Dicarboxylic acids and related compounds in fine particulate matter aerosols in Huangshi, central China

Abstract

PM 2.5 (particulate matter with an aerodynamic diameter <2.5 μm) samples were collected in Huangshi, central China, from March 2012 to February 2013 and were analyzed for dicarboxylic acids (diacids) and related compounds (DARCs). Oxalic acid (C 2 ; 416 ng m −3 ) was the most abundant species, followed by phthalic (Ph; 122 ng m −3 ), terephthalic (tPh; 116 ng m −3 ), succinic (C 4 ; 70.4 ng m −3 ), azelaic (C 9 ; 67.9 ng m −3 ), and adipic (C 6 ; 57.8 ng m −3 ) acids. Relatively high abundances of Ph and tPh differed from the distribution in urban and marine aerosols, indicating contributions from nearby anthropogenic sources. Glyoxylic acid (ωC 2 ; 41.4 ng m −3 ) was the dominant oxoacid, followed by 9-oxononanoic (ωC 9 ; 40.8 ng m −3 ) and pyruvic (Pyr; 24.1 ng m −3 ) acids. Glyoxal (Gly; 35.5 ng m −3 ) was the dominant α-dicarbonyl. Highest average concentrations were found for C 2 , ωC 2 , and C 9 in autumn, for C 4 , for Pyr and C 6 in spring, for Ph, ωC 9 , and Gly in summer, whereas the lowest values were observed in winter. Seasonal variations and correlation coefficients of DARCs demonstrate that both primary emissions and secondary production are important sources. Principal component analysis of selected DARCs species suggests that a mixing of air masses from anthropogenic and biogenic sources contribute to the Huangshi aerosols.Implications: Both primary emissions and secondary production are important sources of diacids and related compounds in PM 2.5 from Huangshi, central China. Principal component analysis of selected diacids in Huangshi aerosols suggests that mixing of air masses from anthropogenic and biogenic sources contribute to ambient aerosols in central China.

Molecular Distribution, Seasonal Variations, and Sources of Typical Polar Organics in PM2.5 from Jinzhong, China

“…2,7,12,14,34,47 Therefore, o-Ph/C 9 and C 6 /C 9 ratios were considered as indicators to evaluate the relative contribution of anthropogenic and biogenic precursors, and higher values implied more anthropogenic contribution. 2,7,52 In this study, o-Ph/C 9 and C 6 /C 9 achieved the maximum value in autumn (o-Ph/C 9 : 4.78; C 6 /C 9 : 0.43) and winter (o-Ph/C 9 : 5.57; C 6 /C 9 : 0.36), proving that there is more contribution from anthropogenic sources in these seasons. The annual average of o-Ph/C 9 (2.90) was much higher than that observed in urban areas such as Shanghai (0.60), Huangshi (1.80), and Beijing (1.12), whereas the C 6 /C 9 ratio (0.32) was lower than those in Huangshi (0.85) and Beijing (0.50) (Table 1).…”

“…The annual average of o-Ph/C 9 (2.90) was much higher than that observed in urban areas such as Shanghai (0.60), Huangshi (1.80), and Beijing (1.12), whereas the C 6 /C 9 ratio (0.32) was lower than those in Huangshi (0.85) and Beijing (0.50) (Table 1). 7,33,52 For the secondary formation of o-ph, the contribution of anthropogenic precursors in Jinzhong was higher than those in Shanghai, Huangshi, and Beijing, whereas the contribution of C 6 anthropogenic precursors was lower than those in Huangshi and Beijing.…”

“…o -Ph and adipic acid (C 6 ) are produced by the photochemical oxidation of aromatic hydrocarbons (e.g., naphthalene) and cyclic olefins (such as cyclohexane) emitted from anthropogenic sources, respectively, whereas azelaic acid (C 9 ) is mainly formed by the photochemical oxidation of unsaturated fatty acids derived from natural biological sources. ,,,,, Therefore, o -Ph/C 9 and C 6 /C 9 ratios were considered as indicators to evaluate the relative contribution of anthropogenic and biogenic precursors, and higher values implied more anthropogenic contribution. ,, In this study, o -Ph/C 9 and C 6 /C 9 achieved the maximum value in autumn ( o -Ph/C 9 : 4.78; C 6 /C 9 : 0.43) and winter ( o -Ph/C 9 : 5.57; C 6 /C 9 : 0.36), proving that there is more contribution from anthropogenic sources in these seasons. The annual average of o -Ph/C 9 (2.90) was much higher than that observed in urban areas such as Shanghai (0.60), Huangshi (1.80), and Beijing (1.12), whereas the C 6 /C 9 ratio (0.32) was lower than those in Huangshi (0.85) and Beijing (0.50) (Table ).…”

Molecular Speciation of Size Fractionated Particulate Water-Soluble Organic Carbon by Two-Dimensional Nuclear Magnetic Resonance (NMR) Spectroscopy

“…In all, aliphatic compounds R-H and H-C-C= contributed a significant fraction of the total hydrogen resonances and ranged from 47.5% in particle of the 7.2-3.0 µm size range to 71.2% in the 0.96-0.5 µm size range. Traces of anthropogenic phthalate and terephthalate were detected on large particles [44]; however, there was a significant overlap of resonances from other chemical species including ammonium resonances for smaller particle sizes.…”

“…The presence of methylated ethanolamines (i.e., animal husbandry [45]) and ammonium further indicated the presence of secondary organic aerosol through the neutralization of sulfuric and nitric acids. Finally, the detection of monoand dicarboxylic acids indicated the possible contribution of soil particles and secondary aerosol [44]. The analysis of the distribution of functional groups of non-exchangeable organic hydrogen also showed a mixture of sources.…”