Multi-year trend in fine and coarse particle mass, carbon, and ions in downtown Tokyo, Japan

Minoura, Hiroaki; Takahashi, Katsuyuki; Chow, Judith C.; Watson, John G.

doi:10.1016/j.atmosenv.2005.12.029

Cited by 59 publications

(31 citation statements)

References 23 publications

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“…Recently, concentrations of primary aerosols (particles emitted directly into the atmosphere) have decreased in the Tokyo urban area because of a reduction in their emission, but concentrations of secondary aerosols (particles formed by gas-to-particle conversion in the atmosphere) have not been reduced as expected (Minoura et al, 2006). In general, production pathways and atmospheric behavior of secondary pollutants are more complicated than those of primary pollutants, and concentrations of secondary pollutants do not decrease linearly with reductions in their precursors' emission rates.…”

Section: Introductionmentioning

confidence: 97%

Evaluation of Ensemble Approach for O3 and PM2.5 Simulation

Morino¹,

Chatani²,

Hayami³

et al. 2010

ajae

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Inter-comparison of chemical transport models (CTMs) was conducted among four modeling research groups. Model performance of the ensemble approach to O 3 and PM 2.5 simulation was evaluated by using observational data with a time resolution of 1 or 6 hours at four sites in the Kanto area, Japan, in summer 2007. All groups applied the Community Multiscale Air Quality model. The ensemble average of the four CTMs reproduced well the temporal variation of O 3 (r= =0.65-0.85) and the daily maximum O 3 concentration within a factor of 1.3. By contrast, it underestimated PM 2.5 concentrations by a factor of 1.4-2, and did not reproduce the PM 2.5 temporal variation at two suburban sites (r= =~0.2). The ensemble average improved the simulation of SO 4 2-, NO 3 -, and NH 4 + + , whose production pathways are well known. In particular, the ensemble approach effectively simulated NO 3 -, despite the large variability among CTMs (up to a factor of 10). However, the ensemble average did not improve the simulation of organic aerosols (OAs), underestimating their concentrations by a factor of 5. The contribution of OAs to PM 2.5 (36-39%) was large, so improvement of the OA simulation model is essential to improve the PM 2.5 simulation.

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Section: Introductionmentioning

confidence: 97%

Evaluation of Ensemble Approach for O3 and PM2.5 Simulation

Morino¹,

Chatani²,

Hayami³

et al. 2010

ajae

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show abstract

“…: 81-561-71-7724; Fax: 81-561-63-6559 E-mail address: schatani@mosk.tytlabs.co.jp reactions in the atmosphere, is becoming important (Minoura et al, 2006). To seek effective strategies for reducing PM 2.5 concentration including secondary components, it is essential to use air quality models that represent physical and chemical processes in the atmosphere, such as emission, advection, diffusion, photochemical reactions, and deposition.…”

Section: Introductionmentioning

confidence: 99%

Multi-Model Analyses of Dominant Factors Influencing Elemental Carbon in Tokyo Metropolitan Area of Japan

Chatani

Morino

Shimadera

et al. 2014

Aerosol Air Qual. Res.

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The first phase of the Urban air quality Model InterComparison Study in Japan (UMICS) has been conducted to find ways to improve model performance with regard to elemental carbon (EC). Common meteorology and emission datasets are used with eight different models. All the models underestimate the EC concentrations observed in Tokyo Metropolitan Area in the summer of 2007. Sensitivity analyses are conducted using these models to investigate the causes of this underestimation. The results of the analyses reveal that emissions and vertical diffusion are dominant factors that affect the simulated EC concentrations. A significant improvement in the accuracy of EC concentrations could be realized by applying appropriate scaling factors to EC emissions and boundary concentrations. Observation data from Lidar and radiosonde suggest the possible overestimation of planetary boundary layer height, which is a vital parameter representing vertical diffusion. The findings of this work can help to improve air quality models to that they can be used to develop more effective strategies for reducing PM 2.5 concentrations.

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“…Due to the difference in the cut-off property of particles between PM 10 (50% cut-off at 10 μm) and SPM (100% cut-off at 10 μm), SPM concentration was approximately equivalent to PM 7 (Minoura et al 2006).…”

Section: Datamentioning

confidence: 99%

Asian Dust Transport to Kanto by Flow around Japan's Central Mountains

Hayasaki

Yamamoto

Higuchi

et al. 2011

SOLA

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During the Typical Asian Dust episode from the end of March−early April 2007 (TAD-2007, the mass concentration of suspended particulate matter (SPM) began to increase rapidly on the morning of 1 April in Hokuriku and Tohoku but remained low in Kanto. Ground-level lidar and rawinsonde sounding in Hokuriku observed a dust layer at ~2 km corresponding to the base of the temperature inversion. In Kanto, which is leeward of Japan's central mountain ranges, SPM increase began from the east coast and then advanced westward after 18 JST with easterly winds. Merged CloudSat and CALIPSO datasets indicated that clouds over mainland Japan and the Sea of Japan were located in the upper-level atmosphere (> 6 km). Continuous meteorological observations showed that cloud condensation and rainfall were not observed over the mountains during the daytime of 1 April. These results suggest that the delay in the SPM increase in Kanto was caused by dust being indirectly transported to that region by flowing around the central mountains. concentrations that affected all of East Asia, and its large-scale three-dimensional structure has been intensively documented in previous studies (e.g., Yumimoto et al. 2008;Park et al. 2010). On a regional scale, however, complex spatial and temporal variations of dust concentrations occurred over Japan. Tsunematsu et al. (2009) examined the regional-scale characteristics of the TAD-2007 using Doppler lidar observations, ground-based meteorological observations, and a regional atmospheric model for the Kanto region on the eastern side of central Japan. They concluded that the surface-based stable layer in Kanto prevented downward transport of elevated dust particles to the ground in the early morning on 1 April. They also noted that the dust layer extended to the ground after breakup of the stable layer. In addition, Takahashi et al. (2010) reported that dust transport from TAD-2007 was delayed over the Kanto plain compared to the highland observatory at Mt. Haruna (1365 m altitude), which is located on the northwestern edge of the plain. In Tsukuba (see Fig. 1b), lidar observations showed that the dust increase started with a southeasterly wind and was restricted to the near surface level (below approximately 1 km) after 16 Japan Standard Time (JST: UTC+9). They noted that the low-level dust layer was advected via a different route to the upper dust layer. Although these studies documented regional-scale features of TAD-2007, there were no sufficient explanations for the delayed dust transport in Kanto on 1 April 2007. From a visible image taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua, dust plumes and clouds widely covered Japan and surrounding area in the daytime of 1 April (Fig. 1a). Wet deposition processes play an important role in dust scavenging in a downstream region (e.g., Han et al. 2004). IntroductionThe main objective of this study was to identify the major cause(s) for the delay in dust transport to Kanto, Japan. To investigate the temporal and ...

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Multi-year trend in fine and coarse particle mass, carbon, and ions in downtown Tokyo, Japan

Cited by 59 publications

References 23 publications

Evaluation of Ensemble Approach for O3 and PM2.5 Simulation

Evaluation of Ensemble Approach for O3 and PM2.5 Simulation

Multi-Model Analyses of Dominant Factors Influencing Elemental Carbon in Tokyo Metropolitan Area of Japan

Asian Dust Transport to Kanto by Flow around Japan's Central Mountains

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