Insights on the combination of off-line and on-line measurement approaches for source apportionment studies

Alice C Forello; Inés Cunha-Lopes; Susana M Almeida; Célia A Alves; Oxana Tchepel; Federica Crova; Roberta Vecchi

doi:10.1016/j.scitotenv.2023.165860

Insights on the combination of off-line and on-line measurement approaches for source apportionment studies

Sci Total Environ. 2023 Nov 20:900:165860. doi: 10.1016/j.scitotenv.2023.165860. Epub 2023 Jul 28.

Authors

Alice C Forello¹, Inés Cunha-Lopes², Susana M Almeida², Célia A Alves³, Oxana Tchepel⁴, Federica Crova¹, Roberta Vecchi⁵

Affiliations

¹ Department of Physics, Università degli Studi di Milano, Milan 20133, Italy; National Institute of Nuclear Physics INFN-Milan, Milan 20133, Italy.
² Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela-LRS, Portugal.
³ Centre of Environmental and Marine Studies, Department of Environment, University of Aveiro, 3810-193 Aveiro, Portugal.
⁴ CITTA, Faculty of Sciences and Technology, University of Coimbra, 3004-531 Coimbra, Portugal.
⁵ Department of Physics, Università degli Studi di Milano, Milan 20133, Italy; National Institute of Nuclear Physics INFN-Milan, Milan 20133, Italy. Electronic address: roberta.vecchi@unimi.it.

PMID: 37516189
DOI: 10.1016/j.scitotenv.2023.165860

Abstract

This paper presents a source apportionment study performed on a dataset collected at a trafficked site in Coimbra (Portugal) during the period December 2018-June 2019. The novelty of this work consists in the methodological approach used and the sensitivity study carried out to give hints to potential future applications. Indeed, a multi-time resolution and multi-parameter study was performed joining together aerosol data from 24-h chemically characterized samples and high-time resolution multi-wavelength absorption coefficients retrieved by an Aethalometer. A detailed sensitivity study on the most suitable combination of time resolution and uncertainties was carried out to obtain reliable physical and stable solutions over all analyses. In parallel, a regular EPA-PMF source apportionment study using chemical and optical variables averaged on 24 h is presented and discussed in comparison to the more complex multi-time and multi-parameter approach. Apart from results pertaining to the identification and relevance of different sources in Coimbra, the methodological results shown here can give guidance for readers who want to implement optical variables jointly with chemical ones in the same model run.

Keywords: Multi-time resolution; Optical variables; PM sources; Sensitivity study.