Why clean air
Schools and child care programs are inspected for safety, food handling and building conditions, and increasingly tested for lead in water. Most have never measured the air children breathe.
90%
Of our time is spent indoors
Children spend roughly half their waking hours in classrooms. Young children in child care spend about 30 hours a week there, roughly a full-time job, almost entirely indoors. In K–12, air quality shows up in learning, attendance and behavior: the outcomes schools already work hardest to improve.
12.5%
fewer absences with classroom air cleaning
0.1–0.2
standard deviations higher math and English scores after air purifiers went in
18%
fewer new infections in daycare centers with air cleaners
77%
less particle pollution in classrooms with in-room filters
01
In a randomized trial of more than 2,000 children, classroom air cleaning cut absences by 12.5%, with the largest gains among students missing the most school. In Helsinki daycare centers, room air cleaners cut new infections by 18% (95% CI 2–31%), from 0.95 to 0.78 per child per month.
02
Even air pollution below federal standards can cut student learning gains by nearly 20%. After air purifiers were introduced, math and English scores rose by 0.1–0.2 standard deviations, an unusually large gain for about $1,000 per classroom.
03
Air pollution is linked across multiple studies to more school discipline incidents, including fighting, defiance and conflict. Students at a school downwind of a major highway have lower test scores, more absences and more behavioral incidents than at comparable upwind schools.
04
Studies across three continents link higher fine-particle exposure in early life to lower childhood IQ. A review of 40 brain-imaging studies of children from birth to 18 links air pollution to differences in brain structure and function.
05
Fine particles reach deep into the lungs and enter the bloodstream, and are linked to asthma, heart disease and cognitive development. Young children are more vulnerable: they breathe more air per pound of body weight, and their lungs and brains are still developing.
06
“Go inside” isn’t enough. During one smoke event, 71% of K–12 campus buildings exceeded the daily air quality limit, including buildings with upgraded HVAC filters. Wildfire smoke has lowered test scores across thousands of U.S. districts, and low-income communities lose the most.
Outside the school
Inside the classroom
On bad-air days we tell children to go indoors, but indoor air comes from outside unless the building removes the pollution.
HVAC setting changes and filter upgrades can make a difference inexpensively, overnight. Modern in-room filtration goes further, dramatically cutting airborne particles from the day it goes in.
That combination is rare in education: a fix for a large problem that is inexpensive, light on administration, and directly benefits students, parents and teachers. Leaders can start this school year and see effects on exposure, attendance and learning within months.
What it does not require
What it costs
$5–10 per student per year
About $1,000 per classroom to put in place.
Lead in paint
Asbestos in schools
Smoke in restaurants
Pathogens in drinking water
Each was an ordinary part of life until the evidence became impossible to ignore. Clean indoor air could be approaching the same moment.
The first step is a conversation about your priorities, what is already in place, and whether the fit is right. Or get updates as the program takes shape.
