This page has only limited features, please log in for full access.

Unclaimed
Satoru Chatani
National Institute for Environmental Studies (NIES), 16-2, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 04 August 2021 in Atmospheric Environment: X
Reads 0
Downloads 0

Sulfate aerosol (SO42−) is a main component of particulate matter in Asian countries. Accurate numerical modeling is important for appropriate policy-making aimed at reducing SO42− concentrations. The modeling performance for SO42− is superior among aerosol components, however, current models underestimate SO42− concentrations during winter over Asia. Previous studies have proposed a heterogeneous process for winter haze events, but these kinds of studies are limited spatially and temporally because they cover only mainland China in winter. Underestimation has also been reported in other regions where the aerosol concentration is much lower than in China. In this study, the aqueous- and gas-phase oxidation processes in the current modeling were reconsidered, and their roles were evaluated over Asia using a year-round simulation. The existing aqueous-phase oxidation of O2 with Fe and Mn as catalysts was refined, and oxidation with NO2 was added due to the neutralized atmosphere over Asia. For gas-phase oxidation, three stabilized Criegee intermediates (SCIs; formaldehyde oxide (CH2OO), acetaldehyde oxide (CH3CHOO), and propionaldehyde oxide ((CH3)2COO)) were introduced. Considering the uncertainty of the reaction of CH2OO with water, the upper and lower limits of the rate constant were applied. The updated oxidation processes led to an increase in the modeled SO42− concentration. The model performance over Asia in winter was effectively improved, and the updates did not degrade the model performance in other seasons. The improvements in biases were approximately 3% during winter, whereas the deterioration in biases were within 1% in spring to summer and 2% in autumn, when the lower limit of the CH2OO rate constant with water was used. The role of SCIs depended strongly on the rate constants of the reaction of CH2OO with water. The simulated concentration of SCIs agreed well with the estimated levels, and the lower limit of the rate constant of CH2OO with water fitted within the estimated SCIs concentration levels. SCIs may play an important role in SO42− production over Asia in winter, especially the downwind region of China. The approach taken in this study has the potential to improve modeling performance in other regions as well.

ACS Style

Syuichi Itahashi; Risa Uchida; Kazuyo Yamaji; Satoru Chatani. Year-round modeling of sulfate aerosol over Asia through updates of aqueous-phase oxidation and gas-phase reactions with stabilized Criegee intermediates. Atmospheric Environment: X 2021, 100123 .

AMA Style

Syuichi Itahashi, Risa Uchida, Kazuyo Yamaji, Satoru Chatani. Year-round modeling of sulfate aerosol over Asia through updates of aqueous-phase oxidation and gas-phase reactions with stabilized Criegee intermediates. Atmospheric Environment: X. 2021; ():100123.

Chicago/Turabian Style

Syuichi Itahashi; Risa Uchida; Kazuyo Yamaji; Satoru Chatani. 2021. "Year-round modeling of sulfate aerosol over Asia through updates of aqueous-phase oxidation and gas-phase reactions with stabilized Criegee intermediates." Atmospheric Environment: X , no. : 100123.

Journal article
Published: 30 June 2021 in Asian Journal of Atmospheric Environment
Reads 0
Downloads 0
ACS Style

Satoru Chatani; Syuichi Itahashi; Kazuyo Yamaji. Advantages of Continuous Monitoring of Hourly PM2.5 Component Concentrations in Japan for Model Validation and Source Sensitivity Analyses. Asian Journal of Atmospheric Environment 2021, 15, 1 -29.

AMA Style

Satoru Chatani, Syuichi Itahashi, Kazuyo Yamaji. Advantages of Continuous Monitoring of Hourly PM2.5 Component Concentrations in Japan for Model Validation and Source Sensitivity Analyses. Asian Journal of Atmospheric Environment. 2021; 15 (2):1-29.

Chicago/Turabian Style

Satoru Chatani; Syuichi Itahashi; Kazuyo Yamaji. 2021. "Advantages of Continuous Monitoring of Hourly PM2.5 Component Concentrations in Japan for Model Validation and Source Sensitivity Analyses." Asian Journal of Atmospheric Environment 15, no. 2: 1-29.

Research article
Published: 04 September 2020 in Atmospheric Chemistry and Physics
Reads 0
Downloads 0

Source sensitivity and source apportionment are two major indicators representing source–receptor relationships, which serve as essential information when considering effective strategies to accomplish improved air quality. This study evaluated source sensitivities and apportionments of ambient ozone and PM2.5 concentrations over Japan with multiple numerical techniques embedded in regional chemical transport models, including a brute-force method (BFM), a high-order decoupled direct method (HDDM), and an integrated source apportionment method (ISAM), to update the source–receptor relationships considering stringent emission controls recently implemented in Japan and surrounding countries. We also attempted to understand the differences among source sensitivities and source apportionments calculated by multiple techniques. While a part of ozone concentrations was apportioned to domestic sources, their sensitivities were small or even negative; ozone concentrations were exclusively sensitive to transport from outside Japan. Although the simulated PM2.5 concentrations were significantly lower than those reported by previous studies, their sensitivity to transport from outside Japan was still relatively large, implying that there has been a reduction in Japanese emissions, similar to surrounding countries including China, due to implementation of stringent emission controls. HDDM allowed us to understand the importance of the non-linear responses of PM2.5 concentrations to precursor emissions. Apportionments derived by ISAM were useful in distinguishing various direct and indirect influences on ozone and PM2.5 concentrations by combining with sensitivities. The results indicate that ozone transported from outside Japan plays a key role in exerting various indirect influences on the formation of ozone and secondary PM2.5 components. While the sensitivities come closer to the apportionments when perturbations in emissions are larger in highly non-linear relationships – including those between NH3 emissions and NH4+ concentrations, NOx emissions and NO3- concentrations, and NOx emissions and ozone concentrations – the sensitivities did not reach the apportionments because there were various indirect influences including other sectors, complex photochemical reactions, and gas–aerosol partitioning. It is essential to consider non-linear influences to derive strategies for effectively suppressing concentrations of secondary pollutants.

