Personal particulate matter exposure assessment of rural Malawian children and device wearability considerations

摘要

Aim: Three billion of the world's poorest people rely on solid fuels (wood, crop wastes, dung, charcoal and coal) and simple open fires and stoves for their everyday cooking needs. This results in high levels of exposure to smoke pollution among family members, including young children. This study aims to: (1) quantify the personal particulate matter (PM) exposures of children <5 years of age, (2) examine the child/mother exposure relationship, (3) assess the comfort and wearability of personal exposure platforms for children, and (4) provide wearing platform recommendations to aid future study design. Methods: This study is being carried out at the Karonga Prevention Study site of the CAPS Trial in conjunction with another effort focusing on the impact of improved stoves on reductions in PM2.5 exposure and nasopharyngeal carriage of streptococcus pneumoniae in 6 month old Malawian children. Newborns are recruited through study site surveillance in homes recruited to CAPS, and for which the intervention group already has the Philips stove. A subset of these children, along with older siblings (< 5 years) and their mothers, are recruited to take part in the current study. The 48-hour PM2.5 personal exposure levels and patterns of the children are measured using the RTI Enhanced Children's MicroPEM (ECM) monitor while the mother wears a v3.2 MicroPEM. Results: Preliminary data for 6 month and 6 week olds from this cohort indicate that children residing in homes using an improved Philips stove have slightly lower exposures 53.9 [38.1, 69.6] ug/m3 than those in homes using a 3-stone fire 66.8 [47.7, 85.9] ug/m3. Additionally, we observed that PM2.5 exposures are significantly higher (p=0.0476) for 6 month old children 72.1 [42.7, 101.4] μg/m3 when compared to 6 week old children 48.7 [42.0, 55.5] ug/m3. The waking hour wearing compliance (% sample time device is moving) was calculated using the monitor's onboard accelerometer and determined to be 44.6% [41.6, 47.6]. These data indicate the device is being properly deployed for the youngest and most at-risk children. Conclusions: While this work is ongoing, the preliminary results demonstrate that it's possible to confidently and accurately measure the personal PM exposures of small children. Accurate assessment of children's exposure to PM from solid fuel cooking is necessary to define exposure/health relationships and to inform research funding and policy decisions. Additional pilot efforts, with similar goals to this study, will be underway in Peru and Ghana in the spring of 2016.