Introduction of our laboratory
The surface atmosphere (troposphere) where we live has several problems, for example:
1. Increase of oxidants (e.g. ozone).
2. Acidification of environment (ex. acid rain).
3. Accumulation of greenhouse gases.
The ultimate goals of our research are that these phenomena are revealed and that the detailed future prospects are supplied. For example, although ozone concentrations in the stratosphere are decreasing, those in the troposphere are increasing. Ozone is toxic and damages human bodies and vegetation. Ozone itself is also a greenhouse gas. Ozone increase in the troposphere is caused by rises of nitrogen oxides (NOx), carbon monoxide and hydrocarbons, which are released anthoropogenically into the atmosphere. Photochemical reactions in the troposphere by sunlight proceed and then tropospheric ozone is produced. In order to investigate these detailed mechanisms, it is necessary to measure concentrations of radicals, which are key species for the photochemical processes, in the troposphere.
In our laboratory, new measurement systems of the radicals and trace species in the troposphere are developed by use of laser spectrometry and mass spectroscopy. It was difficult to measure such species accurately so far because of their very-low concentrations and high reactivities. Also, long-term observations of ozone, carbon monoxide and volatile organic compounds are performed in various areas in East Asia.
1. Observations of ozone, carbon monoxide, hydrocarbons in the atmosphere
We are performing observations of ozone, carbon monoxide and hydrocarbons in the clean atmosphere where influence of human activity is sufficiently low. We are also investigating the atmospheric change in East Asia. So far, we have been performing the surface observations in Moshiri (Hokkaido), Happo (Nagano), Oki (Shimane) and Cape Hedo (Okinawa). We have also conducted the observations in the sea off Japan by the oceanographic research vessel "MIRAI".
2. Investigation of atmospheric photochemical reactions in the urban area
The urban atmosphere has high concentrations of pollutants (NOx, SO2, volatile organic compounds and so on) emitted from automobiles, plants and so on. In addition, the secondary pollutants (ozone, aerosol and so on) exist in the urban atmosphere. They are produced via the photochemical reactions from NOx, SO2, volatile organic compounds and so on. In order to get information about reduction strategy for such oxidants, we are investigating fundamental data of such pollutant concentrations via the comprehensive observations.
3. Development of highly sensitive systems for measuring reactive trace species in the atmosphere by laser-induced fluorescence technique
We have been developing highly sensitive measurement systems of trace species in the atmosphere by use of laser-induced fluorescence technique.
1. HOx radicals (OH, HO2) are reactive and unstable and therefore these concentrations are extremely low. However, they play central roles in the photochemical reactions in the atmosphere. Therefore, the accurate measurements are important.
2. Nitrogen oxides (NO, NO2, NO3) are precursors of photochemical ozone production. They also play a central role for nitrogen cycles in the atmosphere.
Apr 2014 Welcome Party
Tokyo Metroporitan University
Oct 2010 Masao Horiba Awards