Increasing the energy efficiency of end-use equipment in the residential, commercial, and industrial sectors can reduce air pollution emissions and greenhouse gases significantly. Because energy efficiency is an effective means of reducing multi-pollutant emissions, it is important to ensure that energy efficiency is a fully engaged component of emission-reduction programs. However, while energy-efficiency measures are perceived by many stakeholders to be important options for improving air quality, some members in the air quality community are concerned about the ability of these measures to fit in a regulatory framework-in particular, the ability of emissions reductions from energy-efficiency measures to be real, quantifiable, certifiable, and enforceable. Hence, there are few air quality programs that include energy efficiency as a tool for complying with air quality regulations. This paper describes the connection between energy consumption and air quality, the potential role of energy-efficiency measures to meet air quality regulations, the barriers and challenges to the use of these measures in the air quality regulatory environment, and the opportunities that organizations could exploit in this area.