2001 Progress Report: Hazardous Air Pollutant Mixtures: Measuring and Modeling Complex ExposureEPA Grant Number: R827928
Title: Hazardous Air Pollutant Mixtures: Measuring and Modeling Complex Exposure
Investigators: Adgate, John L. , Pratt, Greg , Ramachandran, Gurumurthy , Sexton, Ken , Zhang, Junfeng
Current Investigators: Adgate, John L. , Church, Timothy , Pratt, Greg , Ramachandran, Gurumurthy , Sexton, Ken , Zhang, Junfeng
Institution: University of Minnesota - Twin Cities , Minnesota Pollution Control Agency , University of Medicine and Dentistry of New Jersey
Current Institution: University of Minnesota , Minnesota Pollution Control Agency , University of Medicine and Dentistry of New Jersey
EPA Project Officer: Chung, Serena
Project Period: December 20, 1999 through December 19, 2002 (Extended to June 19, 2004)
Project Period Covered by this Report: December 20, 2000 through December 19, 2001
Project Amount: $510,012
RFA: Urban Air Toxics (1999) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Objective:This research project builds upon an existing U.S. Environmental Protection Agency grant (STAR Grant No. R825241: Measurement and Source Apportionment of Human Exposures to Toxic Air Pollutants in the MinneapolisSt. Paul Metropolitan Area; herein HAPS) and University of Minnesota-funded studies in the MinneapolisSt. Paul Metropolitan Area. The objectives of the project are to: (1) examine the relationships between ambient monitoring (i.e., outdoor central sites), indoor air monitoring, and personal exposure monitoring for a mixture of selected hazardous air pollutants (HAPs); i.e., eight volatile organic compounds (VOCs) and six particle-bound metals in the PM2.5 size fraction; and (2) examine the relationship between modeling and monitoring results for exposures to VOCs and metals.
In the course of attaining these objectives, the study will test seven related hypotheses: (1) central site measurements of metal concentrations in the PM2.5 fraction provide reasonable estimates (i.e., within a factor of 2) of indoor concentrations for these particle-bound metals; (2) central site measurements of metal concentrations in the PM2.5 fraction provide reasonable estimates (i.e., within a factor of 2) of personal exposure concentrations for these particle-bound metals; (3) variability in personal metal concentrations in the PM2.5 fraction is related to variability in indoor at home metal concentrations in the PM2.5 fraction; (4) variability in personal exposure to metals in the PM2.5 fraction is related to variability in indoor at home and personal VOC levels; (5) for the general adult population, personal exposure concentrations for a complex mixture of metals and VOCs can be predicted based on time activity profiles and ambient dispersion modeling of these HAPs; (6) for the general adult population, the primary sources contributing to indoor and personal exposure to a complex mixture of metals and VOCs can be predicted based on source apportionment modeling results; and (7) continuous measures of indoor PM2.5 levels can be used to characterize and explain day-to-day variability in 24-hour gravimetric samples.
Progress Summary:In Project Year 2, the following tasks were completed: (1) summary statistical analysis of trace metal concentration data obtained by x-ray fluorescence analysis of the outdoor PM2.5 central site filters; (2) digestion and analysis by high resolution inductively coupled plasma mass spectroscopy (HR-ICPMS) analysis of approximately 75 percent of personal and indoor samples collected as part of HAPs; and (3) continued development of an integrated database of all outdoor, indoor, and personal VOC and PM measurements from the HAPs; study.
At present, we are behind the schedule outlined in the original grant. This is due to the heavy demand on the HR-ICPMS instrument used to analyze trace metals on our air filters. As of the writing of this report in early March 2002, digestion and analysis of 90 percent of the air filters has been completed, and the remaining 10 percent will be completed by the end of March 2002. Our collaborators at the Minnesota Pollution Control Agency have developed an updated VOC source inventory to facilitate modeling of outdoor VOC concentrations in the Twin Cities air shed.