I didn't take your statement as being Concorde related, it looked more like a general one to me. However, do you have any reference on this one?

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most things I have read on the Concorde do mention environmental concerns as a reason that SST's are not practical and why the Concorde is no longer in service.

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so you can imagine the kinds of protests the Concorde could stir up.

Well, lets say I know pretty much about the 'protests' and their topics within the Concorde era, maybe that's why your new fact base now raises questions. Maybe I was missing some vital data until now though.
I could name some environmental concerns regarding that old plane, but I'm mainly surprised about the context you are using them so far, which is a new one for me.  Hence the question regarding references.