Particle number concentration measurements on public transport in Bangkok, Thailand

James C Matthews*, Chalida Chompoobut, Panida Navasumrit, M. Anwar H. Khan, Matthew D Wright, Mathuros Ruchirawat, Dudley E Shallcross

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review


Traffic is a major source of particulate pollution in large cities, and particulate matter (PM) level in Bangkok often exceeds World Health Organisation limits. While PM2.5 and PM10 are both measured in Bangkok regularly, the sub-micron range of PM, of specific interest as regards possible adverse health effects, is very limited. In the study, particle number concentration (PNC) was measured on public transport in Bangkok. A travel route through Bangkok using the state railway, the mass rapid transport underground system, the Bangkok Mass Transit System (BTS) Skytrain and public buses on the road network, with walking routes between, was taken whilst measuring particle levels with a hand-held concentration particle counter. The route was repeated 19 times covering different seasons during either morning or evening rush hours. The highest particle concentrations were found on the state railway, followed by the bus, the BTS Skytrain, and the MRT underground with measured peaks of 350,000, 330,000, 33,000 and 9,000 cm-3, respectively, though particle numbers over 100,000 cm 3 may be an underestimation due to undercounting in the instrument. Inside each form of public transport, particle numbers would peak when stopping to collect passengers (doors opening) and decay with a half-life between 2-3 minutes. There was a weak correlation between particle concentration on bus, train and BTS and Skytrain with carbon monoxide concentration as measured at a fixed location in the city.
Original languageEnglish
Article number5316
JournalInternational Journal of Environmental Research and Public Health
Issue number7
Publication statusPublished - 29 Mar 2023

Bibliographical note

Funding Information:
This work was funded by Newton Fund NERC grant number NE/P014674/1 and Thailand Research Fund grant RDG6030008. We thank the Pollution Control Department, Thailand, for providing pollutant data.

Publisher Copyright:
© 2023 by the authors.


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