Figure 4.

Oversampled TROPOMI data averaged across original 1938 financial securities map districts show increasing NO₂ column with decreasing grade A–D. Grid points were averaged proportionally to their area inside each district, then averaged together with their like-graded districts, weighted proportionally to the district areas. (a) Oversampled TROPOMI map of the area, (b) same TROPOMI data zoomed to the center over the HOLC districts, and (c) depicts the annual spatial average of the TROPOMI NO₂ columns for each HOLC district type. Origin value of 2.5 × 10^–5 mol m^–2 is the annual average regional background for this area. Error bars show the standard error. The thick black corner represents the inverted L.