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Opinion: We need safer air in Colorado’s schools — but let’s be careful how we get there

Investments in indoor air quality can dramatically improve health for students, teachers, and school staff for the rest of this pandemic and the next generation.

Centennial Elementary School first graders eat lunch in the school cafeteria Wednesday, February 10, 2021 in Colorado Springs. Harrison School District officials installed plexiglass shields down the middle of all the lunchroom tables. Photo by Mark Reis

Colorado needs to make the indoor air of our schools safer. 

Protecting against the airborne spread of COVID-19, as well as smog and wildfires, will pay dividends in the health of our children both now and for the future — but the funding could easily be wasted or even make the air more dangerous. Avoid gimmicks. Follow the science. Filter and ventilate the air.

The newly passed federal American Rescue Plan promises $1.9 trillion of economic stimulus to the country, $130 billion of which is promised to K-12 schools nationally. Included is $1.2 billion for Colorado schools through Elementary and Secondary School Emergency Relief funding to help reopen schools safely. 

Alex Huffman, Delphine Farmer and Marina Vance

The plan specifically encourages using funding to “improve the indoor air quality in school facilities.” Our schools urgently need the money to help keep students, teachers, and staff as safe as possible against the still-raging COVID-19 pandemic. 

If done properly, the same investments will also help improve the air our children breathe when in school and reduce asthma, allergies, and effects from worsening air pollution from Colorado wildfires and urban smog.

However, school districts are presented with a minefield of air cleaning options and must separate the good from the inefficient — or even dangerous — products being pushed heavily by opportunistic companies

School districts have already spent millions of dollars on questionably effective interventions, like Plexiglas desk barriers and chemical air cleaners. While masks, distancing, hand hygiene, and cleaning all remain essential as we continue to ramp up Colorado’s vaccination efforts, schools need significant infrastructure improvements to clean the air. 

We strongly advocate using well-established methods of ventilation and filtration — approaches based in evidenced-based decision-making that will pay dividends to student health now and for a generation. And we also encourage constituents across the state to advocate for these decisions to be made in their local districts.

READ: Colorado Sun opinion columnists.

Clean air means breathing air without harmful pollutants. Small particles (aerosols), ozone, and other toxic chemicals from car exhaust and increasingly common Colorado wildfire smoke cause serious health problems including asthma and allergies. Aerosols can carry airborne diseases, such as influenza, measles and COVID-19. 

Fortunately, the same methods that clean smoke-filled air provide allergen- and pathogen-free air for school children. 

Investment in healthy air quality should focus on improving ventilation systems. Increasing the amount of outdoor air brought into school HVAC systems and circulated, using high-quality HVAC filters, and achieving a minimum of about five air changes per hour will all improve indoor air quality. Monitoring indoor air with relatively inexpensive carbon dioxide sensors can often help make sure ventilation is sufficient. 

We acknowledge that major changes to building ventilation systems can be very expensive. Portable HEPA filters in each room are an excellent and cheaper alternative for safer air. Portable filters can be moved easily between rooms to where students are exercising or masks are removed, like lunchrooms, gyms, and music rooms. 

Colorado researchers have even provided resources for schools to calculate how many portable filters you need.

The consistent message from experts is to avoid being too creative with airborne solutions. Stay away from worthless — or even dangerous — add-ons to filtration like bipolar ionization, hydroxyl or ozone generators, and fumigation with disinfectants. Instead, simple building ventilation and portable filtration strategies make air safer not only from airborne diseases, but also from air pollution. 

Improved indoor air quality, including lower carbon dioxide levels, in schools can even increase test scores and human cognition! 

A rough cost analysis suggested that adding in-room HEPA filtration to every schoolroom in the United States would cost less than $10 per student, and solutions like increasingly widespread DIY box fan-filter air cleaners can add even more cost-effective options to consider

When people are within a few feet of each other, tight-fitting masks and a little extra distance are still the only preventative measures against the cloud of aerosol from an infected person. However, improved indoor ventilation and filtration are essential for everyone else in the room. 

We encourage school districts to use stimulus funds to improve the indoor air quality of their schools. Follow the guidance suggested by the CDC, WHO, industry groups, and other reputable sources. Use evidence-based strategies. Avoid technologies that have not been proven by peer-reviewed scientific research. 

We encourage students, teachers, and the community to engage with district administrators and encourage them to leverage funds to support both the immediate and long-term health of students and staff.

The stakes are high for schools across Colorado and the rest of the country. Airborne transmission of COVID-19 remains a threat to every community, especially as more transmissible and dangerous variants rise. 

The same, crucial investments in indoor air quality can dramatically improve health for students, teachers, and school staff for the rest of this pandemic and the next generation.


Alex Huffman is an associate professor of chemistry at the University of Denver. Delphine Farmer is an associate professor of chemistry at Colorado State University.  Marina Vance is an assistant professor of mechanical engineering at the University of Colorado Boulder. All three are aerosol scientists who study the air we breathe both indoors and out.


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