Perhaps historicization. a time-based mapping (overlays) of demographic change and the emergence (and remediation) of toxic sites determined by each decennial census since 1990 (1990, 2000, 2010, 2020? - forthcoming). Also, an added layer of land-use zoning adjustments, official comprehensive planning documents, remediation policies, variances granted by local planning authorities and litigation gathered from court cases.
One way to enrich this image might be to surround the initial map with other aerial images which represent sites from within the different TRI clusters, or locations of the emissions of particular air toxics, so that the harmful qualities of industrialization can be visualized.
Another possibility might be to compare this map with a more recent map, and pinpoint areas of recent deindustrialization, in order to see if it has a relationship with ongoing gentrification?
A third possibility would be to integrate “illegal” toxic emissions in some format—either through highlighting several industries which might get exemptions from the TRI, or marking other forms of toxic waste sites (continuing from image 1).