Precision and Accuracy of a Direct-Reading Miniaturized Monitor in PM2.5 Exposure Assessment

The aim of this study was to evaluate the precision, accuracy, practicality, and potential
uses of a PM2.5 miniaturized monitor (MM) in exposure assessment. These monitors (AirBeam,
HabitatMap) were compared with the widely used direct-reading particulate matter monitors and
a gravimetric reference method for PM2.5. Instruments were tested during 20 monitoring sessions
that were subdivided in two different seasons to evaluate the performance of sensors across
various environmental and meteorological conditions. Measurements were performed at an urban
background site in Como, Italy. To evaluate the performance of the instruments, different analyses
were conducted on 8-h averaged PM2.5 concentrations for comparison between direct-reading
monitors and the gravimetric method, and minute-averaged data for comparison between the
direct-reading instruments. A linear regression analysis was performed to evaluate whether the
two measurement methods, when compared, could be considered comparable and/or mutually
predictive. Further, Bland-Altman plots were used to determine whether the methods were
characterized by specific biases. Finally, the correlations between the error associated with the
direct-reading instruments and the meteorological parameters acquired at the sampling point were
investigated. Principal results show a moderate degree of agreement between MMs and the
reference method and a bias that increased with an increase in PM2.5 concentrations