Models for the diffusion process of particle were proposed.
The study contains two main parts as follows. The one is an analysis of an equation of motion of a particle and the other is the concentration of the models of atmospheric turbulence to estimate velocity which are substituted into velocity terms of the equation of motion of a particle. A movement of particle is governed by forces of gravity, viscosity of air, pressure, accerelation and Basset. The effect of each force was evaluated. The following results were recognized.(1) Forces of gravity and viscosity are important, if the particle is small.(2) The movement of particle is almost similar to that of air when the diameter of particle is smaller than several microns, in the conditions that the density is 3.0 g/cm³ and the integral time scale of turbulent eddy is 9.0 sec.
Three models to simulate atmospheric turbulence were evaluated.
These are a simple Monte Carlo method (Model I), a first order Markov process model taken into account past wind speed (Model II) and a stochastic differential equation taken into account past noise for wind speed (Model III). As a result, it was recognized that Model III is best to express turbulence characteristics as variance, integral time scale and energy spectrum of wind velocity, and atmospheric stability by combining with a higher order self-regression model to self-correlation function of wind velocity.

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In recent years assessment methods for environmental impacts of air contaminants released and dispersed in a region of complex terrain have been focused on. The purpose of this paper is to present a patctical model to predict pollutant dispersion in complex terrain. The study included experiments conducted in such region.
At first the field of wind flow in an area concerned is determined by the modified potential flow model. Second we present the calculation procedure of ground level concentration using the modified plume model. Characteristics of the model are as follows:
1) It is easier to estimate air pollutant concentration by means of a modified Gaussian plume model.
2) By applying the wind profile model which is able to express a trajectory of wind along complex terrain, its plume axis is in accord with the streamine which runs through emission source.
3) The precision of model prediction is improved in comparison with the other model which does not take the effect of complex terrain into consideration.
As a result of agreement between predicted and actual concentration, the proposed model is found to be applicable to the real problem.

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A new type of collector-injector using Tenax GC adsorbent was developed for collection and analysis of tracelevel volatile organic compounds in air. The collector is simple shape made of 6mm o.d.× 16cm glass tube, and desorption is carried out in an airtight desorption chamber directly connected with a gas chromatograph. Performance of the collector was tested under conditions relevant to field sampling, compared with a needle type collector which is commercially available as a styrene collector.
Background of desorption chromatogram of usual collectors is influenced by contamination during storage period before and after sampling in field survey, but the influence of contamination on desorption chromatogram by this method was negligible in case of measuring ppb-level organic pollutants during 4 days storage period, while the needle type collectors gave maximum 6 ppb error in measuring 1 liter air sample. Peaks of desorption chromatogram by this method were not so broadened, gas chromatographic separation is maintained. Separabilities of p-and m-xylene (concentration ratio 1: 1) were 1.17, 1.02, and 0.84 in direct injection by a syringe, this method, and the needle collector, respectively.

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Vehicle exhaust odor from 6 cars (gasoline: 2, diesel: 4) was analyzed. Odor concentration was measured by triangle odor bag method at car speed condition of every 20 km/h. And odor intensity and THC etc. were measured. The following results were obtained.
1) Odor concentration of exhaust from diesel engine was higher than gasoline-powered engine and increased with increasing in displacement of engine.
2) Odor concentration of large diesels were about 10, 000-30, 000 (odor index: 40-45), and O.E.R. were about 10⁵.
3) Relationship between dilution ratio (x) and odor intensity (y) in diesel engine was y=7.1-1.7×log (x)

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In order to evaluate the state of the environmental pollution in Chiba City, the distribution patterns of trace metal concentrations in the soil and in the air pollutants have been investigated. The elements of Zn, Pb, and Cd as a pollutant indicator were extracted from soil by conventional method and their concentrations were determined. On the other hand, the dust in the atmosphere was collected by the high volume air sampler and the concentrations of the above-mentioned metal components of the dust were determined with an atomic absorption spectrophotometer.
The following results were obtained:
1) Metal concentrations in the soil were widely changed at each sampling station and the average concentration of Zn, Pb, and Cd were 137 μg/dry-g, 59 μg/dry-g, and 0.26 μg/dry-g respectively.
2) Metal concentrations were high on the surface zero to 15 cm in depth and low at 60 cm in depth.
3) The concentrations of Zn and Pb in the soil were correlated with those of Zn and Pb in the air pollutants, while little correlation was found in the case of Cd. The coefficient of correlation between Zn in the soil and that in the air pollutant was 0.87, and that of Pb was 0.70.
4) These concentrations of metallic pollutants were compared with those of the typical gaseous pollutants such as NO_x and SO₂. Some metals were correlated with the above gaseous pollutants. The highest coeffi cient of correlation, 0.89 was obtained between Pb and NO_x.

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The regional differences and changes with year in total air pollution levels in the main industrial zones of Fukuoka Prefecture, the Omuta and Kitakyushu areas, were evaluated on the basis of the epiphytic lichen and bryophyte vegetation on the tree trunks of shrine woods. The 1st investigation was made in the preiod from 1978 to 1979 to learn the regional differences and the 2nd investigation in 1982 to manifest the chronic changes.
In order more reasonably to determine air pollution levels, a new index “IAP” is devised instead of the “IAP” of LeBlanc & De Sloover (1970) in the present study: preparatorily, the IAP index was given at each spot (50×200 cm2 quadrat), and then the new index IAP at a given quadrat is expressed as the arithmetic mean of the four IAP values including those at the relevant quadrat and its adjacent four quadrats, but excluding the lowest value among them.
In both investigations, a considerable correspondence was recognized between the regional differences in the IAP value and those in the air pollution level which was indicated by the sulfur oxides concentration measured by the lead dioxide method.
The IAP levels determined in the 2nd investigation were, in general, higher than those of the 1st one in the two areas. This fact may suggest that the chronic total air pollution level is changing for the better condition in both areas. The increasing tendency of the IAP values was more obvious in the Kitakyushu area than in the Omuta area.
As a result of the analysis of the species composition and its chronic change in the zones classified by the IAP values, a general reciprocal relationship was found between the specific sensitivity of epiphytes as represented by the number of companion species per quadrat and the air pollution levels.

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This is a translated article from “A Review on the Control of Atmospheric Particulate Pollutants in Taiwan, by C.-Y. Chuang (1984).” The air pollution surveillance network in Taiwan covers Dustfall, Total suspended particulates, Sulfur dioxide, Nitrogen dioxide, Carbon monooxide, etc. Trends and status especially of particulate air pollutants are reviewed and discussed in this article.

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