The New Source Review (NSR) permitting regulations require that the measurement and control of PM from new major stationary sources and major modifications include the condensable component for both PM2.5 and PM10 emissions. Stakeholders have expressed concern that source-specific condensable particulate matter test results obtained with Method 202 could include positive bias that translates into overestimations of emissions. Some of these stakeholder issues involve the quality of reagent chemicals used in the method, while other issues involve equipment preparation or contamination pre- and post-sampling. The EPA is revising sections of Method 202 including, but not limited to, the proof blank train preparation and recovery requirements in the method and use of the proof and field train blanks. The revisions would address consistency in the execution of Method 202, which has shown wide variation in its implementation, and allows many performance-based options and procedures.