Volume 1: TRAQS User Guide (2018)

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TRAQS User Guide Page 141 11. AERMOD RESULTS Under the TRAQS main window, press the AERMOD Results button to access the results from the air quality modeling. 11.1. GRID VIEW The Grid View tab of the AERMOD Results window contains the following options: Plotfiles List This section shows a list of the pollutants that are being modeled and their respective AERMOD Plot- files. Plotfiles contain pollutant specific concentration results are generated when the AERMOD model is run and are produced for a specific averaging period and high value combination.

TRAQS User Guide Page 142 Grid View The Grid View tab displays a grid with the contents of the Plotfile for the currently selected Plot- file List item. This grid contains the following columns:  X Coordinate (m): This column contains the X UTM coordinate in meters for all receptors.  Y Coordinate (m): This column contains the Y UTM coordinate in meters for all receptors.  AERMOD Concentration (µg/m3): This column contains the AERMOD calculated pollutant- specific concentrations in micrograms per cubic meter at the receptor location. These values can have up to 5 decimal places.  Background Concentration (µg/m3): This column is populated by the user after the Background Concentration value is specified under the Design Value Calculation Op- tion section (see below). AERMOD Results - Grid View tab

TRAQS User Guide Page 143  Design Value (µg/m3): This column shows the calculated design value (Design Value = AERMOD Concentration + Background Concentration) rounded to the specified rounding value. Design values greater than the NAAQS value will be displayed in red color.  Date and Time: This is the date and time the AERMOD concentration occurred. Press this button to export the contents of the current grid to a csv file. Design Value Calculation Options This section contains options for the calculation of the design value as follows:  Get Default: Press this button to get default values for NAAQS and rounding options for the current pollutant and averaging period (see table NAAQS and Rounding Convention).  NAAQS (µg/m3): This field displays the US NAAQS value for the selected pollutant and av- eraging period. The table, provided at the end of this help page, shows the NAAQS values used by TRAQS.  Show only above NAAQS: When this box is checked, only Design Values above the NAAQS value will be displayed on the grid.  Round Design Values To (µg/m3): This field displays the rounding convention available for each averaging period.  Background Concentration (µg/m3): This value must be specified by the user and should be based on US EPA guidance. See the 2 notes below. See Appendix K - Examples of Design Value Calculations for PM Hot-spot Analyses of the "Transportation Conformity Guidance for Quantitative Hot-spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance Areas" (https://ne- pis.epa.gov/Exe/ZyPdf.cgi?Dockey=P100NN22.pdf)

TRAQS User Guide Page 144 See Appendix L – Calculating 24-hour PM2.5 Design Values Using a Second Tier Approach of the "Transportation Conformity Guidance for Quantitative Hot- spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance Areas" (https://nepis.epa.gov/Exe/ZyPdf.cgi?Dockey=P100NN22.pdf) TRAQS applies default NAAQS values and rounding conventions based on the following table: Table: NAAQS and Rounding Convention Pollutant Averaging Time NAAQS Form Rounding Convention CO 1-hour 35 ppm* Not to be exceeded more than once per year Rounded to the nearest 0.1 ppm 8-hour 9 ppm* Rounded to the nearest 0.1 ppm PM2.5 24-hour 35 µg/m3 98th percentile Rounded to the nearest 1 µg/m3 Annual 15 µg/m3 annual mean Rounded to the nearest 0.1 µg/m3 PM10 24-hour 150 µg/m3 Not to be exceeded more than once per year Rounded to the nearest 10 µg/m3

TRAQS User Guide Page 145 11.2. MAP VIEW The Map View tab of the AERMOD Results window contains the following options: Plotfiles List This section shows a list of the pollutants that are being modeled and their respective AERMOD Plot- files. Plotfiles are generated when the AERMOD model is run and are produced for each averaging period and high value combination specified in the AERMOD Input File. Map View The Map View tab displays a map with the visual representation of design values for the selected Plotfile List item. The map area contains the following elements: AERMOD Results - Map View tab

TRAQS User Guide Page 146  Plot Title: This title displays the pollutant and averaging period corresponding to the plot that is being displayed on the map (e.g., Design Values for PM2.5 – ANNUAL).  Press this button to export the map and plot to a PDF file.  Color Ramp: This object displays the range of colors and concentration levels used for the design values plot.  Press this button to set the view to the domain extents. Design Value Calculation Options See description of these options under the AERMOD Results – Grid View page.