While there is a Kickstarter funding drive to get your own AirBeam portable air monitor and I encourage people who can to contribute, the portable air monitor is an Arduino based open source project that anyone can construct. There is a lot of really interesting things being done here and it deserves more attention.
https://www.kickstarter.com/projects/741031201/airbeam-share-and-improve-your-air
All hardware and software can be found on github at:
https://github.com/cloudformdesign/Airbeam
Here is a great interview with Tim Dye who talks a bit about air monitoring and a few of the early AirBeam devices that anyone can build: