subject: Managing Ragweed Allergies--7 Tips for Surviving Ragweed Allergy Season [print this page] By definition this kind of filter must remove 99,997 out of every 10,000 airborne pollutants to have the HEPA designation. The fact that it can operate continually means that indoor airborne irritants are never allowed to build to a level that would make symptoms flare.
Managing Ragweed Allergies--7 Tips for Surviving Ragweed Allergy Season
