Measurement report: Evaluation of the TOF-ACSM-CV for PM<sub>1.0</sub> and PM<sub>2.5</sub> measurements during the RITA-2021 field campaign
<p>The recently developed time-of-flight aerosol chemical speciation monitor with a capture vaporizer and a PM<span class="inline-formula"><sub>2.5</sub></span> aerodynamic lens (TOF-ACSM-CV-PM<span class="inline-formula"><sub>2.5</sub...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/24/3405/2024/acp-24-3405-2024.pdf |
| Summary: | <p>The recently developed time-of-flight aerosol chemical speciation monitor with a capture vaporizer and a PM<span class="inline-formula"><sub>2.5</sub></span> aerodynamic lens (TOF-ACSM-CV-PM<span class="inline-formula"><sub>2.5</sub></span>) aims to improve the collection efficiency and chemical characterization of aerosol particles with a diameter smaller than 2.5 <span class="inline-formula">µm</span>. In this study, comprehensive cross-comparisons were performed between real-time online measurements and offline filter analysis with 24 h collection time. The goal was to evaluate the capabilities of the TOF-ACSM-CV-PM<span class="inline-formula"><sub>2.5</sub></span> lens, as well as the accuracy of the TOF-ACSM-CV-PM<span class="inline-formula"><sub>2.5</sub></span>. The experiments were conducted at Cabauw Experimental Site for Atmospheric Research (CESAR) during the RITA-2021 campaign. The non-refractory fine particulate matter (PM<span class="inline-formula"><sub>1.0</sub></span> and PM<span class="inline-formula"><sub>2.5</sub></span>) was measured by two collocated TOF-ACSM-CV-PM<span class="inline-formula"><sub>2.5</sub></span> instruments by placing them behind a PM<span class="inline-formula"><sub>2.5</sub></span> and PM<span class="inline-formula"><sub>1.0</sub></span> inlet, respectively. A comparison between the ACSMs and PM<span class="inline-formula"><sub>2.5</sub></span> and PM<span class="inline-formula"><sub>1.0</sub></span> filter samples showed a much better accuracy than <span class="inline-formula">±30</span> % less given in the previous reports, with average differences less than <span class="inline-formula">±10</span> % for all inorganic chemical species. In addition, the ACSMs were compared to the Monitoring Instrument for Aerosol and Gas (MARGA) (slope between 0.78 and 0.97 for inorganic compounds, <span class="inline-formula"><i>R</i><sup>2</sup>≥</span> 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, <span class="inline-formula"><i>R</i><sup>2</sup>=</span> 0.91). The intercomparison of the online measurements and the comparison between the online and offline measurements indicated a low bias (<span class="inline-formula"><</span> 10 % for inorganic compounds) and demonstrated the high accuracy and stability of the TOF-ACSM-CV-PM<span class="inline-formula"><sub>2.5</sub></span> lens for the atmospheric observations of particle matter. The two ACSMs exhibited an excellent agreement, with differences less than 7 %, which allowed a quantitative estimate of PM<span class="inline-formula"><sub>1.0</sub></span> vs. PM<span class="inline-formula"><sub>2.5</sub></span> chemical composition. The result showed that the PM<span class="inline-formula"><sub>1.0</sub></span> accounted for about 70 %–80 % of the PM<span class="inline-formula"><sub>2.5</sub></span> on average. The NO<span class="inline-formula"><sub>3</sub></span> mass fraction increased, but the organic carbon (OC) mass fraction decreased from PM<span class="inline-formula"><sub>1.0</sub></span> to PM<span class="inline-formula"><sub>2.5</sub></span>, indicating the size dependence on chemical composition.</p> |
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| ISSN: | 1680-7316 1680-7324 |