Changes in the relationship between Index of Concentration at the Extremes and U.S. urban greenspace: a longitudinal...

Urban greenspace is associated with a wide variety of human health benefits, from improved mental health to reduced violent crime and infant birth outcomes. This study investigates long-term trends in the distribution of greenspace across census tracts in the 260 U.S. cities with populations greater than 100,000 residents based on economic privilege and deprivation. Satellite-acquired Normalized Difference Vegetation Index (NDVI) images were used as a measure of greenspace, and the Index of Concentration at the Extremes (ICE) was used as a measure spatial social polarizations of deprived and priveliged populations. From 2001 to 2019, the most privileged, highest ICE quintile census tracts had both the highest mean NDVI and experienced a significantly greater increase in greenspace than the least privileged tracts, indicating that the disparity in greenspace access is widening. Public greenspace initiatives need to focus on programs that are more equitable across the spectrum of economic strata to reduce urban health disparities and address concerns of environmental justice.