Effectiveness of Air Filters and Air Cleaners in Allergic Respiratory Diseases

Air filtration is frequently recommended as a component of environmental control measures for patients with allergic respiratory disease. Residential air

filtration can be provided by whole house filtration via the home’s heating, ventilation, or air conditioning system, by portable room air cleaners, or a

combination of the two. Appliances to filter the sleep breathing zone also have been developed. High-efficiency whole house filtration, high-efficiency

particulate air sleep zone air filtration, and high-efficiency particulate air room air cleaners all appear to provide various degrees of benefit. Recent

studies of various types of filtration, used alone or as part of more comprehensive environmental control measures, are reviewed.

Keywords: Air cleaner, Air filter, Air filtration, Breathing zone, CADR, Clean air

delivery rate, Environmental control, Furnace filter, HEPA, HVAC, Indoor air, Indoor allergens, Intervention measures, Ozone, Particulate matter, PM, Room

air cleaner, Sleep breathing zone, Ventilation, Whole house filtration

Environmental control practices (ECPs) are a group of measures recommended to reduce exposure to indoor allergens (eg, dust mites, household pets,

cockroaches, mold, mice) or nonallergic triggers (eg, environmental tobacco smoke [ETS], wood smoke, volatile organic compounds, particulate matter [PM])

[1]. Historically, many of the common suggestions have been empiric and not based on scientific data or evidence-based clinical trials. As a better

understanding of the impact of the characteristics of housing stock [2, 3] and occupants [4] on the indoor living environment has evolved, more effective

measures have been identified. These may include modification of the occupant’s habits, remediation, and/or modification of the dwelling and its

furnishings, structure, or ventilation, including the use of air filtration. One major drawback in many ECP studies has been the focus on a single allergen

(eg, dust mites [5]) or intervention (eg, room air filtration for cat or dog allergy [6–8]). In fact, most allergic individuals have polysensitivity to

multiple allergens. ECPs are therefore much more likely to be beneficial if targeted against triggers or allergens known to be problematic for the

individual.