ACS Style

Satoru Chatani; Hikari Shimadera; Syuichi Itahashi; Kazuyo Yamaji. Comprehensive analyses of source sensitivities and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques. Atmospheric Chemistry and Physics 2020, 20, 10311 -10329.

AMA Style

Satoru Chatani, Hikari Shimadera, Syuichi Itahashi, Kazuyo Yamaji. Comprehensive analyses of source sensitivities and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques. Atmospheric Chemistry and Physics. 2020; 20 (17):10311-10329.

Chicago/Turabian Style

Satoru Chatani; Hikari Shimadera; Syuichi Itahashi; Kazuyo Yamaji. 2020. "Comprehensive analyses of source sensitivities and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques." Atmospheric Chemistry and Physics 20, no. 17: 10311-10329.

Journal article
Published: 15 May 2020 in Earth System Dynamics
Reads 0
Downloads 0

In 2015, El Niño contributed to severe droughts in equatorial Asia (EA). The severe droughts enhanced fire activity in the dry season (June–November), leading to massive fire emissions of CO2 and aerosols. Based on large event attribution ensembles of the MIROC5 atmospheric global climate model, we suggest that historical anthropogenic warming increased the chances of meteorological droughts exceeding the 2015 observations in the EA area. We also investigate changes in drought in future climate simulations, in which prescribed sea surface temperature data have the same spatial patterns as the 2015 El Niño with long-term warming trends. Large probability increases of stronger droughts than the 2015 event are projected when events like the 2015 El Niño occur in the 1.5 and 2.0 ∘C warmed climate ensembles according to the Paris Agreement goals. Further drying is projected in the 3.0 ∘C ensemble according to the current mitigation policies of nations. We use observation-based empirical functions to estimate burned area, fire CO2 emissions and fine (

ACS Style

Hideo Shiogama; Ryuichi Hirata; Tomoko Hasegawa; Shinichiro Fujimori; Noriko N. Ishizaki; Satoru Chatani; Masahiro Watanabe; Daniel Mitchell; Eunice Lo. Historical and future anthropogenic warming effects on droughts, fires and fire emissions of CO2 and PM2.5 in equatorial Asia when 2015-like El Niño events occur. Earth System Dynamics 2020, 11, 435 -445.

AMA Style

Hideo Shiogama, Ryuichi Hirata, Tomoko Hasegawa, Shinichiro Fujimori, Noriko N. Ishizaki, Satoru Chatani, Masahiro Watanabe, Daniel Mitchell, Eunice Lo. Historical and future anthropogenic warming effects on droughts, fires and fire emissions of CO2 and PM2.5 in equatorial Asia when 2015-like El Niño events occur. Earth System Dynamics. 2020; 11 (2):435-445.

Chicago/Turabian Style

Hideo Shiogama; Ryuichi Hirata; Tomoko Hasegawa; Shinichiro Fujimori; Noriko N. Ishizaki; Satoru Chatani; Masahiro Watanabe; Daniel Mitchell; Eunice Lo. 2020. "Historical and future anthropogenic warming effects on droughts, fires and fire emissions of CO2 and PM2.5 in equatorial Asia when 2015-like El Niño events occur." Earth System Dynamics 11, no. 2: 435-445.

Journal article
Published: 15 May 2020 in Atmosphere
Reads 0
Downloads 0

In this study, the results for nitrate (NO3−) aerosol during winter from the first-phase model inter-comparison study of Japan’s Study for Reference Air Quality Modeling (J-STREAM) were analyzed. To investigate the models’ external and internal settings, the results were limited to Community Multiscale Air Quality (CMAQ) models. All submitted models generally underestimated NO3− over the urban areas in Japan (e.g., Osaka, Nagoya, and Tokyo); however, some model settings showed distinct behavior. The differences due to the model external settings were larger than the model internal settings. Emissions were an important factor, and emissions configured with lower NOx emissions and higher NH3 emissions led to a higher NO3− concentration as the NH3 was consumed under NH3-rich conditions. The model internal settings of the chemical mechanisms caused differences over China, and this could affect western Japan; however, the difference over Tokyo was lower. To obtain a higher NO3− concentration over the urban areas in Japan, the selection of the HONO option for the heterogenous reaction and the inline calculation of photolysis was desired. For future studies, the external settings of the boundary condition and the meteorological field require further investigation.

ACS Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Kyo Kitayama; Yu Morino; Tatsuya Nagashima; Masahiko Saito; Masayuki Takigawa; Tazuko Morikawa; Isao Kanda; Yukako Miya; Hiroaki Komatsu; Tatsuya Sakurai; Hikari Shimadera; Katsushige Uranishi; Yuzuru Fujiwara; Tomoaki Hashimoto; Hiroshi Hayami. Model Performance Differences in Fine-Mode Nitrate Aerosol during Wintertime over Japan in the J-STREAM Model Inter-Comparison Study. Atmosphere 2020, 11, 511 .

AMA Style

Syuichi Itahashi, Kazuyo Yamaji, Satoru Chatani, Kyo Kitayama, Yu Morino, Tatsuya Nagashima, Masahiko Saito, Masayuki Takigawa, Tazuko Morikawa, Isao Kanda, Yukako Miya, Hiroaki Komatsu, Tatsuya Sakurai, Hikari Shimadera, Katsushige Uranishi, Yuzuru Fujiwara, Tomoaki Hashimoto, Hiroshi Hayami. Model Performance Differences in Fine-Mode Nitrate Aerosol during Wintertime over Japan in the J-STREAM Model Inter-Comparison Study. Atmosphere. 2020; 11 (5):511.

Chicago/Turabian Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Kyo Kitayama; Yu Morino; Tatsuya Nagashima; Masahiko Saito; Masayuki Takigawa; Tazuko Morikawa; Isao Kanda; Yukako Miya; Hiroaki Komatsu; Tatsuya Sakurai; Hikari Shimadera; Katsushige Uranishi; Yuzuru Fujiwara; Tomoaki Hashimoto; Hiroshi Hayami. 2020. "Model Performance Differences in Fine-Mode Nitrate Aerosol during Wintertime over Japan in the J-STREAM Model Inter-Comparison Study." Atmosphere 11, no. 5: 511.

