Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Airflow and Aerosol Transport Modeling in Hart Senate Office Building



Steven J. Emmerich, Cynthia H. Reed, Andrew K. Persily


A modeling study of airflow and contaminant transport in the Hart Senate Office Building (HSOB) was performed to obtain insight into the transport of anthrax spores within the building after a short-term release in October 2001. This analysis employed an idealization of the building in the multizone airflow and contaminant dispersal model CONTAMW (Dols et al. 2000). Based on limitations in the information available at the time of the study, the building model and the simulations were necessarily based on numerous assumptions.This study was performed at the request of the Mechanical Engineering Division of the Office of the Architect of the Capitol (AOC), in consultation with the Emergency Response Team of the U.S. Environmental Protection Agency (EPA). The objective of the study was to provide insight into the transport of anthrax spores via airflow in support of interpretation of the sampling results already obtained by EPA, the planning of additional sampling and the planning of decontamination efforts.It should be noted that the simulations performed as part of this study are based on assumptions about the building due to a lack of access to the building and its ventilation systems and the fact that some of the required data were not available for the HSOB. These data include the airtightness values for the exterior walls and interior partitions, actual airflow rates in the ventilation systems and various portions of the air distribution ductwork, and size characteristics and deposition rates for the spores. In order to perform the simulations, these values had to be assumed based on data from other buildings, design values and the intention to be somewhat conservative in the analysis. Therefore, care must be exercised in interpreting and applying the results of this study. These results are best used as a first order estimate of what could reasonably have occurred in terms of airflow and airflow-driven spore transport and should be used in conjunction with other information such as the results of sampling in the building.
Airflow and Aerosol Transport Modeling in Hart Senate Office Building


building, building technology, CONTAMW, HVAC, simulations


Emmerich, S. , Reed, C. and Persily, A. (2002), Airflow and Aerosol Transport Modeling in Hart Senate Office Building, Airflow and Aerosol Transport Modeling in Hart Senate Office Building (Accessed June 17, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 23, 2002, Updated February 19, 2017