Air quality and acid deposition impacts of local emissions and transboundary air pollution in Japan and South Korea

Steve Hung Lam Yim,Brent Stephens,Yefu Gu,Matthew A Shapiro

doi:10.5194/acp-19-13309-2019

Abstract

Abstract. Numerous studies have reported that ambient air pollution, which has both local and long-range sources, causes adverse impacts on the environment and human health. Previous studies have investigated the impacts of transboundary air pollution (TAP) in East Asia, albeit primarily through analyses of episodic events. In addition, it is useful to better understand the spatiotemporal variations in TAP and the resultant impact on the environment and human health. This study aimed at assessing and quantifying the air quality impacts in Japan and South Korea due to local emissions and TAP from sources in East Asia - one of the most polluted regions in the world. We applied state-of-the-science atmospheric models to simulate air quality in East Asia and then analyzed the air quality and acid deposition impacts of both local emissions and TAP sources in Japan and South Korea. Our results show that ∼ 30 % of the annual average ambient PM2.5 concentrations in Japan and South Korea in 2010 were contributed to by local emissions within each country, while the remaining ∼ 70 % were contributed to by TAP from other countries in the region. More detailed analyses also revealed that the local contribution was higher in the metropolises of Japan (∼ 40 %–79 %) and South Korea (∼ 31 %–55 %) and that minimal seasonal variations in surface PM2.5 occurred in Japan, whereas there was a relatively large variation in South Korea in the winter. Further, among all five studied anthropogenic emission sectors of China, the industrial sector represented the greatest contributor to annual surface PM2.5 concentrations in Japan and South Korea, followed by the residential and power generation sectors. Results also show that TAP's impact on acid deposition (SO42- and NO3-) was larger than TAP's impact on PM2.5 concentrations (accounting for over 80 % of the total deposition), and that seasonal variations in acid deposition were similar for both Japan and South Korea (i.e., higher in both the winter and summer). Finally, wet deposition had a greater impact on mixed forests in Japan and savannas in South Korea. Given these significant impacts of TAP in the region, it is paramount that cross-national efforts should be taken to mitigate air pollution problems across East Asia.

Highlights

This study estimated the contributions of both local sources and transboundary air pollution (TAP) from Asia on surface PM2.5 in Japan and South Korea
Among various emission sectors of China, our results show that, with favorable prevailing wind, China’s industrial emissions were the major contributor (∼ 20 %) to surface PM2.5 as well as to acid deposition in Japan and South Korea
Previous studies have reported a downward trend of SO24− deposition in East Asia in recent years due to substantial SO2 emissions reductions in China (Itahashi et al, 2018; Seto et al, 2004)

Summary

Introduction

Air pollution is one of the major environmental problems facing the modern world, leading to adverse impacts on human health (Brook et al, 2004; Brunekreef and Holgate, 2002; Cook et al, 2005; Dockery et al, 1993; Lelieveld et al, 2015; Nel, 2005; Pope III and Dockery, 2006; Samet et al, 2000; Yim and Barrett, 2012; Yim et al, 2013, 2015, 2019a), the environment (Gu et al, 2018; Lee et al, 2005; Rodhe et al, 2002), climate (Guo et al, 2016; Koren et al, 2012; Li et al, 2011; Liu et al, 2018, 2019), and economic costs Zhang et al (2017) investigated the health impacts due to global transboundary air pollution and international trade, estimating that ∼ 411 000 deaths worldwide have resulted from TAP, while 762 000 deaths have resulted from international tradeassociated emissions. J. Lin et al (2014) investigated the air pollution in the United States due to the emissions of its international trade in China, estimating air pollution of China contributed to 3 %–10 % and 0.5 %–1.5 % of the annual surface sulfate and ozone concentrations, respectively, in the western United States

Objectives

Methods

Results

Conclusion