Accepted manuscript
Published: 30 April 2020 in Environmental Research Communications
Reads 0
Downloads 0

Economic development, transport demand, and air pollution are interrelated. The heterogeneity of economic development among regions and the freezing of exhaust emission regulations for approximately a decade in Thailand were the motivations for this study. Herein we provide a comprehensive analysis of vehicle exhaust emission projections for up to 2050 with specific regional breakdown for passenger transport mode and volume; we also provide region-wise and mode-wise outcomes to help understand the effects of enhancing exhaust emissions regulation for future air pollutant emissions. The results from this study reveal the limitations of current regulations and establish the need to enhance regulations within this decade to cope with air pollution for the long-term growth of regional economic development.

ACS Style

Penwadee Cheewaphongphan; Tatsuya Hanaoka; Satoru Chatani. Long-term trend of regional passenger road transport demand and emission estimation under exhaust emission regulation scenario in Thailand. Environmental Research Communications 2020, 2, 051009 .

AMA Style

Penwadee Cheewaphongphan, Tatsuya Hanaoka, Satoru Chatani. Long-term trend of regional passenger road transport demand and emission estimation under exhaust emission regulation scenario in Thailand. Environmental Research Communications. 2020; 2 (5):051009.

Chicago/Turabian Style

Penwadee Cheewaphongphan; Tatsuya Hanaoka; Satoru Chatani. 2020. "Long-term trend of regional passenger road transport demand and emission estimation under exhaust emission regulation scenario in Thailand." Environmental Research Communications 2, no. 5: 051009.

Preprint content
Published: 20 April 2020
Reads 0
Downloads 0

Source sensitivity and source apportionment are two major indicators representing source-receptor relationships, which serve as essential information when considering effective strategies to accomplish improved air quality. This study evaluated source sensitivities to and apportionments of ambient ozone and PM2.5 concentrations over Japan with multiple numerical techniques embedded in regional chemical transport models, including a brute forth method (BFM), a high-order decoupled direct method (HDDM), and an integrated source apportionment method (ISAM), to update the source-receptor relationships considering stringent emission controls recently implemented in Japan and surrounding countries. We also attempted to understand the differences among source sensitivities and apportionments calculated by multiple techniques. While domestic sources had certain source apportionments to ozone concentrations, transport from outside Japan dominated the source sensitivities. Although the PM2.5 concentrations and absolute magnitudes of their source sensitivities were significantly lower than those reported by previous studies, transport from outside Japan still has relatively large contributions to PM2.5 concentrations, implying that there has been a reduction in Japanese emissions, similar to surrounding countries including China, due to implementation of stringent emission controls. HDDM allowed us to effectively understand the importance of the nonlinear responses of PM2.5 concentrations to precursor emissions. Apportionments derived by ISAM were useful in distinguishing various direct and indirect influences on ozone and PM2.5 concentrations. It was suggested that that ozone transported from outside Japan plays a key role in exerting various indirect influences on the formation of ozone and secondary PM2.5 components. This study demonstrated that a combination of sensitivities and apportionments derived by the BFM, HDDM, and ISAM can provide critical information to identify key emission sources and processes in the atmosphere, which are vital for the development of effective strategies for improved air quality.

ACS Style

Satoru Chatani; Hikari Shimadera; Syuichi Itahashi; Kazuyo Yamaji. Comprehensive analyses of source sensitivities to and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques. 2020, 2020, 1 -31.

AMA Style

Satoru Chatani, Hikari Shimadera, Syuichi Itahashi, Kazuyo Yamaji. Comprehensive analyses of source sensitivities to and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques. . 2020; 2020 ():1-31.

Chicago/Turabian Style

Satoru Chatani; Hikari Shimadera; Syuichi Itahashi; Kazuyo Yamaji. 2020. "Comprehensive analyses of source sensitivities to and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques." 2020, no. : 1-31.

Preprint content
Published: 20 April 2020
Reads 0
Downloads 0
ACS Style

Satoru Chatani; Hikari Shimadera; Syuichi Itahashi; Kazuyo Yamaji. Supplementary material to "Comprehensive analyses of source sensitivities to and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques". 2020, 1 .

AMA Style

Satoru Chatani, Hikari Shimadera, Syuichi Itahashi, Kazuyo Yamaji. Supplementary material to "Comprehensive analyses of source sensitivities to and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques". . 2020; ():1.

Chicago/Turabian Style

Satoru Chatani; Hikari Shimadera; Syuichi Itahashi; Kazuyo Yamaji. 2020. "Supplementary material to "Comprehensive analyses of source sensitivities to and apportionments of PM2.5 and ozone over Japan via multiple numerical techniques"." , no. : 1.

Journal article
Published: 25 February 2020 in Atmosphere
Reads 0
Downloads 0

A model inter-comparison of secondary pollutant simulations over urban areas in Japan, the first phase of Japan’s study for reference air quality modeling (J-STREAM Phase I), was conducted using 32 model settings. Simulated hourly concentrations of nitric oxide (NO) and nitrogen dioxide (NO2), which are primary pollutant precursors of particulate matter with a diameter of 2.5 µm or less (PM2.5), showed good agreement with the observed concentrations, but most of the simulated hourly sulfur oxide (SO2) concentrations were much higher than the observations. Simulated concentrations of PM2.5 and its components were compared to daily observed concentrations by using the filter pack method at selected ambient air pollution monitoring stations (AAPMSs) for each season. In general, most models showed good agreement with the observed total PM2.5 mass concentration levels in each season and provided goal or criteria levels of model ensemble statistics in warmer seasons. The good performances of these models were associated with the simulated reproducibility of some dominant components, sulfates (SO42−) and ammonium (NH4+). The other simulated PM2.5 components, i.e., nitrates (NO3−), elemental carbon (EC), and organic carbon (OC), often show clear deviations from the observations. The considerable underestimations (approximately 30 µg/m3 for total PM2.5) of all participant models found on heavily polluted days with approximately 40–50 µg/m3 for total PM2.5 indicated some problems in the simulated local meteorology such as the atmospheric stability. This model inter-comparison suggests that these deviations may be owing to a need for further improvements both in the emission inventories and additional formation pathways in chemical transport models, and meteorological conditions also require improvement to simulate elevated atmospheric pollutants. Additional accumulated observations are likely needed to further evaluate the simulated concentrations and improve the model performance.

