That's not partial zero in my book. It's at best "50% polluting" (making up the expected value here, but you get the point). Or "less polluting".. anything but "partial zero"

I think of it as a vector quantity with one (or more) components zero, and the rest nonzero. I agree it's a stupid name, but at least there's some reason to it. Misleading, but not entirely inaccurate.