In past modeling tips, we have discussed how to estimate sub-hourly pollutant concentrations using AERMOD, a Gaussian plume dispersion model with an hourly minimum time step. Now we look at how a similar concept can be modeled using a different modeling system – CALPUFF.
Dispersion within urban environments has different characteristics than that occurring in a rural environment. The urban boundary layer will behave in a more convective, turbulent manner during the hours just after sunset due to the urban heat island effect. AERMOD has capabilities to model this boundary layer by enabling the urban dispersion coefficient.
The Ontario Ministry of the Environment, Conservation and Parks (MECP) distributes pre-processed regional meteorological data and terrain data as required under Ontario Regulation 419/05. Data are hosted on the MECP website at https://www.ontario.ca/environment-and-energy/map-regional-meteorological-and-terrain-data-air-dispersion-modelling.
The U.S. EPA released the latest update to the AERMOD modeling system – dated 19191 – on August 21, 2019. One of the major formulation updates in this release is the addition of the RLINE source type .
When viewing results from an air dispersion model run, the primary concern of many modelers are conditions measured at receptors located in areas generally accessible by the public. This may preclude modeling from occurring within well-defined property boundaries that restrict public access to a facility.
AERSURFACE is a tool developed by the U.S. Environmental Protection Agency (US EPA) which uses digital land cover data to objectively calculate numeric values of surface characteristics (i.e. albedo, Bowen ratio, and surface roughness) required by AERMET, the meteorological preprocessor for the AERMOD air dispersion model.