ZWEDC avecon data. linear scale for color and opacity.
converted csv to geojson, but still just point data.
gist on how this was put together: https://gist.github.com/tin6150/e271e5d3bef6d93ebc6817170ddd2456/
Mapbox style: Cali Terrain, some terrain polygon. not satellite map. thought it maybe useful for plume data to give insight how air maybe trapped.
CalTrans provided cities population. Said source to be TASS (Tax Area Service Section). 2011, 2015 data.
http://www.dot.ca.gov/hq/tsip/gis/datalibrary/Metadata/cities.html
Population is a count at this time, need to calculate density...
Alternate approach, see choropleth for census track https://blog.mapbox.com/dive-into-large-datasets-with-3d-shapes-in-mapbox-gl-c89023ef291