Air-Quality Assessment of On-Site Brick-Kiln Worker Housing in Bhaktapur, Nepal: Chemical Speciation of Indoor and Outdoor PM2.5 Pollution

Abstract

Brick workers and their families in Nepal generally live in poorly ventilated on-site housing at the brick kiln, and may be at higher risk for non-occupational exposure to fine particulate matter air pollution and subsequent respiratory diseases due to indoor and outdoor sources. This study characterized non-occupational exposure to PM_2.5 by comparing overall concentrations and specific chemical components of PM_2.5 inside and outside of brick workers' on-site housing. For all samples, the geometric mean PM_2.5 concentration was 184.65 μg/m³ (95% confidence interval: 134.70, 253.12 μg/m³). PM_2.5 concentrations differed by kiln number (<i>p</i> = 0.009). Kiln number was significantly associated with 16 of 29 (55%) air pollutant, temperature, or relative humidity variables. There was not a significant interaction between kiln number and location of sample for PM_2.5 (<i>p</i> = 0.16), but there was for relative humidity (<i>p</i> = 0.02) and temperature (<i>p</i> = 0.01). Results were qualitatively similar when we repeated analyses using indoor samples only. There was no difference in the chemical makeup of indoor and outdoor PM_2.5 in this study, suggesting that outdoor PM_2.5 air pollution easily infiltrates into on-site brick worker housing. Outdoor and indoor PM_2.5 concentrations found in this study far exceed recommended levels. These findings warrant future interventions targeted to this vulnerable population.