1 International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
2 School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
3 International Joint Research Center for Arctic Environment and Ecosystem (IJRC-AEE), Polar Academy, Harbin Institute of Technology, Harbin 150090, China.
4 Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec H3G 1M8, Canada.
5 Key Laboratory of Polar Science, Ministry of Natural Resources, Polar Research Institute of China, Shanghai 200136, China.
6 Faculty of Chemistry, Biotechnology and Food Science, Norwegian University Life Sciences (NMBU), Ås NO-1432, Norway.
7 University of the Arctic (UArctic), Rovaniemi 96300, Finland.
8 IJRC-PTS-NA, Toronto, Ontario M2N 6X9, Canada.
9 School of Environmental Sciences

Spatial variations of atmospheric alkylated polycyclic aromatic hydrocarbons (Alk-PAHs) are key to understanding their long-range atmospheric transport (LRAT). However, limited Alk-PAHs data have hindered their LRAT characterizations on a global scale. In this study, 49 Alk-PAHs were measured in the atmospheric samples collected across the Western Pacific to the Southern Ocean. The summed concentration of 39 frequently detected Alk-PAHs (S₃₉Alk-PAHs) was 25.8 ± 25.3 ng m^-3. The concentrations of S₃₉Alk-PAHs significantly declined with the decrease in latitude (°N). Higher concentrations (55.8 ± 33.8 ng m^-3) were linked to continental air mass compared to oceanic/Antarctica air mass (17.0 ± 13.6 ng m^-3), highlighting continental emissions as the primary source of marine atmospheric Alk-PAHs. An unexpected increase in the G/P partitioning ratio (K_P) was found in samples farther away from the continent, which cannot be explained by the influence of temperature on the partitioning process. Deposition analysis suggested that gaseous concentrations and the G/P partitioning largely influenced deposition patterns. Hypothetical scenario analysis indicated that increased K_P under snowy conditions could enhance the total Alk-PAH deposition. These findings emphasize the need for accurate characterization of partitioning and deposition processes when studying the global fate of Alk-PAHs, particularly in remote and polar regions.