank and flared nostrils. During exercise, it will take longer for the horse to return to baseline heart rate and respiration. Normal respiration in the horse at rest is 12 to 24 breaths per minute.

Signs that your horse is experiencing a respiratory medical event and needs immediate veterinary attention include:

  • Respiration at rest is consistently greater than 30 breaths per minute
  • Increased effort breathing at rest (flared nostrils, heaving flank)
  • Repetitive or deep coughing
  • Abnormal nasal discharge – a change in quantity or color of nasal discharge

How To Monitor Air Quality for Horses

The Air Quality Index (AQI), which was originally developed for people, is a great resource to monitor air quality with the aim of supporting our horses. The AQI measures the level of particulates in the air, a lower number is indicative of healthier air. This value is readily available through weather apps, making it easy to monitor exact conditions in your area.

Air Quality Index




No precautions necessary




Limit exercise for horses with underlying respiratory issues.



Unhealthy for sensitive groups

Limit exercise for healthy horses. Discontinue forced exercise of horses with underlying conditions.




Discontinue exercise for all horses.



Very Unhealthy to Hazardous

Discontinue exercise for all horses.


Making Changes to Training Plans Based on Air Quality

Daily AQI conditions in your area can be used in developing a training plan during periods of poor air quality.

  • An AQI value below 50 is considered good quality and should not impact your horse’s respiratory health, although those with underlying respiratory issues can still have complications with otherwise good air quality due to specific barn environments.
  • Between 51 and 100 AQI is moderate air quality. Healthy horses are unlikely to experience issues but those with underlying respiratory issues should have their workload reduced.
  • At an AQI of 101 to 150, the workload of healthy horses should be reduced and horses with underlying issues should not be exercised.
  • With an AQI above 151, all forced exercise should be discontinued.

Equine sport organizations often implement a system to monitor air quality and may cancel or postpone competitions depending on air quality.

Supplements for Horses During Periods of Poor Air Quality

Additional nutritional support can be added to a well-fortified diet to support respiratory health. Horses with equine asthma benefit from continuous support and healthy horses may need periodic support based on seasonal conditions.

Omega 3 fatty acids are part of the natural anti-inflammatory cascade in the body and have been found to help decrease allergic inflammation.

Products like Natural Remedy® or Wholesome Blends® Omega Plus Oil are good sources of Omega 3’s that can be incorporated both short and long term into your horse’s diet.

If you have questions about your horse’s diet, please contact us for a personalized equine feeding plan.

Article By: Nicole Rambo, Ph.D.
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