1. Measurement report: Evaluation of the TOF-ACSM-CV for PM1.0 and PM2.5 measurements during the RITA-2021 field campaign
- Author
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Liu, Xinya, Henzing, Bas, Hensen, Arjan, Mulder, Jan, Yao, Peng, Dinther, Danielle, Bronckhorst, Jerry, Huang, Rujin, and Dusek, Ulrike
- Abstract
The recently developed time of flight-aerosol chemical speciation monitor with the capture vaporizer and a PM2.5 aerodynamic lens (TOF-ACSM-CV-PM2.5) aims to improve the collection efficiency and chemical characterization of aerosol particles with a diameter smaller than 2.5 µm. In this study, comprehensive cross-comparisons were performed between real-time online measurements and offline filter analysis with 24-hour collection time. The goal was to evaluate the capabilities of the TOF-ACSM-CV-PM2.5 lens, as well as the accuracy of the TOF-ACSM-CV-PM2.5. The experiments were conducted at Cabauw Experimental Site for Atmospheric Research (CESAR) during the RITA-2021 campaign. The non-refractory fine particulate matter PM1.0 and PM2.5 were measured by two co-located TOF-ACSM-CV-PM2.5 by placing them behind a PM2.5 and PM1.0 inlet, respectively. A comparison between the ACSMs and PM2.5 and PM1.0 filter samples showed a much better accuracy than ±30 % less given in the previous reports, with average differences less than ± 10 % for all inorganic chemical species. In addition, the ACSMs were compared to a Monitoring Instrument for Aerosol and Gas (MARGA) (slope between 0.78–0.97 for inorganic compounds, R2 ≥ 0.93), and a Mobility Particle Size Spectrometer (MPSS) measuring the particle size distribution from around 10 to 800 nm (slope was around 1.00, R2 = 0.91). The intercomparison of the online measurements and the comparison between the online and offline measurements indicated a low bias (< 10 % for inorganic compounds) and demonstrated the high accuracy and stability of the TOF-ACSM-CV-PM2.5 lens for the atmospheric observations of particle matters. The two ACSMs exhibited an excellent agreement, with differences less than 7 %, which allowed a quantitative estimate of PM1.0 vs PM2.5 chemical composition. The result showed that the PM1.0 accounted for about 70–80 % of the PM2.5 on average. The NO3 mass fraction increased but the OC mass fraction decreased from PM1.0 to PM2.5, indicating the size-dependence on chemical composition.
- Published
- 2023