Iodine speciation and size distribution in ambient aerosols at a coastal new particle formation hotspot of China

Abstract

<p><strong>Abstract.</strong> Intense new particle formation (NPF) events were observed in the coastal atmosphere during algae growth and farming season at Xiangshan Gulf of east China coast. High nucleation-mode iodine concentrations measured by ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry (UPLC/Q-TOF-MS) confirmed that the NPF events were induced by iodine species. Farmed microalgae, as well as wild algae, could be an important NPF source in coastal areas of China. For the first time, we identified 5 inorganic iodine species, 45 organic iodine compounds (35 molecular formulas) and a group of iodide-organic adducts in ambient aerosols. The concentrations and size distributions of iodine species down to 10 nanometers were measured during the iodine-induced NPF, continental NPF and non-NPF days at the coastal site and compared to those at an inland site. The iodine in the above four types of aerosol samples were characterized by iodate, aromatic iodine compounds, iodoacetic acid/iodopropenoic acid and iodide-organic adducts, respectively. This study sheds light on the iodine sources, formation mechanism and its contribution to the coastal NPF in the context of heavy air pollution in eastern China.</p>

New Particle Formation in the Atmosphere: From Molecular Clusters to Global Climate

“…NPF has been long observed in the coastal regions of Ireland, Scotland, France, Australia, Antarctica and China (Bigg & Turvey, ; Flanagan et al, ; Huang et al, ; O'Dowd et al, ; Saiz‐Lopez et al, ; Wiedensohler et al, ; Y. Hu et al, ). The North Atlantic Aerosols and Marine Ecosystems Study NAAMES campaign has elucidated the contribution of NPF involving sulfur to CCN concentrations in the marine atmosphere (Sanchez et al, ).…”

“…Vaattovaara et al () observed that organics also contribute to the growth of freshly formed coastal (iodine) particles. Recently H. Yu et al () have shown that previously unidentified organic iodine compounds, such as iodate, aromatic iodinecompounds, iodoacetic acid or iodopropenoic acid, and iodide–organic adducts can also participate in NPF in an iodine hotspot at the east coast of China.…”