The White House in a memorandum issued April 12, 2018 (NAAQS Memorandum) instructed the U.S. Environmental Protection Agency (EPA) to take “specific actions” to reduce burdens on states and the regulated community under the National Ambient Air Quality Standards (NAAQS). The Clean Air Act (CAA) requires EPA to review existing standards every five years. Once a final standard is promulgated, a state must submit for EPA approval a state implementation plan (SIP) or EPA will issue its own federal implementation plan (FIP). Additionally, regulated entities seeking to obtain permits under the CAA must meet emission limits designed to satisfy the NAAQS, which could involve applying costly control technologies. The NAAQS Memorandum directs EPA to evaluate or revise existing agency processes for evaluating SIPs and permit applications. It also directs EPA to improve efficiency in issuing revised NAAQS. William Wehrum, Assistant Administrator for EPA’s Office of Air and Radiation (OAR), cited the Supreme Court’s decision in Utility Air Regulatory Group v. EPA, 134 S. Ct. 2427 (2014), to explain that EPA should reevaluate its reading of the CAA’s NAAQS provisions to avoid reaching “wacky” results, such as setting a NAAQS below background levels. Wehrum stated that OAR will seek to streamline its NAAQS review process to reduce some scientific adviser input and to rely on existing modeling data that may be less than perfect. EPA’s approach could signal that rather than revising the 2015 ozone NAAQS of 70 parts per billion (ppb), the agency will focus on revising the NAAQS process for future NAAQS. As a further indication of this approach, EPA recently issued a final rule retaining the existing nitrogen dioxide NAAQS of 100 ppb over one hour.