Organic molecular compositions and temporal variations of summertime mountain aerosols over Mt. Tai, North China Plain

Abstract

1] Total suspended particles (TSP) were collected at the summit of Mt. Tai (1534 m above sea level) on a daytime and nighttime basis during a summertime campaign (May-June 2006) and were characterized for organic molecular compositions using solvent extraction/derivatization and gas chromatography/mass spectrometry technique. The n-Alkanes, fatty acids, fatty alcohols, sugars, glycerol and polyacids, and phthalate esters were found as major organic compound classes, whereas lignin and resin products, sterols, aromatic acids, hopanes, and polycyclic aromatic hydrocarbons (PAHs) were detected as minor classes. Sugars (49.8-2115 ng m À3 , average 640 ng m À3 in daytime; 18.1-4348 ng m À3 , 799 ng m À3 in nighttime) were found to be the dominant compound class. Levoglucosan, a specific cellulose pyrolysis product, was detected as the most abundant single compound, followed by C 28 fatty alcohol, diisobutyl and di-n-butyl phthalates, C 29 n-alkane, C 16 and C 28 fatty acids, and malic acid. By grouping organic compounds based on their sources, we found that emission of terrestrial plant waxes was the most significant source (30-34%) of the TSP, followed by biomass burning products (25-27%) (e.g., levoglucosan and lignin and resin products), soil resuspension (15-18%) due to agricultural activities, secondary oxidation products (8-10%), plastic emission (3-10%), marine/microbial sources (6%), and urban/industrial emissions from fossil fuel use (4%). However, low molecular weight dicarboxylic acids (such as oxalic acid) of photochemical origin were not included in this study. Malic acid was found to be much higher than those reported in the ground level, suggesting an enhanced photochemical production in the free troposphere over mountain areas. Temporal variations of biomass burning tracers (e.g., levoglucosan, galactosan, mannosan) and some higher plant wax derived compound classes suggested that there were two major (E1 and E2) and one minor (E3) biomass-burning events during this campaign. Most of the compound classes showed higher concentrations in nighttime samples when organic aerosols can be long-range transported from different source regions to the summit of Mt. Tai above the planetary boundary layer (PBL). This study also demonstrates that the free troposphere over Mt. Tai is heavily influenced by field burning of agricultural wastes such as wheat straws in the North China Plain during the harvest season in early summer.

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, south China

“…Detected 40 organic acids totaled 82.6-756 ng/m 3 with an average value of 280 ng/m 3 , and accounted for 0.66%-3.69% of OC with an av- Saturated fatty acids (C14:0-C32:0) from this study in the PRD region showed a strong even carbon number predominance with a maximum at palmitic acid (C16:0) and stearic acid (C18:0) ( Table 1). This was quite similar to the distribution patterns reported in the urban areas (Fraser et al, 2002;Fu et al, 2010;Ho et al, 2011), but different from the bimodal distribution observed at the mountain site (Fu et al, 2008) or in marine aerosols (Fu et al, 2011;Kawamura et al, 2003) with maximums at C16:0 and C24:0/C28:0. The concentrations of C16:0 and C18:0 in the PRD region averaged 85.8 and 27.8 ng/m 3 , respectively, comparable with those reported in some urban sites, such as Nanjing in China (Wang and Kawamura, 2005) and Chennai in India (Fu et al, 2010).…”

Anthropogenic and biogenic organic compounds in summertime fine aerosols (PM2.5) in Beijing, China

“…Because of their inverse health effects, phthalates have been intensively investigated in both ambient and indoor air (Wang et al, 2006;Fu et al, 2008Fu et al, , 2012bXu et al, 2015). Five phthalates were detected in this study, i.e., dimethyl (DMP), diethyl (DEP), diisobutyl (DiBP), di-n-butyl (DnBP), and di-(2-ethylhexyl) (DEHP) phthalates.…”

“…Individual compounds were identified by comparison of mass spectra with those of authentic standards or literature data Fu et al, 2008;Hu et al, 2008). Its relative standard deviation based on these two methods was <5%.…”

Diurnal and temporal variations of water-soluble dicarboxylic acids and related compounds in aerosols from the northern vicinity of Beijing: Implication for photochemical aging during atmospheric transport

“…It has been successfully used for a series of dicarboxylic acids and other atmospheric trace species (Fu et al, 2008;Kawamura and Sakaguchi, 1999b;Wolff and Korsog, 1985). The data sets of diacids and related compounds for daytime (n = 38) and nighttime (n = 20) aerosol samples from Mangshan were subjected to PCA analysis based on their correlation matrix, followed by the varimax rotation of the eigenvectors (Table 3).…”