# Characteristics and sources of aerosol aminiums over the eastern coast of China: insights from the integrated observations in a coastal city, adjacent island and surrounding marginal seas

An integrated observation of aerosol aminiums was conducted in a coastal city (Shanghai) in eastern China, a nearby island (Huaniao Island), and over the Yellow Sea and East China Sea (YECS). Triethylaminium (TEAHinline-formula+) was abundant over Shanghai but not detected over the island and the open seas, suggesting its predominantly terrestrial origin. By contrast, relatively high concentrations of dimethylaminium (DMAHinline-formula+) and trimethylaminium inline-formula+ diethylaminium (TMDEAHinline-formula+) were measured over the ocean sites, indicating the significant marine source contribution. Environmental factors, including boundary layer height (BLH), temperature, atmospheric oxidizing capacity and relative humidity, were found to be related to aminium concentrations. All the detected aminiums demonstrated the highest levels in winter in Shanghai, consistent with the lowest BLH and temperature in this season. Aminiums mainly existed in fine particles and showed a bimodal distribution, with two peaks at 0.18–0.32 inline-formulaµm and 0.56–1.0 inline-formulaµm, indicating that condensation and cloud processing were the main formation pathways for aminiums in analogy with inline-formula $M7inlinescrollmathmlchem{\mathrm{normal NH}}_{normal 4}^{+}$ 24pt15ptsvg-formulamathimg3226c502fdca30fe88bf9305df4b3716 acp-19-10447-2019-ie00001.svg24pt15ptacp-19-10447-2019-ie00001.png and non-sea-salt inline-formula $M8inlinescrollmathmlchem{\mathrm{normal SO}}_{normal 4}^{normal 2-}$ 29pt17ptsvg-formulamathimg40da026c69d6bb7b362f8aefb7758b92 acp-19-10447-2019-ie00002.svg29pt17ptacp-19-10447-2019-ie00002.png (nss-SOinline-formula $M9inlinescrollmathml{}_{normal 4}^{normal 2-}$ 13pt17ptsvg-formulamathimg5471cf9633c00eb7ce2a8165ca87d146 acp-19-10447-2019-ie00003.svg13pt17ptacp-19-10447-2019-ie00003.png ). Nonetheless, a unimodal distribution for aerosol aminiums was usually measured over the YECS or over Huaniao Island when influenced mainly by the marine air mass, which suggested that aminiums in marine aerosols may undergo different formation pathways from those on the land. Terrestrial anthropogenic sources and marine biogenic sources were both important contributors for DMAHinline-formula+ and TMDEAHinline-formula+, and the latter exhibited a significantly higher TMDEAHinline-formula+ to DMAHinline-formula+ ratio. By using the mass ratio of methanesulfonate (MSA) to nss-inline-formula $M14inlinescrollmathmlchem{\mathrm{normal SO}}_{normal 4}^{normal 2-}$ 29pt17ptsvg-formulamathimg14485914c781d9e26f0da54782d5723d acp-19-10447-2019-ie00004.svg29pt17ptacp-19-10447-2019-ie00004.png as an indicator of marine biogenic source, we estimated that marine biogenic source contributed to 26 %–31 % and 53 %–78 % of aerosol aminiums over Huaniao Island in the autumn of 2016 and summer of 2017, respectively. Due to the important role of atmospheric amines in new particle formation, the estimation results highlighted the importance of marine biogenic emission of amines on the eastern coast of China, especially in summer.

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Zhou, Shengqian / Li, Haowen / Yang, Tianjiao / et al: Characteristics and sources of aerosol aminiums over the eastern coast of China: insights from the integrated observations in a coastal city, adjacent island and surrounding marginal seas. 2019. Copernicus Publications.

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