Indirect Personal Household Air Pollution Exposure Assessment for Children under 1 Year of Age Using Bluetooth Low Energy (BLE) Beacon System

摘要

Background: Household air pollution (HAP) generated from solid fuel combustion is associated with a large health burden in children under 1 year. However, assessing personal exposure to HAP for children is challenging, leading to uncertainties in estimating effects of a clean cookstove intervention program. Methods: We recruited 20 households cooking with open fires in Guatemala with women and children under 1 year and conducted two 24-hour PM2.5 samplings before and two after a liquefied petroleum gas (LPG) stove intervention for each household. In each assessment, we measured 24-hour PM2.5 levels in kitchens, sleeping rooms and outdoor patios as well as personal PM2.5 exposure for 20 mothers using Enhanced Children's MicroPEM (ECM). We concurrently deployed a Bluetooth Low Energy (BLE) Beacon system to estimate the microenvironment location (kitchen, sleeping room and outdoor) for mothers and children longitudinally. PM2.5 levels in the assigned microenvironments were used as indirect PM2.5 estimates. We evaluated the performance of the Beacon system in predicting micro-environmental locations and personal PM2.5 exposure. Results: Beacon system can predict microenvironment locations correctly over 70% of time, on average. After revising deployment strategies to reduce signal disturbance, this correct location rate increased to 80%. The mean of 24-hour Beacon-derived indirect nephelometric PM2.5 exposure decreased from 110 μg/m3 to 13 μg/m3 for mothers and from 90 μg/m3 to 9 μg/m3 for children before and after the LPG intervention. The spearman correlation coefficient between hourly indirect and direct personal PM2.5 exposure for mothers was 0.92 before and 0.73 after LPG intervention. Conclusion: The BLE Beacon system can provide acceptable information of microenvironment location and estimate satisfactory personal PM2.5 exposure in this LPG intervention pilot study. This novel exposure assessment method can be applied in future cookstove intervention studies.