A study of the atmospheric boundary layer using radon and air pollutants as tracers

Concentrations of radon Rn-222 and air pollutants, meteorological parameter s near the surface and vertical profiles of meteorological elements were me asured at Uchio (Okayama City, Okayama Prefecture, Japan) 12 km north from the coast of the Inland Sea of Japan. In the nighttime, the Rn-222 concentr ation increased in the case of weak winds, but did not increase as much in the case of moderate or strong winds, as had been expected. In the daytime, the (2)22Rn concentration held at a slightly higher than average level for the period from sunrise to about 1100 JST. It is considered that this phen omenon is due to a period of morning calm, that is, a transition period fro m land breeze to sea breeze. NO, which is sensitive to traffic volume, brou ght information concerning advection. Oxidant concentrations, which reflect the availability of sunlight, acted in the reverse manner to Rn-222 concen trations. Thus, a set of Rn-222 and air pollutants could provide useful inf ormation regarding the local conditions of the atmospheric boundary layer.