Air purifiers are among the most common purchases for allergy sufferers. But do they help? The answer is nuanced—they can reduce airborne allergens, but they're not a cure-all.
What Air Purifiers Can Help With
HEPA filters effectively capture common airborne allergens:
- Pollen: Particles typically 10-100 microns, easily captured
- Dust mite allergens: Fecal particles and body fragments, 1-10 microns
- Pet dander: Skin flakes, typically 2.5-10 microns
- Mold spores: Typically 1-30 microns
All of these are well within HEPA's capture range.
What Air Purifiers Can't Do
- Remove settled allergens: Allergens on surfaces, bedding, and carpets aren't airborne—purifiers only capture what's in the air
- Address sources: If you have a pet, dust mites in bedding, or mold growing somewhere, the purifier manages symptoms, not causes
- Replace other measures: Cleaning, allergen-proof bedding, and source control are important companions to air purification
What to Look For
True HEPA Filter
Essential for allergen capture. Avoid "HEPA-like" or "HEPA-type" claims. True HEPA captures 99.97% of particles at 0.3 microns and performs even better on larger allergen particles.
Appropriate CADR
Size matters for effectiveness. An undersized purifier won't cycle enough air to make a meaningful difference. For allergy relief, err on the larger side—more air changes means fewer allergens at any given moment.
Quiet Operation
Bedroom placement is particularly valuable since you spend 7-8 hours there. A purifier that's too loud to run at night defeats the purpose.
Avoid Ionizers and Ozone Generators
Some ionizers produce ozone, which can irritate airways. For allergy sufferers, this is counterproductive. Stick with mechanical HEPA filtration.
Best Practices for Allergy Relief
Bedroom Priority
Focus on the bedroom first. Running a purifier overnight means hours of breathing cleaner air during sleep. Keep the door closed to maintain air quality in that room.
Continuous Operation
Run the purifier continuously, not just when you notice symptoms. Allergens accumulate—keeping levels consistently low is more effective than reacting after exposure.
Combine with Other Measures
- Wash bedding weekly in hot water
- Use allergen-proof pillow and mattress covers
- Vacuum with a HEPA-filter vacuum
- Keep humidity between 30-50% to discourage dust mites
- Remove carpets if possible, or clean frequently
Seasonal Adjustments
During high pollen seasons, keep windows closed and let the purifier work. When pollen is low, opening windows can reduce other indoor pollutants while you rely less on the purifier.
Realistic Expectations
Air purifiers reduce airborne allergens—they don't eliminate allergy symptoms. Most people with allergies find them helpful as part of a broader strategy, not as a standalone solution. If you're expecting complete relief, you may be disappointed.