Han Daikwon, Lee Kiyoung, Kim Jongyun, Bennett Deborah H, Cassady Diana, Hertz-Picciotto Irva
Department of Epidemiology and Biostatistics, Texas A&M School of Rural Public Health, College Station, TX, USA.
Environ Health Toxicol. 2013 May 7;28:e2013005. doi: 10.5620/eht.2013.28.e2013005. Print 2013.
Despite increasing availability of global positioning system (GPS), no research has been conducted to analyze GPS data for exposure opportunities associated with time at indoor and outdoor microenvironments. We developed location-based and time-weighted spatial measures that incorporate indoor and outdoor time-location data collected by GPS.
Time-location data were drawn from 38 female subjects in California who wore a GPS device for seven days. Ambient standard deviational ellipse was determined based on outdoor locations and time duration, while indoor time weighted standard deviational ellipse (SDE) was developed to incorporate indoor and outdoor times and locations data into the ellipse measure.
Our findings indicated that there was considerable difference in the sizes of exposure potential measures when indoor time was taken into consideration, and that they were associated with day type (weekday/weekend) and employment status.
This study provides evidence that time-location weighted measure may provide better accuracy in assessing exposure opportunities at different microenvironments. The use of GPS likely improves the geographical details and accuracy of time-location data, and further development of such location-time weighted spatial measure is encouraged.
尽管全球定位系统（GPS）的可用性不断提高，但尚未开展研究来分析与室内和室外微环境中的时间相关的暴露机会的GPS数据。我们开发了基于位置和时间加权的空间测量方法，该方法纳入了由GPS收集的室内和室外时间-位置数据。
时间-位置数据来自加利福尼亚州的38名女性受试者，她们佩戴GPS设备达7天。基于室外位置和持续时间确定环境标准偏差椭圆，同时开发了室内时间加权标准偏差椭圆（SDE），以便将室内和室外时间及位置数据纳入椭圆测量。
我们的研究结果表明，考虑室内时间时，暴露潜在测量的大小存在显著差异，并且它们与日类型（工作日/周末）和就业状况相关。
本研究提供了证据，表明时间-位置加权测量在评估不同微环境中的暴露机会时可能提供更高的准确性。GPS的使用可能会改善时间-位置数据的地理细节和准确性，鼓励进一步开发这种位置-时间加权空间测量方法。