ACS Style

Kazuyo Yamaji; Satoru Chatani; Syuichi Itahashi; Masahiko Saito; Masayuki Takigawa; Tazuko Morikawa; Isao Kanda; Yukako Miya; Hiroaki Komatsu; Tatsuya Sakurai; Yu Morino; Kyo Kitayama; Tatsuya Nagashima; Hikari Shimadera; Katsushige Uranishi; Yuzuru Fujiwara; Tomoaki Hashimoto; Kengo Sudo; Takeshi Misaki; Hiroshi Hayami. Model Inter-Comparison for PM2.5 Components over urban Areas in Japan in the J-STREAM Framework. Atmosphere 2020, 11, 222 .

AMA Style

Kazuyo Yamaji, Satoru Chatani, Syuichi Itahashi, Masahiko Saito, Masayuki Takigawa, Tazuko Morikawa, Isao Kanda, Yukako Miya, Hiroaki Komatsu, Tatsuya Sakurai, Yu Morino, Kyo Kitayama, Tatsuya Nagashima, Hikari Shimadera, Katsushige Uranishi, Yuzuru Fujiwara, Tomoaki Hashimoto, Kengo Sudo, Takeshi Misaki, Hiroshi Hayami. Model Inter-Comparison for PM2.5 Components over urban Areas in Japan in the J-STREAM Framework. Atmosphere. 2020; 11 (3):222.

Chicago/Turabian Style

Kazuyo Yamaji; Satoru Chatani; Syuichi Itahashi; Masahiko Saito; Masayuki Takigawa; Tazuko Morikawa; Isao Kanda; Yukako Miya; Hiroaki Komatsu; Tatsuya Sakurai; Yu Morino; Kyo Kitayama; Tatsuya Nagashima; Hikari Shimadera; Katsushige Uranishi; Yuzuru Fujiwara; Tomoaki Hashimoto; Kengo Sudo; Takeshi Misaki; Hiroshi Hayami. 2020. "Model Inter-Comparison for PM2.5 Components over urban Areas in Japan in the J-STREAM Framework." Atmosphere 11, no. 3: 222.

Journal article
Published: 31 December 2019 in Atmospheric Environment
Reads 0
Downloads 0

Ozone is one of remaining air quality issues in Japan. Effective strategies are required to reduce ozone at the ground level. Regional chemical transport models are useful in investigating relationships between precursor emissions and ambient concentrations of secondary pollutants including ozone. Model performance on ozone concentrations over urban areas in Japan were thoroughly evaluated in model inter-comparisons conducted in Japan's study for reference air quality modeling (J-STREAM). Specifically, 33 models with different configurations including the Community Multiscale Air Quality Modeling System (CMAQ), the Comprehensive Air Quality Model with Extensions (CAMx), and the Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem) participated. They realized inter-comparisons with an unprecedented number of different model configurations. All the participating models overestimated ozone concentrations by 22 ± 4.6 ppb over urban areas in Japan during the summer. Spatial and temporal variations in model performance suggest the influence of background ozone concentrations. Based on differences in the participating model configurations, halogen chemistry and deposition, dry deposition velocity, precursor emissions in other countries, and vertical transport were identified as the key factors influencing simulated background ozone concentrations. Specific sensitivity analyses were conducted to evaluate the effects of the key influencing factors. Halogen chemistry and deposition implemented in recent versions of CMAQ caused more than 10 ppb reduction of simulated ozone over the ocean surrounding Japan, while the original dry deposition schemes used in CAMx and WRF-Chem, without any effect of halogen, can also cause larger dry deposition. Horizontal and downward transport of ozone kept in a residual layer over the continent can spread the effect of precursor emissions in other countries to downwind regions, including Japan. Differences in vertical transport can alter the spatial extent of their effects. It is essential to improve the influence of the aforementioned key factors to realize better model performance on ozone concentrations over urban areas, not only in Japan, but all over the world.

ACS Style

Satoru Chatani; Kazuyo Yamaji; Syuichi Itahashi; Masahiko Saito; Masayuki Takigawa; Tazuko Morikawa; Isao Kanda; Yukako Miya; Hiroaki Komatsu; Tatsuya Sakurai; Yu Morino; Tatsuya Nagashima; Kyo Kitayama; Hikari Shimadera; Katsushige Uranishi; Yuzuru Fujiwara; Soma Shintani; Hiroshi Hayami. Identifying key factors influencing model performance on ground-level ozone over urban areas in Japan through model inter-comparisons. Atmospheric Environment 2019, 223, 117255 .

AMA Style

Satoru Chatani, Kazuyo Yamaji, Syuichi Itahashi, Masahiko Saito, Masayuki Takigawa, Tazuko Morikawa, Isao Kanda, Yukako Miya, Hiroaki Komatsu, Tatsuya Sakurai, Yu Morino, Tatsuya Nagashima, Kyo Kitayama, Hikari Shimadera, Katsushige Uranishi, Yuzuru Fujiwara, Soma Shintani, Hiroshi Hayami. Identifying key factors influencing model performance on ground-level ozone over urban areas in Japan through model inter-comparisons. Atmospheric Environment. 2019; 223 ():117255.

