Impact/Purpose:

Overall Goal: To develop spatial analyses using limited network-based air quality and GIS and other ancillary spatial information to estimate exposures for epidemiological analyses in urban populations.

Goal of NERL Contribution: To develop ambient-GIS regression-based spatial models using said ambient measures and ancillary information to predict such exposures at unmonitored locations and assess neighborhood differences in air pollutant concentrations.

Specific Objectives:

1. To determine spatial associations among measured levels of VOC, NO2, and (possibly) PM from mobile and other urban sources in Detroit/Dearborn. Spatial variability in air pollutant concentrations will be determined using the ambient measurements at the schools and available surrogates of motor vehicle and other urban emissions (from GIS databases). These measured or predicted spatial associations will then be used by NHEERL to ultimately assess impact of these pollutants on children's exposures in schools.

2. To evaluate accuracy of VOC, NO2 and PM measurements using passive devices versus collocated FRM devices. In addition, to evaluate precision of collocated passive devices.

Description:

Research Issue: Spatial analyses of gaseous species and (possibly) particulate matter is in support of NHEERL APM 170 "Publish report on effects of particulate matter and volatile organic chemical air pollutants on children." under NHEERL APG "Characterize long term respiratory health effects of PM in children."

Approach: Ambient data will be collected at approximately 25 elementary schools and a central site in Detroit and Dearborn, MI over a 6-week sampling period in the summer of 2005 when meteorological conditions are conducive to concentrating emissions. Schools will be selected (in part) based on their representativeness for traffic sources, industrial sources, and other ancillary space variables; this will be done by analysis of these GIS variables prior to final school selection for field sampling. In addition, schools will include those that are in the exposure monitoring areas delineated in the Detroit Exposure and Aerosol Research Study (DEARS, Task 6387) and which are within the Detroit and Dearborn city limits. Passive sampling of VOC, NO2, and PM of week-long duration (7-days) will be collected at the schools and central site to represent overall long-term exposures; VOC and NO2 passive sampling methods will be the same as being used in DEARS. Monitoring shall be performed concurrent with DEARS (anticipated to be from June 14 to July 31, 2005). The central site will be an existing site operated by the State of Michigan Dept of Environmental Quality (MDEQ) to collocate the passive samplers with reference methods for the same species to qualitatively evaluate any potential correlation, bias, and other quality measures that may be considered in the spatial analysis. Use of the ambient and GIS data from the schools will be used to develop a ambient-GIS regression-based spatial model to assess neighborhood differences of ambient air pollution levels throughout Detroit/Dearborn for use in the epidemiological analyses that will examine ambient exposures to traffic and other urban emissions and their effect on respiratory health among children; that effort will be conducted by NHEERL. Finally, it should be noted that development of this statistical-based spatial model is similar to spatial methods developed in the European Small-Area Variations in Air Quality and Health (SAVIAH) studies, Traffic-Related Air Pollutants and Childhood Asthma (TRAPCA) and recent Canadian studies.

Impact: Results will be of use in: 1) other exposure monitoring studies (Detroit Exposure & Aerosol Research Study or DEARS being one such study) that will be using these same passive samplers for exposure monitoring purposes and 2) assessing neighborhood differences in ambient air pollutant concentrations. The use of identical monitoring methods, in similar areas, and in concurrent time frames for the two studies will be important in the ultimate use of DEARS measurements to evaluate spatial model predictions produced by the DCHS spatial model and to further assess neighborhood-scale differences. Results will also be of use in spatial assessments of traffic and industrial-related air pollutants; it will also be of use in health effects studies (in Detroit) that will attempt to determine if ambient exposure to particulate matter and gaseous pollutants are associated with increased prevalence of respiratory symptoms or other adverse health effects in children.

Record Details:

Record Type:PROJECT

Start Date:07/01/2004

Projected Completion Date:09/01/2007

Record ID: 116303

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Project Information:

Progress :Work assignment to begin process of preliminary analyses to GIS data to determine representative schools and develop the air monitoring study. Air monitoring study to commence in Summer, 2005.

Relevance :Of primary relevance, this work will be used by NHEERL in their continuing efforts investigating asthma and respiratory illness among school age children in Detroit. Results may have impact on their future health studies as part of the National Children's Study. In terms of spatial analysis, the study is one of the few investigations to estimate concentrations of VOC, NO2, and PM at various sites (schools) using traffic indicators and GIS information. Such spatial sampling with GIS variables in a regression framework provides a feasible approach to assess intra-urban variability of air pollutants.

Spatial analysis results may also be applied to DEARS residential monitoring efforts to assess neighborhood differences. The same passive sampler methods for VOC and NO2 evaluations will be used in DEARS to evaluate accuracy/precision issues for exposure monitoring purposes.

Clients :EPA/ORD/NHEERL/HSD/EBB (Lucas Neas), EPA/ORD/NERL/HEASD/EMAB (Ron Williams)

Project IDs:

ID Code :20594

Project type :OMIS