Indoor Air Quality

Your School’s Unseen Health Threat: Indoor Air Quality

With the start of a new school year, the health & wellness of students, teachers, and school district employees has become—more than ever—a top priority and concern.

Faced with this summer’s oppressive heat and torrential rains, and with many HVAC systems turned off or raised higher for June, July, and August, school buildings face more indoor air quality, mold, and airborne contamination issues than in the past.

In many parts of the country (and especially in the Northeast and Midwest) we experienced dozens of heavy rainfalls combined with extremely hot, humid days. This is the perfect storm for mold and bacterial growth. Many schools either had air conditioning systems turned off or used on a limited basis in the summer. Mold grows in humid places with lack of ventilation, and most closed schools check these boxes.

It's commonly thought that mold goes away in winter and the school year, but in fact, it will simply lie dormant and will grow again when conditions are right. Also poorly insulated areas can lead to winter mold growth that can spread quickly.

For example, if an exterior wall is not insulated, cold air from the outside will meet warm air from the inside. This reaches the dew point when moisture forms, and mold will grow. This type of growth is mostly unseen until it becomes a significant problem.

In addition to mold, there’s a new threat to school buildings: wildfire smoke. Most of our schools are not totally sealed from outdoor air; therefore, you feel drafts in the winter. This also means that air laden with contaminants from Canada's wildfire smoke and other sources will find its way into our schools.

Wildfire smoke contains significant PM 2.5 sized particles. These particles are small enough to be breathed in and settle in our lungs, causing respiratory distress.

Proper maintenance and upgrades to a school’s heating and air conditioning system can be key to combatting mold, airborne contaminants, and wildfire smoke as well as providing a healthier indoor environment.

Upgraded filters and UV lights are helpful. The only drawback: airborne contaminants must pass through the filter or light to be effective.

Another interesting and more effective technology is bi-polar ionization. BPI tubes added to a school’s HVAC system proactively release ions into the air 24/7 that seek, attack, and mitigate airborne contaminants—from bacteria and viruses like coronavirus to smoke and fine particles.

The importance of indoor air quality in schools has become a growing priority in our post-pandemic and climate-change world. Studies by groups such as the Harvard School of Public Health and Carnegie Mellon University have shown that by improving IAQ decreases illness and absenteeism.

Classrooms, cafeterias, gyms and locker rooms are locations where airborne illnesses can easily spread from one person to another. Using air purification to reduce the airborne contaminants that lead to illness, dust and spores, bacteria, viruses and germs and VOC’s (Volatile Organic Compounds) can reduce the spread of illness and help to reduce absenteeism by students, teachers and staff.

In addition to health and wellness benefits, reducing absenteeism also has financial impacts. When a teacher is out sick the school will have to pay both the teacher who is home and the substitute teacher who is taking their place.

A recent announcement from ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers)  provides a new answer for school districts and doubles down on the importance of health & wellness in school buildings.

A committee, of which I am a member, created Standard 241, which established minimum requirements to reduce the risk of disease transmission by exposure to infectious aerosols in new buildings, existing buildings, and major renovations.

Implementing this new standard in schools would reduce exposure to SARS-CoV-2 virus (which causes COVID-19), influenza viruses, and other pathogens that cause illness among students, faculty, and school employees.

Standard 241 is a major advance in making school buildings healthier. And as important, it will create a new emphasis and urgency to improve ventilation so our schools will be better prepared for the next pandemic. It’s important that education leaders take note and institute the IAQ improvements proposed by Standard 241.

Indoor air quality will continue to play a vital role in keeping school buildings healthy and reducing student and teacher absenteeism.

School districts and education leaders must now take the lead and re-think how to improve indoor air quality in their schools to provide a healthier environment for  their students, faculty, and school employees.

About the Author

Tony Abate is Vice President and Chief Technology Officer at AtmosAir Solutions (, an indoor air purification and monitoring technology company, and a Certified Indoor Air Quality Professional, as well as an ASHRAE Regular Member and Committee Chair.