Characterization of biogenic primary and secondary organic aerosols in the marine atmosphere over the East China Sea
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, suggesting the terrestrial outflows of organic matter to the East China Sea. Glucose was the dominant sugar species (0.31–209 ng m–3, 18.8 ng m–3), followed by mannitol – a fungal spore tracer. All sugar compounds showed higher concentrations in the nighttime than in the daytime. 3-Methyl-1,2,3-butanetricarboxylic acid, one high-oxidation 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, monoterpene- and isoprene-derived SOC. Larger carbon percentages of biogenic 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 sulfate ammonia, secondary nitrate and biogenic SOA, sea salt and coal combustion were the main sources controlling the marine aerosols over the East China Sea, again highlighting the importance of Asian continent as a natural emitter of biogenic organic aerosols together with anthropogenic aerosols over the coastal marine atmosphere.