Redlining in New York City: impacts on particulate matter exposure during pregnancy and birth outcomes.

Background: Evidence suggests historical redlining shaped the built environment and health outcomes in urban areas. Only a handful of studies have examined redlining's association with air pollution and adverse birth outcomes in New York City (NYC). Additionally, no NYC-specific studies have examined the impact of redlining on birth weight.

Methods: This longitudinal cohort study analysed data from the National Institute of Health Environmental Influences on Child Health Outcomes Programme to investigate the extent to which maternal residence in a historically redlined neighbourhood is associated with fine particulate matter (PM_2.5) exposure during pregnancy using multivariable regression models. Additionally, we examined how maternal residence in a historically redlined neighbourhood during pregnancy influenced birth weight z-score, preterm birth and low birth weight.

Results: Our air pollution model showed that living in a historically redlined census tract or an ungraded census tract was associated with increased PM_2.5 exposure during pregnancy. We also found living in a historically redlined census tract or an ungraded census tract was associated with a lower birth weight z-score. This finding remained significant when controlling for individual and census tract-level race, ethnicity and income. When we controlled PM_2.5 in our models assessing the relationship between redlining grade and birth outcome, our results did not change.

Discussion: Our study supports the literature linking redlining to contemporary outcomes. However, our research in ungraded tracts suggests redlining alone is insufficient to fully explain inequality in birth outcomes and PM_2.5 levels today.