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7. Long-term trends of ozone precursors and ozone sensitivity in Jakarta Metropolitan Area: A view from space

Author

Kusumaningtyas Sheila Dewi Ayu, Tonokura Kenichi, Gunawan Dodo, and Iriana Windy

Subjects
Environmental sciences, GE1-350
Abstract

Jakarta Metropolitan Area (JMA) is an urban agglomeration in Indonesia where the air quality has dramatically changed from relatively clean to polluted. Economic growth, increased population, and village-to-city expansion marked the development of Jakarta and the satellite cities surrounding it, such as Bogor, Depok, Tangerang, and Bekasi. In line with human activities, large amounts of air pollutants are emitted and affect human health and vegetation. Ozone (O3) is a secondary air pollutant formed from volatile organic compounds (VOCs) and nitrogen oxides (NOx). This study aims to investigate the long-term trend of ozone precursors and ozone sensitivity in JMA from space. Trends analysis is studied using quantile regression. We used NO2 and formaldehyde (HCHO) column density from the Ozone Monitoring Instrument (OMI) aboard Aura Satellite from 2011 to 2022. Ozone sensitivity is derived from the ratio of HCHO and NO2 (FNR). The results show an upward trend in HCHO and a slight NO2 downward over JMA. In general, FNR changed from a predominantly VOC-limited regime in urban JMA to a transitional regime suggesting control of VOC and NOx is needed to reduce ozone concentration. Meanwhile, FNR in suburban and rural areas such as Bogor is toward a more NOx-limited regime.

Published
2024
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32. Urban-scale analysis of the seasonal trend of stabilized-Criegee intermediates and their effect on sulphate formation in the Greater Tokyo AreaElectronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3ea00105a

Author

Nakamura, Yuya, Hata, Hiroo, and Tonokura, Kenichi

Abstract

We conducted an urban-scale analysis of the contribution of gas phase stabilized-Criegee intermediates (sCIs) to atmospheric sulphate aerosol (SO42−) formation across four seasons in the Greater Tokyo Area (GTA) using the regional chemical transport model, the community multiscale air quality modelling (CMAQ) system. We analysed the seasonal and temporal trend of sCI formation in three areas: Tokyo Bay (urban), suburban, and mountainous areas. In all three areas, the sCI concentrations were high in the morning (7 a.m.) and early evening (6 p.m.) owing to the high frequency of vigorous traffic activities causing intense alkene emissions. The results suggest that more than 90% of the sCIs generated in the target areas are consumed by the unimolecular decomposition of sCIs themselves or by reactions with water, which are consistent with estimates from previous kinetic analysis studies targeting other regions. The contribution of sCIs to SO42−formation estimated in this study was a maximum of 0.25% in the rural area, which is approximately 10-fold lower than that of previous studies. The results of the sCI loss pathway analysis suggested that the unimolecular decomposition of sCIs and the reaction between sCIs and water contribute comparably to the loss of sCIs, which caused less of an effect of sCIs on SO42−formation compared with that in previous studies.

Published
2023
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33. Spatial correlativity of atmospheric particulate components simultaneously collected in Japan

Author

Funasaka, Kunihiro, Asakawa, Daichi, Oku, Yuichiro, Kishikawa, Naoya, Deguchi, Yuya, Sera, Nobuyuki, Seiyama, Tetsurou, Horasaki, Kazunori, Arashidani, Keiichi, Toriba, Akira, Hayakawa, Kazuichi, Watanabe, Masanari, Kataoka, Hiroyuki, Yamaguchi, Takako, Ikemori, Fumikazu, Inaba, Yohei, Tonokura, Kenichi, Akiyama, Masayuki, Kokunai, Osamu, Coulibaly, Souleymane, Hasei, Tomohiro, and Watanabe, Tetsushi

Published
2016
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38. Kinetics and rate constants of the reaction C[H.sub.2]OH+[O.sub.2]->C[H.sub.2]O+H[O.sub.2] in the temperature range of 236-600 K

Author

Schocker, Alexander, Uetake, Masanori, Kanno, Nozumu, Koshi, Mitsuo, and Tonokura, Kenichi

Subjects
Formaldehyde -- Chemical properties, Formaldehyde -- Thermal properties, Infrared spectroscopy -- Usage, Hydroxides -- Chemical properties, Hydroxides -- Thermal properties, Chemicals, plastics and rubber industries
Abstract

The kinetics and absolute rate constants of the gas-phase reaction of the hydroxymethyl radical (C[H.sub.2]OH) with molecular oxygen were studied using laser photolysis/near-IR absorption spectroscopy. The results showed slight negative temperature dependence in the measured temperature region.

Published
2007

40. Thermal decomposition mechanism of disilane

Author

Yoshida, Kazumasa, Matsumoto, Keiji, Oguchi, Tatsuo, Tonokura, Kenichi, and Koshi, Mitsuo

Subjects
Photons -- Research, Chemical reaction, Rate of -- Research, Mass spectrometry -- Research, Chemicals, plastics and rubber industries
Abstract

Thermal decomposition of disilane was investigated using time-of-flight(TOF) mass spectrometry coupled with vacuum ultraviolet single-photon ionization (VUV-SPI) at a temperature range of 675-740 K and total pressure of 20-40 Torr. Comparison between the experimental results and the kinetic simulation results suggested that about 70% of consumed disilane was converted to trisilane, which was observed as one of the main reaction products under the present experimental conditions.

Published
2006

41. Observation of adducts in the reaction of C1 atoms with XCH(sub 2)I (X=H, CH(sub 3), C1, Br, I) using cavity ring-down spectroscopy

Author

Enami, Shinichi, Hashimoto, Satoshi, Kawasaki, Masahiro, Nakano, Yukio, Ishiwata, Takashi, Tonokura, Kenichi, and Wallington, Timothy J.

Subjects
Nuclear spectroscopy -- Observations, Absorption spectra -- Observations, Carbon compounds -- Atomic properties, Chemicals, plastics and rubber industries
Abstract

The reactions of C1 atoms with XCH(sub 2)I (X=H, CH(sub 3), C1, Br, I) were studied using cavity ring-down spectroscopy in 25-125 Torr total pressure of N(sub 2) diluent at 250K. Absorption attributable to the formation of the XCH(sub 2)I-C1 adduct following the reaction of C1 atoms with XCH(sub 2)I (X=H, CH(sub 3), C1, Br, I) was measured as a function of temperature over the range 250-320 K.

Published
2005

44. Cavity Ring-down spectroscoy of the benzyl radical

Author

Tonokura, Kenichi and Koshi, Mitsuo

Subjects
Benzene -- Research, Absorption spectra -- Usage, Toluene -- Research, Chemicals, plastics and rubber industries
Abstract

The absolute absorption spectrum of the benzyl radical in the visible region measured by ring-down spectroscopy in the visible region measured by cavity ring-down spectroscopy is presented. The absorption cross sections reported would facilitate the quantification of the benzyl radical in future kinetic studies.

Published
2003

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