Who knew the air quality in indoor arenas was this bad for you?

… all the arena setups had dust levels—and more specifically, dust particle sizes of less than 0.5 micrometers, which can lodge in the alveoli (microscopic air sacs located at the end of the bronchioles where gas exchange—or respiration—occurs) and contribute to airway disease. The vast majority of particles, regardless of time of year or arena type, were smaller than 0.5 micrometers, and in fact, most of those were actually less than 0.3 micrometers. What’s more, the average concentrations of particles in this study were up to 10 times higher than those found in towns with air pollution. Considering that fact, it’s not surprising that 35% of riding instructors in a recent survey showed a prevalence of chronic bronchitis, Kemper said, and that recurrent airway obstruction (also known as heaves) in riding horses is widespread.

“… Training outside in fresh air, whenever possible, is also a good option.”
— TheHorse.com