While I was out trying to find the possible applications for Sunon's adorable 9mm blowers[1], I came across Cairpol's Cairsens devices[2]. I'm not sure what the technology they're using is, but they're claiming to measure about ten different classes of air pollutants out of a cylinder that looks about the size of a D-Cell battery.

[1] http://www.sunon.com/publication_page.php?pkid=3 [2] http://cairpol.com/en/home/