The current studies for measurement of the mass concentration of particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers [SPM or PM10] in a ambient air were reviewed. The major contents are as follows: reference and equivalent methods for the suspendid particulate matter for purposes attainment and maintenance of the national ambient air quality standards of Japan, reference method for the determination of particulate matter as PM10 for purposes of determining attainment and maintenance of the primary and secondary national ambient air quality standards of U.S.A., portable samples for the monitoring of exposure level of individuals and the evaluate of spatial distribution of SPM.

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Nitrogen derived from atmospheric nitrogen dioxide (NO₂) in plant tissue was determined by the ¹⁵N dilution method. Seedlings of sunflower, tomato and rice plants which were grown in nutrient solution containing ¹⁵N-labelled nitrogenous compounds were exposed to low concentrations (0.1 and 0.2 ppm, v/v) of NO2 for three weeks. Dilution rate of ¹⁵N abundance in plant tissue by NO₂ was calculated by the following equation.
Rate= (1-¹⁵N abundance in plant tissue/¹⁵N abundaace in nutnient sohltion)
Amount of NO₂-nitrogen was determined by multiplying the rate by total nitrogen in plant.
The dilution rate of ¹⁵N abundance in plant tissue was proportional to the concentrations of NO₂, indicating the rate can be used as an indicator of NO₂ level in the atmosphere. Plant species with a higher rate of ¹⁵N dilution would be suitable for the detection of difference in NO₂ levels among sites. Critical concentration of NO₂ detectable by the method employed in the present study was 42-44 ppb.
The results indicated that the ¹⁵N dilution method would be applicable for the biomonitoring of NOx pollution in the atmosphere.

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Individual particle analysis combined with cluster analysis of airborne particulates collected beside a roadway was performed to make a source apportionment and to conduct a methodological investigation. Samples (fractions Al-A8 and BF) were collected at a site situated at 0.5 m from the roadway by an Andersen air sampler. Fractions Al to A8 were collected on the 1st stage to 8th stage and the fraction BF was collected on the backfi lter of the sampler, respectively. Their aerodynamic sizes were >11μm, 7-11μm, 4.7-7μm, 3.3-4.7μm, 2.1 3.3μm, 1.1-2.1μm, 0.65-1.1μm, 0.43-0.65μm, and <0.43μm, respectively. Cluster analysis was performed on the EPMA results from individual particle analysis of 100 particles in each of Al-A8 fractions. The results of source apportionment for each fraction showed that the fractions of particle size >2.1μm had more tire dusts and soil minerals; and the fractions of particle size 0.43μm-2.1μm had more motor exhausted soot. Particles mainly containing iron, calcium, silicon or sea salt were also detected. Contributions of the seven kinds of cluster described above were 27, 10, 33, 9.5, 6.7, 4.0, and 1.7 by weight percent in total analyzed particles. Although particles of <0.43μm diameter were not analyzed, it is thought that the contribution of scot to total collected particles is far larger than 33%, because larger contribution of soot was observed in smaller particle fractions. So that, we can conclude that source apportionment of airborne particulates by this method is effective and practically useful.

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The number concentration of ambient aerosol particles near the ground were measured and compared with the inversion layer in the central Tokyo in winter. The inversion layer was determined from the upper wind observation by using pilot balloons. Vertical profiles of aerosol particles were evaluated from the relation between inversion layer heights and concentrations near the su rface.
Our analysis of the results clarified the followiings:
(1) When the inversion layer was formed in winter, particles tend to increase irrespectively of their sizes. When the inversion layer disappears, however, the accompanied strong wind. frequently blows large particles off. This is the main reason why Aitken particle concentration shows the maximum in winter.
(2) Mie particle concentration has a negative gradient profile and Aitken particle concentration has a nearly constant profile. The wind speed effect appears dominantly the vertical transport which makes the lower air mix with the upper air to yield low concentration of larger particles. Therefore Mie particles are selectively affected by the wind speed.

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Analyses of day averaged NO_x and SP concentrations in early winter obtained at general environmental monitoring stations in Tokyo show that those two kinds of concentrations become lowest after the passage of trough of air pressure and in a winter monsoon pressure pattern. When a winter monsoon pressure pattern loosens and a travelling anticyclone prevails, NO_x concentration increases relatively faster than SP. As for SP, it usually increases to very high level in the next trough of pressure. Therefore, the ratio SP/NO_x. decreases just after the passage of cold front or trough of pressure, then gradually increases toward the next trough of pressure, like a shape of saw teeth. This pattern is similar to the daily variation of relative humidity. Thus, we can say that NO_x concentration increases even in rather dry air after winter monsoon pressure pattern, whereas SP concentration increasesvith the increase of moisture of the air.
Analyses for SP were carried out by using data of light scattering method but with β-ray absorption method or piezo-balance method, very high concentrations were obtained in high relative humidity condition in early winter. Theseresults suggest that suspended particulates are strongly affected by the moisture itself. Therefore, it should be necessary to estimate the contribution of water in the suspended particulates quantitatively.

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In sensory evaluation of odor, odor thresholds are very important indicators. We examined correlation between odor thresholds and affinity of odorants for phospholipids for the purpose of developing a method to estimate odor thresholds. Phospholipids are main components in biomembranes of olfactory cells. And we developed a new method of estimate affinity between odorants and phospholipids. Namely, the method is that retention times of odorants are measured by the Gas Chromatography with a column packing a support coated with a phospholipid. The phospholipid is phosphatidylcholine or phosphatidyl ethanolamine in this experiment. Generally, the longer a retention time of an odorant is, the higher a degree of affinity for the phospholipid is. Therefore, the retention time is very rather effective parameter to represent a degree of affinity for the phospholipid.
Odor thresholds of 136 odorants in eight homologous series, those are alkanes, alcohols, ketones, aldehydes, esters, acids, aromatic compounds, sulfuric compounds and amines, were measured by the triangle-choise method with odor bags. Moreover, retention times of the odorants, excepting two seties of acids and amines, were measured by the GC-FID (Flame Ionization Detector) method and GC-FPD (Flame Photometric Detector) method. And correlation between odor thresholds and retention times of the odorants were examined in each series.
As a result, it was made clear that the both have very good relationship mutually in six series, excepting one series of sulfuric compounds. From this result, moreover, it was supposed that phospholipid membrane plays an essential role in olfactory recepting process of molecules.

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The variability of threshold odor number (TON) using olfactory sensory test by triangle flask method was analyzed, for the purpose to discussed the effect of water temperature.
The water quality and TON of main rivers in Tokyo were measured at same time. The following results were obtained.
1) The average of TON of river water were measured at various temperatures 13°C, 25°C, and 40°C. The sensitivity of TON (40°C) increased 1.5 times to compared with TON (25°C). But the within-individual variability of TON (40°C) increase d 1.5 times to compared with TON (25°C).
2) TON (25°C)[Y] of 34 river watres in Tokyo Metropolitan were 2-130, and BOD [X] were 1>-23 ppm.Relati onship between Y and X wasy=4.6X+0.8
a coefficient of correlation was 0.71.
3) From the questionnaire investigation of odor around riv, r, guideline of TON (25°C) is considered to reduce about 50 at the place of the width of river under 10 m, to keep minimum the influence for extent of odor from river.

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