The tools listed here support the Harvard “Schools for Health” report on risk reduction strategies for schools and should not be used in isolation. Their guidance does not supersede guidance from CDC, WHO, state and local guidance, or other bodies.
This tool is intended to simplify decision-making around portable air cleaners in schools for airborne transmission control (it can also be applied to residential or office air cleaning, noting differences in ventilation practices and occupancy). It is provided to support efforts to supplement outside air ventilation with air cleaning using well established particle filtration strategies. Airborne transmission is not the only mode of transmission, therefore additional risk reduction strategies are required.
This tool was developed to support the use of real-time carbon dioxide (CO2) sensors indoors as a way to help evaluate ventilation rates in classrooms. Users input their target air changes per hour through ventilation and information about the classroom, and the calculator returns the estimated CO2 concentration. IMPORTANT: sufficient clean air delivery can be achieved through any combination of outdoor air ventilation and filtration, but this tool is only for assessing outdoor air ventilation. It is possible to exceed these target CO2 concentrations and still be meeting targets for clean air through filtration.
These tools are provided for informational and educational purposes only. They are intended to offer guidance regarding questions about best practices in an effort to reduce the risk of disease transmission, specifically novel coronavirus SARS-CoV-2 and the disease it causes, COVID-19. Adherence to any information included in these tools will not ensure successful treatment in every situation, and the user should acknowledge that there is no “zero risk” scenario, that each building and situation are unique and some of the guidance contained in these tools may not apply to all buildings, or countries outside the United States.
