This article is a review on the recent development in the chemical analysis and the characterization of particulate matter in the atmosphere.
In Chapter 1 (by A. Mizohata and Y. Matsuda), the non-destructive methods applied to the chemical element analysis are reviewed. Chapter 2 (by K. Sakamoto) deals with the analysis and the characterization of carbonaceous compounds. Inorganic water-soluble compounds in particulate matter are treated in Chapter 3 (by S. Kadowaki).

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A Gaussian trajectory model was developed to predict atmospheric diffusion phenomena in complex terrain. The Gaussian trajectory model has the following features.
(1) The evaluation of plume trajectory is to be made either using the potential flow model or the quasi-potential flow model, both of which were developed by authors to find the wind field over complex terrain. The use of these models allowed to find the wind components at any given points, thus facilitating the trajectory evaluation.
(2) As for the standard deviation of plume width, the parameters including terrain effects, which have been estimated on the basis of the results of wind tunnel experiments, are used.
Outdoor model experiments were conducted to examine the validity of the developed calculation model. The results obtained by the Gaussian trajectory model are in good agreement with the diffusion characteristics estimated from the outdoor experiment. A comparative study of the Gaussian trajectory model and a finite difference method model was also made. The calculation results by the two models can be said to closely agree with each other. The Gaussian trajectory model proposed in this report is almost free from computer restrictions and requires only a few of meteorological data. This model is therefore applicable to the atmospheric environment assessment system.

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A histopathological study was performed on Wistar male rats exposed to 10 ppm nitrogen dioxide for two weeks in order to observe the effects of nitrogen dioxide upon pulmonary alveoli.
Histological changes of the lungs were clearly observed in a short period of time after the exposure to nitrogen dioxide: On the 3rd day, irregular blebing of the cytoplasm and small vacuoles in the cytoplasm of the Type I alveolar cells were observed: On teh 7th day, the blebing enlarged to become cyst-like structures, and Type I alveolar cells desquamated from the basement lamina: The Type II alveolar cells increased in numbers with prominent vacuolar degeneration, disappearance of cell organelles and concentration of the nuclei. Transformation of Type II to Type I alveolar cells can not be observed even on the 14th day.
The changes in the capillary endothelial cells of the alveolar walls were as follows: On the 3rd day, the distinguished increase of the pinocytotic vesicles was observed: On the 7th day, vacuolar degeneration appeared in some parts: On the 14th day, the separation of cells from the basement lamina and the detachment of the junction of endothelial cells with the leakage of erythrocytes through the intercellular spaces were observed. The edema in the pulmonary interstitial tissue appeared 3 days after the exposure, which was clearly observed on the 14th day.
In tracheal and bronchial walls, goblet cells marked increased in numbers and its mucus content increased 3 days after the exposure. Seven days after the exposure, proliferation of non-ciliated epithelial cells in terminal bronchioles was observed. There was a mild degree of inflammatory cell infiltration in some parts of the tracheal and bronchial walls, and 14 days after the exposure, the increase of reticular fibers in submucosa was seen.

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The photochemical reactivities of non-methane hydrocarbons (NMHC) in emission sources and environments were studied by ultraviolet irradiation test of NMHC complexes, which had approximately source and environment compositions. Each complexes were composed of 18 kinds of NMHC, which were chosen from the results of environment analysis. As the emission sources, gasoline vapor, oil refinery, petrochemical facility, solvent and automobile were chosen.
For irradiation test, the bellows type smog chambei. of 6.64m³ was used under ultraviolet intensity 7mw/cm² (k₁=0.41 min^-1), temperature 30°C, relative humidity 50%, initial concentration HC 10 ppm, NO 1 ppm, irradiation time 5 h. The results were as follows:
The photochemical reactivities of source NMHC showed the highest in petrochemical facility containing a lot of ethylene and the lowest in gasoline vapor being mainly composed by paraffins. The reactivities of source NMHC mixture, which were made in consideration of hydrocarbon emission amounts for each sources, were considerably similar to that of environment NMHC complexes. The reactivities of NMHC in sources and environments tended to increase with the increase of olefin and aromatic contents in relation to O₃ dosage, consequently it was considered that olefin and aromatic contents were useful for evaluation of photochemical reactivities of source and environment NMHC.

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By using seventeen rainwater samplers of ten different designs, the effects of these designs such as the aerodynamic design, the collection surface diameter, and the height from the set up ground on the collection efficiency were investigated to find a suitable sampling method.
The efficiencies were almost same due to the changes of the diameter from 17.0cm to 35.7cm and the changes of the height from 25cm to 125cm. However, the efficiencies of the sophisticated samplers equipped with the special function such as the filtration for particulate matters and the automatic lid opening during rain periods were slightly decreased.
Almost all the collection efficiencies of the samplers having a enough collection surface diameter and located with a enough height from the ground were not deviated for short period sampling (e.g. event basis).

