Comparison of Liquefied Petroleum Gas Cookstoves and Wood Cooking Fires on PM2.5 Trends in Brick Workers’ Homes in Nepal

Abstract

Prior studies document a high prevalence of respiratory symptoms among brick workers in Nepal, which may be partially caused by non-occupational exposure to fine particulate matter (PM2.5) from cooking. In this study, we compared PM2.5 levels and 24 h trends in brick workers’ homes that used wood or liquefied petroleum gas (LPG) cooking fuel. PM2.5 filter-based and real-time nephelometer data were collected for approximately 24 h in homes and outdoors. PM2.5 was significantly associated with fuel type and location (p < 0.0001). Pairwise comparisons found significant differences between gas, indoor (geometric mean (GM): 79.32 μg/m3), and wood, indoor (GM: 541.14 μg/m3; p = 0.0002), and between wood, indoor, and outdoor (GM: 48.38 μg/m3; p = 0.0006) but not between gas, indoor, and outdoor (p = 0.56). For wood fuel homes, exposure peaks coincided with mealtimes. For LPG fuel homes, indoor levels may be explained by infiltration of ambient air pollution. In both wood and LPG fuel homes, PM2.5 levels exceeded the 24 h limit (25.0 µg/m3) proposed by the World Health Organization. Our findings suggest that increasing the adoption of LPG cookstoves and decreasing ambient air pollution in the Kathmandu valley will significantly lower daily PM2.5 exposures of brick workers and their families.

Chemical Composition of PM2.5 in Wood Fire and LPG Cookstove Homes of Nepali Brick Workers

“…Previous studies by our group found that Nepali brick workers, in addition to having hazardous work-related respiratory exposures [20], experience significant PM 2.5 exposures during non-working hours [18,19]. Indoor PM 2.5 concentrations in brick workers' homes with wood fire and LPG cookstoves were 541.14 and 79.32 µg/m 3 , respectively, and these elevated levels coincided with meal and sleep times [19].…”

“…We collected PM 2.5 samples using both filter-based and real-time nephelometer methods. Our previous study reported the PM 2.5 total mass and nephelometer trend analyses [19]. For this study, we analyzed the 25 mm 3.0 µm PTFE filters (Zefon International, Ocala, FL, USA) for 35 chemical constituents.…”

“…For this study, we analyzed the 25 mm 3.0 µm PTFE filters (Zefon International, Ocala, FL, USA) for 35 chemical constituents. The methods for home selection, measures of housing characteristics, and air filter handling and sampling strategy, described briefly here, are described in full in our previously published paper [19]. We used a cross-sectional study design to measure PM 2.5 constituents in brick workers' homes (n = 17) from a single brick kiln in Bhaktapur, Nepal.…”

“…Previous studies by our group found that Nepali brick workers, in addition to having hazardous work-related respiratory exposures [20], experience significant PM 2.5 exposures during non-working hours [18,19]. Indoor PM 2.5 concentrations in brick workers' homes with wood fire and LPG cookstoves were 541.14 and 79.32 µg/m 3 , respectively, and these elevated levels coincided with meal and sleep times [19]. Brick workers suffer a disproportionate burden of respiratory symptoms compared to other workers in the same community [21], and we propose that these symptoms may be partially explained by elevated PM 2.5 levels in brick workers' homes, particularly among those cooking indoors with open wood fires.…”

“…Most brick workers in Nepal live on-site at the brick kiln [18]. The most common type of housing for these workers is brick huts with tin roofs, often with poor ventilation to the outdoors [19]. Within this population of workers, the two primary methods of cooking are with indoor open wood fires or with liquefied petroleum gas (LPG) cookstoves [18,19].…”