Exposure to fine particulate matter (PM2.5) among highway toll workers in Taipei: Direct and indirect exposure assessment

Research output: Contribution to journalArticle


  • CH Lai
  • SH Liou
  • TS Shih
  • PY Tsai
  • HL Chen
  • YC Chang
  • T Buckley
  • P Strickland


In this study, the authors assessed occupational exposure to PM2.5 among 47 highway toll station workers in Taipei, Taiwan. The subjects were monitored for 10 days to assess integrated 8-hr fine particulate matter (PM2.5) breathing zone concentration. Researchers constructed a microenvironment-time-concentration matrix and applied direct and indirect approaches to assess cumulative exposure. Mean PM2.5 concentration for workers in the truck and bus lanes was 308 microg/m3 (SD = 115.5 microg/m3), substantially higher compared with cash-payment car lanes (mean 115, SD = 41.8, p <0.001) and ticket-payment car lanes (mean 109, SD = 48.7, p <0.001). Concentration per vehicle in the truck and bus lanes was 6.4 and 3.7 times higher, respectively, than that of ticket- or cash-payment car lanes. Mean cumulative exposure for the 10-day period was 4,900-13,407 microg/m3.hr, with a mean of 8,019 microg/m3.hr (SD = 2,375.3). Indirect and direct concentrations were strongly correlated (r2 = .61, F(1,125); p = 0.000). The results of this study show that personal exposure to PM2.5 can be reliably estimated using indirect approaches.


Original languageEnglish
Pages (from-to)138-148
Number of pages11
JournalArch Environ Health
Publication statusPublished - 1 Mar 2004