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In order to predict air pollution concentration from a road more precisely, it is important to clarify how atmospheric diffusion is influenced by the direction of wind to the road. In the present paper we mathematically derive a formula applicable for predicting air pollution concentration from infinite line source when the wind blows in oblique. It is assumed that the line source consists of numerous point sources. The air pollution concentration is obtained as sum of the concentrations from these numerous point sources, and therefore thes um is first expressed as integral form.
Gaussian plume formula is used in the calculation of the concentration from the point source. The dispersion parameters, σ_Y, σ_z, are assumed as σ_Y=αX^α, σ_z=bX^β, respectively, where a, b, α and β are constants. We find that mathematically exact solutions can be obtained in the cases where α, β and the direction of wind, θ, are specific values. For example, when α=1, β=1, the concentration can be expressed in relatively simple form. Especially, when the observation point is on the ground, the concentration, C, is given as follows:
_??_
and D is the perpendicular distance from the observation point to the road, U is the wind velocity, q is the strength of emission per unit length, and H_e is the effective height of emission source. Explanations of the effects of H_e and θ on the concentration are given.

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The air pollution level by suspended particulate matter (SPM) has been lowered in the last few years and the achievement ratio of Environmental Quality Standard for SPM increased rapidly. The achievement ratio means here the number percentage of monitoring stations where the Environmental Quality Standard is achieved. The achievement ratio is still unsatisfactory level than those of other gaseous pollutants.
In this note, the data of SPM measured at the monitoring station in Japan between 1974 and 1983 (Showa 49 and 58) are analysed from several view points and discussed comparing with the Environmental Quality Standard for SPM.

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Parmelia tinctorum, epiphytic lichen sensitive to air pollutants, were collected around a steelworks in Eastern Harima area and ten components including mercury in the thallus were analyzed.
Mercury concentration of P.tinctorum decreased with the distance from the steelworks.
As a result of regression analysis between the mercury uptake into the thallus and the atmospheric mercury concentration, a significant correlation between the both elements was found.
These results suggested that P.tinctorum was useful as an indicator of atmospheric mercury contamination.

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Suspended particulate matter (SPM) in the atmosphere was collected by Andersen impactors for the past four years (April 1977-March 1981) in Kitakyushu and the amounts of heavy metals (Mn, Fe, Cu, Zn) contained in SPM were determined to investigate the atmospheric concentration of the heavy metals and its relationship with the size distribution of SPM.
The results showed little difference among seven sampling sites in mass-size distribution of SPM, where particles below 0.43μm in diameter accounted for a very large proportion of SPM mass. The mass-size distribution of SPM was also proved to be bimodal in terms of probability density function. From mass-size relationship between the heavy metals and SPM, it was found that Mn and Fe abounded in particles above 2.1 am in diameter, while Cu and Zn in particles below 2.1μm.
Sampling sites near the industrial areas were shown to have higher concentration of the heavy metals and SPM than the control site, regardless of particle size. Therefore, it is evident that places adjacent to the industrial areas are substantially subjected to particles of various sizes, which contain these metals.
SPM was classified into fine particles below 1.1μm in diameter and coarse ones above 1.1μm and the amounts of the heavy metals in the fine particles were estimated on the grounds that particles below 1.1μm in diameter are said to be small enough to be inhaled even into the lungs. The results revealed that the atmospheric concentration of the heavy metals was higher at the sites near the industrial areas than at the control site in the fine particles and the coarse ones, and that Cu and Zn were more concentrated than Mn and Fe in the fine particles. In addition, it was found that both the fine particles and the coarse ones in Kitakyushu were different from soil particles in composition.

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During the period from Nov.1 to 30, 1984, pH, E.C. and concentrations of dissolved ions in rain waters at Mt. Ohdaigahara, a mountainous area, were measured.
The pH and E.C. of rain waters were in the range of 4.32 to 5.15 (mean value 4.67) and of 6.45 to 55.52 (mean value 14.79)μS/cm, respectively. The concentration of SO₄^2-, NO₃^-, NH₄⁺ and Ca²⁺ that were main ionic components in rain waters were 1.45, 0.53, 0.05 and 0.21 μg/ml, respectively.
The ionic components in the rain water at Mt. Ohdaigahara were nearly similar to that of the average succeeding rain water (6 mm-rainfall amount) in Nara city.
At Mt. Ohdaigahara, Cl^-/Na⁺ (ratio of equivalent composition) in the rain water was closely resemble to that of sea water and the NH₄⁺ concentration in the rain water was far low value compared to that in the urban areas.
The amount of deposits of NH₄⁺, Ca²⁺ and NO₃^- components of dustfall were remarkably revealed in locational difference and those were considered to apply the index of mountainous areas.

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