COVID-19 and Improving Indoor Air Quality in Schools

Having good ventilation and air filtration in schools is very important to reduce COVID-19 and other diseases that spread through the air. Improving indoor air quality also creates a healthier school environment by limiting exposure to harmful chemicals and wildfire smoke. In addition, better air quality increases student performance and attendance. You can improve indoor air quality using one or more of the following strategies:

Optimize or Upgrade Your Mechanical Ventilation (HVAC) System

The HVAC system reduces hazards in the air by pulling in outdoor air and circulating indoor air through filters. Work with facility managers to optimize your system by reviewing the CDPH Guidance for Ventilation. Use federal stimulus funding to work with indoor air quality or ventilation consultants to assess whether your system needs an upgrade.

Open Doors and Windows (Natural Ventilation)

While natural ventilation can be an important tool to improve air quality, it is not as easy to control as mechanical ventilation. Opening windows and hallway doors on opposite sides of the room creates a cross draft which is the best way to naturally introduce outside air. Use CO2 monitors to determine if enough outdoor air is being brought into a classroom from natural or mechanical ventilation. Levels above 800 parts per million (ppm) can indicate more outdoor air is needed.

Add Portable Air Cleaning Devices (PACs)

You can add portable air cleaning devices to classrooms (PDF) to supplement mechanical and natural ventilation. Purchase PACs that are sized appropriately and circulate air through High Efficiency Particulate Air or "HEPA" filters. Most PACs will list the intended room size. Avoid devices that advertise "ionizer" or "ozone" technology. Alternatively, a low-cost DIY PAC can be built and added to classrooms.