Chicago/Turabian Style

Satoru Chatani; Kazuyo Yamaji; Syuichi Itahashi; Masahiko Saito; Masayuki Takigawa; Tazuko Morikawa; Isao Kanda; Yukako Miya; Hiroaki Komatsu; Tatsuya Sakurai; Yu Morino; Tatsuya Nagashima; Kyo Kitayama; Hikari Shimadera; Katsushige Uranishi; Yuzuru Fujiwara; Soma Shintani; Hiroshi Hayami. 2019. "Identifying key factors influencing model performance on ground-level ozone over urban areas in Japan through model inter-comparisons." Atmospheric Environment 223, no. : 117255.

Journal article
Published: 12 September 2019 in Atmosphere
Reads 0
Downloads 0

During the Japanese intercomparison study, Japan’s Study for Reference Air Quality Modeling (J-STREAM), it was found that wintertime SO42– concentrations were underestimated over Japan with the Community Multiscale Air Quality (CMAQ) modeling system. Previously, following two development phases, model performance was improved by refining the Fe- and Mn-catalyzed oxidation pathways and by including an additional aqueous-phase pathway via NO2 oxidation. In a third phase, we examined a winter haze period in December 2016, involving a gas-phase oxidation pathway whereby three stabilized Criegee intermediates (SCI) were incorporated into the model. We also included options for a kinetic mass transfer aqueous-phase calculation. According to statistical analysis, simulations compared well with hourly SO42– observations in Tokyo. Source sensitivities for four domestic emission sources (transportation, stationary combustion, fugitive VOC, and agricultural NH3) were investigated. During the haze period, contributions from other sources (overseas and volcanic emissions) dominated, while domestic sources, including transportation and fuel combustion, played a role in enhancing SO42– concentrations around Tokyo Bay. Updating the aqueous phase metal catalyzed and NO2 oxidation pathways lead to increase contribution from other sources, and the additional gas phase SCI chemistry provided a link between fugitive VOC emission and SO42– concentration via changes in O3 concentration.

ACS Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Hiroshi Hayami. Differences in Model Performance and Source Sensitivities for Sulfate Aerosol Resulting from Updates of the Aqueous- and Gas-Phase Oxidation Pathways for a Winter Pollution Episode in Tokyo, Japan. Atmosphere 2019, 10, 544 .

AMA Style

Syuichi Itahashi, Kazuyo Yamaji, Satoru Chatani, Hiroshi Hayami. Differences in Model Performance and Source Sensitivities for Sulfate Aerosol Resulting from Updates of the Aqueous- and Gas-Phase Oxidation Pathways for a Winter Pollution Episode in Tokyo, Japan. Atmosphere. 2019; 10 (9):544.

Chicago/Turabian Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Hiroshi Hayami. 2019. "Differences in Model Performance and Source Sensitivities for Sulfate Aerosol Resulting from Updates of the Aqueous- and Gas-Phase Oxidation Pathways for a Winter Pollution Episode in Tokyo, Japan." Atmosphere 10, no. 9: 544.

Preprint content
Published: 08 August 2019
Reads 0
Downloads 0

In 2015, El Niño caused severe droughts in equatorial Asia (EA). The severe droughts enhanced fire activities in the dry seasons, leading to massive fire emissions of CO2 and aerosols. Using large event attribution ensembles of the MIROC5 atmospheric global climate model, we suggest that historical anthropogenic warming increased the chances of meteorological droughts exceeding the 2015 observations in the EA area. Large probability increases in stronger droughts than the 2015 event are found in the ensemble simulations of 1.5 °C and 2.0 °C global warming according to the Paris Agreement goals. Further drying is projected in the 3.0 °C ensemble. We combine these experiments and empirical functions between precipitation, burned area, and fire emissions of CO2 and PM2.5. Increases in the chances of the burned area and the emissions of CO2 and PM2.5 exceeding the 2015 observations due to anthropogenic climate change in the past are not significant. In contrast, there are significant increases in the burned area and CO2 and PM2.5 emissions even if the 1.5 °C and 2.0 °C goals are achieved. If global warming reaches 3.0 °C, as is expected from the current mitigation policies of nations, the chances of the burned area, CO2 and PM2.5 emissions exceeding the 2015 observed values become approximately 100 %, at least in the single model ensembles. We also compare changes in fire CO2 emissions due to climate changes and the land-use CO2 emission scenarios of five shared socio-economic pathways, where the climate change effects on fire are not considered. There are two main implications. First, in a national policy context, future EA climate policy will need to consider these climate change effects regarding both mitigation and adaptation aspects. Second, the consideration of fire increases would change global CO2 emissions and the mitigation strategy, which suggests that future climate change mitigation studies should take these factors into account.

ACS Style

Hideo Shiogama; Ryuichi Hirata; Tomoko Hasegawa; Shinichiro Fujimori; Noriko Ishizaki; Satoru Chatani; Masahiro Watanabe; Daniel Mitchell; Y. T. Eunice Lo. Historical and future anthropogenic warming effects on the year 2015 droughts, fires and fire emissions of CO2 and PM2.5 in equatorial Asia. 2019, 1 .

AMA Style

Hideo Shiogama, Ryuichi Hirata, Tomoko Hasegawa, Shinichiro Fujimori, Noriko Ishizaki, Satoru Chatani, Masahiro Watanabe, Daniel Mitchell, Y. T. Eunice Lo. Historical and future anthropogenic warming effects on the year 2015 droughts, fires and fire emissions of CO2 and PM2.5 in equatorial Asia. . 2019; ():1.

Chicago/Turabian Style

Hideo Shiogama; Ryuichi Hirata; Tomoko Hasegawa; Shinichiro Fujimori; Noriko Ishizaki; Satoru Chatani; Masahiro Watanabe; Daniel Mitchell; Y. T. Eunice Lo. 2019. "Historical and future anthropogenic warming effects on the year 2015 droughts, fires and fire emissions of CO2 and PM2.5 in equatorial Asia." , no. : 1.

