Stan Hayes has more than 40 years of experience in environmental science and engineering, with particular emphasis on air impact and health risk analysis for both national ambient air quality standard (NAAQS) and hazardous air pollutant (HAP) purposes, including air quality modeling, strategic and regulatory policy analysis, climate assessment, compliance evaluation, exposure and health risk assessment, and air monitoring and meteorological data analysis. He is a Fellow of the Air & Waste Management Association, for whom he has chaired or co-chaired national and international specialty conferences on climate change, greenhouse gas reporting, and homeland security. He was a member of the EPA Science Advisory Board Risk and Technology Review (RTR) Methods Panel. He was a member and chair of the advisory council of the Bay Area Air Quality Management District. He is the primary author of more than 70 scientific papers and presentations, as well as several hundred technical reports on air-related subjects. He has provided expert testimony before federal, state, and local regulatory agencies and in court. Upon invitation, he has given scientific briefings to members of the California legislature and political leaders elsewhere. For 25 years, until 2015, Stan was a Principal with global environmental consulting firm ENVIRON (now Ramboll). He is now emeritus.Stan earned an M.S. in aeronautics and astronautics and a B.S. in mechanical engineering, both from Stanford University.