2012 Progress Report: A Multi-City Time-Series Study of Pollutant Mixtures and Acute MorbidityEPA Grant Number: R834799C004
Subproject: this is subproject number 004 , established and managed by the Center Director under grant R834799
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: The Southeastern Center for Air Pollution and Epidemiology: Multiscale Measurements and Modeling of Mixtures
Center Director: Tolbert, Paige
Title: A Multi-City Time-Series Study of Pollutant Mixtures and Acute Morbidity
Investigators: Sarnat, Stefanie Ebelt , Chang, Howard , Darrow, Lyndsey , Klein, Mitchel , Mulholland, James , Russell, Armistead G. , Tolbert, Paige , Winquist, Andrea
Current Investigators: Sarnat, Stefanie Ebelt , Bilonick, Richard , Darrow, Lyndsey , Klein, Mitchel , Mulholland, James , Russell, Armistead G. , Talbott, Evelynn , Tolbert, Paige , Winquist, Andrea
Institution: Emory University , Georgia Institute of Technology
EPA Project Officer: Chung, Serena
Project Period: January 1, 2011 through December 31, 2016
Project Period Covered by this Report: August 1, 2011 through July 31,2012
RFA: Clean Air Research Centers (2009) RFA Text | Recipients Lists
Research Category: Health Effects , Air
Although associations between ambient air pollution and acute cardiorespiratory outcomes have been observed in numerous studies, questions remain about the degree to which these findings are generalizable between locations and whether the observed health effects are due to the individual pollutants measured or to pollutants acting in combination with other pollutants. In Project 4, we are conducting a multi-city time-series study to clarify the impacts of air quality on acute cardiorespiratory morbidity in five U.S. cities (Atlanta, GA; Birmingham, AL; Dallas, TX; Pittsburgh, PA; St. Louis, IL-MO) using novel mixture characterization metrics. Our overarching hypothesis is that factors related to air pollution mixtures, seasonality and climate, concentration-response functions, exposure measurement error, and population susceptibility and vulnerability can help explain apparent between-city heterogeneity in short-term associations between air quality measures and cardiorespiratory emergency department (ED) visits and hospital admissions (HAs).
During the current reporting period (8/1/2011-7/31/2012), work on Project 4 has focused on data collection and management activities, epidemiologic analyses in Atlanta and St. Louis, and development of approaches to studying air pollution mixtures.
Air quality data. Air quality monitoring data for the relevant study periods in each of the five cities were acquired by the Air Quality Core from state and federal monitoring networks, and data from local intensive monitoring programs (e.g., the SouthEastern Aerosol Research and Characterization [SEARCH] network). Data were processed, data formats and variable labeling approaches were standardized, and the approach for computing population-weighted averages for all cities was finalized. Data for Atlanta (1993-2009) are final and have been posted to the SCAPE private site for sharing among Center investigators. Data for the other cities are being finalized and will be available by August 2012. As described by the Air Quality Core, work also has commenced on developing the proposed mixture characterization metrics, including source-resolved PM metrics in each city.
Health outcome data. Progress on ED visit and HA data collection in each of the five cities also was made. For Atlanta, existing ED visit and HA databases covering the 1993-2004 time period were extended through 2009 with data acquired from the Georgia Hospital Association and processing of these data was completed over the past year. For Birmingham, hospital recruitment activities were initiated in September 2011. Sixteen acute care hospitals with emergency departments in the 7-county Birmingham study area were approached for participation to provide ED visit and HA data for the 1999-2010 time period. To date, 12 of 16 hospitals have agreed to participate and corresponding data use agreements or hospital-specific Institutional Review Board protocols have been approved; of these, 7 hospitals have provided full data sets and 4 hospitals have provided partial data to Emory investigators. Processing is under way for these data sets. Recruitment of the 4 remaining (non-participating) hospitals is anticipated to continue into fall 2012. For Dallas, a data use agreement between Emory and the Dallas-Fort Worth Hospital Council Foundation was finalized and data were transferred to Emory investigators in fall 2011. These data currently are being processed and a final analytic dataset is anticipated by August 2012. The feasibility of including data from the Pittsburgh ARIES study in the current project was assessed over the past year. University of Pittsburgh investigators have begun setting up data sharing procedures, such as revision of data use agreements with Pittsburgh hospitals to include Emory investigators. Data sharing is anticipated to take place by fall 2012. For St. Louis, MO-IL, all ED visit, hospitalization, and AQ monitoring data were acquired previously and data analyses are continuing.
