抄録
The observed results of CO and NO2 concentration in and around a tunnel are summarized in Table 1. Dimensions of this tunnel, called Shinobu-yama Tunnel, are about 700 m in length and 56m2 in cross-sectional area. From these data, we find that the concentration of NO2 seems to be related with sunshine as if the photochemical reaction occurs outside of the tunnel but not inside of it, and that the wind direction controls the distribution of pollutants in the tunnel.
The tunnel must be artificially ventilated by fans because of the extremely weak wind and great deal of automobiles, judging from empirical equations (1) or (2) concerning ventilation, where L, C and Q are the length of the tunnel the traffic density and the ventilation volume respectively.
The relationship between the wind in and around the tunnel was clarified using the wind tunnel equipment. Table 2 and Fig. 3 are a part of obtained results. The distribution of pollutants in the tunnel can not be measured but we can estimate it from the air-temperature distribution shown in Fig. 4.
