Infant Exposures to PM-Bound Metals Associated with Household Air Pollution and Cooking

Abstract

BackgroundAround 3 billion people globally rely on solid fuels for their household energy needs. Exposure to high levels of the resultant household air pollution (HAP) has been linked to a plethora of adverse health outcomes. Until the recent development of the MicroPEM and Enhanced Children’s MicroPEM, it was not possible to accurately quantify the levels, patterns, and composition, of personal HAP exposures of small children.MethodsThe study was carried out at the Karonga Prevention Study, Malawi, where children born in homes with improved (Philips HD4012) and 3-stone stoves were followed at 6 weeks and 6 months. Nasopharyngeal swabs were collected and 48-hour real-time and integrated PM2.5 exposures were measured using the RTI MicroPEM. Following gravimetric analysis of PM2.5 mass, the filters were analyzed for 33 metals with x-ray fluorescence spectroscopy.ResultsValid personal exposure measurements are available on 694 children. Overall, we did not observe a difference in geometric mean PM2.5 exposure levels between children in homes with a traditional stove compared to those in intervention homes (p=0.153, 53.4 95%CI[49.9,57.1]µg/m3, 48.0 [42.1, 54.6]µg/m3; respectively) (p=0.153), except when cooking occurred indoors (p=0.002, 91.8 [75.1, 112.4] µg/m3; 54.7 [42.4, 70.4] µg/m3; respectively). Preliminary data show that children in homes using the Philips stove were exposed to higher levels of Aluminium (170%), copper (185%), chromium (240%), and iron (187%), than children living in homes using a traditional 3-stone stove.ConclusionsExposure to PM-bound metals have been shown to have immunotoxic effects in animal models and exposures to high levels of PM-bound metals such as iron have correlated with increased rates of severe pneumonia in some populations. To our knowledge, this is the first study to report direct infant personal exposures of PM-bound metals associated with household air pollution; the first step towards quantifying potential health impacts.