Microenvironmental Exposure to Ultrafine Particles Among Adolescent Children Characterized by A Personal Sensor with High Spatial and Temporal Resolution

摘要

Background: Ultrafine particles (UFPs) exhibit high spatiotemporal variation, which makes assigning individual level exposures challenging. Additionally, the dynamic time-activity patterns of individuals in daily life further complicate exposure assessment and necessitate exposure methods with high spatial and temporal resolution. To address this need, a personal UFP sensor (PUFP C100) capable of measuring GPS location and UFP concentration at 1 second intervals has been developed (Enmont, LLC). Based on user feedback from previous field testing of the PUFP C100 model, significant improvements have been made while maintaining sensor performance. The purpose of this report is to detail the results of additional field testing to assess the performance and user satisfaction with the modified sensor (PUFP C200). Methods: Adolescent children (n = 10; ages 13-17) will wear the second generation UFP sensor for 3 hours after school for 7 consecutive days in Spring 2016. During sensor operation, participants will document their activity patterns including location and exposure sources (tobacco smoke, cooking, etc.). We will use the documented activity patterns to validate GPS location and to develop an algorithm to characterize UFP concentrations within different exposure microenvironments (home, transit, school). We will also examine the inter/intra-personal variation of UFP concentration by microenvironment. Results: The PUFP C200 has significant reductions in size (40%; 910 cc vs. 1500 cc) and weight (25%; 0.75kg vs. 1 kg). A new software interface (EView~(™)) complete with data visualization tools for real-time UFP monitoring via Bluetooth has also been developed. Furthermore, the software translates GPS location data into Google Earth compatible files with formatting options to indicate the degree of UFP exposure. Participant recruitment has been completed, and field testing is currently underway. Once field testing has concluded in Spring 2016, over 200 hours of sampling data will be collected, analyzed prepared and for presentation. Conclusion: We hypothesize that sensor improvements will increase user satisfaction and that personal exposures will differ significantly by study participant and microenvironment. In the future, the PUFP C200 will be deployed in a larger epidemiological study to characterize UFP exposure. The goal of this prospective study will be to examine the association between UFP exposure and pulmonary function in adolescents with and without asthma.