Table 2 Comparison of outdoor PM_2.5 measurements taken by AirBeam sensors vs. time-matched measurements taken by nearby EPA monitors

Federal equivalent method

No

Yes

Yes

Yes

Measurement method

Optical sensor

Beta attenuation monitor

Beta attenuation monitor

Beta attenuation monitor

Measurement interval

1 s

1 h

1 h

1 h

Number of measurements

117,510

52

41

42

PM_2.5, μg/m³, mean (range)

6.8 (0.6, 97.6)

10.3 (2.9, 22.6)

7.1 (0, 11.9)

9.2 (0.1, 19.7)

Data missingness, %

0

1.8

22.6

20.8