Assessment models

The impact assessment study uses several cascading or nested models:

• Distributed meteorology (MM5):

  The impact assessment simulation runs are based on a three year period of meteorological data to eleminate bias from specific meteorological situations as much as possible. For the years, 2008,2009, and 2010 detailed meteorological fields (interpolated down to 1 km hourly values) are used. They are generated with MM5, a 3D non-hydrostatic prognostic model system based on global NCEP NFL data. The meteorological data are generated as 3D fields (3 km model output with diagnostic interpolation to 1 km, 1 hr resolution) and also extracted as time series for a number of monitoring locations.

• Dynamic boundary conditions (CAMx, continous forecasts (GFS), episodes (FNL):

  CAMx is a dynamic, 3D nested grid photochemical simulation model. To generate dynamic estimates of boundary condition (starting at a European scale and the latest EMEP emision data from 2009) it is used doen to sub-national scale. Nested model domains include a 2,400 km, 240 km and 40 km domain (width).

  
  

• Regulatory long-term modeling (AERMOD, annual at hourly resolution):

  AERMOD (latest release: 09292) is used with AERMAP terrain data, AERMET meteorological input files (generated from MM5 re-analysis runs to guarantee spatial consistency), and the FASTALL option for best computational performance; the model is run for each substance and year. Model output includes, in additioan to the standard AERMOD ASCII output files:

  • annual average as a topical map, color coded concentrations and user defined isolines, global maximum of annual average, comparison with standard, area above standard if applicable;
  • average and mximum concentration at user defined receptor locations, with a link to the complete time series of hourly concentration for the year simulated at that location, indication of compliance or violation statistics;
  • tabular summary of the 30 hourly maxima (NOx) or 24 hour average maxima, date and location of occurence, assciated meteorological conditions;
  • tabular summaries and corresponding topical maps for violation maxima, highest average over standard, and number of violations at a given location, together with precentile table, total number of hour and total number of location experiencing violations of the applicable standard.
  • population exposure: summary of area and total number of people lliving in the area where a violation of the standard is predicted.

• Regulatory (worst case episodes) modeling (AERMOD, daily, at hourly resolution):

  For the dates (days) that include violations of the hourly standard, the basic regulatory assessment model AERMOD is run for 24 hours at higher resolution (50 and 25 m), generating hourly concentration matrices as topical maps.

• Regulatory (direct NO2 modeling) (AERMOD/OLM, annual and daily, at hourly resolution):

• Dynamic simulation of worst case episodes, full photochemistry (CAMx):

• Near field, line sources (TRAFFIC):

• Dynamic and mobile sources (PUFF):