Can Air Purifiers in Schools Improve Academic Performance?

After purifiers were installed in southern California classrooms following a gas leak, students saw gains on math and English tests.

A 2015 gas leak that belched toxic chemicals into the air and spread panic may have indirectly led to higher student test scores.

photo of classroom
California students who breathed purified air in classrooms saw modest improvements in their math and English test scores. Photo by Alliance for Excellent Education.

In the days after a gas leak was discovered in Aliso Canyon, 30 miles north of Los Angeles, thousands of residents were evacuated from the area, many of whom reported headaches, nausea, stomach aches, dizziness, or breathing problems. Students from two nearby schools were relocated and 18 other schools were impacted.

The gas field owner, Southern California Gas Company, responded to the backlash and installed air purifiers in every classroom and office within a five-mile radius of the leak.

The air purifiers appear to have been installed in an abundance of caution. By the time SoCalGas installed them months after the gas leak, testing showed air at those schools had levels of pollutants within the normal range.

Regardless, the circumstances created an unlikely laboratory to study air quality and its impact on learning. A working paper from the New York University researcher Michael Gilraine found that students who breathed purified air saw gains on math and English tests greater than those who attended schools outside of the boundary.

There’s some dispute over the significance of those gains (an increase of 2.0 standard deviations in math and 0.18 in English). Vox compares the effect to what’s been seen in classrooms that have fewer students, and suggests schools can boost student performance simply by installing simple air purifiers. Mother Jones is skeptical about how impressive those gains are and whether they would justify costs of $1,000 a classroom.

But the study adds to the mounting body of research on what we intuitively know is true: polluted air is bad for brains and bodies.

Research has shown that those living close to refineries, plants, and interstates see higher rates of asthma, heart attacks, strokes, and deficits in lung function that can lead to a lifetime of health problems.

Despite the fact a state law passed in 2003 prohibits school districts from building new schools within 500 feet of a freeway, tens of thousands of students in Los Angeles still attend schools within that distance.

A Los Angeles Unified school district spokesperson said officials have taken a number of steps to protect air quality: the use of pesticides and harmful chemicals is limited or prohibited at schools; the district communicates with outside agencies to monitor air pollution; and all schools have air conditioner systems with filters. (The schools near Aliso Canyon got purifiers, not just filters, so students were essentially breathing extra-filtered air.)

In California, as is true elsewhere, people of color and those living in poor neighborhoods breathe more polluted air.

A study published in the American Journal of Public Health found alarming disparities: Hispanic people were 6.2 times more likely than whites to live in the zip codes that saw the worst pollution; African Americans were 5.8 times more likely. Native Americans, Asian and Pacific Islanders, and multiracial individuals were all worse off than white people.

The problem was most pronounced in the San Joaquin Valley and near Los Angeles, data showed.

In the San Joaquin Valley, California’s agricultural center, nearly one-quarter of the population suffers from asthma. Most of those affected are poor and not white.

In Boyle Heights, an east Los Angeles community where more than 90 percent of residents are Hispanic, children grow up around a tangle of freeways, four rail yards emitting diesel exhaust, body shops, and chrome-platers.

Experts say that air filters can help clean the air, but can’t filter out all particles and caution against looking to them as fix, the Los Angeles Times reported. Addressing the problem more holistically might involve increasing the housing stock so developers don’t have to build homes and schools so close to freeways.

Similarly, while filtered air is no panacea for schools, studying its impact is part of a growing awareness that myriad factors outside of school affect learning, and an example of willingness to look to unlikely places to address problems — whether that means providing free breakfasts, adding washing machines, or installing air purifiers.

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