Improvements to the CAL3QHCR Model

The CAL3QHCR model is designated as a preferred model for regulatory applications involving highways in the U.S. Environmental Protection Agency’s (EPA) Guideline on Air Quality Models. As a result, it is used for a number of regulatory and non-regulatory applications, including project-level conformity analyses, highway air quality analyses relevant to the National Environmental Policy Act; health impact studies; and research. The model improvements that have been made include: 1) simplify and update the input file structure; 2) allocate receptor and link arrays at runtime; 3) eliminate the internal rounding of 1-hour average concentration predictions; 4) enhance the emission, traffic, and signalization (ETS) pattern function to account for month of year and hour of day variations in addition to day of week variations; 5) supplement the ability to consider background concentrations as a function of ETS patterns; 6) add the capability to process multiple years of meteorology in a concatenated file; and 7) update the output file structure. These improvement were made without affecting the concentration estimates produced by CAL3QHCR and as such, the preferred status of the model is unchanged a provided for in Title 40 of the Code of Federal Regulations, Part 51, Appendix W, Section 3.1.2b. Two non-regulatory options have also been added: 1) using meteorology processed by the AERMOD meteorological processor, AERMET and 2) estimating downwind dispersion based on the AERMOD formulation for computing vertical and horizontal dispersion coefficients.

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• Supplemental Notes:
  • This paper was sponsored by TRB committee ADC20 Transportation and Air Quality. Alternate title: Improvements to CAL3QHCR Model
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Claggett, Michael
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 18p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Air quality; Meteorology; Pollutants; Regulation; Signalization
• Identifier Terms: CAL3QHCR (Computer program); National Environmental Policy Act; U.S. Environmental Protection Agency
• Subject Areas: Environment; Highways; I15: Environment;

Filing Info

• Accession Number: 01515408
• Record Type: Publication
• Report/Paper Numbers: 14-5142
• Files: PRP, TRIS, TRB, ATRI
• Created Date: Feb 24 2014 8:42AM