Historical policies have been shown to underpin environmental quality. In the 1930s, the federal Home Owners’ Loan Corporation (HOLC) developed the most comprehensive archive of neighborhoods that would have been redlined by local lenders and the Federal Housing Administration, often applying racist criteria. Our study explored how redlining is associated with environmental quality across eight California cities. We integrated HOLC’s graded maps [grades A (i.e., “best” and “greenlined”), B, C, and D (i.e., “hazardous” and “redlined”)] with 10 environmental hazards using data from 2018 to 2021 to quantify the spatial overlap among redlined neighborhoods and environmental hazards. We found that formerly redlined neighborhoods have poorer environmental quality relative to those of other HOLC grades via higher pollution, more noise, less vegetation, and elevated temperatures. Additionally, we found that intraurban disparities were consistently worse for formerly redlined neighborhoods across environmental hazards, with redlined neighborhoods having higher pollution burdens (77% of redlined neighborhoods vs 18% of greenlined neighborhoods), more noise (72% vs 18%), less vegetation (86% vs 12%), and elevated temperature (72% vs 20%), than their respective city’s average. Our findings highlight that redlining, a policy abolished in 1968, remains an environmental justice concern by shaping the environmental quality of Californian urban neighborhoods.

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历史红线与加州各地环境质量的差异有关

历史政策已被证明可以支撑环境质量。20 世纪 30 年代，联邦房主贷款公司 (HOLC) 开发了最全面的社区档案，当地贷款机构和联邦住房管理局经常采用种族主义标准对这些社区进行红线修改。我们的研究探讨了加州八个城市的红线与环境质量之间的关系。我们使用 2018 年至 2021 年的数据将 HOLC 的分级地图 [A 级（即“最佳”和“绿线”）、B、C 和 D 级（即“危险”和“红线”]）与 10 种环境危害相结合，以进行量化红线社区和环境危害之间的空间重叠。我们发现，与其他 HOLC 等级相比，以前的红线社区的环境质量较差，污染更高，噪音更大，植被更少，温度升高。此外，我们发现，以前的红线社区在环境危害方面的城市内差异一直更严重，红线社区的污染负担更高（红线社区为 77%，绿线社区为 18%），噪音更大（72% 比 18%），噪音更少。植被（86% vs 12%）和气温升高（72% vs 20%）均高于各自城市的平均水平。我们的研究结果强调，1968 年废除的红线政策通过塑造加州城市社区的环境质量，仍然是一个环境正义问题。