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Experts Encourage School Administrators to Reduce COVID-19 Transmission by Improving Indoor Air in Schools

Center News


January 11, 2022 – Experts from the Johns Hopkins Center for Health Security call on school administrators across the United States to reduce COVID-19 transmission by improving indoor air in schools.

Emphasizing the findings of their May 2021 report, School Ventilation: A Vital Tool to Reduce COVID-19 Spread, on December 22, 2021, these experts sent a letter to leaders in the 10 largest US public school districts, sharing detailed recommendations on how to reduce the spread of SARS-CoV-2 in indoor environments.

“Ensuring that schools have healthy air to breathe is a no-regrets investment and a cost-effective public health measure to reduce SARS-CoV-2 transmission, provide a safer environment, and improve learning,” wrote Dr. Paula Olsiewski, a biochemist and contributing scholar to the Center; Dr. Gigi Gronvall, an immunologist and senior scholar at the Center; Dr. Richard Bruns, an economist and senior scholar at the Center; and Dr. William P. Bahnfleth, a mechanical engineer at Penn State University and a fellow/presidential member at ASHRAE.

They recommend that school administrators should:

  • Assess classrooms and common areas to ensure that they can meet updated COVID-19 air filtration guidance, including MERV-13 filters and at least 6 air changes per hour of outdoor or filtered air, as recommended by ASHRAE and the CDC.
  • Purchase or build HEPA air filtration units to be placed in classrooms and commonly occupied areas that do not or cannot meet updated standards.
  • Upgrade heating, ventilation, and air conditioning systems so that they can bring in as much outdoor air as safely possible.
  • Use only proven technologies for improving indoor air quality: ventilation, filtration, or ultraviolet germicidal irradiation.
  • NOT USE unproven or additive technologies such as ionization, ozone generators, plasma, and air disinfection with chemical foggers and sprays, as the health benefits of these technologies are not clear and many scientists and engineers are concerned about potential adverse health impacts. 

Read the full letter. (PDF)

Read School Ventilation: A Vital Tool to Reduce COVID-19 Spread.

Read COVID-19 Infographic: Tips to Improve Indoor Ventilation in K-12 Schools to Help Reduce COVID-19 Transmission.