In this review receptor models, such as chemical mass balances (CMBs), factor analysis, multiple linear regression are described.
Good results of CMBs can be oftained only when the source profiles closely match those of components actually present. New markers have been identified; e. g. rare earths, which are associatedwith oil refineries and possibly late-model automobiles equipped with catalytic converters. Even now, however, source identification of trace elements in fine particles have not been sufficiently performed.
Regional sulfate in earstern United States is accompanied with specific trace elements. Concentration ratios of sixtrace elements (As, Sb, Zn, In, noncrustal V, and noncrustal Mn) to that of Se are used to identify particles from any of their five pollution source regions. The most promising hybrid regional-scale model is quantitative transport bias analysis (QTBA), which can treat receptor data to obtain contour maps of concentrations of sulfate and various trace elements at the receptor when air masses arrived from the surrounding areas.
Organic compounds are also used for source apportionment. Contributions from threeurban sources of PAHs, domestic heating, petrol vehicles and diesel v ehicles, were calculated by CMB from six PAHs that are present in the atmosphere only in particle form. On the other hand, several volatile organic compounds have been identified as candidates for tracers of fine-particulate carbon and extractable organic matter from mobile sources.
To save the need to identify and assay the hundreds of organic compound that may be mutagenic, multiple linear regression of revertant colonies vs. K and Pb was applied to apportion mutagens to motor vehicle emissions and wood smoke.
There is great potential for development of highly definitive identification of particles by analyzing the data obtained by using the scanning electron microscope equipped with the X-ray fluorescence system.
The use of accelerator mass spectrometry has enabled one to measure the 14C/total carbon ratio from the several ten micrograms carbon sample. This technique may be applied to assign clearly individual compounds and individual carbonaceous particles to fossil fuel or temporary carbon sources.
Factor analysis models have been widely applied to the screening for unexpected sources, source apportionment, and deriving source compositions, and many reasonable results have been obtained. But factor analysis cannot be successfully applied to all the data sets. The success of this method strongly depends partly on the adequate selection of the species to include in the data set and partly on the coordinate rotation technique. New models which include such complex algorithms as non-negative transformation have been developed actively because of the wide use of computers.

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Photodegradation of gaseous trichloroethylene by ultraviolet (UV) irradiation was studied in nitrogen and air. Reagent loss and product formation were analyzed by using GC/MS.
Trichloroethylene was degrated about 30% of it's initial concentration by 2.5 hours UV irradiation in nitrogen. The observed products were mainly HC1, cis-1, 2-dichloroethylene, chloroform and pentachloroethane. More than 99% of trichloroethylene was degrated by 15 min. UV irradiation in air. The major products were HC1 and dichloroacethylchloride. Additionally, small amounts of tetrachloroethane, pentachloroethane and trichloroacetic acid were observed.

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The recovery of chlorofluorocarbons (CFC) by adsorption-desorption method using activated carbons is among the most practical means for the prevention of stratospheric ozone depletion. The efficiency of the recovery can be determined not only by the adsorption capacity of activated carbons but also by the desorption characteristics. In this study, the desorption behavior of CFC-113 was investigated in relation to the physical properties of activated carbons, especially pore size distribution. The experiments were carried out using a temperature-programmed desorption apparatus with nitrogen gas as a carrier. No definite relation was observed between the surface area of the carbons and the desorption efficiency. It was found that the desorption was largely affected by the following three factors, namely the pore volume of transitional pores (40-2000 A), the average pore size of micro pores (10-40 A) and the fraction of surface area occupied by the micro pores smaller than 10 A.

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The induction of nuclear anomalies including pyknosis, karyorrhexis and micronuclei in tracheal epithelium of mice exposed to aerosol mists of the following 3 genotoxic chemicals was investigated: mitomycin C (MMC), ethylcarbamate (EC) and colchicine (COL). Exposure of mice to these mutagenic mists significantly increased in the number of nuclear aberrated cells in tracheal epithelium dose-dependently. The sensitivity of this assay was tested by comparing with results of the micronucleus test in bone marrow cells. It was found that the sensitivity was almost similar in both assays. These results suggest that the nuclear aberration test in mouse tracheal epithelial cells will be useful as a screen for cytogenetic chemicals in air environment.

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It is very important to estimate precisely the amount of traffic NOx emission for controlling traffic air pollutions. However, the methods which have been currently used are very complicated. Then, it takes much time and man-powers to estimate the amount of traffic NOx emission.
Therefore we studied a simple method to calculate traffic NOx emissions with processing concentration and wind speed data at a monitoring site for traffic air pollution.
In this study a ventilation model with perfect mixing was used and the parameters of this model were determined from data of 6 monitoring sites in Osaka prefecture.
It was found that the parameters are related to the properties of wind speed and adjacent structures. The emission, which were good agreeded with the emisisons estimated from traffics and emission factors, were calculated with the parameters obtained by our analysis.
It is found that it is possible to estimate NOx emissions from traffics with using the simple model of this report.

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[in Japanese]

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