News Brief

Air Filtration in Schools May Improve Test Scores

Students with cleaner indoor air significantly out-performed their peers in a recent study.

The cognitive effects of outdoor air pollution can be devastating, particularly for schoolchildren. A new working paper suggests that there may be an inexpensive correction for this—cleaning up indoor air using air filters.

The study took advantage of the political fallout from a 2015–16 gas leak in California. Residents demanded protection from the effects of the gas, and as part of that, the gas company ended up installing air filters in schools located within five miles of the leak. It turned out that the gas dissipated before ever entering the schools, but the circumstances inspired working paper author Michael Gilraine, Ph.D., of New York University to study the impacts of the air filters.

He compared test scores between schools with air filtration and those nearby that did not have air filtration. Students with filtered air significantly out-performed their peers without filtered air on both math and English tests. The effects were comparable to decreasing class size by a third, according to Matthew Yglesias, writing for Vox.

Gilraine claims that air filtration might be the most cost-effective way to boost test performance, adding that the impacts could be greatest for low-income students, who tend to live in the most polluted neighborhoods. “Installing air filters in schools throughout many areas of the United States should generate similar test score gains,” he concludes, adding that this relatively inexpensive fix could even potentially remove persistent test score gaps between low-income children and more affluent students.

The study did not address the level of filtration that might be required, nor did it assess the potential energy costs associated with filtering air.

For more information:

National Education Working Papers

Published March 2, 2020

Melton, P. (2020, February 25). Air Filtration in Schools May Improve Test Scores. Retrieved from

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March 4, 2020 - 6:58 pm

You may wish to check into this further.


June 3, 2020 - 12:15 pm

I am surprised & disappointed that BuildingGreen would so sorely miss the important points here.  BuildingGreen's whole premise is to ID the key problem & come up with solutions that PREVENT & SOLVE the source of a problem!  The stated solution [air filters] & goal [improving test scores] of this paper are sorely misdirected & misunderstood.  It's NOT just 'outdoor pollution' that deteriorates children & staff health--it's well documented that INDOOR contaminants [mold mycotoxins; chemical fumes outgassing from building materials & from toxic maintenance products/practices] are a major cause of adverse health effects in schools [& other buildings].  Of course air filters [of the correct filtration media] will improve air quality to a degree, & one positive effect may be 'higher test scores'. BUT THE BASIC PRINCIPLE IN AIR QUALITY IS that the most effective way to achieve healthy air is TO 1st PREVENT introducing air contaminants into the air. Dilution & filtration of contaminants are less effective methods than PREVENTION.  So the correct goal & most effective way to protect the health [& test scores] of children is to design, choose building materials, furnishings, & maintenance materials that do NOT TOXIFY & CONTAMINATE the indoor air! Example: many schools have serious mold problems nationally. The solution to that is (1) properly fully remediate the mold & (2) construct & (3) maintain buildings so they do not have hi humidity or water leak problesm that enable mold growth. Air filtration of moldy buildings is NOT a real solution to mold mycotoxins in the indoor air. Finally, the GOAL should be improving & maintaining HEALTH generally NOT for the purpose of 'high test scores', but so that staff & children do not develop chronic health problems [asthma, neurological deficiencies, etc] that impair ALL of their life activities, not only their 'test scores'.  

June 4, 2020 - 9:15 am

I certainly appreciate your focus on IAQ here, and I completely agree with your assessment that prevention (good building science + not introducing VOCs in the first place) is better than dilution. But this particular paper was about preventing outdoor air pollution from making things worse when "fresh" air comes in. Our newsbriefs are designed to make people aware of new findings in a variety of areas. We have covered the issue of VOCs and mold extensively elsewhere. Thanks again for your feedback!