Journal article
Published: 06 April 2019 in Sustainability
Reads 0
Downloads 0

Bottom-up CH4 emission inventories, which have been developed from statistical analyses of activity data and country specific emission factors (EFs), have high uncertainty in terms of the estimations, according to results from top-down inverse model studies. This study aimed to determine the causes of overestimation in CH4 bottom-up emission inventories across China by applying parameter variability uncertainty analysis to three sets of CH4 emission inventories titled PENG, GAINS, and EDGAR. The top three major sources of CH4 emissions in China during the years 1990–2010, namely, coal mining, livestock, and rice cultivation, were selected for the investigation. The results of this study confirm the concerns raised by inverse modeling results in which we found significantly higher bottom-up emissions for the rice cultivation and coal mining sectors. The largest uncertainties were detected in the rice cultivation estimates and were caused by variations in the proportions of rice cultivation ecosystems and EFs; specifically, higher rates for both parameters were used in EDGAR. The coal mining sector was associated with the second highest level of uncertainty, and this was caused by variations in mining types and EFs, for which rather consistent parameters were used in EDGAR and GAINS, but values were slightly higher than those used in PENG. Insignificant differences were detected among the three sets of inventories for the livestock sector.

ACS Style

Penwadee Cheewaphongphan; Satoru Chatani; Nobuko Saigusa. Exploring Gaps between Bottom-Up and Top-Down Emission Estimates Based on Uncertainties in Multiple Emission Inventories: A Case Study on CH4 Emissions in China. Sustainability 2019, 11, 2054 .

AMA Style

Penwadee Cheewaphongphan, Satoru Chatani, Nobuko Saigusa. Exploring Gaps between Bottom-Up and Top-Down Emission Estimates Based on Uncertainties in Multiple Emission Inventories: A Case Study on CH4 Emissions in China. Sustainability. 2019; 11 (7):2054.

Chicago/Turabian Style

Penwadee Cheewaphongphan; Satoru Chatani; Nobuko Saigusa. 2019. "Exploring Gaps between Bottom-Up and Top-Down Emission Estimates Based on Uncertainties in Multiple Emission Inventories: A Case Study on CH4 Emissions in China." Sustainability 11, no. 7: 2054.

Journal article
Published: 10 December 2018 in Atmosphere
Reads 0
Downloads 0

Sulfate aerosol (SO42−) is a major component of particulate matter in Japan. The Japanese model intercomparison study, J-STREAM, found that although SO42− is well captured by models, it is underestimated during winter. In the first phase of J-STREAM, we refined the Fe- and Mn-catalyzed oxidation and partly improved the underestimation. The winter haze in December 2016 was a target period in the second phase. The results from the Community Multiscale Air Quality (CMAQ) and Comprehensive Air quality Model with eXtentions (CAMx) regional chemical transport models were compared with observations from the network over Japan and intensive observations at Nagoya and Tokyo. Statistical analysis showed both models satisfied the suggested model performance criteria. CMAQ sensitivity simulations explained the improvements in model performance. CMAQ modeled lower SO42− concentrations than CAMx, despite increased aqueous oxidation via the metal catalysis pathway and NO2 reaction in CMAQ. Deposition explained this difference. A scatter plot demonstrated that the lower SO42− concentration in CMAQ than in CAMx arose from the lower SO2 concentration and higher SO42− wet deposition in CMAQ. The dry deposition velocity caused the difference in SO2 concentration. These results suggest the importance of deposition in improving our understanding of ambient concentration behavior.

ACS Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Kunihiro Hisatsune; Shinji Saito; Hiroshi Hayami. Model Performance Differences in Sulfate Aerosol in Winter over Japan Based on Regional Chemical Transport Models of CMAQ and CAMx. Atmosphere 2018, 9, 488 .

AMA Style

Syuichi Itahashi, Kazuyo Yamaji, Satoru Chatani, Kunihiro Hisatsune, Shinji Saito, Hiroshi Hayami. Model Performance Differences in Sulfate Aerosol in Winter over Japan Based on Regional Chemical Transport Models of CMAQ and CAMx. Atmosphere. 2018; 9 (12):488.

Chicago/Turabian Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Kunihiro Hisatsune; Shinji Saito; Hiroshi Hayami. 2018. "Model Performance Differences in Sulfate Aerosol in Winter over Japan Based on Regional Chemical Transport Models of CMAQ and CAMx." Atmosphere 9, no. 12: 488.

Journal article
Published: 08 November 2018 in Atmospheric Environment
Reads 0
Downloads 0

Uncertainty was evaluated in four chemical mechanisms pertaining to O3 concentrations predicted over Japan by the Community Multiscale Air Quality Model (CMAQ) to investigate factors contributing to model overestimation of O3 concentration. The model setting and meteorological and emissions input data were obtained from a Japanese model inter-comparison project, Japan's Study for Reference Air Quality Modeling (J-STREAM). The compared gas-phase chemical mechanisms included the Carbon Bond Mechanism (CB05TUCL), Regional Atmospheric Chemical Mechanism (RACM2), and two mechanisms developed by the State Air Pollution Research Center (SAPRC), namely SAPRC07TC and SAPRC99. The O3 concentrations produced by CB05TUCL were low compared to those from SAPRC07TC. The RACM2 concentrations were similar to those from SAPRC07TC over inland Japan and lower over the sea. The concentrations from SAPRC99 were higher than those from SAPRC07TC in urban areas and lower in other areas. At most of the monitoring sites in Japan, the modeled O3 concentrations were higher than those from observations. Module overestimation can be ranked in the order of SAPRC99 > SAPRC07TC > RACM2 > CB05TUCL for urban sites and SAPRC07TC > SAPRC99 > RACM2 > CB05TUCL for rural sites. The concentration differences between the chemical mechanisms were within 10 ppb, whereas those between the observed and simulated O3 concentrations reached 40 ppb. Differences in O3 concentrations between the chemical mechanisms accounted for only a part of the model overestimation, while the rest remained unexplained. To investigate factors influencing the differences in O3 concentration between the chemical mechanisms, domain- and 10-vertical-layer-average hourly integrated process rates (IPRs) and integrated reaction rates (IRRs) were calculated using process analysis in CMAQ. The O3 chemical IPRs from SAPRC07TC were higher than those from CB05TUCL and RACM2. The SAPRC99 IPRs were higher than those from SAPRC07TC in urban areas and lower in other areas. The IRR differences in the chemical mechanisms showed that IRRs for the O3 and NO reactions were responsible for the differences in the O3 chemical IPR. The coefficients of determination between the O3 chemical process IPR and IRR differences in the chemical mechanisms were highest for the HO2-NO reaction in CB05TUCL and SAPRC99 and the RO2-NO reaction in RACM2. Differences in reaction rate constants and lumped volatile organic compounds may have caused some of the differences in O3 production between the chemical mechanisms.

