AB096. School-time exposure to ambient PM2.5 in Thailand: a nationwide spatiotemporal analysis
Abstract

AB096. School-time exposure to ambient PM2.5 in Thailand: a nationwide spatiotemporal analysis

Kae Pinpairoh Kitamura1, Ussanai Nithirochananont2, Kulawadee Wonganun1, Ratchaneewan Sinitkul3

1The Newton Sixth Form School, Bangkok, Thailand; 2Geo-Informatics and Space Technology Development Agency, Chon Buri, Thailand; 3Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand

Background: Fine particulate matter ≤2.5 µm (PM2.5) is a significant environmental health risk to children, and avoidance of exposure is universally recommended. However, estimates of school-time PM2.5 exposure in Thailand to inform outdoor activity scheduling remain limited. This study examined ambient PM2.5 exposure patterns at schools during school hours across Thailand in 2024.

Methods: A nationwide descriptive analysis and pattern visualization of ambient PM2.5 at schools were conducted from January to December 2024. School hourly PM2.5 levels were estimated using inverse distance weighted (IDW) interpolation based on air quality monitoring data from the Pollution Control Department (PCD) and the Bangkok Metropolitan Administration (BMA). School-time exposure was defined as a 10-hour average (7.00–17.00) on weekdays. Monthly and regional exposure patterns were visualized. A mean 10-hour PM2.5 concentration <25 µg/m3 was defined as a low-exposure period, based on the 2021 World Health Organization (WHO) 24-hour interim target 4.

Results: A total of 29,082 public schools nationwide were included. The national mean ± standard deviation (SD) school-hours PM2.5 concentration was 27.3 ± 15.4 µg/m³. PM2.5 exhibited clear seasonal variation, peaking during the dry season (March–April) and declining during the wet season (June–November). School semester 2 (November–March) overlapped with higher PM2.5 levels, whereas the school break (mid-March to mid-May) coincided with a decreasing trend. Spatially, average school-time PM2.5 exceeded the 2021 WHO daily guideline (15 µg/m3) across all regions, with the highest levels in the North and the lowest in the South.

Conclusions: In 2024, a nationwide low PM2.5 exposure period at Thai schools occurred between June and November. Rescheduling outdoor school activities to this period may reduce PM2.5 exposure without disrupting education. Further time-series analysis incorporating meteorological factors is warranted.

Keywords: Particulate matter ≤2.5 µm (PM2.5); air pollution; school exposure; children; Thailand

Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the noncommercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

doi: 10.21037/jphe-26-ab096
Cite this abstract as: Kitamura KP, Nithirochananont U, Wonganun K, Sinitkul R. AB096. School-time exposure to ambient PM2.5 in Thailand: a nationwide spatiotemporal analysis. J Public Health Emerg 2026;10:AB096.

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