Section 109(d)(1) of the CAA requires that the Agency periodically review and revise, as appropriate, the air quality criteria and the NAAQS for the six “criteria” air pollutants, including lead. In November 2008, EPA published the final rule for the NAAQS for lead (73 FR 66934), revising the primary standard from 1.5 µg/m3 to 0.15 µg/m3, and setting the secondary standard equal to the primary standard. The indicator for the Lead NAAQS did not change and remains as lead in total suspended particles (Pb-TSP).
The Federal Reference Method (FRM) for Pb-TSP (40 CFR part 50, Appendix G) was promulgated in 1979 and is based on Flame Atomic Absorption Spectroscopy (FAAS). There is a need for a new FRM due to advances in analytical measurement technologies, such as improved analytical sensitivity, more efficient extraction methods, and new analytical instrumentation. EPA has developed the white paper, "Approach for the Development of a New Federal Reference Method (FRM) for Lead (Pb) in Total Suspended Particles (TSP)," which outlines the approach for the development a new FRM for lead. EPA's Office of Air and Radiation requested CASAC advice on several issues in the white paper including: extraction methods, analytical methods, validation and testing, and inter-laboratory variability.