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

Seshananda Sanjel,Haley Mcbride,James D Johnston,John D Beard,Emma J Montague,James H Lu,Ryan T Chartier,Frank X Weber

doi:10.3390/atmos12070911

Seshananda Sanjel, Haley Mcbride + Show 6 more

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https://doi.org/10.3390/atmos12070911

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Abstract

Household air pollution is a major cause of morbidity and mortality worldwide, largely due to particles ≤ 2.5 µm (PM2.5). The toxicity of PM2.5, however, depends on its physical properties and chemical composition. In this cross-sectional study, we compared the chemical composition of PM2.5 in brick workers’ homes (n = 16) based on use of wood cooking fire or liquefied petroleum gas (LPG) cookstoves. We collected samples using RTI International particulate matter (PM) exposure monitors (MicroPEMs). We analyzed filters for 33 elements using energy-dispersive X-ray fluorescence and, for black (BC) and brown carbon (BrC), integrating sphere optical transmittance. Wood fire homes had significantly higher concentrations of BC (349 µg/m3) than LPG homes (6.27 µg/m3, p < 0.0001) or outdoor air (5.36 µg/m3, p = 0.002). Indoor chlorine in wood fire homes averaged 5.86 µg/m3, which was approximately 34 times the average level in LPG homes (0.17 µg/m3, p = 0.0006). Similarly, potassium in wood fire homes (4.17 µg/m3) was approximately four times the level in LPG homes (0.98 µg/m3, p = 0.001). In all locations, we found aluminum, calcium, copper, iron, silicon, and titanium in concentrations exceeding those shown to cause respiratory effects in other studies. Our findings suggest the need for multi-faceted interventions to improve air quality for brick workers in Nepal.

Highlights

IntroductionHousehold air pollution from the indoor burning of solid fuels, such as wood, crop residues, dung, or coal, is associated with 3.8 million deaths annually worldwide [1,2].Exposure to household air pollution is associated with low birth weight, asthma, chronic obstructive pulmonary disease (COPD), respiratory infections, impaired immune function, coronary heart disease (CHD), stroke, cataracts, and cancers, including lung cancer [3,4,5,6].Among household air pollutants generated from solid fuels, particulate matter (PM) less than or equal to 2.5 microns (μm) in aerodynamic diameter (PM2.5 ), called fine particulate matter, may be the single largest contributor to this excess disease burden [7,8].the toxicity of PM2.5 appears to be partially dependent on its chemical composition, which varies widely based on local emission sources [9,10,11,12,13,14,15,16].In the Kathmandu Valley, Nepal, there are over 30,000 seasonal brick workers [17].Most brick workers in Nepal live on-site at the brick kiln [18]
We found each of these constituents in our samples, and in most cases at higher concentrations than those reported by Ostro et al Differences in concentrations were most pronounced in wood fire homes, where element concentrations ranged from 1.9–35 times the ambient concentrations reported by Ostro et al We propose that repeated exposure to the high concentrations of metals and other elements in both indoor and outdoor air may contribute significantly to the respiratory symptoms seen among brick workers in Nepal
Based on the findings of this and other studies [18,19], we suggest a multi-faceted approach is needed to protect brick workers in the Kathmandu Valley from the adverse health effects associated with poor air quality

Summary

Introduction

Household air pollution from the indoor burning of solid fuels, such as wood, crop residues, dung, or coal, is associated with 3.8 million deaths annually worldwide [1,2].Exposure to household air pollution is associated with low birth weight, asthma, chronic obstructive pulmonary disease (COPD), respiratory infections, impaired immune function, coronary heart disease (CHD), stroke, cataracts, and cancers, including lung cancer [3,4,5,6].Among household air pollutants generated from solid fuels, particulate matter (PM) less than or equal to 2.5 microns (μm) in aerodynamic diameter (PM2.5 ), called fine particulate matter, may be the single largest contributor to this excess disease burden [7,8].the toxicity of PM2.5 appears to be partially dependent on its chemical composition, which varies widely based on local emission sources [9,10,11,12,13,14,15,16].In the Kathmandu Valley, Nepal, there are over 30,000 seasonal brick workers [17].Most brick workers in Nepal live on-site at the brick kiln [18]. Household air pollution from the indoor burning of solid fuels, such as wood, crop residues, dung, or coal, is associated with 3.8 million deaths annually worldwide [1,2]. 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]

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