I have a rich friend.  Just one really.  Whenever I ride in his car, I love the sound the doors make when they close. Unlike the tinny “clank” when the doors of my elegantly rusty SUV slam, his doors have a deep, reassuring, “clomp” sound.  Inside, you are cocooned, secure, padded, and hermetically sealed. More and more often, our buildings are “sealed” like my friend’s car and that isn’t necessarily a good thing. Modern building techniques and materials have given us an almost airtight environment to live and work in, which means the dust we generate or track in from outside, stays inside.  It’s no surprise that allergies in developed countries are on the rise.  When I was a kid allergies were a rarity but nowadays we’re all clamoring for the Benadryl, Claritin, or something like it. Because of this, hard surface floors in homes and businesses are increasingly commonplace, while carpet sales decline.  Hard surface fl ...