Analyses of Factors Causing Changes in Pollutant Emissions in Japan

Satoru Chatani 한국대기환경학회 2022 한국대기환경학회 학술대회논문집 Vol.2022 No.10

Advantages of Continuous Monitoring of Hourly PM2.5 Component Concentrations in Japan for Model Validation and Source Sensitivity Analyses

Satoru Chatani,Syuichi Itahashi,Kazuyo Yamaji 한국대기환경학회 2021 Asian Journal of Atmospheric Environment (AJAE) Vol.15 No.2

Continuous monitoring of hourly PM2.5 component concentrations has been performed in Japan. The objective of this study was to evaluate the advantages of continuous monitoring to obtain data that can be useful for regional air quality simulations. Inclusion of transboundary transport in the simulations improved the correlation between the observed and simulated hourly concentrations of SO4 2-, NO3 -, secondary organic aerosols (SOA), and metals in PM2.5. Black carbon was an exception, suggesting the overestimation of emissions in upwind countries. Including volcanic and dust emissions also improved the correlations between the observed and simulated hourly concentrations of SO4 2- and metals, respectively. However, despite the good correlation achieved by including transboundary transport, it also resulted in overestimated NO3 - and SOA concentrations in western Japan during the winter. Further improvements are necessary, such as balancing with SO4 2- and the dry deposition of gaseous HNO3 for NO3 -, and new treatment of the partitioning and aging of semivolatile organic aerosols, which have been incorporated into recent models for SOA. The differences in model performance with regard to simulating metal concentrations suggest imbalances in the speciation profiles used for countries other than Japan. Further, comparing the observed and simulated hourly concentrations helped identify the key processes driving air quality. This revealed evening peaks in black carbon concentrations, owing to the relatively stable atmosphere; and early morning peaks in NO3 - concentration, owing to the low temperature and high humidity through thermodynamic equilibrium. This study demonstrated that continuous monitoring of hourly variations in PM2.5 composition is valuable for understanding the roles of the emission sources and for improving future models, both of which contribute to deriving effective PM2.5 suppression strategies.

Urban Air Quality Model Inter-Comparison Study (UMICS) for Improvement of PM2.5 Simulation in Greater Tokyo Area of Japan

Hikari Shimadera,Hiroshi Hayami,Satoru Chatani,Tazuko Morikawa,Yu Morino,Yasuaki Mori,Kazuyo Yamaji,Seiji Nakatsuka,Toshimasa Ohara 한국대기환경학회 2018 Asian Journal of Atmospheric Environment (AJAE) Vol.12 No.2

The urban model inter-comparison study (UMICS) was conducted in order to improve the performance of air quality models (AQMs) for simulating fine particulate matter (PM2.5) in the Greater Tokyo Area of Japan. UMICS consists of three phases: the first phase focusing on elemental carbon (UMICS1), the second phase focusing on sulfate, nitrate and ammonium (UMICS2), and the third phase focusing on organic aerosol (OA) (UMICS 3). In UMICS2/3, all the participating AQMs were the Community Multiscale Air Quality modeling system (CMAQ) with different configurations, and they similarly overestimated PM2.5 nitrate concentration and underestimated PM2.5 OA concentration. Various sensitivity analyses on CMAQ configurations, emissions and boundary concentrations, and meteorological fields were conducted in order to seek pathways for improvement of PM2.5 simulation. The sensitivity analyses revealed that PM2.5 nitrate concentration was highly sensitive to emissions of ammonia (NH3) and dry deposition of nitric acid (HNO3) and NH3, and PM2.5 OA concentration was highly sensitive to emissions of condensable organic compounds (COC). It was found that PM2.5 simulation was substantially improved by using modified monthly profile of NH3 emissions, larger dry deposition velocities of HNO3 and NH3, and additionally estimated COC emissions. Moreover, variability in PM2.5 simulation was estimated from the results of all the sensitivity analyses. The variabilities on CMAQ configurations, chemical inputs (emissions and boundary concentrations), and meteorological fields were 6.1-6.5, 9.7-10.9, and 10.3-12.3%, respectively.

Long‑term historical trends in air pollutant emissions in South Korea (2000–2018)

우정헌,김진석,박준희,허혜정,Monica Crippa,Diego Guizzardi,Satoru Chatani,Junichi Kurokawa,Tazuko Morikawa,여소영,진형아 한국대기환경학회 2023 Asian Journal of Atmospheric Environment (AJAE) Vol.17 No.1

