The purpose of the design overlay district is to protect developed areas of the City characterized by uniqueness of established neighborhood character, architectural coherence and harmony, or vulnerability to deterioration. This is accomplished through controlling the patterns of architectural design and development in residential and commercial neighborhoods, which may include new construction, alterations, and demolitions. Only exterior changes to buildings, structures, and sites within public view may be regulated. Design Overlay Districts are also used for GIS mapping and analysis.

This dataset contains remotely sensed estimates of nitrogen dioxide (NO2, via TROPOMI accessed via Google Earth Engine) for HOLC neighborhoods in 11 US Midwestern cities, and corresponding coarse geographic and demographic data of those cities. NO2 data is reported daily for the entire calendar year of 2019, geographic and demographic variables are fixed for each city for the entire year. Each HOLC-graded neighborhood included in this dataset was filtered to be greater than 2 km2. The number of pixels used to calculate the area-weighted mean of NO2 is also reported, as is the area of the neighborhood. The dataset has also been filtered for observations that did not pass quality filters for L3 TROPOMI data. The cities included in the study are: Chicago IL, Milwaukee WI, Saint Paul MN, Minneapolis MN, Indianapolis IN, Cleveland OH, Wichita KS, Greater Kansas City KS and MO, Columbus OH, Detroit MI, and Omaha NE. HOLC neighborhood shapefiles were obtained from the Mapping Inequality project website, hosted by the University of Richmond, and resulting polygons used in analysis were created by dissolving shared boundaries in Google Earth Engine. City populations and population density were obtained from the US 2010 Census data. All data was collected and organized to assess if current day NO2 levels varied with HOLC grades in these major cities.

Robert K. Nelson, LaDale Winling, Richard Marciano, Nathan Connolly, et al., “Mapping Inequality,” American Panorama, ed. https://dsl.richmond.edu/panorama/redlining/#loc=5/39.1/-94.58&text=downloads

Dataset for all analyses presented in Hrycyna et al. Columns described below:

HOLC_grade: A, B, C, D (neighborhood grade categories obtained from Mapping Inequality project, indicate historic HOLC designations of neighborhoods).

HOLCAreaKm2: continuous area value in km2 of the HOLC neighborhood polygon, which may be more than one HOLC designated polygon merged from the shapefiles downloaded from Mapping Inequality.

pixelcount: integer values of the number of TROPOMI NO2 pixels used to produce the area-weighted mean NO2 value.

NO2_mol_m2: area-weighted mean value of TROPOMI NO2 for that HOLC neighborhood polygon in mol m-2

system.index: designated date and time boundary of the observation collected via TROPOMI

date: date of observation

month: month of observation

City: city in the US Midwest

State: state for the city of focus

Population: urban population obtained from 2010 census

PopDensity: urban population density obtained from 2010 census, based on modern city boundaries (in people per square miles)

CityArea_mi2: Area of the city of interest, in square miles.

ln_NO2: natural log transformed NO2 values in mol m-2

NO2_DU: NO2 value converted from mol m-2 to DU (Dobsons Units, converted by multiplying 2241.15)

NO2_lnDU: natural log transformed NO2 values in DU

Comment: We have submitted the manuscript to Elementa, where it is currently undergoing revisions. We will update references when the final DOI of the manuscript is available.

The Home Owners’ Loan Corporation (HOLC) was a New Deal era program that graded neighborhoods based on perceived loan risk, but largely based on immigrant status and populations of color. Affluent areas were often graded as “A” or “Best” due to the low perceived risk of loan default. The riskiest grade was “D” or “Hazardous” and were predominantly communities of color and immigrant neighborhoods. These practices, while banned in 1968, have been linked to significant and increasing economic and demographic disparities through time. We are now also finding that these redlined areas are also associated with more extreme urban heat island effects, and that this is likely due to their lack of tree canopy and greater impervious surface (things like asphalt and cement roads) percentage. A recent paper by Hoffman et al. (2020) has connected these borrowing practices with the resulting impacts on local climate impacts along with human health. This map includes the following information for U.S. city neighborhoods:HOLC Grade (from the University of Richmond Digital Scholarship Lab)Average land surface temperature difference from citywide HOLC normal (reported in Hoffman et al., 2020)Tree cover percentage (from the National Land Cover Database)Impervious surface percentage (from the National Land Cover Database)Demographic information (from the American Community Survey)