Characterization of biogenic primary and secondary organic aerosols in the marine atmosphere over the East China Sea

Abstract

Abstract. Molecular composition and abundance of sugars and secondary organic aerosols (SOA) from biogenic sources over the East China Sea were investigated based on gas chromatography–mass spectrometry. Biogenic SOA tracers and sugars exhibit higher levels in the samples affected by continental air masses, demonstrating the terrestrial outflows of organic matter to the East China Sea. Glucose was the dominant sugar species (0.31–209, 18.8 ng m−3), followed by mannitol – a fungal spore tracer. All sugar compounds show generally higher average concentrations in the nighttime than in the daytime. 3-Methyl-1,2,3-butanetricarboxylic acid, one higher generation photooxidation tracer of monoterpene SOA, was found to be the most abundant species among measured biogenic SOA markers, suggesting the input of aged organic aerosols through long-range transport. Fungal-spore-derived organic carbon (OC) was the biggest contributor to total OC (0.03 %–19.8 %, 3.1 %), followed by sesquiterpene-derived secondary OC (SOC), biomass-burning-derived OC, and monoterpene- and isoprene-derived SOC. Larger carbon percentages of biogenic primary OCs and SOCs in total OC presented in the terrestrially influenced aerosols indicate significant contributions of continental aerosols through long-range transport. Positive matrix factorization results illustrate that the secondary nitrate and biogenic SOA, biomass burning, and fungal spores were the main sources of OC in marine aerosols over the East China Sea, again highlighting the importance of the Asian continent as a natural emitter of biogenic organic aerosols together with anthropogenic aerosols over the coastal marine atmosphere.

Polyols and glucose particulate species as tracers of primary biogenic organic aerosols at 28 French sites

“…Such covariations indicate that both species are most probably coemitted, by one or several type(s) of sources, at each site during the summer-autumn period. These observations are in agreement with previous studies also showing strong covariations between arabitol and mannitol (Kang et al, 2018;Verma et al, 2018;Zhu et al, 2015). Therefore, it seemed reasonable to consider both species together so that their concentrations are summed up and labeled as "polyols" in the following sections.…”

“…Interestingly, opposite to the case of the Alpine valleys where this proportion is the highest, the ratios OM PBOA -to-OM tot are amongst the lowest for coastal environments (Talence, Marseille, Nice), a possible indication that the marine environment is not a large emitter for these species. Recently, much lower concentrations of polyols in aerosols from marine environments than those in terrestrially influenced sites were also reported off the coast of Japan, also suggesting a higher contribution from terrestrial sources (Kang et al, 2018).…”

“…This OM-to-OC ratio value of 1.8 was chosen based on previous studies performed in France (Favez et al, 2010;Petit et al, 2015, and reference therein) and around the world. (e.g., Aiken et al, 2008;Li et al, 2018;Ruthenburg et al, 2014;Vlachou et al, 2018), with a typical range of 1.2-2.4 for these values.…”

Molecular characterization of organic aerosols in the Kathmandu Valley, Nepal: insights into primary and secondary sources

“…55.5 %), including LMW dicar-X. Wan et al: Molecular characterization of organic aerosols in the Kathmandu Valley boxylic acids (Kawamura and Sakaguchi, 1999;Kawamura and Bikkina, 2016), need further investigation to better understand the atmospheric aerosols from both urban and rural sources such as the KV and other sites in the Himalayan foothills and the Indo-Gangetic Plain regions. These observations of severe air pollution, particularly the particulate matter pollution, provide valuable support for air pollution control measures, especially in determining which sources and sectors to first focus on in the KV and the surrounding region in order to reduce the air pollution from being severe to become much cleaner in the near future.…”

“…Furthermore, fossil fuel combustion and soil dust could also be notable fractions of OC in Bode aerosols. Additionally, low-molecular-weight (LMW) dicarboxylic acids from both primary and secondary sources are also a remarkable contributor to atmospheric organic aerosols (Kawamura and Bikkina, 2016). Humic-like substances and amines can constitute another fraction of OC, but are not well studied (Wu et al, 2018;Laskin et al, 2015).…”