Abundance and Sources of Phthalic Acids, Benzene-Tricarboxylic Acids, and Phenolic Acids in PM_2.5 at Urban and Suburban Sites in Southern China

Abstract

The organic composition of airborne fine particulate matter (PM 2.5 , aerodynamic diameter less than 2.5 μm) at a molecular level has yet to be achieved, hindering a full understanding of the climatic impacts and health effects of PM 2.5 . Compounds containing aromatic rings are closely associated with optically active brown carbon and toxicologically important quinones. In this work, a group of ten aromatic organic acids including three phthalic acids, four phenolic acids, and three benzene-tricarboxylic acids (BTCAs) in PM 2.5 were studied for their abundance and potential sources through quantifying their ambient concentrations at four sites in the Pearl River Delta (PRD) region in Southern China, where biomass burning and anthropogenic emissions are both significant PM sources. Average concentrations of individual aromatic acids in a total of 240 PM 2.5 samples collected throughout 2012 were in the order of 0.1−20 ng/m 3 with p-and o-phthalic acid being the most abundant. Interspecies correlation analysis with known PM source tracers reveals different source origins for the ten aromatic acids. The four phenolic acids, all possessing partial lignin structures, are highly correlated with levoglucosan, indicating their association with biomass burning emissions. Specific lignin tracer ratios characteristic of different types of biomass fuels (i.e., cinnamyl-to vanillyl-phenol ratio) revealed the significant influence of crop burning emissions in the PRD region. The three BTCAs have moderate correlation with sulfate but no correlation with levoglucosan, suggesting a strong association with secondary formation origins while negating a strong link with biomass burning. The three phthalic acids are moderately correlated with sulfate, levoglucosan, and a number of polycyclic aromatic hydrocarbons (PAHs), indicating multiple significant sources. This study provides a valuable data set toward establishing quantitative links between molecular composition of organic matter and the optical and toxicological properties of PM 2.5 as well as assisting identification of tracers for PM 2.5 sources.

Urban organic aerosol composition in Eastern China differs from North to South: Molecular insight from a liquid chromatography-Orbitrap mass spectrometry study

“…In addition, through mass spectrometric analysis of individual compounds, we find that for the Changchun− samples, formulas of C8H6O4, C7H6O2, C7H6O3, C8H8O2, and C8H8O3 with DBE values of 6, 5, 5, 5, and 5 dominate the assigned CHO formulas with respect to peak abundance. According to previous studies, C8H6O4, C7H6O2 and C7H6O3 are suggested to be phthalic acid, benzoic acid and monohydroxy benzoic acid, respectively, which are derived from naphthalene (Kautzman et al, 2010;Riva et al, 2015;Wang et al, 2017;He et al, 2018;Huang et al, 2019). C8H8O2 and C8H8O3 are likely 4-hydroxy acetophenone and 4-methoxybenzoic acid which could be derived from estragole (Lee et al, 2006;Pereira et al, 2014).…”

Organic aerosol source apportionment in Zurich using an extractive electrospray ionization time-of-flight mass spectrometry (EESI-TOF): Part II, biomass burning influences in winter

“…Here 86 % of nitrocatechol is apportioned to the less aged (49 %) and more aged (37 %) biomass burning factors. Syringic acid and vanillic acid are phenolic acids derived from the oxidation of lignin decomposition products (He et al, 2018), which in turn are a major component of biomass combustion emissions, and are apportioned primarily to the MABB EESI factors (68 % for syringic acid and 78 % for vanillic acid).…”

“…Offline analysis identified winter OOA and summer OOA which to some extent appears to be linked to sources (Daellenbach et al, 2017;Bozzetti et al, 2016), even though the corresponding sources cannot be retrieved (Lu et al, in prep.). Zhang et al, (2018) combined the offline GC-MS method and online FIGAERO-CIMS measurements to better characterize summertime monoterpene SOA.…”

“…Various tracer compounds for biomass burning were reported, including levoglucosan, which is a sugar anhydride compound produced from the pyrolysis of cellulose and hemicellulose (Fine et al, 2001), or methoxyphenols (e.g. guaiacol and syringol), derived from the pyrolysis of lignin (Coeur-Tourneur et al, 2009;Veres et al, 2010;He et al, 2018), and methyl-nitrocatechols, nitrated aromatic compounds from biomass burning (Iimuma et al, 2010a). Furthermore, biomass burning has been shown to produce significant SOA in laboratory measurements (Bruns et al, 2016;Nakao et al, 2011;Yee et al, 2013;Stefenelli et al, 2019), but this component…”

Minimizing Contamination from Plastic Labware in the Quantification of C16 and C18 Fatty Acids in Filter Samples of Atmospheric Particulate Matter and Their Utility in Apportioning Cooking Source Contribution to Urban PM2.5

“…Since the amount of fatty acid contamination might also be affected by different product brands, solvents used or different apparatus [28], the amount of contamination could be unique to different laboratories and method specific. Therefore, we have conducted this study to assess the fatty acid contamination level in the method used by our laboratory, which is a typical method for determining polar organic compounds in aerosol samples [29]. We examined the contamination of palmitic acid and stearic acid in different combinations of plastic ware and glassware used.…”