Dust Management in Horse Facilities

Why should horse owners be worried about the air quality in their equine facilities? Is there really anything that can be done to improve the quality once the barn is built? 
This article addresses these questions by providing management practices that can promote ideal air quality. The quality of air in barns and stables is important because high levels of dust mold and other airborne irritants often occur in horse environments. In particular dust can lead to or aggravate respiratory health issues see page 16 Breathtaking A Close Look at Equine Respiratory Diseases. Both recurrent airway obstruction and inflammatory airway disease are examples of common diseases that can increase in severity upon exposure to dusty environments.

The clinical signs of respiratory disease include cough nasal discharge wheezing flared nostrils and laboured breathing reduced performance and exercise intolerance. Often overlooked is the fact that many of our equine companions spend at least half their day confined to the stable. As horse owners come and go throughout the day they dont always think about how a little bit of dust in the corner or a hint of ammonia in the air can have a profound affect on the health of their horses and stable employees. Steps can be taken to reduce prolonged exposure to those irritants.
Factors of Air Quality
In the barn airborne dust is composed of particulates from various sources including soil mold bacteria insects and mite fragments hair manure and plant material to name a few. Dusts and molds can be recognized by the naked eye and by smell but most airborne particulates even aerosolized molds are microscopic less than 10 microns and cannot be seen. 
Dust particles are classified based upon size and expected penetration into the human airways
Total dust
Inhalable dust
Thoracic dust
Respirable dust
Fine particles
Ultrafine particles
Total dust represents all dust particles and is mostly composed of dust that can be physically cleaned from barns. Thoracic dust is a slightly smaller particle size than total dust able to reach only the upper portion of a humans airways. Respirable dust can reach the deepest airways and is so small in diameter that often it is not trapped by natural clearance mechanisms such as mucus. This particle is of particular interest because it is thought to be important in the common lower airway diseases in horses. Ultrafine dust has yet to be thoroughly researched but is so small it is thought to be able to