ACS Style

Kyo Kitayama; Yu Morino; Kazuyo Yamaji; Satoru Chatani. Uncertainties in O3 concentrations simulated by CMAQ over Japan using four chemical mechanisms. Atmospheric Environment 2018, 198, 448 -462.

AMA Style

Kyo Kitayama, Yu Morino, Kazuyo Yamaji, Satoru Chatani. Uncertainties in O3 concentrations simulated by CMAQ over Japan using four chemical mechanisms. Atmospheric Environment. 2018; 198 ():448-462.

Chicago/Turabian Style

Kyo Kitayama; Yu Morino; Kazuyo Yamaji; Satoru Chatani. 2018. "Uncertainties in O3 concentrations simulated by CMAQ over Japan using four chemical mechanisms." Atmospheric Environment 198, no. : 448-462.

Research article
Published: 05 July 2018 in Environmental Science & Technology
Reads 0
Downloads 0

Because emission rates of particulate matter (PM) from stationary combustion sources have been measured without dilution or cooling in Japan, condensable PM has not been included in Japanese emission inventories. In this study, we modified an emission inventory to include condensable PM from stationary combustion sources based on the recent emission surveys using a dilution method. As a result, emission rates of organic aerosol (OA) increased by a factor of 7 over Japan. Stationary combustion sources in the industrial and energy sectors became the largest contributors to OA emissions over Japan in the revised estimates (filterable-plus-condensable PM), while road transport and biomass burning were the dominant OA sources in the previous estimate (filterable PM). These results indicate that condensable PM from large combustion sources makes critical contributions to total PM2.5 emissions. Simulated contributions of condensable PM from combustion sources to atmospheric OA drastically increased around urban and industrial areas, including the Kanto region, where OA concentrations increased by factors of 2.5–6.1. Consideration of condensable PM from stationary combustion sources improved model estimates of OA in winter but caused overestimation of OA concentrations in summer. Contributions of primary and secondary OA should be further evaluated by comparing with organic tracer measurements.

ACS Style

Yu Morino; Satoru Chatani; Kiyoshi Tanabe; Yuji Fujitani; Tazuko Morikawa; Katsuyuki Takahashi; Kei Sato; Seiji Sugata. Contributions of Condensable Particulate Matter to Atmospheric Organic Aerosol over Japan. Environmental Science & Technology 2018, 52, 8456 -8466.

AMA Style

Yu Morino, Satoru Chatani, Kiyoshi Tanabe, Yuji Fujitani, Tazuko Morikawa, Katsuyuki Takahashi, Kei Sato, Seiji Sugata. Contributions of Condensable Particulate Matter to Atmospheric Organic Aerosol over Japan. Environmental Science & Technology. 2018; 52 (15):8456-8466.

Chicago/Turabian Style

Yu Morino; Satoru Chatani; Kiyoshi Tanabe; Yuji Fujitani; Tazuko Morikawa; Katsuyuki Takahashi; Kei Sato; Seiji Sugata. 2018. "Contributions of Condensable Particulate Matter to Atmospheric Organic Aerosol over Japan." Environmental Science & Technology 52, no. 15: 8456-8466.

Journal article
Published: 30 June 2018 in Asian Journal of Atmospheric Environment
Reads 0
Downloads 0
ACS Style

Hikari Shimadera; Hiroshi Hayami; Satoru Chatani; Tazuko Morikawa; Yu Morino; Yasuaki Mori; Kazuyo Yamaji; Seiji Nakatsuka; Toshimasa Ohara. Urban Air Quality Model Inter-Comparison Study (UMICS) for Improvement of PM2.5 Simulation in Greater Tokyo Area of Japan. Asian Journal of Atmospheric Environment 2018, 12, 139 -152.

AMA Style

Hikari Shimadera, Hiroshi Hayami, Satoru Chatani, Tazuko Morikawa, Yu Morino, Yasuaki Mori, Kazuyo Yamaji, Seiji Nakatsuka, Toshimasa Ohara. Urban Air Quality Model Inter-Comparison Study (UMICS) for Improvement of PM2.5 Simulation in Greater Tokyo Area of Japan. Asian Journal of Atmospheric Environment. 2018; 12 (2):139-152.

Chicago/Turabian Style

Hikari Shimadera; Hiroshi Hayami; Satoru Chatani; Tazuko Morikawa; Yu Morino; Yasuaki Mori; Kazuyo Yamaji; Seiji Nakatsuka; Toshimasa Ohara. 2018. "Urban Air Quality Model Inter-Comparison Study (UMICS) for Improvement of PM2.5 Simulation in Greater Tokyo Area of Japan." Asian Journal of Atmospheric Environment 12, no. 2: 139-152.

Journal article
Published: 09 May 2018 in Atmosphere
Reads 0
Downloads 0

Regional air quality simulations provide powerful tools for clarifying mechanisms of heavy air pollution and for considering effective strategies for better air quality. This study introduces a new vegetation database for Japan, which could provide inputs for regional meteorological modeling, and estimating emissions of biogenic volatile organic compounds (BVOCs), both of which are essential components of simulations. It includes newly developed emission factors (EFs) of BVOCs for major vegetation types in Japan, based on existing literature. The new database contributes to improved modeling of meteorological fields due to its updated representation of larger urban areas. Using the new vegetation and EF database, lower isoprene and monoterpene, and higher sesquiterpene emissions are estimated for Japan than those derived from previously available default datasets. These slightly reduce the overestimation of ozone concentrations obtained by a regional chemical transport model, whereas their effects on underestimated secondary organic aerosol (SOA) concentrations are marginal. Further work is necessary, not only on BVOC emissions but also the other simulation components, to further improve the modeling of ozone and SOA concentrations in Japan.

