Courtesy axlrosen and apparently covered on Slashdot as well.
Nasal rangers! They always get their booger nuggets!
This is a nasal ranger, and that thing he's using is an "olfactometer", a portable device that helps you smell. But not how you'd think. It actually dilutes the surrounding air by seven times, and if you can still smell whatever's making the air stinky, that's considered "excessive".
Iowa has trained 34 of these guys to test the air quality around farms and such.