Covid-19 Mitigation: Air Quality, Ventilation and Filtration

  • A large HEPA filter cleans the air in an Elizabeth High School classroom.

    A large HEPA filter cleans the air in an Elizabeth High School classroom.

    Elizabeth School District has taken – and will continue to take – several important steps to minimize virus transmission within district school buildings, buses and administrative offices. This page serves as an ongoing resource, as well as an archive, for providing safe environments for teaching and learning. 

    Students' educational needs are best served when they can be present in school, with the fewest possible personal restrictions. The district has been able to safely provide in-person learning consistently since the beginning of the 2020-21 school year, with a minimum of individual requirements. On this page, you will find information behind the steps taken by the district to allow the greatest freedom, and fewest personal constraints, for students and staff.

    Data has consistently shown that our schools have not been a vector for community spread of Covid-19. This is the result of a true community partnership because of:

    • Parents ensuring sick and Covid-exposed students stay home.
    • School staff members maintaining safe practices.
    • The availability of rapid, at-home antigen tests for students, families and employees.
    • HEPA air purifiers in classrooms.
    • Comprehensive building-level air-quality measures.

    The supporting documentation below cites experts in air quality, medical science and related fields on the aerosol nature of the virus and the steps to minimize its spread. Since August of 2020, the district has systematically and comprehensively followed the findings of experts and decision makers from around the world to create safe environments for learning that do not require individual action beyond staying at home when sick and voluntary at-home Covid testing. Vaccines and masks are welcomed but not required to maintain a safe educational setting in our schools. 

    As noted in communications to parents (archived at right), district staff have been measuring air quality in each building since the start of the 2020 school year, while tracking the number of cases in schools focusing on instances of likely or confirmed virus spread within the schools. 

    The resources below, coupled with the district's data, have shown that we can continue in-person education while containing the spread of Covid-19 without individual mandates.

    A carbon dioxide monitor sits on a shelf in an Elizabeth High School office.

    A carbon dioxide monitor sits on a shelf in an Elizabeth High School office. The monitors are moved to different locations in each school building to measure air quality.


    Air Filtration, Ventilation and CO² monitoring steps in Elizabeth School District

    • Heating, Ventilation and Air Conditioning (HVAC) Systems.
      • MERV 13 level filters installed in all units.
      • HVAC programmed to run continuously when the building is occupied.
      • HVAC vents adjusted to increase amount of outside air pulled into the system.
      • HVAC system monitored, tuned and maintained regularly.
    • At least two large, standalone HEPA air purifiers placed in every classroom and all occupied, small- and medium-sized indoor spaces (HEPA air purifiers are not effective in open spaces such as gymnasiums and large cafeterias).
    • All spaces monitored for CO² levels within target ranges. More than 1,500 readings have been taken since August 2021. See PDF file of actual readings to date for the 2021-22 school year.
  • The photos in the slideshow above represent some of the aspects and systems that are used to exchange outdoor and indoor air. The first few images show one of three units on the roof above the EHS gym. Each unit has mixed-air dampers that are controlled remotely by software. The dampers are opened to certain amounts for specific periods of time each day to allow fresh, outdoor air to replace indoor air. The air flows through 21 industrial-quality MERV 13 air filters in each unit (for a total of 63 above the gym alone) before being pumped into the building’s HVAC system. The next three images show some of the various displays of the building management system that allow staff to both monitor and control the amounts and timing of fresh air pumped into the buildings as well as temperature and operational status for each unit that controls specific parts of the buildings. The final image shows filters and dampers at Singing Hills Elementary School.

Research and Resources

  • Below is a collection of dozens of research studies, reports, guiding documents and more that were used to inform choices made in Elizabeth School District. The large body of scientific evidence that the virus which causes Covid-19 primarily travels through the air, and the related studies of ventilation and air filtration, were important factors in the allocation of resources to ensure Elizabeth Schools could remain safely in-person throughout the 2020-21 and 2021-22 school years. 

  • Air Quality and Ventilation (CDC, EPA)

  • Covid in Colorado

  • Major Media Reports

Previous Messages to Parents

  • Larry Lorimer inspects a MERV-13 filter on the roof of EHS.

    Larry Lorimer, head custodian at Elizabeth High School, checks the status of industrial-grade MERV 13 filters on one of 26 rooftop units at EHS. Multiple filters are used in each unit.

ESSER III Use of Funds Plan

  • The publishing of the following notice is required by the Colorado Department of Education for Elementary and Secondary School Emergency Relief (ESSER III) funding, which is the state-level administration of federal American Rescue Plan funds.

    Elizabeth School District 
    ESSER III – Use of Funds Plan

    Under this multi-year grant, the district has until September 30, 2024, to spend ESSER III funds. As priorities change in responding to COVID-19 and its effect on students and staff, the use of funds plan may be revised.

    As of January 2022, ESSER III funds will be used to address the four main areas of focus as follows:

    1. Academic Learning Loss
      1. Extend and enhance summer school offerings
      2. Inscreas after-school tutoring
      3. Purchase instruction and assessment materials
    2. Mental Health Supports
      1. Add behavior support specialists
      2. Purchase assessment materials
      3. Add counseling support
    3. Health and Safety Needs
      1. Improve air quality and ventilation by replacing HVAC units
    4. Continuity of Operations
      1. Increase substitute pay for teachers and support staff