During the summer and fall of 2018, South Coast Air Quality Management District (SCAQMD) evaluated the field performance of the AirBeam2 against three Federal Equivalent Method (FEM) instruments. The results were positive for the AirBeam2’s PM1 and PM2.5 measurements, with R-squared values ranging from .64 to .94, and negative for the AirBeam2s PM10 measurements, with R-squared values ranging from .0 to .06. An R-squared value of 1 would mean there was a perfect correlation between the measurements from the FEM instrument and the AirBeam2. The above graph is taken from SCAQMD’s Airbeam2 evaluation. The red line represents the measurements taken by the reference instrument while the blue, green, and yellow lines represent the measurements taken by three colocated AirBeam2s. The complete results from the evaluation can be downloaded via SCAQMD’s AQ-SPEC website. We’d like to thank the folks at SCAQMD for running the AQ-SPEC program and evaluating the AirBeam2. The AQ-SPEC program is an invaluable and impartial source of information on low-cost air quality instruments.