Has spurred investment in air filtering for K-12 schools
A survey on infrastructure reported that more than one-third of nearly 100,000 public school buildings in the U.S. need immediate upgrades to ventilation systems. These improvements are required in order to control indoor air pollution and the spread of “aerosols.”
Aerosols are microscopic particles in the air that float both indoors and outdoors. Aerosols are constantly exhaled and inhaled by people, including allergens, automobile exhaust particles, wildfire ash, and microbes.
For more than 25 years, the University of Colorado Environmental Engineering team have been researching microbiological components of air indoors called “bioaerosols”. We have studied the ventilation systems in hundreds of classrooms, hospitals , and restaurants. We have also provided facility managers with cost-effective plans to improve the indoor air quality.
We have found in our own and others that classrooms are often poorly ventilated. This can lead to a reduction in student absences due to illness, both during pandemics and normal times.
We found that air filtration systems can improve classroom air quality by lowering the aerosol level, which reduces the COVID-19 risk. But the key is effective installation.
The new age of filtration
As the epidemic continues to bring to light the need for improved ventilation and indoor air, academic institutions and government agencies, as well as non-governmental organizations and professional societies of building science, are promoting better building management practices to improve school ventilation.
Some building scientists recommend that schools be ventilated to the same standards as medical clinics. The infrastructure investment required to upgrade public buildings at this level is not feasible for most. Between 2008 and 2017, state funding for schools has been cut by 20 billion dollars, or 31 percent.
Some schools have installed simple in-room filters to improve ventilation, in the absence of funding that would allow for major building upgrades. Many students spend most of their day in close quarters. These filters are only used in a fraction of the public schools in the United States.
The aerospace industry has been using this technology for more than 50 year. HEPA filtration is proven to remove airborne microscopic particles, including respiratory viruses, from high occupancy spaces such as classrooms.
In the last few years, the commercial sector in the United States has developed a new generation of HEPA filters. These filters are less intrusive and more suitable for educational settings than the research-grade versions that are used by many industries, such as aerospace and pharmaceuticals, to create “clean rooms”. The latest models have improved features like multidirectional intakes, reduced noise, low power requirements, better durability, and small footprints.
In recent years, HEPA filters are also being used more in homes due to the rising asthma rates in children. They were not used much in schools until the COVID-19 epidemic.
Bring fresh air into classrooms
Our team installed hundreds of new HEPA filters during the spring 2021 academic semester in Denver, Colorado. Denver is the largest school district in Mountain West. The University of Colorado, Intel Foundation and Carrier Corporation, an international ventilation equipment company, collaborated to upgrade these classrooms. These organizations have contributed together more than $500,000. This money was used to fund large-scale ventilation assessment, HEPA filters, and other improvements in air quality for Denver area schools.
Mark Hernandez of the University of Colorado Boulder, Ricardo Reyes, an engineering student, and Halle Sago, a student of architecture, count microbial colonies on a desk in a Boulder classroom in spring 2021. Glenn Asakawa/CU Boulder CC-BY-ND
Teachers in many of these classrooms, in a poll that has not yet been published, reported overwhelmingly that the new generation HEPA filters are welcome and easy to install in their classrooms.