CDC Ventilation and Indoor Air Quality for K-12 Schools and Early Care

CDC Updated Recommendations to Optimize Ventilation and Indoor Air Quality for K-12 Schools and Early Care and Education Programs

The Centers for Disease Control and Prevention (CDC) updated operational guidance for K-12 Schools and Early Care and Education (ECE) Programs to Support Safe In-Person Learning provides school administrators with recommendations on how to anticipate and control outbreaks to reduce the risk of spreading infectious diseases including COVID-19. The operational strategies outlined in the guidance include administrative controls for staff and students, prevention strategies to aid community leaders and the public, and recommendations to optimize school building engineering controls for clean air.

CDC guidance states schools and ECE programs can optimize ventilation and maintain school building HVAC systems (repairs, upgrades, and replacements) to optimize indoor air quality and reduce the risk of contaminants spreading through the air. Ventilation systems should provide indoor air quality that meets the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards for each space’s occupancy level.

Improving indoor air quality can reduce the risk of exposure to particles, aerosols, and other contaminants that facilitate the spread of infectious diseases like COVID-19 through inhalation of airborne particles and aerosols. One single action cannot fully eliminate the risk of disease, but it can still significantly reduce risk. Through use of DNA-powered aerosol tracers to evaluate the aerosol mobility throughout your school buildings, RHP Risk Management’s Certified Industrial Hygienists can identify issues within your existing HVAC system, pinpoint problem spaces and confirm successful implementation of best-practice recommendations for reducing risk for disease transmission to help keep students and faculty safe and healthy.

Funds provided through the U.S. Department of Education’s Elementary and Secondary Schools Emergency Relief (ESSER) Programs and the Governor’s Emergency Education Relief (GEER) Programs and the Department of Health and Human Services’ Head Start and Child Care American Rescue Plan are available to alleviate the financial strain of administrative and engineering controls laid out in the guidance.

Optimizing Ventilation and Enhancing Air Filtration

Although ventilation can be improved by increasing the amount of outdoor air in the building by opening doors and windows, the climate and region may dictate when and how this is feasible. Reducing air recirculation and increasing overall airflow increases the frequency of air filtration and changing in thermostat settings to “Fan On” instead of “Auto” mode will allow for continuous air filtration and distribution. Portable air cleaners that use high-efficiency particulate air (HEPA) filters can be used to improve air cleaning and can be particularly effective for higher-risk areas identified within a school or childcare center. Child-safe fans can increase the effectiveness of open doors and windows, and exhaust fans should be maintained in restrooms and kitchens. Open windows on transportation vehicles, when safe and weather permitted, can be used to limit the spread of particles and contaminants in confined spaces.

Considering At-Risk Groups to Ensure Health Equity

Risk levels for children vary between communities, schools, and ECE programs, and the local health departments must work together to prioritize the safety of vulnerable populations. Community health standards can be modified to prioritize health equity in all populations based on age, disability status, high-risk students and faculty.

Children younger than two years old should not wear masks, and many young children may have trouble consistently wearing masks that fit them properly. This limits their ability to protect themselves from illness, but school administration and staff can improve student safety by vigilance, vaccinating, improving ventilation, and limiting/avoiding crowded areas.

Health equity considerations are crucial when evaluating community safety in schools and ECE centers. Decisions regarding disease prevention strategies should not disproportionately affect specific groups of people and resources and services should be available to all members of a district or community. Federal and state regulations require businesses that work with children who have disabilities to provide in-person learning opportunities equal to those available for children without disabilities. The United States Department of Education has published resources regarding health equity for students with disabilities.

High-risk individuals or those with high-risk family members may require additional protection measures when attending in-person educational learning or ECE programs. These measures may include masking even when the Community Risk Level is low, vaccination when possible, and ensuring adequate indoor ventilation. Even though children’s risk of severe illness from COVID-19 is low, there is still a possibility of hospitalization, and the health and safety of especially vulnerable individuals is of high importance.

Resource availability varies by community, but long-term solutions such as improving ventilation can be extremely effective in preventing disease.

Prioritizing Strategies

The U.S. EPA recommends first creating an action plan to ensure clean air in indoor facilities. This plan should include systematic assessments of indoor air quality, evaluating proposals for recommended improvements to HVAC systems, and regular HVAC inspections and maintenance. HVAC system evaluation includes ventilation, filtration, and air cleaning inspection through carbon dioxide monitoring, air delivery measurements, and air flow direction data. Action plans should further include regular filter replacement and monitoring requirements. Once an action plan is in place and implemented, the use of fresh air and HVAC ventilation should then be optimized. Regional air quality awareness and monitoring should be a consideration, and adequate filtration can be evaluated through a series of air quality tests to filter out undesirable outdoor air contaminates. Economizers may also be used to improve air quality through their functions of supplement mechanical cooling with fresh air and reduce costs and increase the amount of fresh air in a building. HVAC systems should be in operation at all times when buildings are occupied, and weather-permitting, windows can be opened to promote increased and cross ventilation. Finally, air filtration and cleaning can be improved using engineering controls such as MERV-rated air filters and portable air cleaners. Increased exhaust ventilation may also be used to increase air cleaning rates.

How RHP Can Help K-12 Schools and Early Care and Education (ECE) Programs to Support In-Person Learning

RHP professionals have a long-standing position as trusted advisors and experts to school boards, administration, and mechanical services to schools as capable of providing hazard assessments to identify risks and address hazards thereby easing fears, of parents, community members and students, and answering concerns of administrators and staff. RHP professionals partner with schools, childcare centers, daycares, and universities and institutions for higher education to analyze infectious disease plans for best practices, protocols, and guidance in effectively providing a clean and safe learning environment. Through engineering and administrative controls, RHP works with building maintenance, engineers, and administrators to assess and validate procedures which will lead to safer, trusted, and practical procedures. Effective solutions are not limited to a single control mechanism or practice, instead effective and sustaining solutions include the implementation of multiple control measures that add layers of protection working together to reduce risk. CDC offers general guidelines for improving ventilation, and RHP can translate these guidelines to practical and understandable strategies, processes and procedures that best fit your education center. Contact RHP for an initial consultation at or call (773) 867-6010.