Development of Time-location Weighted Spatial Measures Using Global Positioning System Data

한대권,이기영,Jongyun Kim,Deborah H. Bennett,Diana Cassady,Irva Hertz-Picciotto 환경독성보건학회 2013 환경독성보건학회지 Vol.28 No.-

Objectives 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. Methods 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. Results 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. Conclusions 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. Keywords Global positioning system, Indoor time-location weighted spatial measure,Time-location data

Use of Portable Global Positioning System (GPS) Devices in Exposure Analysis for Time-location Measurement

이기영,Diana Cassady,김정윤,Kiran Putti,Deborah H. Bennett,Irva Hertz-Picciotto 한국환경보건학회 2009 한국환경보건학회지 Vol.35 No.6

Exposure analysis is a critical component of determining the health impact of pollutants. Global positioning systems (GPS) could be useful in developing time-location information for use in exposure analysis. This study compares four low cost GPS receivers with data logging capability (Garmin 60, Garmin Forerunner 201, GeoStats GeoLogger and Skytrx minitracker MT4100) in terms of accuracy, precision, and ease of use. The accuracy of the devices was determined at two known National Geodetic Survey points. The coordinates logged by the devices were compared when the devices were carried while walking and driving. The Garmin 60 showed better accuracy and precision than the GeoLogger when they were placed at the geodetic points. The Forerunner and Skytrx did not record when they were kept stationary. When the subject wore the devices while walking, the location of the devices differed by about 8 m on average between any two device combinations involving the four devices. The distance between the coordinates logged by the devices decreased when the devices were carried with their antennas facing the sky. All the devices showed similar routes when they were used in a car. All the devices except the Forerunner had satisfactory signal reception when they were worn and when they were carried in the car. The GeoLogger is less comfortable for the subject because of specific wearing requirements. This evaluation found that the Garmin 60 and the Skytrx may be useful in personal exposure analysis studies to record time-location data.

Development of Time-location Weighted Spatial Measures Using Global Positioning System Data

Daikwon Han,Kiyoung Lee,Jongyun Kim,Deborah H. Bennett,Diana Cassady,Irva Hertz-Picciotto 환경독성보건학회 2013 환경독성보건학회지 Vol.28 No.-

Objectives 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. Methods 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. Results 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. Conclusions 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.

Development of Time-location Weighted Spatial Measures Using Global Positioning System Data

Han, Daikwon,Lee, Kiyoung,Kim, Jongyun,Bennett, Deborah H.,Cassady, Diana,Hertz-Picciotto, Irva The Korean Society of Environmental Toxicology 2013 환경독성보건학회지 Vol.28 No.-

Objectives 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. Methods 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. Results 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. Conclusions 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.

반휘발성유기화합물을 위한 수동형 공기 샘플러로서 소파 내 폴리우레탄 폼의 사용 가능성 연구

김경훈,Hyeong-Moo Shin,Luann Wong,Thomas M. Young,Deborah H. Bennett 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

폴리우레탄 폼(polyurenthane foam, PUF)은 유기화합물을 위한 수동형 공기 샘플러에 흡착제로 쓰이고 있다. PUF는 실내 가구 충전재로써 쓰이고, 기존 연구를 통해 가구 속 PUF가 실내에서 반휘발성유기화합물(Semivolatile organic compounds, SVOCs)을 흡수한다는 것이 밝혀졌다. 본 연구에서는 소파 속 PUF의 SVOCs 보유능력을 평가하고, 실내 SVOCs 노출 평가를 위한 소파 PUF 내 SVOCs 농도의 대체지표물 사용 가능성을 확인하고자 하였다. 이를 위해 캘리포니아 13개 집에서 사용 중인 소파에서 PUF 샘플을 수집했다. 소파 표면으로부터 깊이 별 PUF 내 SVOCs 농도 변화를 알고자 3개의 다른 깊이에서 PUF를 샘플링했다. 동일 집에서 측정한 집 먼지 내 SVOCs 농도를 이용하여 실내 공기 내 SVOCs 농도를 추정하였고, PUF와 실내 공기 간 SVOCs 분배계수를 계산하였다. 마지막으로, PUF의 SVOCs 보유능력을 추정하였고, SVOCs가 실내 환경 미디엄(PUF/공기/카펫/벽/비닐표면)에 어떤 비율로 존재하는지 질량 분배를 추정하였다. 64개 분석대상 SVOCs 중 29종이 실내 소파 내 PUF에서 검출되었다. 이 중 5개 종의 농도는 소파 표면에서 내부 방향으로 감소했다. 화장품에 포함된 3개의 화합물과 페놀은 실내 환경미디엄에 존재하는 전체 질량 중 20% 이상의 질량이 소파 PUF에 존재하는 것을 확인했다. 본 연구를 통해, 소파 내 PUF가 다양한 SVOCs를 흡수하여 보유하고 있음을 확인했다. 또한, 소파 표면과의 피부 접촉이 화장품 함유 SVOCs 및 페놀의 노출 경로가 될 수 있음을 확인했다.

Use of Portable Global Positioning System (GPS) Devices in Exposure Analysis for Time-location Measurement

Lee, Ki-Young,Kim, Joung-Yoon,Putti, Kiran,Bennett, Deborah H.,Cassady, Diana,Hertz-Picciotto, Irva Korean Society of Environmental Health 2009 한국환경보건학회지 Vol.35 No.6

Exposure analysis is a critical component of determining the health impact of pollutants. Global positioning systems (GPS) could be useful in developing time-location information for use in exposure analysis. This study compares four low cost GPS receivers with data logging capability (Garmin 60, Garmin Forerunner 201, GeoStats GeoLogger and Skytrx minitracker MT4100) in terms of accuracy, precision, and ease of use. The accuracy of the devices was determined at two known National Geodetic Survey points. The coordinates logged by the devices were compared when the devices were carried while walking and driving. The Garmin 60 showed better accuracy and precision than the GeoLogger when they were placed at the geodetic points. The Forerunner and Skytrx did not record when they were kept stationary. When the subject wore the devices while walking, the location of the devices differed by about 8 m on average between any two device combinations involving the four devices. The distance between the coordinates logged by the devices decreased when the devices were carried with their antennas facing the sky. All the devices showed similar routes when they were used in a car. All the devices except the Forerunner had satisfactory signal reception when they were worn and when they were carried in the car. The GeoLogger is less comfortable for the subject because of specific wearing requirements. This evaluation found that the Garmin 60 and the Skytrx may be useful in personal exposure analysis studies to record time-location data.