Proper ventilation is a key to reopening American schools in the fall

Updated CDC guidelines make it clear that ventilation systems that pull in fresh air from the outside are a key tool to enable schools to safely reopen in the fall. While many schools have adopted measures such as masks, distancing and testing, it has become clear that recirculating indoor air and lacking proper filtration has been a key reason why the efforts of so many schools to reopen over the past few months have failed.

According to updated CDC guidelines:

  • A key tool in the CDC COVID-19 “mitigation toolbox” is to Increase the introduction of outdoor air to reduce or eliminate HVAC air recirculation. "There is now good evidence that good ventilation reduces the risk of transmission when indoors. SARS-CoV-2 viral particles spread between people more readily indoors than outdoors. When indoors, ventilation mitigation strategies can help reduce viral particle concentration.”
  • Another tool is to consider using portable high-efficiency particulate air (HEPA) fan/filtration systems that are equivalent to MERV-13 (Minimum Evaluation Reporting Value, a rating used by ASHRAE to enhance air cleaning.

According to the CDC, “research shows that the particle size of SARS-CoV-2 is around 0.1 micrometer (µm). However, the virus generally does not travel through the air by itself. The viral particles are trapped in respiratory droplets that are larger. By definition, a High Efficiency Particulate Air (HEPA) filter rated for HEPA H13 (medical grade) is at least 99.97% efficient at capturing particles 0.3 µm in size.”

BROAD air purification, ventilation and filtration solutions improve and maintain healthy indoor air quality.  BROAD’s Fresh Air systems deliver 99.9% fresh air from the outside, and apply HEPA H13 filtration before the air supply is delivered to the indoor spaces.  Exhaust air is efficiently removed.  An air exchange system warms the incoming air in the winter (or cools incoming air in the warmer months) to save energy costs. 

Ventilation systems are a critical layer in a multi-layer approach to safe re-opening of schools.  And beyond the elimination of pathogens, these fresh air systems eliminate PM2.5 (sources of indoor air pollution) from a range of sources to improve overall air quality. 

For more information on BROAD Fresh Air solutions, visit

Fresh Air units


CDC “Ventilation in Buildings” (updated March 23, 2021):

CDC “Ventilation in Schools and Childcare programs” (updated Feb 26, 2021)