Apparently I suffer from exercise induced rhinitis (thanks to someone in this forum mentioning the diagnosis, it definitely applies to me).    However, if I was to attend to it with tissues, I'd end a ride with a pile of 
mucous soaked tissues, and a lot of stops to deploy them or inevitable falls when riding one hand while distracted by the search for a clean one.  So I do the best I can.  And yes it is disgusting and 
unhealthy (though I definitely don't have tb!), it's not more disgusting or unhealthy than diesel fumes (I'm looking at you VW drivers, though I know you tried).  I wouldn't do it on shared path where someone might step onto it, but after a quick shoulder check on a busy road where it will quickly be ground into the surface and mostly evaporate - well, it's not going to be the worst thing on there, by a long shot.