In the last few years, the achievement ratio of Environmental Quality Standard remains in 50% level and is still in extremely lower level than those of gaseous pollutants. In order to get the better atmospheric environment, it is required first to know the characteristics and behavior of particulate matters in the atmosphere. Characteristics of particulate pollutants are expressed by a number of physical and chemical factors such as particle size, concentration, chemical composition, shape and so on. The release sources of particulate pollutants are diverse and have different peculiarity from gaseous pollutants. Particle formation from gaseous pollutants by gas-to-particle conversion is an important mechanism in the atmosphere. Source apportionment of particulate matters in urban atmosphere is essential to devise a plan for improving the atmospheric environment.
In this paper, the following topics are reviewed and discussed;(1) Source of particulate pollutants, (2) Physical and chemical characteristics of particulate pollutants, (3) Source apportionment analysis, (4) Gas-to-particle conversion in the atmosphere, (5) Importance of informations with high time-resolution, (6) Appropriate evaluation method of particulate pollution level.

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Concentrations of chlordane homologues (chlordanes) in outdoor air in Kawasaki area and in indoor air in Tokyo and Kanagawa area were measured by GC with selective ion monitoring MS (GC/SIM).
The concentrations of the sum of the eight chlordanes (total chlordane: TC) in outdoor air were ranged from 0.5 to 3μg/m³, and the mean value was 1.7μg/m³.
On the other hand, the concentrations of TC in houses treated for termites were approximately 1000 times as high as in outdoor air, and decreased as the time. The mean values classified with the elapsed time were as follows: 5.8 μg/m³ (less than 1 year), 1.7μg/m³ (1-2 years), 1.3μg/m³ (2-3 years), 0.6 μg/m³ (4 or 5 years), 0.4μg/m³ (8 or 9 years).
The result suggests that indoor air of the houses treated for termites might have heavily been polluted by insecticide containing technical chlordane.
Amounts of chlordane exposure to human being were estimated from the results. The consequence of the estimation suggest that a dweller who spent more than eighteen hours per day in a house might have inhalated more than 0.5μg/kg weight/day (acceptable daily intake decided by FAO/WHO) of chlordanes during 2, 5 years after termite treatment. Even a dweller who was in a house for ten hours per day might usually have inhalated more than 0.5μg/kg weight/day of chlordanes during a year or longer.

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A continuous air analyzer and an automatic air sampler were experimentally developed to measure the time dependence of concentrations of atmospheric pesticides. The analyzer and sampler operated in field measurement to confirm their effectiveness.
Collection tubes were packed with TENAX-GC to absorb air pollutants. Experiments showed that the tubes could recover 100% of the original amount of the added typical insecticide, Fenitrothion.
The continuous air analyzer directly connected to a gas chromatography unit was in operation for three months in Maebashi city to measure a fungcide, Quintozene (PCNB), as a pollutant and Dibutylphtalate (DBP) as a continuously existing atmospheric substance. A total of 790 measurements were taken at every two hours; PCNB was detected in 308 measurements and the maximum concentration was 185ng/m³. The deviation of the difference of both retention times was small (±0.07 min.) enough to allow qualitative analyses of pollutants. The analyzer is prospective as a monitoring device installed, for example, in the neighborhood of a stationary source of pesticides.
The automatic air sampler worked in a number of field measurements. For example, an insecticide, Chlordane, sprayed in a living room four years before was collected. When all the windows were closed, the concentration of atmospheric Chlordane remained 0.44±0.12μg/m³ for six days sampling. The sampler was also used for two days to measure the concentration of a herbicide, Simazin, sprayed on the grass around an apartment complex; the maximum value was 0.71μg/m³. The lightweight, easy-to-operate sampler permits analyzing a number of samples in field works about atmospheric pesticides throughout the world.

