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MODELING AIR POLLUTION FROM THE COLLAPSE OF THE WORLD TRADE CENTER AND ASSESSING THE POTENTIAL IMPACTS ON HUMAN EXPOSURE
Citation:
HUBER, A. H., P. GEORGOPOULOS, R. GILLIAM, G. STENCHIKOV, S. WANG, B. KELLY, AND H. FEINGERSH. MODELING AIR POLLUTION FROM THE COLLAPSE OF THE WORLD TRADE CENTER AND ASSESSING THE POTENTIAL IMPACTS ON HUMAN EXPOSURE. EM: AIR AND WASTE MANAGEMENT ASSOCIATION'S MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, , 35-40, (2004).
Impact/Purpose:
The objective of this task is to improve EPA's ability to accurately predict the concentrations and deposition of air pollutants in the atmosphere that are known or suspected to cause cancer or other serious health effects to humans, or adverse environmental effects. It is an essential component of EPA's National Air Toxics Assessment (NATA), which seeks to identify and quantify the concentrations and sources of those hazardous air pollutants which are of greatest potential concern, in terms of contribution to population risk. It is a major contributor to NERL's Air Toxics Research Program.
"Air toxics" or "hazardous air pollutants" (HAPs) is a category that covers a large variety of chemicals, which range from relatively non reactive to extremely reactive; can exist in the gas, aqueous, and/or particle phases; display a large range of volatilities; experience varying deposition velocities, including in some cases revolatilization; and are emitted from a wide variety of sources at a large variety of different scales. In addition, concentrations of air toxics are needed by regulators for both short (days) as well as long (up to a year) time scales. These requirements challenge our current capabilities in air quality models far beyond the needs for other pollutants, such as ozone. The specific work being done under this task involves 1.) developing and testing chemical mechanisms which are appropriate for describing the chemistry of air toxics; 2.) incorporating these chemical and physical mechanisms into EPA's CMAQ modeling system and applying the model at a variety of scales; and 3.) developing the methods for using models to predict HAPs concentrations at subgrid or neighborhood scales; and 4.) using these tools to assess the magnitude and variability of concentrations to which urban populations are exposed.
Description:
The US EPA National Exposure Research Laboratory (NERL) and the Environmental and Occupational Health Sciences Institute (EOHSI) have been working together under a University Partnership Agreement to develop improved methods for human exposure modeling. This partnership was ongoing prior to September 11, 2001 but has since directed part of its efforts to support EPA assessment studies of potential human exposures following the collapses of the twin towers and the fires that burned at the site of the World Trade Center. The scope of the modeling reported in this paper has three principal modeling topics: a) meteorology and pollutant plume in the Metropolitan NY area and impact on downwind locations, b) fine-scale pollution impact in the local area of lower Manhattan South of Canal Street, and c) human exposure assessment to ambient pollution. Also, a wind tunnel model study of was conducted to support understanding of fine-scale pollution in the urban street canyons of lower Manhattan is reported in a separate paper. Additional research and application development will continue as part of the total effort, and will be reported as it is developed and projects completed. The collapse of the World Trade Center (WTC) towers increased the awareness that there are scientific shortcomings when it is necessary to do exposure modeling of air pollution events in urban environments and in being able to provide timely modeling support. The scientific shortcoming is most serious when the air pollution events occur in an urban center where the understanding of airflow around large buildings is poor. The larger purpose of ongoing modeling developments and applications is to work to provide demonstrated the tools for future application in support of the Program and Regional Offices at EPA.