Environmental quality in sixty primary and secondary school classrooms in London

• Published in: Journal of Building Engineering 2024-08, Vol.91, p.109549, Article 109549
• Main Authors: Kumar, Prashant, Hama, Sarkawt, Abbass, Rana Alaa, Abhijith, K.V., Tiwari, Arvind, Grassie, Duncan, Mitsakou, Christina
• Format: Article
• Language: English
• Subjects: CO2; Indoor air quality; PM10; Thermal comfort; UK schools; Ventilation rates
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2024.109549

Poor environmental quality in school classrooms can have a detrimental impact on children's health, nevertheless, the association between air pollutants and physical features of classrooms is poorly understood. We monitored particulate matter (PM), carbon dioxide (CO2) and thermal comfort in sixty classrooms across ten London primary and secondary schools using similar equipment to produce a comparable dataset. The overall research objective was to understand the association of classroom air quality with occupancy levels, floor types, classroom locations, classroom volume, ventilation types and different year groups. Average in-classroom PM10 (29 ± 20), PM2.5 (10 ± 2) and PM1 (5 ± 2 μg m-3) during occupied hours were ∼150 % (PM10) and 110 % (PM2.5) higher compared to non-occupied hours. PM10 concentration was reduced by 30 % for dual (mechanical + natural) compared to natural ventilation only; the corresponding reduction was slightly lower for PM2.5 (28 %) and PM1 (20 %). PM10 almost doubled for wooden floored classrooms compared with those having carpets. During high occupancy (>26 occupants), the average CO2 (935 ± 453 ppm) was ∼140 % higher than non-occupancy. The average CO2 in classrooms occupied by younger children (reception and year one) was ∼190 % higher than those with older children (years eight and nine). 68 % of classrooms exceeded the minimum recommended levels of 40 % relative humidity. Low PM10 concentrations coincided with low CO2 concentrations in classrooms across all schools. These findings highlight the importance of simultaneously addressing both thermal comfort and the resuspension of PM10 to achieve comprehensive improvements in classroom air quality. Classroom settings where indoor environment is likely to be compromised can also be identified and addressed. [Display omitted] •Particulate matter, CO2 and thermal comfort were monitored in 60 classrooms.•High occupancy classrooms showed an increase in PM10 of 150 % and in CO2 of 140 %.•Dual ventilation lowered PM10 concentration by 30 % compared to natural ventilation.•Hardwood had double the PM10 concentration compared to carpeted floored classrooms.•Low PM10 events coincided with low CO2 events in classrooms across studied schools.