Assessing classroom ventilation rates using CO2 data from a nationwide study of UK schools and identifying school-wide correlation factors
File(s)
Published version
Author(s)
Wood, Samuel
Handy, Alice
Katherine, Roberts
Burridge, Henry
Type
Journal Article
Abstract
Per-person ventilation rates were assessed from data measured in 322 UK schools throughout the Autumn term, 2023. It
was found that the overall mean ventilation rate was 5.3 L s−1 p
−1
; rising to 6.8 L s−1 p
−1 during warmer weather and
falling to 3.8 L s−1 p
−1 during colder weather. Daily mean CO2 levels recorded in the majority of schools consistently
fell below the 1 500 ppm threshold within government school ventilation guidance but the contribution of relatively few
very high CO2 levels in some classrooms shows the need for targeted improvement and highlights the value of large-scale
datasets. Exceedance of the 1 500 ppm threshold rose to approximately 20% when the daily mean outdoor temperature fell
to around 5 ◦C indicating a barrier to ventilation. Controlling for outdoor temperature as a covariate, analysis of the CO2
measurements indicated schools in more-deprived regions, state-funded schools (relative to private), and secondary schools
(relative to primary) exhibited statistically-significant higher CO2 concentration. Reassuringly, these findings remained
unchanged when the analysis was deployed on estimated per-person ventilation rates; except that this enhanced analysis
accounted for the greater CO2 production associated with older children and demonstrated that ventilation rates were not
significantly different between primary and secondary schools.
was found that the overall mean ventilation rate was 5.3 L s−1 p
−1
; rising to 6.8 L s−1 p
−1 during warmer weather and
falling to 3.8 L s−1 p
−1 during colder weather. Daily mean CO2 levels recorded in the majority of schools consistently
fell below the 1 500 ppm threshold within government school ventilation guidance but the contribution of relatively few
very high CO2 levels in some classrooms shows the need for targeted improvement and highlights the value of large-scale
datasets. Exceedance of the 1 500 ppm threshold rose to approximately 20% when the daily mean outdoor temperature fell
to around 5 ◦C indicating a barrier to ventilation. Controlling for outdoor temperature as a covariate, analysis of the CO2
measurements indicated schools in more-deprived regions, state-funded schools (relative to private), and secondary schools
(relative to primary) exhibited statistically-significant higher CO2 concentration. Reassuringly, these findings remained
unchanged when the analysis was deployed on estimated per-person ventilation rates; except that this enhanced analysis
accounted for the greater CO2 production associated with older children and demonstrated that ventilation rates were not
significantly different between primary and secondary schools.
Date Issued
2024-10
Date Acceptance
2024-08-07
Citation
Developments in the Built Environment, 2024, 19
ISSN
2666-1659
Publisher
Elsevier
Journal / Book Title
Developments in the Built Environment
Volume
19
Copyright Statement
© 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
https://www.sciencedirect.com/science/article/pii/S2666165924002011
Publication Status
Published
Article Number
100520
Date Publish Online
2024-08-12