HIDOE assessing classroom airflow quality at 7 O‘ahu schools


Of the 12,000 classrooms in public schools statewide, approximately 10% — 1,261 classrooms — have limited access to outside air due to central air conditioning.

HONOLULU — The Hawai‘i State Department of Education (HIDOE) is working with seven O‘ahu schools to assess ventilation quality in classrooms to determine if additional resources are needed to increase air exchange.

As part of a study initiated in September 2021, HIDOE contractors assessed carbon dioxide levels in classrooms identified as potentially having limited ventilation. Of the 12,000 classrooms in public schools statewide, approximately 10% — 1,261 classrooms — have limited access to outside air due to central air conditioning. The remaining classrooms have access to outside air with windows and doors, and are able to naturally increase airflow in the classroom.

A total of 335 classrooms were equipped with carbon dioxide sensors that tracked levels for 12 hours a day on weekdays, excluding holidays and school breaks. The data collected informed the estimated carbon dioxide levels for the remaining classrooms based on similar room configurations and air conditioning supply. Rooms were placed in the tier in which the highest 5% of readings occurred. The tiers help to prioritize classrooms that warrant further actions to increase ventilation. 

The table below indicates the number of classrooms within each tier. The carbon dioxide levels infer the probability of breathing in another's exhalation; the higher the levels, the greater the probability. Carbon dioxide levels are measured by parts per million (ppm).

Tier 1 (<800 ppm)
337 rooms
Tier 2 (800–1100 ppm)
525 rooms
Tier 3 (1100–1500 ppm)
304 rooms
Tier 4 (1500–2000 ppm)
70 rooms
Tier 5 (>2000 ppm)
3 rooms

The HIDOE’s Office of Facilities and Operations is following up on the classrooms identified in Tiers 4 and 5 to ensure steps are being taken to improve air quality to the extent possible. The Department’s latest COVID-19 Health and Safety Guidance includes an updated section on ventilation with steps to take to improve ventilation in classrooms based on a classroom’s access to outside air (see pages 8-10).

The 73 rooms ranked in Tiers 4 and 5 include 67 classrooms and six other rooms including office and storage space, a workroom and resource room. They are located at the following seven schools on O‘ahu (see spreadsheet below with classroom details. Parent letters are going out this week to families at the seven impacted schools.):

  • Kauluwela Elementary: 24 classrooms 
  • Keone‘ula Elementary: 19 classrooms
  • McKinley High: 10 classrooms, 6 rooms 
  • Pu‘uhale Elementary: 8 classrooms in library
  • Royal Elementary: 3 classrooms
  • Mililani High: 1 classroom
  • Mililani Middle: 2 classrooms

"The Department is addressing the classrooms identified in Tiers 4 and 5 by working closely with the complex area superintendents and principals at the impacted schools," Superintendent Keith Hayashi said. "Carbon dioxide readings are only one type of measurement for ventilation. Air purifiers, which we’ve made available to schools throughout the pandemic, do not bring carbon dioxide levels down but help to improve indoor air quality. Box fans that have been distributed for all classrooms in every school also increase ventilation."

The Department has taken the following steps to improve overall indoor air quality at schools to reduce the risk of airborne spread of COVID-19. 

  • To facilitate outside air exchange, 12,000 20-inch box fans were centrally purchased and distributed for every HIDOE classroom prior to the 2021-2022 school year. 
  • Over 4,000 HEPA air cleaners have been distributed to schools to increase air exchange in air-conditioned spaces, especially in rooms lacking windows or doors that open to outside). 
  • Schools were also given the opportunity to build their own CorsiRosenthal air cleaners with MERV-13 filters and box fans purchased by the Office of Facilities and Operations. 
  • The Office of Facilities and Operations also purchased 600 carbon dioxide sensors and distributed them, with instructions for proper use, to schools statewide for schools to assess the carbon dioxide levels in their rooms.

Contact Information

Communications Branch

Phone: 808-784-6200

Email: doeinfo@k12.hi.us


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