As policymakers increasingly focus on environmental justice, a key question is whether emissions reductions aimed at addressing air quality or climate change can also ameliorate persistent air pollution exposure disparities. We examine evidence from California’s aggressive vehicle emissions control policy from 2000 to 2019. We find a 65% reduction in modeled statewide average exposure to PM 2.5 from on-road vehicles, yet for people of color and overburdened community residents, relative exposure disparities increased. Light-duty vehicle emissions are the main driver of the exposure and exposure disparity, although smaller contributions from heavy-duty vehicles especially affect some overburdened groups. Our findings suggest that a continued trend of emissions reductions will likely reduce concentrations and absolute disparity but may not reduce relative disparities without greater attention to the systemic factors leading to this disparity.

中文翻译：

---

尽管加州严格控制车辆排放，但 PM 2.5 暴露差异仍然存在


随着政策制定者越来越关注环境正义，一个关键问题是旨在解决空气质量或气候变化问题的减排是否也能改善持续的空气污染暴露差异。我们研究了 2000 年至 2019 年加州激进的车辆排放控制政策的证据。我们发现，全州公路车辆对 PM 2.5 的建模平均暴露量减少了 65%，但对于有色人种和负担过重的社区居民来说，相对暴露差异增加了。轻型车辆排放是暴露和暴露差异的主要驱动因素，尽管重型车辆的较小贡献尤其影响到一些负担过重的群体。我们的研究结果表明，持续的减排趋势可能会降低浓度和绝对差异，但如果不更多地关注导致这种差异的系统性因素，可能不会减少相对差异。