The Coalition for Safe Schools and Communities believes that schools are the best place for students to be when air quality is poor as they are well-supervised, can be kept indoors, and are able to continue to learn. This page includes information to help you track air quality and prepare for when air quality is not good.

AQI scale graphic

Keep Track of Air Quality

The following sites track air quality data using professional quality monitors that are regularly maintained, independently audited, and have high standards for quality assurance and quality control.

The County Office of Education and the San Mateo County Health Department use these official BAAQMD and AirNow sites to track data because they rely on professional quality monitors that are regularly maintained, independently audited, and have high standards for quality assurance and quality control.

When Outdoor Air Quality is Poor

Stay indoors and reduce outdoor activity based upon your area's Air Quality Index. When air quality improves, even temporarily, "air out" buildings and homes to reduce air pollution. Further guidance, recommendations, and information for schools and families can be found below.

Indoor Ventilation During COVID-19

Schools can follow these recommendations for creating clean air space that reduces the risk of transmitting COVID-19.

  • If HVAC filter was upgraded (HEPA or MERV-13 or higher is recommended), set the central system’s circulating fan to operate continuously (set to “ON” rather than “AUTO”).
  • Maintain outdoor air rates at 15 CFM per person.
  • Note: closing outdoor air dampers is unsafe when COVID spread is of concern.
  • HVAC, air conditioning wall units, and fans without upgraded filters should be turned off.
  • Use a portable air cleaner in one or more rooms. Portable air cleaners work best when run continuously with doors and windows closed.
  • When air quality improves, even temporarily, “air out” buildings to reduce indoor air pollution.

Sensitive Groups

Children with certain medical conditions may be impacted by air quality in the moderate (yellow – 51-100) and unhealthy for sensitive groups (orange – 101-150) levels. Parents/guardians of these children should notify their schools.

Very Unhealthy Air

When air quality dips to very unhealthy levels (purple – 201-300), many schools in San Mateo County will practice the Shelter in Place protocol, which includes keeping all activities indoors, limiting physical activity, and minimizing the opening and closing of doors. Regular classroom instruction continues during Shelter in Place. If AQI hits 250+ a school may consider closing.

Hazardous Air 

If air quality becomes hazardous (maroon – 301-500) and schools do not have the ability to keep outdoor air from easily entering the school, then a school may decide to close. Schools make this decision based on their own local factors

Additional Resources

Ventilation FAQs: Smoke Days and COVID-19: Information about how to keep air safe to breathe in classrooms while still observing COVID-19 safety standards.

Guidance Concerning Air Quality: A handy one-sheet document to help you track air quality and prepare your family and school for days when air quality is poor.

School Air Quality Activity Recommendations: This document was developed with content from the California Department of Education, is geared toward schools. However, it provides families with insight into how schools might address differing levels of air quality.

Air Quality Flag Program: The Environmental Protection Agency (EPA) provides flags for all of the EPA Air Quality levels as well as information on the types of outdoor activity and exposure that are appropriate for each level. While these resources are aimed at schools, they provide helpful information on activities that are appropriate for each air quality level.

Wildfire Smoke and COVID-19: The Centers for Disease Control and Prevention (CDC) has compiled resources to prepare for and respond to wildfires and smoke during the COVID-19 pandemic.

Learn More

California Department of Education Resources

California Air Resources Board

To learn more about the Coalition for Safe Schools and Communities’ recommendations for preparing for unhealthy air quality, see page 14 of its Hazards Responses guidance and pages 10-11 of its Facilities Report.