This study aims to evaluate the accuracy and effectiveness of real-time personal monitoring of exposure to PM concentrations using low-cost sensors, in comparison to conventional data collection method based on fixed stations. PM_2.5 data were measured every 5 min using a low-cost sensor attached to a bag carried by 47 asthmatic children living in the Seoul Metropolitan area between November 2019 and March 2020, along with the real-time GPS location, temperature, and humidity. The mobile sensor data were then matched with station-based hourly PM_2.5 data using the time and location. Despite some uncertainty and inaccuracy of the sensor data, similar temporal patterns were found between the two sources of PM_2.5 data on an aggregate level. However, average PM_2.5 concentrations via personal monitoring tended to be lower than those from the fixed stations, particularly when the subjects were indoors, during nighttime, and located farther from the fixed station. On an individual level, a substantial discrepancy is observed between the two PM2.5 data sources while staying indoors. This study provides guidance to policymakers and researchers on improving the feasibility of personal monitoring via low-cost mobile sensors as an alternative or supplement to the conventional station-based monitoring.

中文翻译：

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哮喘儿童 PM2.5 暴露的实时低成本个人监测：机遇和挑战

本研究旨在评估使用低成本传感器实时个人监测 PM 浓度暴露的准确性和有效性，与基于固定站的传统数据收集方法相比。2019 年 11 月至 2020 年 3 月期间，居住在首尔市区的 47 名哮喘儿童携带的一个袋子上安装了一个低成本传感器，每 5 分钟测量一次PM _2.5数据，以及实时 GPS 位置、温度和湿度。然后使用时间和位置将移动传感器数据与基于站点的每小时 PM _2.5数据进行匹配。尽管传感器数据存在一些不确定性和不准确之处，但在总体水平上，在两个 PM _2.5数据来源之间发现了类似的时间模式。然而，平均 PM_2.5个人监测的浓度往往低于固定站的浓度，尤其是当受试者在室内、夜间和远离固定站时。在个人层面上，在室内时，两个 PM2.5 数据源之间存在很大差异。本研究为政策制定者和研究人员提供指导，以提高通过低成本移动传感器进行个人监测的可行性，作为传统基于站的监测的替代或补充。