4. Instrument development and laboratory studies
We are specialized in optics and atmospheric radical chemistry. We have developed a laser-induced fluorescence (LIF) instrument to measure ultra-low concentrations of atmospheric OH radicals, controlling the atmospheric oxidative capacity, and have conducted numbers of field observations. Recently, a hypothesis that its reservoir species, HO2 radicals, have missing sink on aerosol surfaces has been tested in the laboratory using an aerosol flow tube combined with the OH instrument. Our technology is applied to detection of autofluorescence from single aerosol particles, aiming at bioaerosol studies. Besides our past studies at ground sites, ship-borne observations are planned to test a hypothesis that marine-originating bacteria, blown off to the atmosphere are important ice nuclei, controlling climate system. To ensure that bioaerosols are measured, off-line, stained fluorescence of collected aerosol samples is also measured for comparisons. Electron microscopes are used for the observation of morphology of sampled particles. Also, BC amount in the precipitation, accumulated snow/sea ice will be analyzed in the laboratory (with IACE).
- Taketani, F. et al., 2012: Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China), Atmos. Chem. Phys., 12, 11907-11916, doi:10.5194/acp-12-11907-2012.
- Taketani, F. et al., 2008: Kinetics of heterogeneous reaction of HO2 radical at ambient concentration levels with (NH4)2SO4 and NaCl aerosol particles, J. Phys. Chem. A, 112 (11), 2370 -2377, doi:10.1021/jp0769936.
- Taketani, F. et al. (2015): Analysis of the mixing State of airborne particles using a tandem combination of laser-induced fluorescence and incandescence techniques, J. Aerosol. Sci. 87,102-110.
- Miyakawa, T. et al. (2015): Ground-based measurement of fluorescent aerosol particles in Tokyo in the spring of 2013: Potential Impacts of non-biological materials on autofluorescence measurements of airborne particles, J. Geophys. Res. Atmos.,, 120, 1171–1185, doi:10.1002/2014JD022189
- Kanaya, Y. et al. (2007): Urban photochemistry in central Tokyo: 1. Observed and modeled OH and HO2 radical concentrations during the winter and summer of 2004, J. Geophys. Res., 112, D21312, doi:10.1029/2007JD008670.