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Meteorological condition when suspended particulates (SP) increase to extremely high level in early winter were investigated using data obtained at many air pollution monitoring stations in Kanto district, AMeDAS, radio-sonde (Aerological) data at Tsukuba and weather maps.
Usually, 1-day average SP concentration varies similarly in the wide area of Kanto Plain and increases from the rear part of moving anticyclone to the trough of air pressure, where air temperature at higher altitude of 900 mb (-4000 m) is increasing or near the peak. In the rear part of anticyclone, high concentration occurs from the evening to the morning during night when surface wind becomes weak and land breeze bows to Tokyo Bay. In the trough of air pressure, SP concentration sometimes increases even during the daytime. When Kanto plain comes in a warm region of the cyclone passing in the northern part of Japan, geostrophic wind from SW-, -WSW prevails and a local front is often formed across Tokyo bay in the direction of WSW to ENE, SP concentrations become extremely high in the northern area of this local front, where a strong inversion layer or a stagnant region is formed. This local front could be held for more than 1 day, though it becomes weaker in daytime and stronger at night.
In this weather condition, SP/NO_x (where NO_x is nitrogen oxide concentration) and relative humidity of the air increase at the same time. Thus the effect of water in the air should be large on SP concentration.

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Chemical composition of precipitation and particulate were measured at three sites in the Northwestern Kyushu region during the period from June 1986 to May 1987. The origin and transport of sulfur compounds are discussed on the basis of the data obtained.
Precipitation weighted annual mean concentration of sulfate in this region was about 1.9mg/l and over 81% of this was excess or not of sea salt origin. Concentration of excess sulfate varied seasonally and high concentrations were frequently observed during the cold season. Estimated wet and dry deposition of sulfur compounds was about two times larger than the man-made emissions in this season in this region. Contribution of natural emissions were relatively small and the in-flow from outside the region plays an important role in the budget of sulfur in this region. Meteorological analysis suggested that sulfate associated with the high concentration were continental origin, which had been transported by the northwesterly wind prevailing during the cold season.

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A simple measurement method of ammonia (NH₃) concentration in the atmosphere during a long-term and over a wide-area was examined.
The method was as follows: a molecular diffusion sampler which was a silica fiber cylindrical filter (PA-CF) treated with a mixed solution of 5% phosphoric acid and 5% glycerin and covered with a polyfuron filter was exposed in the atmosphere for a month. NH⁴⁺ in an aqueous extract of the PA-CF was analyzed with a ion chromatograph.
It became evidence that this method was a rapid determination and an effective simple measurement of NH₃ concentration in the atmosphere for a month long term.
Influences of meteorological factors (temperature, relative humidity and wind velocity) on this method was not noticed for measurement of NH₃ in the chamber experiment, in the case the PA-CF sampler was set in the shelter which was 20% ventilation rate.
By comparing data sets gained with this method to those with imprigated cartridge method for NH₃ concentration, the correlation coefficients (r) and the sample numbers (n) were r=0.96 (n=24), and hence the correlation was recognized at 1% significant level.
The method established in this study was applied to the measurement of NH₃ at 9 sites in Nara Prefecture in a period from Apr., 1988 to Mar., 1989. The annual mean concentration (ppb) of NH₃ turned out to be as follows: 11-15 at commercial, 5.0, 5.4 at mountainous, 0.2, 1.6 at clean and 0.2 at mountainous clean. Hence, the main origin of generation of NH₃ in the atmosphere was suggested to be causedby the artificial generation of human activity.

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Behavior of atmospheric aerosol in the urban area and its surroundings was investigated using 11 sites data in Fukuoka area. Particulate samples were collected during 11-21 May 1987 using hi-volume air samplers and analyzed for 22 components. The following results were obtained.
High TSP (total suspended particulate) concentration was observed when rear of migratory anticyclone passed through. Multiple regression analysis for data of Fukuoka City revealed that the increase of TSP were mainly affected by carbonaceous material.
Electrolyte (NO^3-, SO₄^2-, Cl^-, Na⁺ etc.) and water soluble organic carbon (SOC) were analyzed to examine their behavior.
Na. originated from sea entered 30 km inland from seaside on windy days.
NO and NO² are oxidized to NO^3- and decreased in concentration in accord with the generation of Ox. SOC was correlated well with NO^3- and daily-maximum of Ox. Therefore, it was assumed that SOC was mainly produced by photochemical reactions. Average contribution of the secondary carbon to total carbon was estimated to be 12%.
Concentration of SO₄^2- increased by 2μg/m³ per day during the pass of migratory anticyclone in background sites. It was due to long residence time of SO₄^2- in air without deposition.

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