Anthropogenic and biogenic tracers in fine aerosol based on seasonal distributions of dicarboxylic acids, sugars and related compounds at a rural background site in Central Europe. (15th April 2023)

• Record Type: Journal Article
• Authors: Vodička, Petr; Kawamura, Kimitaka; Deshmukh, Dhananjay K.; Pokorná, Petra; Schwarz, Jaroslav; Ždímal, Vladimír
• Is Part Of: Atmospheric environment. Volume 299(2023)
• Publication Date: 2023-04-15
• Subjects: Dicarboxylic acids -- PM1 aerosol -- Seasonal variations -- Source apportionment -- Central Europe; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2023.119619
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: Water-soluble organic compounds in aerosols are considered as relevant indicators of atmospheric processes. Fine particulate matter (PM1 ) samples were collected at National Atmospheric Observatory Košetice (NAOK), a rural background site representative of Central Europe, from September 27, 2013 to August 9, 2014. The samples (n = 146) were analyzed for water-soluble dicarboxylic acids (hereafter referred to as diacids) and related compounds to identify their seasonal variations and origins. Based on the Positive Matrix Factorization (PMF) analysis, we identified 5 factors – 2 anthropogenic, 2 biogenic and 1 background factors. In winter, anthropogenic contributions dominated in total organic matter (OM). Typical tracers for the main winter anthropogenic factor 1, connected with biomass burning (BB), were anhydrosugars together with maleic (M), methylmaleic (mM) and methylsuccinic (iC5 ) acids. This BB factor accounted for 64.1 ± 14.3% of OM in winter (annual avg. 36.7 ± 27.4%). A secondary anthropogenic factor 2 was characterized by phthalic (Ph), terephthalic (tPh) and ketomalonic (kC3 ) acids, which we assigned to secondary combustion products. The contribution of anthropogenic factor 2 was at a similar level throughout the year (12.5 ± 10.1% in OM). Mainly in winter, although also in spring and autumn, was the characteristic formation of diacids by secondary aqueous phase reactions, typically accompanied by lower temperatures, global radiation and ozone (O3 ) concentrations, yet higher relative humidity (RH) and aerosol liquid water content (ALWC). In summer, contributions of biogenic origin dominated. Secondary organic aerosols (SOA) of biogenic origin were typically represented by malonic (C3 ), methylmalonic (iC4 ), 3-oxopropanoic (ωC3 ), 4-ketopimelic (kC7 ), 7-oxoheptanoic (ωC7 ), pimelic (C7 ) and suberic (C8 ) acids. The factor, named as Biogenic 1, was dominant in summer with a contribution of 40.3 ± 19.6% in OM, while in other seasons, its contribution was below 10%. This factor was mainly characterized by a relative summer increase in the concentrations of kC7 and ωC7 acids. The second biogenic factor 2, also significant in summer (36.8 ± 20.5%) and dominant in spring (34.9 ± 19.9%), was represented by primary sugars (fructose, galactose and sucrose), normal chain diacids (oxalic (C2 ) to azelaic (C9 )) and their oxidative precursors (ωC3, 4-oxobutanoic (ωC4 ) and 5-oxopentanoic (ωC5 ) acids). The photochemical formation of SOA in the gas phase was characteristic mostly for the summer season, accompanied by higher temperatures, global radiation and O3 concentrations, and lower RH. Additionally, background factor was resolved, which represents compounds with no distinctive seasonal variation and can therefore be of both anthropogenic and biogenic origin and contained mainly less oxidized compounds (methylglyoxal (MeGly), glyoxal (Gly), glyoxylic acid (ωC2 ) and pyruvic acid (Pyr)). Graphical abstract: Image 1 Highlights: Clear difference between winter and summer compositions of diacids identified in PM1 . Two biogenic, two anthropogenic and one background factor was resolved by PMF analysis. Methylsuccinic, aromatic and aliphatic unsaturated acids were typical anthropogenic tracers. Organic acids with seven and three carbons were determined as biogenic tracers. Preferred aqueous-phase SOA formation in winter, while gaseous-phase in summer.