Inter-annual variability of source contributions to PM10, PM2.5, and oxidative potential in an urban background site in the central mediterranean

Lorena Carla Giannossa; Daniela Cesari; Eva Merico; Adelaide Dinoi; Annarosa Mangone; Maria Rachele Guascito; Daniele Contini

doi:10.1016/j.jenvman.2022.115752

Inter-annual variability of source contributions to PM₁₀, PM_2.5, and oxidative potential in an urban background site in the central mediterranean

J Environ Manage. 2022 Oct 1:319:115752. doi: 10.1016/j.jenvman.2022.115752. Epub 2022 Jul 30.

Authors

Lorena Carla Giannossa¹, Daniela Cesari², Eva Merico³, Adelaide Dinoi³, Annarosa Mangone¹, Maria Rachele Guascito⁴, Daniele Contini³

Affiliations

¹ University of Bari Aldo Moro, Department of Chemistry, I-70125, Bari, Italy.
² Italy National Research Council of Italy, Institute of Atmospheric Sciences and Climate (CNR-ISAC), Lecce, 73100, Italy. Electronic address: d.cesari@isac.cnr.it.
³ Italy National Research Council of Italy, Institute of Atmospheric Sciences and Climate (CNR-ISAC), Lecce, 73100, Italy.
⁴ Italy National Research Council of Italy, Institute of Atmospheric Sciences and Climate (CNR-ISAC), Lecce, 73100, Italy; Department of Environmental and Biological Sciences and Technologies (DISTEBA), University of Salento, Lecce, 73100, Italy.

PMID: 35982560
DOI: 10.1016/j.jenvman.2022.115752

Abstract

Airborne particulate matter (PM) is studied because of its effects on human health and climate change. PM long-term characterisation allows identifying trends and evaluating the outcomes of environmental protection policies. This work is aimed to study the inter-annual variability of PM_2.5 and PM₁₀ concentrations and chemical composition in an urban background site (Italy). A dataset of daily PM_2.5 and PM₁₀ was collected in the period 2016-2017, including the content of OC, EC, major water-soluble ions, main metals, and compared to a similar dataset collected in the period 2013-2014. Oxidative potential using DTT assay (dithiothreitol) was evaluated and expressed in DTT_V as 0.39 nmol/min·m³ in PM₁₀ and 0.29 in PM_2.5 nmol/min·m³. PM source apportionment was computed using the EPA PMF5.0 model and source contributions compared with those of a previous dataset collected between 2013 and 2014. Multi linear regression analysis identified which source contributed (p < 0.05) to the oxidative potential of each size fraction. Inter-annual trends were more evident on PM_2.5 with reductions of biomass burning contribution and increases in traffic contribution in the 2016-2017 period. Crustal contributions were similar for the two periods, in both size fractions. Carbonates were comparable in PM₁₀ with a slight increase in PM_2.5. Sea spray decreased in PM₁₀. The DTT_V of PM_2.5 peaked during cold periods, while, the DTT_V of the PM_10-2.5 fraction peaked in summer, suggesting that different sources, with different seasonality, influence OP in the PM_2.5 and PM_10-2.5 fractions. Analysis showed that sea spray, crustal, and carbonates sources contribute ∼13.6% to DTT_V in PM_2.5 and ∼62.4% to DTT_V in PM_10-2.5. Combustion sources (biomass burning and traffic) contribute to the majority of DTT_V (50.6%) in PM_2.5 and contribute for ∼26% to DTT_V in PM_10-2.5. Secondary nitrate contributes to DTT_V in both fine and coarse fraction; secondary sulphate contribute to DTT_V in PM_2.5 with negligible contributions to DTT_V in PM_10-2.5.

Keywords: DTT assay; Oxidative potential; PM composition Trend; PMF; Source apportionment.

MeSH terms

Air Pollutants* / analysis
Environmental Monitoring
Humans
Oxidative Stress
Particle Size
Particulate Matter / analysis
Seasons

Substances

Air Pollutants
Particulate Matter