The atmospheric dispersion process of pollutants emitted from a moving aircraft is represented by a puff diffusion model to simulate its movements precisely near the airport, under the assumption of a Gaussian distribution function. Three-dimensional diffusion parameters are estimated by matching calculated concentrations to those measured in the field with tracer experiments. By using these parameters, the time-dependent ground level concentrations of CO and NOx and the isopleths of NOx for quasi-static takeoff operations of aircraft are presented.

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In our previous report, the authors described an experimental study on the influence of carbon monoxide on nitric oxide oxidation and hydrocarbon consumption in photochemical reaction. The estimation of the effect of carbon monoxide on photochemical reaction has been made by a photochemical model in this paper. When the ratio of CO/HC is high and the reactivity of hydrocarbon is low, nitric oxide oxidation and the formation of nitrogen dioxide and ozone are accelerated by carbon monoxide. However, the decrease of hydrocarbon is controlled to the contrary. The result of our study shows good agreement with experimental data obtained previously by the others.

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In our first report, the effect of carbon monoxide on nitric oxide oxidation, ozone formation and hydrocarbon consumption was discussed by a photochemical model. The authors have revealed in the same method the influence of carbon monoxide on photochemical products in this paper. In the presence of HC, it is estimated that the formation of HCHO, RCHO, H₂O₂, CO₂, NO₃ and N₂O₅ is accelerated by CO. On the other hand PAN level is decreased. The effect of CO on HNO₂ and HNO₃ is not distinguished. Furthermore, in the absence of HC, the effect of carbon monoxide become clear on photochemical products of NO-NO₂-CO-Air system. This estimation shows good agreement with the result obtained by K.L. Demerjian et al.

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It was studied with poplar cuttings (Populus × euramericana cv.'I 45/51') grown in filtered air greenhouse (F.A.) and non-filtered air greenhouse (n-F.A.) in the suburbs of Tokyo how photochemical oxidant of ambient air affected the poplar leaves of different ages. These results were as followed.(1) Number of days when the daily maximum concentrations of oxidant in non-filte ed air exceeded 15, 10 or 7 pphm, were 1, 13 and 51 respectively for 104 days exposure period.(2) The young leaves till about the 20th daya fter unfolding in n-F.A. had chlorophyll contents and photosynthetic rates similar to those in F. A.. But, in the mature aged leaves, chlorophyll contents and photosynthetic rates in n-F.A. declined greatly. There was a strong negative relationship between the sum of oxidant dose (from 6 a.m. to 6 p.m.) exposed from the 20th day after each leaf unfolded, and the ratio of chlorophyll contents (n-F.A./ F.A.× 100%) in poplar leaves of different ages. The strong positive correlationship was observed between chlorophyll contents and photosynthetic rates except for young age leaves still about the 20th day after unfolding.(3) Light saturation points of poplar leaves in F.A. and non-injured leaves in n-F.A. were 20-30 Klux, and those of visible injured leaves in n-F.A. were about 10 Klux. If net photosynthetic amounts per plant a day were calculated using the light-photosynthetic curves and leaf area of plant, the values in n-F.A. were half of them in F.A.(4) Dark respiratory rates of mature leaves without visible injury, and of lower leaves with visible injury in n-F.A. were higher than in F.A.(5) Reducing sugar contents of all leaf ages in n-F.A. were almost double in F.A.. Non-reducing sugar contents of all leaf ages in F.A. showed about 30 mg./g.d.w., but those in n-F.A. were lower than 10 mg./g. d.w. except for the 20th day age leaf.(6) Total and protein nitrogen contents of leaves were almost the same values in F.A. and n-F.A. till the 20th day after unfolding. But, in the mature aged leaves, those in n-F.A. were lower values than in F. A..

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Methanethiol and dimethyl stilfide were absorbed and oxidized with sodium hypochlorite solutions, whereby the overall mass transfer coefficients (K_Ga) were examined. The optimum conditions for oxidizing 5 ppm of methanethiol and 5 ppm of dimethyl sulfide at a room temperature were clarified. On the basis of the data obtained, oxidative deodorization of methanethiol and dimethyl sulfide in real exhaust gas from a night soil plant was tested by using a practical oxidation plant.

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Suspended particles released from various small facilities of other kinds than those studied in the preceding report were also subjected to multielement analyses, and the values of “elemental concentration ratio” C_R, which was defined in the preceding report, were also calculated.For each facility studied, the elements are listed, whose C_R values are apparently much larger than unity and which are considered to be much enriched in sus-pended particles released from the facility in question.
Although the values of C_R are in general near unity for most elements, they take values appreciably larger than unity for the elements, which are enriched in suspended particles. Therefore, C_R could be regarded as a simple and convenient measure for presuming what kinds of element are important in the contribution of a facility in question to the atmosphere.

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Airborne flyash-like spherical particles were measured in eruption cloud from Sakurajima volcano in Kyushu on 1st and 3rd September 1979. Sampling was made by a portable dust sampler with Whatman glass-fiber and polycarbonate filter, and observed by SEM after carbon-gold processing.
Spherical particles of 2-5μm diameter with variety of surface shape were shown: spheres coated with other mineral materials and submicron fine coalescence, and plain flyash-like spheres. These inhalable particles were relevant to be suggested to the carrier particles permitting penetration into the alveolar region and enhancement of inhalation hazard affected by other toxic material absorbed on their surface.

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