Seasonal Fluctuation of Polycyclic Aromatic Hydrocarbons and Aerosol Genotoxicity in Long-Range Transported Air Mass Observed at the Western End of Japan

Abstract

In order to clarify the level transboundary air pollution caused by polycyclic aromatic hydrocarbons (PAHs) and genotoxic substances, aerosols were collected from forest and suburban sites in Nagasaki, west Japan, for 6 years. The PAH concentration was measured, and the genotoxicity of the substances were evaluated using the umu test. The results showed no notable trends in the concentration or toxicity of either sites throughout the study period. The suburban and forest sites shared similar seasonal fluctuation patterns and quantitative values, suggesting that the western end of Japan might be affected by long-range transported pollutants, especially in winter. PAH concentration and genotoxicity showed the same seasonal patterns of increased levels in winter and lower levels in summer. This suggests that PAHs and genotoxic substances were correlated and share common sources. Back trajectory and source analyses were conducted using the diagnostic ratios of PAHs. It was predicted that air pollution by PAHs at the forest site arise predominantly as a result of biomass or coal combustion in continental regions, such as northern parts of China and the Korean Peninsula. This is particularly expected in winter. Therefore, genotoxic substances would also be strongly influenced by transboundary pollution from the continental region. In addition, it was estimated that the contribution of transboundary PAH pollution could reach 70% at the suburban site in winter.

Clear Declining Behaviors and Causes in Atmospheric Polycyclic Aromatic Hydrocarbon Concentrations at the West End of Japan from 2017 to 2021

“…As in spring, advection from the northwest of Nagasaki was common in autumn, while advection from directions other than the northwest was increasing compared to winter. These results were almost the same as those of the previous study [19].…”

“…If PAH concentrations in the atmosphere are measured over long duration at Japanese sites that are directly exposed to transboundary pollution from China, the causal relationship between economic activities in China and PAH concentrations in Japan could be determined by tracing behaviors in the measured values. Our previous research showed no notable trends in PAH concentrations in Nagasaki, located at the west end of Japan, from 2012 to 2018 [19]. The purpose of this study was to identify recent behaviors in PAH concentrations in Nagasaki following the previous study and to speculate on the causes of these behaviors.…”

“…The results from this model show the frequency that the trajectory passed over a grid cell taking into account residence time. The main analysis conditions were the same as the previous report [19].…”

Different Transport Behaviors between Asian Dust and Polycyclic Aromatic Hydrocarbons in Urban Areas: Monitoring in Fukuoka and Kanazawa, Japan

“…Long-range transported (LRT) air pollution indicates the atmospheric movement of pollutants for more than 100 km, affecting neighboring countries' air quality across national boundaries. It is well known that Japan has suffered from LRT air pollution such as Asian dust (AD) and acid rain from the Asian continent [1][2][3][4][5]. However, different patterns of LRT may vary air pollutant concentrations in monitoring areas.…”

Spatiotemporal distribution, trend, forecast, and influencing factors of transboundary and local air pollutants in Nagasaki Prefecture, Japan

“…However, rarely studies have combined these to generate a more holistic understanding that can help identify health risk areas, influencing factors, pollution trends, and the efficacy (or lack thereof) of policy interventions 11 . For instance, in Nagasaki Prefecture, most of the studies have only focused on either the health impact caused by air pollutants [14][15][16] , the long-range transport of air pollutants from the Asian continent [17][18][19] , or the effects of climatic variables and the spatial and temporal distribution of PM 2.5 20 . Although these studies provide essential information, a multi-method approach is necessary to understand better the distribution, factors, and current and future trends of PM 2.5 and NO 2 pollution in Nagasaki Prefecture.This study used a multi-method approach to analyze PM 2.5 and NO 2 data in Nagasaki Prefecture from 2013 to 2021.…”