Acid rain is one of he major environmental problems throughout the world, as well as one of those in China. The brief history of acid rain survey in China was summarized and the acid rain survey carried out from 1985 to 1987 was described, including the selection of background sites, the establishment of acid rain monitoring network, the precipitation sampling method, the parameters measured, and the examination methods, as well as present the status, the features, and the problems to be solved in terms of the acid rain in China.

View full abstract

Since the 1970s, many experiments have been conducted on automobile emissions and many dispersion models have been proposed. Although the series of experiments being conducted by GM are the most comprehensive in this field, the experiments being performed in Japan may surpass those in the U.S. both in terms of number and scale. In this review paper, we discuss the recent progress made in the development of automobile emission dispersion models, examine their effectiveness, and look at the more important studies that have been conducted.
The following were examined:
1. Studies on automobile emission dispersion based on data obtained through experiments, and which include the following categories: concentration distribution of pollutants in the vertical direction; vertical spread of automobile emissions σ_z; initial vertical spread of automobile emissions σ_z0; roadside wind conditions; dispersion of pollutar ts in the street canyon; dispersion of pollutants from the entrance/exit of tunnels; effects of road configuration on the dispersion of pollutants.
2. Discussion regarding hitherto proposed dispersion models for predicting pollutant concentration. Evaluation of above models.

View full abstract

High concentration phenomena of SO₂ in Nagasaki prefecture were analyzed using the surface air monitoring data and mountain top measurement at Unzen Nodake (1142m). Results showed good relationship between the high SO₂ concentration at Unzen Nodake and E-SW wind direction of 850 mb level at Kagoshima Meteorological observatory due to the long range transportation of volcanic plume from Mt. Sakurajima. On the other hand, the surface SO₂ concentration in Nagasaki prefecture did not necessarily agree with the high SO₂ concentration at Unzen Nodake. This analysis showed that the surface SO₂ episode were usually observed when Nagasaki prefecture was located just after the passage of moving high atmospheric pressure system. During these period, stable layer is formed aloft and decending wind is observed. Under these meteorological condition, the volcanic plume from Mt. Sakurajima is transported to the surface area.

View full abstract

We measured forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and maximal expiratory flow rates at 50% and 25% FVC (V_max50, V_max25) of school children three times at intervals of two years to estimate between-and within-subject variability of those measurements in the follow-up period. The initial sample was composed of 217 boys and 224 girls. One hundred and seventy three boys and 171 girls performed acceptable measurements at all of three surveys.
Two simple models for repeated measurements explained the distribution of pulmonary function data quite well. Coefficients of determination of the models were more than 0.95 for FVC and FEV1, and were more than 0.85 for V_max50 and V_max25. Estimated between-subject variability of pulmonary function was two to four times greater than within-subject variability both in boys and girls. Summation of longitudinally estimated between-and within-subject variability was comparable with cross-sectionally estimated error variance for all of the pulmonary function indices.
From these results, we concluded that longitudinal analysis of a series of observations must be superior to crosssectioral analysis of a single examination when we study normal growth patterns of children or possible risk factors which might give a change to the course of development of pulmonary function in childhood.

View full abstract

Enoshima area, Kanagawa Pref. is located in the southern part of densely populated areas such as Yokohama and Tokyo, and the land-sea breeze is often observed especially in summer. Air pollutants emitted in inland area are transported by the land breeze toward the sea in the early morning, and then after the wind direction changes to the sea breeze, they are brought back to the land area. In order to investigate the chemical behaviors of organic vapor pollutants while staying in the atmosphere, measurement of organic vapor pollutants was carried out from 7: 00 to 13: 00 at the coast of Enoshima on September 11, 1990. The land-sea breeze was observed on the day, and organic vapor pollutants emitted in inland area were observed at the coast early in the morning, and chemically changed organic compounds were observed later in the morning.
Paraffins and aromatic hydrocarbons contained in exhaust gas of gasoline fuelled vehicles showed a similar trend, and ethyl acetate, which is not contained in exhaust gas of gasoline fuelled vehicles was also similar tothem. Chlorinated hydrocarbons such as 1, 1, 1-trichloroethane, trichloroethylene, tetrachloroethylene and carbon tetrachloride were contained more in the sea breeze than other organic pollutants. The concentrationsof ethylbenzene and xylenes were decreased in accordance with the respective reaction rates with OH radical, but chemical behaviors of benzene and toluene were seemed not to agree with the reactivities with OH radical. Several unidentified peaks were also observed in the chromatogram of the air sampled after the wind direction turned to the sea breeze.

View full abstract

For the ptirpose of evaluating effects of residential location on human lung pollution, elemental constitution of intrapulmonary particulate pollutants (IPP) in autopsy lungs or surgically resected lungs of residents of Tokyo and Saitama area was analysed using X-ray fluorescence analyzer. The levels of Cr, Ni (male nly) and Ca (female only) in non-carbonaceous fraction of IPP were higher in residents of Tokyo area than those of Saitama area, and Si, Al (both sexes), Cu and Mn (female only) were higher in residents of Saitama area than residents of Tokyo. These results indicate that elemental constitution of IPP may reflects features of air pollution in both areas, while personal factors such as occupational histories may also have effects on it.

View full abstract

In order to estimate the effect of road dust on photosynthesis by shading, dust load accumulated on leaf surface of satsuma mandarin trees were investigated. Dust load on leaf surface was indicated by the shading ratio, which was the fraction of light intercepted by the dust on the leaf.
Dust load on lower surface of leaves were much less than that on upper surface. With the increase of distance from the road, the shading ratio decreased. The maximum value of the shading ratio was 30% at 1 m from the road. The shading ratio on leaves of roadside trees changed remarkably with the changes of traffic and precipitation. On inside leaves of the roadside trees' crown, the change of dust load was less than that on outside leaves.
The effect of shading by road dust on the photosynthesis of satsuma mandarin trees was estimated every month from July to October in 1989 by using the shading ratio, solar radiation and a light curve of net photosyntheticrate of satsuma mandarin leaf. As a result, when the shading ratio was 10, 20 and 30%, it was estimated that the net photosynthesis of satsuma mandarin was decreased by 5, 9-12 and 16-19%, respectively.

View full abstract