Look for a climatecontrolled area
Because the goal is to reduce the horse’s exposure to airborne irritants, moving him to an airconditioned space can be a good idea. Not only is the cooler, less humid air easier to breathe, but the airconditioning unit will filter out dust and pollen that can exacerbate the situation. Of course, most barns are not airconditioned, but a horse may benefit from being moved into a climatecontrolled garage or workshop that has been cleared of hazardous objects.