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US EPA has updated the Guideline on Air Quality Models

On December 20, 2016, the US EPA revised the Guideline on Air Quality Models. The Guideline provides EPA-recommended models and other techniques, as well as guidance for their use, for predicting ambient concentrations of air pollutants.

Key things to note:

  • CALINE3 is being replaced by AERMOD as the preferred model for refined mobile source applications including fine particle pollution (PM2.5, PM10), and carbon monoxide (CO) hot-spot analyses.
  • The EPA is finalising modelling techniques to address the secondary chemical formation of fine particle and ozone pollution from direct, single source emissions of sulfur dioxide, oxides of nitrogen for fine particle formation, and volatile organic compounds and oxides of nitrogen for ozone formation. These compounds can react in the atmosphere to form fine particle and ozone pollution.
  • In conjunction with the final Guideline, the EPA is issuing guidance on single-source modeling, “Guidance on the Use of Models for Assessing the Impacts of Emissions from Single Sources on the Secondarily Formed Pollutants Ozone and PM2.5.”
  • Modifications to AERMOD formulation to address issues with overprediction for applications involving relatively tall stacks located near relatively small urban areas (no user input is required).
  • For long-range (> 50km from an emissions source) air quality assessments, the EPA is removing CALPUFF as a preferred model.

EPA originally published the Guideline on Air Quality Models in 1978 and revised it several times since then. The latest revision occurred in November 2005.

Further information available here.

[Source: All4, 20 January 2017]