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

Abstract

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.

Review of the Performance of Low-Cost Sensors for Air Quality Monitoring

“…In addition, 19 projects evaluating OEMs, SSys, or both, and reporting quantitative comparisons of LCS data and reference measurements were identified. They include the Air Quality Egg, Air Quality Station, AirCasting [19,[35][36][37], Carnegie Mellon [36,38], CitiSense [30], Cairsense [39], Developer Kit [19], HKEPD/14-02771 [40], making-sense.eu [41], communitysensing.org [32], MacPoll.eu [20], OpenSense II [42,43], Proof of Concept AirSensEUR [22], and SNAQ Heathrow [44,45]. Out of the 1423 records collected from literature, we identified 1188 records (197 OEMs and 991 SSys) from 89 alive LCS (24 OEMs and 65 SSys) and 235 records (123 OEMs and 112 SSys) from 23 "non active" (or discontinued) LCS (7 OEMs and 16 SSys).…”

“…Those devices are manufactured in emerging economies, such as the Republic of China and the Republic of Korea [50]. Some of these LCS can achieve similar performance to more expensive OEMs [18,19,[29][30][31]37,48,49,[51][52][53][54][55][56].…”

Evaluation of a 10 nm Particle Number Portable Emissions Measurement System (PEMS)

“…Different principles of operation were under discussion to be applied as particle number detectors [4]. The most commonly used PM sensors, such as those in ambient air monitoring [28,29], exposure assessment [30][31][32][33][34], vehicle cabin air quality [35], or even filter monitoring in diesel exhaust [36][37][38], were not applicable to vehicle exhaust due to their relatively large lower size, high detection limit, or slow response time. Currently, there are two concepts for the particle sensors (detectors) inside the on-board systems: condensation particle counters (CPCs), similar to those in laboratory systems, and advanced diffusion chargers (DCs) [4,39,40].…”

Exercise in Thermal Inversions: PM2.5 Air Pollution Effects on Pulmonary Function and Aerobic Performance

“…However, several recent environmental field investigations have showed that although these miniaturized monitors have good reliability, they are only moderately correlated with reference measures and tend to be biased with increasing PM 2.5 concentrations. 21,22 The best solution for future research to overcome this limitation might be to conduct trials as close to the DEQ monitors as possible.…”