A Review of Procedures for Updating Air Quality Modeling Techniques for Regulatory Programs

Abstract Air quality models are a key component in determining pollution control requirements. To ensure that the best techniques are used, modeling guidance must be flexible and include better techniques as they become available. Revisions to modeling guidance require an assessment of the scientific basis, a model performance evaluation using observed data, sensitivity analysis for impact on design concentrations and data input requirements, and public review and comment before formal adoption in regulatory programs. The procedures used in reviewing new techniques are examined in this paper, and past actions are discussed. The appropriateness of adopting a new method for modeling area sources characterized by low-level releases with little buoyancy is provided as an example of the revision review process. While this process is lengthy, it ensures that decisions on potentially costly pollution controls are based on full public participation and sound scientific developments.