Summary

This study by Jeremy S. Hoffman, Vivek Shandas, and Nicholas Pendleton look at redlining and temperature. It is attempting to relate the results of today’s results in temperature distribution within cities across America with the risk assessment for loans of the HOLC(Home Owner’s Loans Corporation). There are four categories for loans. “Best”, “Still Desirable”, “Definitely Declining”, and “Hazardous”. They were categorized A, B, C, and D zones in that order(Hoffman et. al). This study looks at where these neighborhoods are now, temperature wise and tree wise, as a whole. There are four regions observed; Midwest, West, Northeast, and South. They cover HOLC A,B,C, and D zones for 108 cities(Hoffman et. al). Their method of data collection for heat and tree coverage come from satellite data. The satellite data on heat and tree distribution is overlaid with HOLC map data. It is map to map data so they have to line up each of the maps to make the accuracy of the satellite data precise.

Statistics & Results

LST stands for land surface temperature. In the South, the distribution between A and D zones is the most extreme. In the South, temperature wise, the upper 75% of A zones are cooler than all other zones anywhere. Additionally, the middle 50% of B zones are cooler than any of the middle 50% of C & D zones. This is practically the definition of exponential: each zone has a coolness ratio to the zone below and above it. What this means is that the disparity itself increases as you go from D to A. 

Tree canopy percentage is also quite different. The middle 50% of A zone neighborhoods have more tree canopy than the middle any of the 50% of C & D zones. The upper 50% of B zones have more tree canopy than 75% of C & D zones. Clearly, redlining has an affect on housing conditions and neighborhood conditions now even though it happened many years ago.