Bangles, Breath, and Machines - Evaluation of Novel Personal Exposure Methods to Measure Household Air Pollution in Puno, Peru

Abstract

Household air pollution (HAP) adversely affects nearly three billion people worldwide who rely on biomass fuels for cooking and other household energy needs. The incomplete combustion of these types of biofuels leads to emission of a variety of toxic pollutants such as carbon monoxide, fine particulate matter, and nitrogen dioxide among others. While there have been large-scale, global health initiatives to distribute cleaner-burning stoves, the combined uncertainty of whether these cookstoves will reduce HAP exposures to levels beneficial to health, measurement error in exposure estimates, and the unknowns around dose-response estimates of these pollutants to health outcomes makes evaluation and decisions to implement these interventions on a larger scale unclear. Gaps in knowledge remain around characterizing exposure to constituents of household air pollution, namely: 1) Improving personal exposure assessment or exposure classification in challenging field settings of developing countries by using cost-effective, user-friendly, and accurate tools that have high participant acceptability and wearing compliance; 2) Connecting dose-response estimates of air pollution constituents, especially chronic low-dose estimates, to specific health outcomes; and, 3) Using these estimates to evaluate the effectiveness of implementing cookstove interventions in low-resource settings, as well as policy recommendations for designing future clean fuel interventions trials or observational studies. This body of work sought to pilot test the use of three low-cost, easy to use tools in a cookstove intervention study conducted in a low-resource field setting of Puno, Peru. Grameen-Intel’s Carbon Monoxide Exposure Limiter (COEL) Smart Bangle, RTI’s Enhanced Children’s MicroPEM (ECM), Access Sensor Technologies Ultrasonic Personal Air Sampler (UPAS), and the human biomarker exhaled carbon monoxide (eCO) could be strong candidates for future use in estimating personal exposure to two major components of biomass smoke in household air pollution, particulate matter (PM2.5) and carbon monoxide (CO). When co-located and compared against field standard instruments measuring PM2.5 and CO, the ECM, the UPAS, and the COEL Smart Bangle showed promising correlation and agreement results respectively, as well as utility and durability in measuring both high kitchen concentrations and varying, lower personal exposures, in challenging field settings. When evaluated within an ongoing randomized controlled cookstove trial, there were significantly different concentrations of eCO between the control biomass and intervention gas cookstove households at all follow-up visits. In addition to the relative sensitivity of this biomarker to type of cookstove being used in the home, this low-cost, easy to collect marker of exposure shows promise in evaluating chronic exposure to household air pollution. Overall, we recommend the ECM, UPAS, COEL Smart Bangle, and exhaled CO for future use in measuring and improving personal exposure assessment to air pollution in cookstove interventions. However, all four instruments of exposure should be evaluated further for potential utility in assessing chronic exposure to low-dose concentrations of PM2.5 and CO in other global health field settings