This study aims to understand the impact of previous air quality improvement policies on historical emission changes by examining long-term emission trends in Korea. Annual emissions from 2000 to 2018 were estimated using Korea’s official emissions inventory, the Clean Air Policy Support System (CAPSS). To ensure a consistent comparison, standardization of the method for calculating emissions and unification of the reported emission sectors were conducted each year. Furthermore, Korea’s emissions history was compared with that of neighboring countries, such as China and Japan. The annual emissions of these countries were acquired from the HTAPv3 emissions inventory, an international long-term emission trend study. For comparison, the emission source classification of Korea was matched with that of HTAPv3. As a result of the analysis, NOx and SOx emissions in Korea have shown decreasing trends, whereas VOCs (volatile organic compounds) have indicated a gradual increasing trend since 2000. Compared to the previous period of implementing South Korea’s air quality improvement policy, changes in NOx and SOx emissions, which are combustion-related pollutants, showed a relationship with the policy’s timeline. However, noncombustion- related pollutants such as VOCs did not exhibit such a relationship. It was concluded that the related policies were not as effective in reducing VOCs as planned in the policy. By comparing the emission trends of Japan, Korea, and China, it was confirmed that Japan was the first country to experience a decrease in combustion-related pollutants emissions, followed by Korea and China. Additionally, combustion-related pollutants decreased in all three countries, whereas VOCs decreased only in Japan. VOC is a precursor material generating secondary PM2.5 and Ozone; considering that, if relevant policies are additionally implemented to control future PM2.5 concentrations, and to reduce emissions efficiently and effectively, Japan’s VOC reduction policies can be applied to Korea’s emission reduction policies. These results are expected to serve as important references when establishing future air quality improvement policies in Korea.

Analysis of Summertime Atmospheric Transport of Fine Particulate Matter in Northeast Asia

Hikari Shimadera,Hiroshi Hayami,Yu Morino,Toshimasa Ohara,Satoru Chatani,Shuichi Hasegawa,Naoki Kaneyasu 한국기상학회 2013 Asia-Pacific Journal of Atmospheric Sciences Vol.49 No.3

In Northeast Asia, the effect of long-range transport of air pollutants is generally pronounced in spring and winter, but can be important even in summer. This study analyzed summer-time atmospheric transport of elemental carbon (EC) and sulfate (SO42−) with the Community Multiscale Air Quality (CMAQ) model driven by the Weather Research and Forecasting (WRF) model. The WRF/CMAQ modeling system was applied to regions ranging from Northeast Asia to the Greater Tokyo Area in Japan in summer 2007. In terms of EC,while the model simulated well the effect of long-range transport, the simulation results indicated that domestic emissions in Japan dominantly contributed (85%) to EC concentrations in the Greater Tokyo. In terms of SO42−, the simulation results indicated that both domestic emissions (62%) and long-range transport from the other countries (38%) substantially contributed to SO42− concentrations in the Greater Tokyo. Distinctive transport processes of SO42− were associated with typical summer-time meteorological conditions in the study region. When a Pacific high-pressure system covered the main island of Japan, domestic emissions, including volcanic emission, dominantly contributed to SO42− concentrations in the Greater Tokyo. When a high-pressure system prevailed over the East China Sea and lowpressure systems passed north of Japan, synoptic westerly winds associated with this pressure pattern transported a large amount of SO42− from the continent to Japan. In addition, although heavy precipitation and strong wind decreased SO42− concentrations near the center of a typhoon, peripheral typhoon winds occasionally played an important role in long-range transport of SO42−.

NMVOC 배출 저감 정책에 따른 배출 조성 변화 및 대기질 영향 분석

박민우,Younha Kim,Yisheng Sun,한경만,송철한,허혜정,Satoru Chatani,Shuxiao Wang,Zbigniew Klimont,우정헌 한국대기환경학회 2023 한국대기환경학회 학술대회논문집 Vol.2023 No.10

Current Status of Ozone Control Measures in the United States and Europe and Implications for Japan

Hideki Hasunuma,Liliana Martinez Rivera,Hirosato Kobayashi,Kenji Aizu,Kazunori Oshima,Jun Shibutani,Yasuyuki Itano,Satoru Chatani,Shuichi Hasegawa,Makiko Yamagami,Junya Hoshi KOSAE·JSAE·CSES-CSAE 2022 Asian Journal of Atmospheric Environment (AJAE) Vol.16 No.3

In Japan, the achievement rate of environmental standards for air pollution has been improving in recent years, but for photochemical oxidants, including ozone, improvement are required. In this study, we investigated trends in ozone countermeasures in the United States and Europe from the State Implementation Plan (SIP) and National Air Pollution Control Program (NAPCP) and examined whether there are any points recommended in Japan. The United States and Europe have different policies on environmental standards for air pollution and ozone control. In the United States, states that do not meet the environmental standards for ozone concentration are required to develop an SIP to attain the standards. There was an urgent need to find a cost-effective approach to addressing the ozone problem, and forest control measures were one of the possibilities. In Europe, the European Union has set “target values” for ozone and NAPCP does not mention forest control measures or ozone sensitivity regimes. The main focus in Europe is on the win-win solution of reducing emissions of air pollutants at the same time as greenhouse gases. Japan should consider a framework including setting feasible step-by-step goals to attain the desired standards. As ozone is greatly affected by advection, wide-regional measures against ozone precursors and prediction of the future precursor reduction and concentration are required. The preparation of an emissions inventory and estimated reduction amount is prerequisites as basic data for simulation. To achieve this, cooperation between national, local and private research institutes is crucial. Since the international community has agreed to prioritize greenhouse gas countermeasures, Japan could consider a win-win solution for both ozone and greenhouse gas reduction.