Other data. To compare population and other characteristics among the five cities, data on socioeconomic measures and race/ethnicity were acquired from Census 2000 at the ZIP code tabulation area level. The Townsend deprivation score was calculated as a composite measure of relative socioeconomic status. Sources for crime data also are being considered.
Data analyses. A number of analyses using these data were conducted over the project period: 1) Atlanta ED visit data for 2005-2009 were examined in preliminary epidemiologic time-series analyses with air pollution and results compared to analyses of 1998-2004 data; 2) ambient pollen concentrations were examined in association with asthma/wheeze ED visits in Atlanta; 3) daily ZIP code level measures of ambient PM and gaseous pollutants were applied in epidemiologic analyses of the Atlanta ED data and epidemiologic results among multiple exposure metrics were compared; 4) an extensive power estimation analysis for air pollution time-series studies was conducted using a subset of our observed Atlanta data, with a comparison of results using simulations and standard power software; 5) with the Biostatistics Core, work was begun on applying self-organizing maps (SOMs) and classification and regression trees (C&RT) to our Atlanta data as approaches for detecting and analyzing air pollution mixtures; 6) in St. Louis, we conducted a comparison of ED visit and HA data for use in air pollution time-series studies; and 7) St. Louis source apportionment outputs were finalized and were applied to preliminary epidemiologic analyses, comparing results among multiple source apportionment approaches.
Over the coming year, we anticipate completing our data collection and data processing activities, particularly the health data for Birmingham, Dallas, and Pittsburgh. Manuscript preparation will begin and/or continue for analyses conducted over the past year. New analyses also are planned, in particular: 1) epidemiologic analyses of Birmingham, Dallas, and Pittsburgh data; 2) our work on SOMs and possibly C&RT will be extended to other cities; 3) source apportionment outputs for other cities (e.g., Atlanta and Dallas) will be applied in epidemiologic analyses; 4) the Census 2000 and possibly crime data will be assessed and compared among the five study areas; and 5) approaches for comparing epidemiologic results among the five cities will be evaluated.
Journal Articles on this Report : 4 Displayed | Download in RIS Format
|Other subproject views:||All 101 publications||43 publications in selected types||All 42 journal articles|
|Other center views:||All 334 publications||136 publications in selected types||All 132 journal articles|
Supplemental Keywords:ambient air, health effects, sensitive populations, dose-response, cumulative effects, epidemiology, exposure, air quality modeling, PM2.5, fine particulate matter, organics, elemental carbon, metals, oxidants, sulfates, source characterization, Health, Scientific Discipline, Health Risk Assessment, Risk Assessments, Biochemistry, Environmental Monitoring, children's health, particulate matter, ambient air monitoring, morbidity, climate change, air pollution, airshed modeling, ambient particle health effects, susceptibility, human health risk
Progress and Final Reports:Original Abstract
Main Center Abstract and Reports:R834799 The Southeastern Center for Air Pollution and Epidemiology: Multiscale Measurements and Modeling of Mixtures
Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R834799C001 Development and Deployment of an Instrumentation Suite for Comprehensive Air Quality Characterization Including Aerosol ROS
R834799C002 Examining In-Vehicle Pollution and Oxidative Stress in a Cohort of Daily Commuters
R834799C003 Novel Estimates of Pollutant Mixtures and Pediatric Health in Two Birth Cohorts
R834799C004 A Multi-City Time-Series Study of Pollutant Mixtures and Acute Morbidity