California Assembly Bill 32, the Global Warming Solutions Act, was enacted in 2006. The bill sets the 2020 greenhouse gas emissions goal at 1990 levels and provides a policy driver for energy efficiency programs. The San Francisco Department of Public Health recently conducted a health impact assessment related to the potential health outcomes of residential energy efficiency retrofits. The HIA used environmental quality and housing data available from the City and County of San Francisco to evaluate how the health benefits of energy efficiency programs vary with levels of ambient air and noise pollution and filtered mechanical ventilation and building envelope noise protection improvements. Health outcomes addressed include premature mortality associated with ambient particulate matter 2.5 (PM2.5) exposure and subjective annoyance associated with ambient noise. The HIA estimated that standard energy efficiency upgrades would likely reduce deaths attributable to ambient PM2.5 by 4%. The addition of filtered mechanical ventilation to the standard energy efficiency upgrades would likely further reduce PM2.5-attributable deaths by an estimated 43-55%. The HIA estimated that about 14% of the population in San Francisco is negatively impacted by ambient noise levels. Standard energy efficiency upgrades would likely reduce the proportion of the affected population to 8%. Standard energy efficiency upgrades, combined with acoustical protections, would likely further reduce the proportion of the affected population to 2%.
The HIA also made several recommendations, including targeting energy efficiency programs to neighborhoods with higher exposures of ambient air and noise pollutants and developing model building codes to ensure that energy efficiency upgrades are installed and operate as intended and do not adversely affect building ventilation or other indoor environmental quality factors.