Grantee Research Project Results
2000 Progress Report: Air Pollutant Concentrations in the Vicinity of Buildings: Model Development and Evaluation
EPA Grant Number: R826156Title: Air Pollutant Concentrations in the Vicinity of Buildings: Model Development and Evaluation
Investigators: Peterson, Holly G. , Lamb, Brian , Stock, David , Schulman, Lloyd
Institution: Montana Tech of the University of Montana , Washington State University
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1997 through September 30, 2000
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
Project Amount: $360,011
RFA: Exploratory Research - Physics (1997) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Air , Safer Chemicals
Objective:
A better understanding of near-source plume behavior is important for predicting human health risks from acute exposure to toxic air pollutants. In particular, complicated airflow patterns in the vicinity of buildings may cause high concentrations near ground level from short stacks or vents. The Electrical Power Research Institute, in cooperation with the Environmental Protection Agency, recently developed algorithms to predict air pollutant concentrations near buildings. The set of algorithms is known as the Plume Rise Model Enhancement (PRIME), and ISC-PRIME is the corresponding new version of the Industrial Source Complex (ISC) model. The model predicts concentrations downwind of pollutant sources with averaging times between 1 hour and 1 year, including concentrations near buildings in recirculation cavities and downwash regions.The overall goals of this project are to evaluate ISC-PRIME with field data and to improve our fundamental understanding of plume dispersion near buildings. The specific objectives are to: (1) conduct field campaigns to characterize the behavior of tracer gases in the vicinity of a building under a range of meteorological conditions; (2) employ advanced numerical finite element modeling to aid interpretation of field data; and (3) link results from the field work and numerical studies to test ISC-PRIME.
Progress Summary:
Preliminary fieldwork was performed during summer of 1998 near an industrial-sized building located south of Butte, Montana. The building dimensions were 58.6 m x 17.1 m x 12 m with the long axis perpendicular to the predominant wind direction. Approximately 19 tests, each 1 hour in duration, were conducted under afternoon and evening conditions. In 1999, about 50 experiments were conducted during nighttime hours at rural site outside of Colfax, Washington. The building for the 1999 campaign had dimensions of 8.6 x 2.45 x 3.7 m.Throughout the studies, anemometers were used to monitor approach flows and turbulence within the building cavity. Sulfur hexafluoride (SF6) tracer gas was released through calibrated flowmeters from one of several locations (upwind of the building, within the recirculation cavity near the ground, at the top of the roof, and above roof level). An array of syringe samplers was used to measure time-averaged concentrations within and near the cavity while fast-response SF6 analyzers monitored concentration fluctuations.
Results to date have addressed concentration fluctuations within the building recirculation cavity and comparison of 1-h average concentrations to ISC-PRIME predictions. According to the 1998 data, concentration fluctuations in the cavity were dramatic even in tests with steady winds. Intermittency factors ranged from 0.01 to 0.99 and peak-to-mean ratios ranged from 1.5 to 553. ISC-PRIME predicted maximum average concentrations within a factor of 2 for 53 percent of the tests with a tendency to underpredict in 63 percent of the cases. For the 1999 campaign, peak-to-mean ratios were between 2.5 and 6 within the cavity and up to 24.4 near the cavity and wake edges. Likewise, in terms of model performance, ISC-PRIME was within a factor of 2 for 71.9 percent of the measurements, and within a factor of 3 for 89.6 percent. Again, the model showed a tendency to underpredict 80.7 percent of the sample points.
Future Activities:
Processing and analysis of the field data will continue through spring of 2001, and results will be summarized in a paper for publication in a peer-reviewed journal.Journal Articles:
No journal articles submitted with this report: View all 9 publications for this projectSupplemental Keywords:
air, ambient air, modeling., Scientific Discipline, Air, Physics, Environmental Chemistry, Atmospheric Sciences, Engineering, Chemistry, & Physics, building vicinity, aerosol particles, air pollution concentrations, building plume downwash models, database development, air pollution, atmospheric stability, plume dispersion model, tracer experimentRelevant Websites:
http://www.mtech.edu/dispersion/
http:// www.ce.wsu.edu/LAR
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.