Assistant Project Manager Civil & Environmental Consultants, Inc., PA
Accurate meteorological data is a key component of air dispersion modeling conducted using the U.S. Environmental Protection Agency’s (EPA) preferred model, AERMOD. Regulations regarding the selection of meteorological data vary between states, with some states providing preferred meteorological data, and others providing guidance to assist users in determining the most representative meteorological dataset.
Civil & Environmental Consultants, Inc. (CEC) was tasked with modeling a facility in the state of West Virginia. An initial modeling protocol was submitted to the agency which included a meteorological data analysis observing the differences between three potential meteorological data stations with varying proximities to the facility and surface characteristics. After submitting the initial modeling protocol, comments were received from the state agency which requested further refinement of the analysis to include additional parameters. Based on these comments, CEC worked with the state agency, as well as Lakes Environmental Software, to conduct a refined meteorological data sensitivity analysis to ensure that the most representative meteorological data was selected. Based on guidance from the state agency, the three sources of meteorological data were compared using surface characteristics of each data collection station, as well as site specific surface characteristics. Additionally, a detailed analysis of the precipitation conditions at each data collection station was completed to improve the accuracy of the surface moisture conditions at each of the stations and allow for more granular surface moisture content in the analysis.
While the project was focused on a specific facility in the state of West Virginia, many of the methods used in the refinement of the meteorological data sensitivity analysis were taken from the EPA’s AERSURFACE User’s Guide and can be applied to similar analyses conducted for other facilities located within other states. The study underscores the importance of selecting appropriate meteorological data for use in dispersion modeling using AERMOD and provides insights which allow for AERMOD users to make informed decisions about the representativeness of meteorological data.
