December 5, 2022
We are pleased to have the opportunity to share our views with the Environmental Protection Agency (EPA) regarding their requestion for information on better indoor air quality (IAQ) management to help reduce COVID-19 and other disease transmission in buildings, with particular emphasis on schools and commercial buildings.
The National Center for Health Research (NCHR) is a nonprofit think tank that conducts, analyzes, and scrutinizes research on a range of health issues, with a particular focus on which prevention strategies and treatments are most effective for which patients and consumers. We do not accept funding from companies that make products that are the subject of our work, so we have no conflicts of interest.
Indoor air quality (IAQ), particularly in the school environment, is crucial for a child’s health and well-being since approximately 90% of time is spent indoors. The quality of air circulation directly affects the spread of coronaviruses and other respiratory viruses and diseases. The EPA does not currently set IAQ standards for non-industrial settings. However, schools and other commercial buildings would greatly benefit from increased regulation. The Harvard T.H. Chan School of Public Health suggests that schools should aim for 4-6 air changes per hour (ACH) in typical classrooms1, yet many schools struggle to meet that benchmark, especially those with outdated HVAC or other ventilation systems. According to a 2020 Government Accountability Office report, approximately one-third of schools need to update or replace their HVAC systems.2 This report also concluded that of the 50 states and the District of Columbia, a majority of states do not conduct statewide assessments to determine school facilities’ needs and instead leave this task to school districts.
In the absence of proper ventilation, air filtration systems, also referred to as portable or in-room, are an alternative method to improve the clean air delivery rate. However, these portable systems often use HEPA filters and can be very expensive. A “do-it-yourself” lower-cost alternative, known as the Corsi-Rosenthal Box (C-R Box), uses MERV-13 filters with a box fan. These devices have been in use in classrooms nationwide during the COVID-19 pandemic, and new research has shown their clear benefit: C-R Box air cleaners efficiently reduce suspended particle concentrations, including airborne viruses, in indoor environments.3 One 2022 study found that C-R Boxes reduced fine particle number concentrations by 56-91% and particulate matter (PM2.5) concentrations by over 70% after use in an active classroom environment.4 The EPA should provide resources to educate the public on the benefits and use of these air filtration units.
Current IAQ standards are insufficient and poorly regulated at state and local levels to keep the public safe from increased COVID-19 transmission and other respiratory illnesses. Federal mandates would ensure that all indoor public spaces are properly assessed to improve ventilation rates. In the absence of greater regulation, the EPA must promote alternative methods of air filtration such as the Corsi-Rosenthal Box. Clean air can and must be ensured to protect everyone in indoor spaces.
Thank you for considering our recommendations. If you have any questions, we can be reached at info@center4research.org or (202) 223-4000.
1. Jones, E., et al. (2020) Schools for Health: Risk Reduction Strategies for Reopening Schools. Harvard T.H. Chan School of Public Health. https://schools.forhealth.org/wp-content/uploads/sites/19/2020/06/Harvard-Healthy-Buildings-Program-Schools-For-Health-Reopening-Covid19-June2020.pdf
2. U.S. Government Accountability Office. (2020) K-12 Education: School Districts Frequently Identified Multiple Building Systems Needing Updates or Replacement. https://www.gao.gov/products/gao-20-494
3. Dal Porto, R., Kunz, M., Pistochini, T., Corsi, R., & Cappa, C. (2022) Characterizing the performance of a do-it-yourself (DIY) box fan air filter, Aerosol Science and Technology, 56:6, 564-572, DOI: 10.1080/02786826.2022.2054674
4. Gasparrini, W., et al. (2022) Testing the Efficacy of the ‘Corsi-Rosenthal’ Box Fan Filter in an Active Classroom Environment. ChemRxiv. https://chemrxiv.org/engage/chemrxiv/article-details/632dd805e665bda75a1002f8