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PRELIMINARY EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY
Stevens, C, R W. Williams, F L. Chen, A F. Vette, R L. Seila, E. Amos, L S. Sheldon, C. Rodes, AND J. Thornburg. PRELIMINARY EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY. Presented at Tampa Environmental Protection Commission, Tampa, FL, April 29, 2003.
Develop simple questionnaires and measures for input into models to classify children's exposures to CRPs, PM, and air toxics.
Quantify personal, indoor air, outdoor and ambient site concentrations for CRP/PM/air toxics for the participants in this pilot study.
Identify and model key factors contributing to the inter- and intra-personal variability between personal measures and corresponding indoor, outdoor, and ambient air concentrations for CRP/PM/air toxics.
Evaluate the contribution of ambient sources to indoor air and personal concentration measurements for CRP/PM/air toxics.
Apply the scientific tools developed and information gained from this pilot in the NCS to assess children's exposures.
The Tampa Asthmatic Children's Study (TACS) was a pilot study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools. The four-week study was performed in October and November, 2003. The study involved repeated daily personal, residential, and ambient air pollution measurements for a cohort of nine children. Measurements were taken to determine the microenvironmental concentrations of combustion-related products (CRP), particulate matter (PM), and some air toxics. A portable "lunch box" was developed that permitted air in close proximity to the young child (personal) to be continuously monitored. The lunch box was designed to fully contain all of the active and passive sampling devices needed for personal monitoring of each child in a safe and effective manner. The lunch box had to be lightweight, quiet, and portable so that it would be easy to move the box and keep it near their child at all times. Participating children were clinically diagnosed as being asthmatics, less than or equal to 5 years of age, and lived in single family dwellings with nonsmoking parents. They were recruited through a broad-based campaign consisting of public notices, physician and community contacts. The study involved 24-hour integrated PM2.5 and PM10 mass measurements over four consecutive days for each participant. Real-time measurement of PM2.5 mass concentrations were collected using the MIE-pDR nephelometer. These measures and the activities recorded in a daily dairy will be used to correlate the child's personal PM exposure with their activities and the microenvironments where they spend time. Concentrations of a number of criteria pollutants (CO, SO2, NO2, O3) were also measured. Data collection for the study has been completed and an initial data analysis has been performed. Mean daily personal, residential indoor, residential outdoor, and ambient PM2.5 mass concentrations were 12.5, 9.3, 11.3, and 12.7 µg/m3, respectively. Personal PM2.5 mass concentrations ranged from 6.1 to 26.1 µg/m3. Specific source events such as exposure to cooking aerosols, household cleaning events, riding in an automobile, and burning candles were determined to contribute to the children's total personal PM exposure. Personal and residential indoor concentrations of criteria pollutants were below the national ambient air quality standards for all participants.
This work has been funded wholly by the United States Environmental Protection Agency' s Office of Research and Development under contract # 68-D-99-012 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication.