In recent years, more and more regulators view energy efficiency as a viable air quality improvement strategy. While no regulator should expect to solve all air quality challenges through one strategy alone, efficiency has distinct advantages over pollution control methods. This report is premised on the belief that regulators should employ energy efficiency as a first step toward air quality improvement rather than as a last resort. The report provides an introduction for air quality regulators to the rationale and opportunities for using energy efficiency as an air quality improvement strategy, identifies useful data sources, and outlines four basic steps for quantifying the air quality impacts of energy efficiency policies and programs. In addition, the paper explores opportunities to work with energy agencies to communicate air regulators’ energy efficiency data priorities, including ways to improve the data.