ObjectiveThe purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM.MethodsA total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM.ResultsThe geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 μg/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure.ConclusionsWe assessed MHW workers’ exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure.

The objectives of this study to characterize exposure to respirable elemental carbon (EC), organic carbon (OC) and total carbon (TC) in relation to waste-handling activities and vehicle characteristics among workers who collect household wastes, and to examine the relationships among EC, OC and TC. A total of 72 household waste collectors were selected for exposure assessment over a full workday and most (70 of 72) exposures were collected from diesel emissions that underwent catalytic after-treatment by diesel particulate filters (DPFs). The exposure assessments were conducted from June through September 2014. Airborne EC and OC from the breathing zone were collected on pre-fired quartz filters and quantified using the thermal optical reflectance method. The average EC exposure level of the household waste collectors was 7.2 µg m -3 with a range of 2.0-30.4 µg m ), truck age (< 10 year-old vs. ≥ 10 year-old), type of waste collection job (collector vs. driver), current smoking status (yes vs. no) and month were found to significantly influence the level of TC exposure (n = 70, adjusted R 2 = 0.56, p < 0.0001). The average exposure to EC of household waste collectors can be categorized into the relatively low exposure group when compared to other DE exposure jobs. TC was not a best surrogate for DE exposure in household waste collection environments because it was affected by other OC interferences that were not generated from diesel engines.