The atmospheric release rates of I-131 and Cs-137 from the Fukushima Daiichi nuclear power plant in March 2011 were estimated by comparing environmental monitoring data of air concentration and deposition rate on a regional scale with calculated values from an atmospheric dispersion model. Although the release rates were not estimated for all days after 11 March, because of lack of monitoring data, temporal changes in the release rates were reasonably estimated with estimated uncertainties in a factor of 3.3 and 2.9 for I-131 and Cs-137, respectively. A large release was estimated from the night of 14 March to at least the afternoon of 15 March, with maximum values of 7.2 6 10 15 Bq h 71 for I-131 and 1.5 6 10 14 Bq h 71 for Cs-137. The release rates during other periods were estimated at one-to twoorders of magnitude smaller than the largest release rate on 15 March. Uncertainty in the estimated release rate for 15 and 20 March was larger than for other periods. The significant release during 14 and 15 March and the trend of the release rate by the end of March were consistent with previous reports. This agreement, despite using different datasets, shows robustness of the temporal changes estimated in the studies.

Emissions of CO, CH4 and CO2 in East Asia were estimated using the atmospheric concentration of 222Rn measured at Minamitorishima (MNM) and Yonagunijima (YON) with a high-precision 222Rn measuring system. The 222Rn measurements showed a distinct seasonal variation, as well as enhanced 222Rn (ERN) events associated with high-frequency synoptic variations. The enhancements of CO, CH4 and CO2 coincided with the ERN events at MNM and YON. The enhancement ratios ΔCH4/ΔRn, ΔCO2/ΔRn and ΔCO/ΔRn calculated for the ERN events and corrected for the radioactive decay of 222Rn during the transport were used to estimate the emissions of CO, CH4 and CO2 by multiplying a constant 222Rn exhalation rate of 1.0 atom cm−2 s−1 and the associated catchment area estimated by a 3D transport model. By modifying the categorisation of the sources, the 222Rn-derived emissions of CO2 and CH4 were found to be in agreement with the published emission databases. As for the CO emission, results of our study were consistent with the REAS CO emission database but showed that the EDGAR database underestimates the CO emission over East Asia by about 44%. It is demonstrated that the 222Rn tracer method used in this study could provide a useful and independent tool to verify the trace gas emissions in East Asia

A highly sensitive method to analyze the intact lipids in a single zooplankter individual at the level of a few tenths of a microgram was developed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with a direct sampling technique. The sampling procedure involved (1) putting a zooplankter individual sample onto the MALDI sample plate, (2) cutting the sample into a few pieces by means of tweezers, (3) depositing aliquots of matrix and cationization reagent solutions on the zooplankter sample, and (4) irradiating with a N2 laser to cause MALDI. By using this technique, the mass spectra of the single zooplankter samples showed a series of ions generated from phospholipids with 34 or 36 carbons in the acyl groups and neutral lipids such as triglycerides and diacylglyceryl ethers with 50-54 carbons in their acyl and alkenyl groups. Accordingly, this method enabled us to estimate the relative quantity between "structured lipids" (phospholipids) and "storage lipids" (neutral lipids) in an individual zooplankter, which should give us a good clue to elucidate the roles of each class of lipids in its growth.