Residential development and near-roadway air pollution: Assessing risk and mitigation in San Jose, California

Abstract

Air pollution from high-traffic roadways has been connected with serious health conditions and premature death. While housing is commonly built near America's busiest roadways, we know little about the application of mitigation measures that could reduce residents' exposure to transportation-related pollution. This paper assesses the high-traffic roadway proximity of new housing in San Jose (California) and mitigation measures by public and private sector actors. We studied San Jose's 39 largest residential developments approved between 2008 and 2016. We examined project approval documents; visited development sites; measured proximity using geographic information systems (GIS); assessed aerial and Google Street View imagery; and collected data on green building certifications. Many of these developments were near freeways or major highways; about 4% of new housing units were within 500 feet of a high-traffic roadway, and 45% of new units were within 1500 feet of such roads. Public and private sector actors implemented limited mitigation measures. California's state government updated its building energy code and constructed soundwalls along some freeways. Some real estate developers also included green building features that may improve indoor air quality. But, there were no local regulations specifically guiding residential development along high-traffic roadways. In general, public and private sector mitigation measures were limited and uncoordinated. This research informs policymakers' efforts to reduce transportation-related pollution exposure and improve public health.