Not our sensors, no, and not other similarly cheap ones, I think. They are just measuring light scatter (I think).
Whether they can distinguish and reject mist or fog, I’m not sure: they claim to distinguish two classes of particle size, so perhaps.
Thanks for that info Ed.
I see on the news that there is a suggestion for monitoring sewage outfalls into rivers. It may be possible to detect bacteria concentrations using flourescence. UV-A wavelength for common types of bacteria.