The particulate matter (PM) emissions from motor vehicles were studied by measuring the atmospheric PM at the sites near the heavy traffic road in Tokyo. Measurements were performed in December 1997 and in June 1998, and each period was about two weeks.
Size segregated PM samples were collected using the Andersen samplers at two sites, Hatsudai and Matsubara-bashi in December and Hatsudai and Wakamiya in June. Obtained samples were chemically analyzed by applying instrumental neutron activation analysis for elemental measurements, ion chromatography for water soluble ions, and thermal oxidation method for organic and elemental carbon.
Continuous cumulative frequency functions were derived at first from the discrete cumulative percent values obtained experimentally for PM and various chemical components, and there size distributions were determined secondly as the derivatives of the cumulative frequency functions. Size distributions of PM were bimodal pattern with a valley around 1-2 micro-meter of aerodynamic diameter. On the other hand, for chemical components, each size distribution was distinctive reFLecting its emission sources and particle formation processes.
The effect of motor vehicles on the concentration of atmospheric PM was mainly caused by exhaust particles emitted from diesel vehicles which occupied around 30% of traveling vehicles. Exhaust particles from diesel vehicle were dominated by elemental carbon. Approximately 80% of elemental carbon was in fi ne particle fraction, and its size distribution was remarkably one-sided toward small size. Because of resuspended soil and street dust, and emission of tires and brakes abrasion particles, crustal elements like Al, and some elements, Cu, Au, Mo, Sb, Ba, and Hf, attributed to the abrasion particles of tires and brakes were enriched in coarse particle fraction.
Water soluble ions were second to carbonaceous component in atmospheric concentration among analyzed various chemical components, and these occupied considerable concentration in fine particle fraction especially in winter. Motor vehicles were the remarkable emission source of NO which is precursor of nitrate. Diesel exhaust particles contributed few to atmospheric sulfate even at the site near the remarkably heavy traffic road in Tokyo, because the diesel fuel with sulfur content of below 0.05 wt.% has been supplied already at that time.

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Around 10 o'clock, July 2nd, 1997, a large-sized tanker stranded on the center of Tokyo bay and a great deal of crude oils flowed out from the ship. Because the oil was volatile, the about 30 percent of the outflow oil evaporated immediately and was released in the atmosphere as a great deal of petroleum gas. The purpose of this study is to investigate an atmospheric environmental impact by this oil outflow accident by means of the analysis of the monitoring station data and the numerical simulation by chemical transport model.
The result of analyzing observation data shows as follows. A puff with the high concentration NMHC which evaporated from outflow oil on Tokyo bay was transported to the southern part of Ibaraki prefecture passing the northeast part of Tokyo bay in the about 10 m/s southwest wind. Its maximum concentration reached 6 ppmC in the northern coastal area of Tokyo bay. When the high concentration NMHC puff pass, the increases of the NMHC and photochemical oxidant concentrations were detected.
In order to evaluate the atmospheric environmental impact by the accident quantitatively, a numerical simulation was conducted. First, by the computation of the base case, it confirmed that the model could reproduce the basic characteristic of the atmospheric environmental impact caused by the oil outflow. We assumed that the concentration difference between the accident case and the non-accident case was equal to the environmental impact by the accident. As a result of numerical simulations, the 0₃ and NO₂ were produced by the photochemical reactions in the high concentration NMHC puff, and the maximum concentration of O₃ and NO₂ is 18 ppb and 2 ppb, respectively.

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In this report, the monitoring results of dichlorodifluoromethane (CFC12), trichlorofluoromethane (CFC11), 1, 1, 2-trichloro-1, 2, 2-trifluoroethane (CFC113), 1, 1, 1-trichloroethane, cabon tetrachloride, trichloroethylene, tetrachloroethylene, chloroform and dichloromethane in urban atmosphere of coastal industrial area in Kanagawa prefecture were presented. Monitoring term was from Jan. 1990 to Jan. 1997. These chemical substances were measured by using adsorbent collection/solvent extraction/GC-ECD.
During the significant reduction of specific CFCs (CFC12, CFC11, CFC113), atmospheric concentrations of CFCs, 1, 1, 1-trichloroethane and carbon tetrachloride had been decreasing: in 1991, concentrations of CFC12, CFC11, CFC113, 1, 1, 1-trichloroethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene and chloroform were 0.87 ppbv, 0.45 ppbv, 0.53 ppbv, 2.8 ppbv, 0.15 ppbv, 0.46 ppbv, 0.33 ppbv and 0.10 ppbv, respectively, and in 1996, after the total elimination, these were 0.62 ppbv, 0.34 ppbv, 0.16 ppbv, 0.41 ppbv, 0.10 ppbv, 0.65 ppbv, 0.29 ppbv and 0.07 ppbv, respectively. Dichloromethane had been measured from Aug. 1994 and its concentration was 1.9 ppbv in 1996. After reduction of CFCs started, atmospheric concentration of trichloroethylene had been increased.
Formerly, trichloroethylene was replaced by 1, 1, 1-trichloroethane and CFC113 because of their low toxicity, however, specific CFCs were phased out and trichloroethylene became the substitute chemical.

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The coal consumption in Chongqing, which has suffered from serious air pollution and acid rain, is very large. Moreover, the sulfur content in coal produced in the region is very high. SO₂ resulting in serious acidification of rainwater is emitted from coal combustion and is concentrated in lower atmosphere due to few desulfurizing equipment and unfavorable meteorological conditions for the diffusion of air pollutants in the area. For this reason, the control technique for SO₂ emission is very important.
In this paper, the reduction efficiency of SO₂ emitted by combustion of the biobriquette prepared from low graded raw coal with high sulfur content, biomass and slaked lime in Chongqing was investigated by the model combustion experiment. Under our experimental conditions, the reducing efficiency of SO₂ emission from high sulfur coal-biomass briquette amounted to 82-95%. Especially, compared with the coal washing, the coal-biomass briquetting technique can effectively reduce sulfur emission. It was considered that the bio-briquette was useful to civilian and small factory consumes as a part of the countermeasures for SO2 emission control. This result suggested that coal-biomass briquetting technique was suitable in Chongqing.

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