Le Monde, the French newspaper, makes available the data of the Map of Forever Pollution.
Get the data here and the methodology here.
The datasets the team has gathered to develop the map are available for download in two formats. One is the data behind the map. The second one gathers more detailed data, including values detected below 10 ng/L, for experts to explore and reuse.
This data is freely reusable, as long as you cite the Forever Pollution Project and this webpage, and inform us at horel[@]lemonde.fr.