ACS Style

Satoru Chatani; Motonori Okumura; Hikari Shimadera; Kazuyo Yamaji; Kyo Kitayama; Sou N. Matsunaga. Effects of a Detailed Vegetation Database on Simulated Meteorological Fields, Biogenic VOC Emissions, and Ambient Pollutant Concentrations over Japan. Atmosphere 2018, 9, 179 .

AMA Style

Satoru Chatani, Motonori Okumura, Hikari Shimadera, Kazuyo Yamaji, Kyo Kitayama, Sou N. Matsunaga. Effects of a Detailed Vegetation Database on Simulated Meteorological Fields, Biogenic VOC Emissions, and Ambient Pollutant Concentrations over Japan. Atmosphere. 2018; 9 (5):179.

Chicago/Turabian Style

Satoru Chatani; Motonori Okumura; Hikari Shimadera; Kazuyo Yamaji; Kyo Kitayama; Sou N. Matsunaga. 2018. "Effects of a Detailed Vegetation Database on Simulated Meteorological Fields, Biogenic VOC Emissions, and Ambient Pollutant Concentrations over Japan." Atmosphere 9, no. 5: 179.

Journal article
Published: 06 April 2018 in Journal of Geophysical Research: Atmospheres
Reads 0
Downloads 0

Many places in India suffer from severe air pollution. Regional air quality simulations are essential to develop effective strategies for improving air quality, considering the non‐linear relationships between ambient pollutants and their precursor emissions. Meteorological fields used in simulations are derived from regional meteorological models with analysis datasets as inputs. This study reveals that two major analysis datasets provided by the National Centers for Environmental Prediction (NCEP) and the European Centre for Medium‐Range Weather Forecasts (ECMWF) cause significant differences in simulated meteorological fields over India. Especially, relative humidity values simulated using the ECMWF dataset are much higher and closer to the observed values than those simulated using the NCEP dataset. Results simulated using the ECMWF dataset show better model performance for most meteorological parameters over India. Differences in relative humidity originate in the data contained in the analysis datasets through grid nudging. It is not possible to avoid this underestimation by simply turning off grid nudging. The meteorological fields simulated with two major analysis datasets also lead to differences in pollutant concentrations simulated by regional chemical transport models through various physical and chemical processes. Differences originating in the two analysis datasets could be comparable with the uncertainties originating in various emission inventories in some regions and seasons in India. However, discrepancies between observed and simulated pollutant concentrations cannot be explained only by differences of the meteorological fields. Other aspects need to be explored for better performance required to develop effective strategies for India, based on accurate regional air quality simulations.

ACS Style

Satoru Chatani; Sumit Sharma. Uncertainties Caused by Major Meteorological Analysis Data Sets in Simulating Air Quality Over India. Journal of Geophysical Research: Atmospheres 2018, 123, 6230 -6247.

AMA Style

Satoru Chatani, Sumit Sharma. Uncertainties Caused by Major Meteorological Analysis Data Sets in Simulating Air Quality Over India. Journal of Geophysical Research: Atmospheres. 2018; 123 (11):6230-6247.

Chicago/Turabian Style

Satoru Chatani; Sumit Sharma. 2018. "Uncertainties Caused by Major Meteorological Analysis Data Sets in Simulating Air Quality Over India." Journal of Geophysical Research: Atmospheres 123, no. 11: 6230-6247.

Journal article
Published: 01 April 2018 in Atmosphere
Reads 0
Downloads 0

We refined the aqueous-phase sulfate (SO42−) production in the state-of-the-art Community Multiscale Air Quality (CMAQ) model during the Japanese model inter-comparison project, known as Japan’s Study for Reference Air Quality Modeling (J-STREAM). In Japan, SO42− is the major component of PM2.5, and CMAQ reproduces the observed seasonal variation of SO42− with the summer maxima and winter minima. However, CMAQ underestimates the concentration during winter over Japan. Based on a review of the current modeling system, we identified a possible reason as being the inadequate aqueous-phase SO42− production by Fe- and Mn-catalyzed O2 oxidation. This is because these trace metals are not properly included in the Asian emission inventories. Fe and Mn observations over Japan showed that the model concentrations based on the latest Japanese emission inventory were substantially underestimated. Thus, we conducted sensitivity simulations where the modeled Fe and Mn concentrations were adjusted to the observed levels, the Fe and Mn solubilities were increased, and the oxidation rate constant was revised. Adjusting the concentration increased the SO42− concentration during winter, as did increasing the solubilities and revising the rate constant to consider pH dependencies. Statistical analysis showed that these sensitivity simulations improved model performance. The approach adopted in this study can partly improve model performance in terms of the underestimation of SO42− concentration during winter. From our findings, we demonstrated the importance of developing and evaluating trace metal emission inventories in Asia.

ACS Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Hiroshi Hayami. Refinement of Modeled Aqueous-Phase Sulfate Production via the Fe- and Mn-Catalyzed Oxidation Pathway. Atmosphere 2018, 9, 132 .

AMA Style

Syuichi Itahashi, Kazuyo Yamaji, Satoru Chatani, Hiroshi Hayami. Refinement of Modeled Aqueous-Phase Sulfate Production via the Fe- and Mn-Catalyzed Oxidation Pathway. Atmosphere. 2018; 9 (4):132.

Chicago/Turabian Style

Syuichi Itahashi; Kazuyo Yamaji; Satoru Chatani; Hiroshi Hayami. 2018. "Refinement of Modeled Aqueous-Phase Sulfate Production via the Fe- and Mn-Catalyzed Oxidation Pathway." Atmosphere 9, no. 4: 132.