Evaluation of aerosol chemical speciation monitor response to different mixtures of organic and inorganic aerosols

• Published in: Aerosol science and technology 2025-01, Vol.59 (1), p.16-33
• Main Authors: Mărmureanu, Luminița, Marin, Cristina Antonia, Vasilescu, Jeni, Petit, Jean-Eudes, Amodeo, Tanguy, Truong, Francois, Antonescu, Bogdan, Minguillon, Maria Cruz, Green, David C., Zainab, Bibi, Ovadnevaite, Jurgita, Elste, Thomas, Coz, Esther, Allan, James, Croteau, Philip L., Jayne, John, Canagaratna, Manjula R., Williams, Leah, Gros, Valerie, Prevot, Andre S. H., Favez, Olivier, Freney, Evelyn
• Format: Article
• Language: English
• Subjects: Aerosol chemistry; Aerosols; Air quality; Calibration; Chemical speciation; Data processing; Environmental Sciences; Ionization; Jingkun Jiang; Laboratory tests; Measuring instruments; Mixtures; Performance evaluation; Speciation
• ISSN: 0278-6826; 1521-7388
• DOI: 10.1080/02786826.2024.2412999

As national air quality networks and international research infrastructures, such as ACTRIS (EU) and ASCENT (US), continue to expand, the deployment of online aerosol chemistry measurements increases worldwide. These research infrastructures are focused on the ability to compare atmospheric properties from one region to another, making it crucial to understand instrument operation in various settings. This paper is part of a series of publications dedicated to better understanding the operation of these instruments using a series of laboratory tests. A particular focus was made on evaluating the organic aerosol (OA) measurement performance of six Aerosol Chemical Speciation Monitors (ACSMs) when sampling known mixtures of organic and inorganic aerosols and in ambient air. The study focuses on assessing the impact of instrument-to-instrument variability on ACSM data processing as well as identifying and quantifying the previously identified m/z44/NO 3 artifacts that can affect the accuracy of the measurements. A high degree of variability was observed in instrument measurements of the m/z44/NO 3 artifact when compared to results obtained two years earlier (e.g., an increase from ∼0 in 2016 to 0.16 in 2018 or a decrease from 0.12 in 2016 to 0.05 in 2018), confirming the need for frequent evaluation and quantification during calibration. This study underlines that the product between organic aerosol relative ionization efficiency and the instrument collection efficiency value is instrument dependent and that the variability in these values (1.78 ± 0.35) should be considered when estimating the measurement uncertainties. Using a range of specific compounds, an average RIEOA for levoglucosan (1.29 ± 0.23) close to the default value commonly used in ACSM was determined, obtaining a value more specific to each instrument. This study provides valuable information for the calibration and operation of ACSM instruments, ensuring that future studies can build on this work to evaluate and improve instrument performance.