Before going any further I think it is a good idea to check with Brian if it would be feasible to switch (cycle) through 3 addresses in the purple air set up and create 3 separate log files. I guess it would mean a lot of work for him if it is possible at all. Then there is the problem of how to display the results - it might be possible to show a different sensor each time the main screen refreshes but again I suspect a lot of work to do that.
Purple air ? The SDS011 is a lot cheaper alternative but not terribly accurate but OK for a general indication of air quality.
Alan