Contributions of long-range transport from the Asian continent and local emissions on atmospheric PM2.5, polycyclic aromatic hydrocarbons, and their nitro-derivatives in Kanazawa and Noto Peninsula, Japan

Kazuichi Hayakawa; Pham Kim-Oanh; Akinori Takami; Hiroshi Odajima; Edward G Nagato; Akinori Hara; Hiroyuki Nakamura

doi:10.1016/j.heliyon.2024.e27320

Contributions of long-range transport from the Asian continent and local emissions on atmospheric PM_2.5, polycyclic aromatic hydrocarbons, and their nitro-derivatives in Kanazawa and Noto Peninsula, Japan

Heliyon. 2024 Feb 29;10(5):e27320. doi: 10.1016/j.heliyon.2024.e27320. eCollection 2024 Mar 15.

Authors

Kazuichi Hayakawa¹, Pham Kim-Oanh², Akinori Takami³, Hiroshi Odajima⁴, Edward G Nagato⁵, Akinori Hara⁶, Hiroyuki Nakamura⁶

Affiliations

¹ Institute of Nature and Environmental Technology, Kanazawa University, Nomi City, 923-1224, Japan.
² Asia Center for Air Pollution Research, Niigata City, 950-2144, Japan.
³ Regional Environment Conservation Division, National Institute for Environmental Studies, Tsukuba City, 305-8506, Japan.
⁴ Department of Pediatrics, National Hospital Organization Fukuoka National Hospital, Fukuoka City, 811-1394, Japan.
⁵ Faculty of Life and Environmental Sciences, Shimane University, 1060, Nishikawatsu-machi, Matsue, 690-8504, Japan.
⁶ Department of Hygiene and Public Health, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa City, 920-8640, Japan.

Abstract

This study collected samples of particulate matter that are 2.5 μm or less in diameter (PM_2.5) in Kanazawa, Japan, and Noto Peninsula located 100 km north on the windward side of the westerlies from the Asian continent and characterized the extent of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) pollution in Kanazawa. Emission areas and specific sources of PM_2.5 and of PAHs and NPAHs were clarified via back-trajectory analysis and the NP-method, respectively. The results indicate that during 2020 and 2021, most PAHs (93%) in Kanazawa were transported from the Asian continent by westerlies and that the main source was coal and biomass combustion. The presence of NPAHs in Kanazawa was caused by a mixture of transport from the Asian continent (53%) and local emissions (47%), with the main source of the latter being from vehicles. Although the content of combustion-derived particulates (P_c) was <2.4% of PM_2.5 in Kanazawa, this showed a similar seasonal variation (winter > summer) to that of PAHs. The contribution of P_c transported from the Asian continent exceeded that of locally emitted P_c. The current situation of Kanazawa is considerably different from that of 1997, when local vehicles were the main source of pollution.

Keywords: Asian continent; Combustion-derived particulate; Kanazawa; NP-Method; PAHs; Trans-boundary transport.