This detail merits a separate entry only because it CAN be a health issue. In the spring the cotton woods, 'piopo' in Italian explode in snow like avalanches of seeds. At first it is pretty...kind of enchanting. Sort of like God blew on a giant dandelion and all these things are floating all around you. Eventually, much like snow, it starts to interfere because you breathe it in and have to start pulling it out of your mouth.
In extreme cases, it can affect respiratory ailments. I've been in Milan several times during the spring and sometimes it is worse than at other times. And it seems to be concentrated in Milan. When we traveled just slightly away from Milan there was a noticeable reduction. Check out the photo if you want to see how dense it can be. In any case, if you suffer from respiratory ailments try to stay indoors during blizzards of the stuff and be prepared to do whatever you normally do when you are affected. I now travel with a good expectorant, in case it provokes another bronchitis attack as it did the first time.