Question: My city is considering allowing a 755-horse stable with open land, adjacent dirt riding paths and commercial equestrian facilities on an upwind site from a few thousand residents. The residences are anywhere from 500 feet to 1 1/2 miles from the site. Manure mitigation will be done at the facility but no plan exists to control dust (or odor) on the trails. Do the residents need to be concerned that airborne dust might exacerbate allergies and/or respiratory ailments? Is there a reliable calculation to ascertain X-number of horses becomes a human health hazard at X-distance from them? Any additional comments regarding potential human health hazards would be appreciated as well.
Answer: This is a very interesting question to consider. This is a huge operation that sounds like it is in a fairly urban area. A lot will depend on how the facility is built and managed. The type of land surrounding the facility, the number and type of trees, the surrounding environmental moisture levels (i.e. desert, swamp, variation in annual rainfall) and the prevailing winds will all affect the influence of the facility on the surrounding houses.
Most of the research that has been done on animal facility dust generation concerns feedlots where there are considerably more animals than this facility. However, high levels of dust from feed lots have been shown to be problematic for both workers and the livestock (here are a few resources concerning data on the dust generated by a facility: Simple Protocols to Determine Dust Potentials from Cattle Feedlot Soil and Surface Samples, Measuring Dust on Feedlots and Why Tiny Particles Pose Big Problems). Another concern that I would have as a veterinarian would be the respiratory health of the horses kept in such a facility. When large numbers of horses are in one area, ventilation of barns becomes even more critical to prevent allergic respiratory disease. Behavior issues and dietary deficiencies also arise with horses who have limited turn out time.
An additional factor in calculating the dust potential is the type of turnout spaces and how those are managed. In many cases there will be multiple small pens with dirt and no vegetative ground cover. If the environment is dry, dusty and windy when horses are turned out into these lots there is a potential for quite a bit of dust to be stirred up. If the environment tends to be moist, has dirt that packs hard, stone dust or some type of material that does not get stirred up, there may be little dust released into the air.
Horses riding on the trails around the houses will kick up dust in a dry environment, and if there are large numbers of horses on the trails at one time you may see dust affecting the air quality. However, there are many houses lining dirt roads across the country, and air quality is usually only an issue during the driest months and with heavier traffic. If dust becomes a problem, some products may be able to mitigate the dust (like ARENACLEART and Dust-Off ).
Horses being worked in dry outdoor arenas can kick up a lot of dust. A large facility like this may have several arenas going at one time. Some of the dust mitigation products would be useful in the riding arena, especially if the prevailing winds carry that dust toward the houses. Dust in the arenas is a problem for both the riders and the horses because while they are exercising the respiratory rate increases, and they cannot escape from breathing the dust.
There is no one clear answer to your question, but hopefully this will give you some tools to help calculate the potential effects of this facility on your community.
Dr. Joyce Harman is a veterinarian and respected saddle-fitting expert certified in veterinary acupuncture and veterinary chiropractic; she is also trained in homeopathy and herbal medicine. Her Harmany Equine Clinic is in northern Virginia. Visit her online shop, blog and Facebook page.
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