Yoshinori Iizuka, Mai Matsumoto, Kaoru Kawakami, Mahiro Sasage, Sakiko Ishino, Shohei Hattori^#, Ryu Uemura, Hitoshi Matsui, Koji Fujita, Naga Oshima, Andrea Spolaor, Anders Svensson, Bo Møllesøe Vinther, Hiroshi Ohno, Osamu Seki, Sumito Matoba. 2025 Acidity-driven gas-particle partitioning of nitrate regulates its transport to Arctic through the industrial era, Nature Communications, 16: 4272

ABSTRACT

Anthropogenic NOx emissions have altered the biogeochemical nitrogen cycle since the Industrial Revolution, yet Arctic ice core nitrate (NO3−) records are inconsistent with post-1970s NOx emission reductions. Here we show a NO3− deposition history covering 1800–2020 using an ice core from the southeastern Greenland dome with high snow accumulation. The ice core NO3− concentrations are particularly disconnected from NOx source regions during the peak pollution period and post-1990s. A global chemical transport model reproduced these discordances between total NO3− and NOx emissions by altering gaseous HNO3 and particulate NO3− (p-NO3−) ratios and subsequently NO3− lifetime. This result and correlations with acidity parameters recorded in the ice core, suggest that acidity-driven gas-particle partitioning of NO3− regulates its transport to Arctic regions alongside changes in NOx emissions. In the future, despite NOx reductions, the increase in proportion of p-NO3− with longer atmospheric lifetime becomes crucial to control the Arctic NO3− burden.