Many Americans would love to go watch a horse show. The significant drawback for those with breathing difficulties is arena dust. This dust is not only hazardous to the spectators and riders, but also the horses.

Arena dust occurs when the base of an arena is not properly compacted or has become combined with local soil. For an average arena, a normal year's wear and tear will only wear the surface down 1/8 of an inch. As the surface becomes more used, the dirt is reduced down more and more until the particles are small enough to become airborne.
 
Sometimes unwashed sand is used to cover the arena floor, but it does not create dust because the particles are of adequate size to not become airborne. Another quality of unwashed sand is that it has from 10 percent to 30 percent clay. Clay is a fine particle that can become airborne easily, but it has other qualities that minimize the dust. One is that clay has the ability to bind with other particles in the sand. This helps to decrease the smaller particles that could become airborne that are in with the sand.

Water is another method used to minimize the effects of arena dust. This is an effective method, but it is a temporary solution. To increase its potency, it must be done in significant quantities. In most cases, if the ground soaks up the water down to a depth of two inches, this will be sufficient enough until the moisture evaporates. For most arenas to control dust, not only can they make use of water, but they could also use salt.
 
The most common salts are calcium or magnesium chloride. The unique characteristics of these salts are what make them compatible with water. This is their "hydroscopic properties" or ability to absorb moisture. Unfortunately, there is a risk that is associated with calcium chloride and its caustic effect on the horses and a rider's skin. Magnesium chloride is the recommended salt. As an added precaution, it is recommended that the horse's lower legs and hooves be washed down after being in an arena treated with magnesium salts.

There are other dust suppressors for an arena, but magnesium chloride combined with water is the best choice to fight arena dust.