Energy efficiency is a cost-effective, multi-pollutant strategy for addressing air quality, but is rarely utilized to meet air quality standards in the United States. This policy brief provides state air quality regulators and the U.S. Environmental Protection Agency (EPA) with an innovative approach to quantifying efficiency-related emissions reductions with sufficient rigor to meet regulatory standards and without being so onerous as to discourage the use of efficiency in air quality plans. The ‘mobile source analogy’ suggests that the same approaches used to quantify emissions from the country’s cars, buses, and trucks can also be used to quantify the emissions avoided by energy efficiency programs. In addition, the authors offer three complementary approaches EPA could take to connect the dots between energy saved and emissions avoided. Under a “deemed emissions approach”, EPA would establish default emissions reductions for a host of well-established efficiency measures with well-documented outcomes. A second approach suggests that EPA extend its existing AP-42 approach for establishing acceptable emission factors to include acceptable emissions reductions from energy efficiency measures. A third approach would utilize modeling to determine location-specific emissions reductions when important for meeting ambient air quality standards. Regardless of the approach taken, the authors see great potential for energy efficiency as an air quality strategy and encourage EPA to provide the necessary guidance to states to maximize its use.