- In 2011 Archives of Pediatrics & Adolescent Medicine published a 126-subject study in which children with asthm residing with a smoker saw a significant increase in symptom-free days with the introduction of an indoor air purifier – however the authors note it is not enough to prevent second hand smoke inhalation.
Asthma and allergies
- In 2002 Chest published a review of 10 studies totaling 216 participants which demonstrated that the use of air purifiers lead to reduced sleep disturbances and a reduction in overall symptoms in patients with asthma and allergies.
- In 2014 The Journal of Asthma published a study with showed that high performance air filters that remove more than 70 percent of pet dander, fine particulate matter and respiratory virus can lower asthma triggers by more than 50 percent. The authors note that very high performance filters, rated 16 on the MERV (Minimum Efficiency Removal Value) rating system, are only marginally more effective than MERV12 or 13 rated filters.
- In 2017 Allegro Journal International published a study which found that air purifiers reduced indoor pollen which lead to significant reductions in allergic rhinitis symptoms (allergies) in study participants.
- In 2003 International Archives of Allergy and Immunology published a double-blind, placebo-controlled study which found that air filtration systems placed in the bedrooms of volunteers suffering from hay fever resulted in a significant reduction in nighttime symptoms. The same effect was not seen in individuals suffering from from perennial allergies.
Allergies in children
- In 2017 the Journal of Asthma published a 12-week study in which air purifiers were installed in the bedrooms of children with asthma in Fresno, CA. Compared to a control group, the children who received air purifiers saw improvement in asthma test scores and reduced daytime nasal symptoms. Average particulate matter 2.5 concentration was reduced by 43 percent.
Reduced particles in homes with wood burning stoves
- In 2011 the Journal of Environmental and Public Health published a study which found that air purifiers were able to reduced the PM (particulate matter) 2.5 concentration by 61 – 85 percent in homes where wood burning stoves were used as a heat source.
Heart and lung health
- In 2015 the Journal of the American College of Cardiology published a double-blind study in which air purifiers were tested against sham air purifiers in the dorm rooms of 35 healthy college students. The air purifiers lead to a 57 percent reduction in PM 2.5 concentration and were significantly associated with a reduced number of inflammatory bio-markers, in addition to reduced blood pressure.
- In 2010 Yonsei Medical Journal published a study which showed that air purifiers effectively reduced house dust mite particles and according to the authors of the study may be beneficial for individuals with dust mite allergies.
- In 2012 Critical Care published a study in which air purifiers were placed in ICU care rooms. Based on air samples taken before and after a 24-hour period of air purification, airborne bacteria levels were reduced by 72 percent and fungal levels were reduced to be undetectable levels.