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KUWATA, Mikinori
KUWATAMikinori

Nanyang Assistant Professor
National Research Foundation (NRF) Fellow

Education:B.Sc., University of Tokyo,
PhD, University of Tokyo,
Post-doc, Harvard University

Research Area: Atmospheric Chemistry;Aerosol Science

Phone: (+65) 6592 3606

E-mail: Kuwata@ntu.edu.sg

Webpage: Under Construction



Research Interest

Our mission is to provide theories and methods to describe chemistry in the atmosphere based on laboratory and atmospheric observation data. Especially, we are interested in haze in Southeast Asia as well as in chemistry of biogenic species from tropical rainforests. Specific research projects are described below.

Thermodynamics of atmospheric aerosol particles

Chemical thermodynamics governs behaviors of aerosol particles in the following aspects: (1) interaction with gas species, and (2) phase transition such as formation of cloud from water vapor. Although basic principles of those phenomena are known for pure compounds, both gas and particle compositions are complex in the real atmosphere, making direct applications of those theories difficult. We will investigate this question by developing our own aerosol instruments, which can quantify both water uptake and phase transition of aerosol particles. Experiments will be conducted for both pure compounds and haze particles in Southeast Asia. The experimental results will be compared with aerosol chemical composition, which will be measured by a mass spectrometer.

graph1

Fig. Activation mechanism of aerosol particles as cloud droplets (Kuwata et al., 2013)

Chemical reactions of atmospheric aerosol particles

Chemical reactions in the atmosphere changes climatic and environmental impacts of aerosol particles. For instance, toxicity of polycyclic aromatic hydrocarbons increases following oxidation and nitration. Those compounds are included in a matrix of other atmospheric species, meaning that influence of that matrix on mass transfer and reaction mechanisms need to be considered. In addition, thermodynamics and chemical reactions of atmospheric particles are tightly linked, since phase of particles is important for mass transfer. We are currently designing an environmental chamber to investigate this problem using a large scale chemical reactor. Experimental results will be quantitatively analyzed numerically.

Field observation

NTU campus is uniquely located at the west coast of Singapore, which is very close to the source region of haze particles from Indonesia. Those haze events have significant impacts on regional air quality as well as on global climate. We will measure chemical composition and properties of those particles to investigate chemistry of ambient particles. In addition, field observations at other Southeast Asian countries such as Indonesia and Malaysia are also planned.


Selected Publications

  1. Kuwata, M., Y. Kondo, Y. Miyazaki, Y. Komazaki, J. H. Kim, S. S. Yum, H. Tanimoto, and H. Matsueda (2008), Cloud condensation nuclei activity at Jeju Island, Korea in spring 2005, Atmospheric Chemistry and Physics, 8(11), 2933-2948.

  2. Kuwata, M., and S. T. Martin (2012), Particle Size Distributions following Condensational Growth in Continuous Flow Aerosol Reactors as Derived from Residence Time Distributions: Theoretical Development and Application to Secondary Organic Aerosol, Aerosol Science and Technology, 46(8), 937-949.

  3. Kuwata, M., and S. T. Martin (2012), Phase of atmospheric secondary organic material affects its reactivity, Proceedings of the National Academy of Sciences of the United States of America, 109(43), 17354-17359.

  4. Kuwata, M., S. R. Zorn, and S. T. Martin (2012), Using Elemental Ratios to Predict the Density of Organic Material Composed of Carbon, Hydrogen, and Oxygen, Environmental Science & Technology, 46(2), 787-794.

  5. Kuwata, M., W. Shao, R. Lebouteiller, and S. T. Martin (2013), Classifying organic materials by oxygen-to-carbon elemental ratio to predict the activation regime of Cloud Condensation Nuclei (CCN), Atmospheric Chemistry and Physics, 13(10), 5309-5324.