The U.S. Environmental Protection Agency (EPA) has released two draft technical assistance documents regarding sulfur dioxide (SO2) national ambient air quality standards (NAAQS): the SO2 NAAQS Designations Modeling Technical Assistance Document (SO2 Modeling TAD) and the SO2 NAAQS Designations Source-Oriented Monitoring Technical Assistance Document (SO2 Monitoring TAD).
The draft SO2 Modeling TAD provides recommendations on how air agencies might appropriately model SO2 emissions for purposes of designations. It specifically discusses the use of temporally varying actual emissions, source characterization, meteorological data, model selection, and background concentrations.
The draft SO2 Monitoring TAD provides recommendations related to monitoring ambient air near an SO2 emission source, and specifically discusses steps to prepare for the source-oriented, SO2 monitor site-identification process that may proceed under EPA’s upcoming SO2 data requirements rule.
Comments are due to EPA by July 22, 2013, after which EPA intends to release a revised version of each technical assistance document.
For additional information, contact Andrew Holway.