Are 80% of these not just portraits or photos of people, I know some will say that they've been taken in an environment, but that definition applies to all photographs.
For me an environmental portrait should feed the viewer more personal information about that subject, and the environment should pertain to them personally, otherwise it's a portrait taken in a park, cafe, street or whatever.
If not, then a surely a head and shoulder shot taken aginst a white backdrop in a studio environment becomes an environmental portrait.