N₂O is one of the most interesting gases in the earth's atmosphere, but its sources, sinks and residence time poorly known. In this paper, an attempt has been made to summarize what is known about the processes which drive the cycle of atmospheric N₂O.

View full abstract

Mercury was discharged together with smoke and dust when several sorts of sludge were incinerated. The emissions of Hg in the incineration as follows:
(1) The most of Hg contained in sludge escaped in vapor as metal in the sludge incineration.
(2) The collection efficiency of Hg by the smoke and dust control facility (scrubber et al.) was a little less than 15%.
(3) In the incineration of residua, that were discharged from the process of waste oil treatment, the emission factor of Hg were especially as high as 4.49 to 4.84g/t. But, in the incineration of excess sludge, that were discharged from the process of factory effluent treatment, the emission factor of Hg were 0.26 to 1.55g/t, and these factor with the excess sludge were 1/10 to 3/5 of those with the sludge.

View full abstract

For the purpose of the quantitative evaluation of tobacco smoke exposure, a convenient personal monitoring system of nicotine specific for tobacco smoke was developed.
Nicotine was collected by passing ambient air through a sampler tube (12cm long, 5mm i. d.) at a flow rate of 40ml/min for a maximum period of 8 hours with a personal pump. The sampler tube contains 450mg of Chromosorb W (AW-DMCS, 30-60mesh) coated with 10wt% of Silicon OV-17. After the completion of sampling period, the sampler tube was placed in a cylindrical furnace heated at 280°C and connected with the injection port of a gas chromatograph via an injection needle. Passing the carrier gas through the tube, nicotine was transported quantitatively onto a column.
Amounts of passive inhalation of nicotine in some places were estimated to be in the range of 5-37μg for 8 hours. The valid range of the determination of ambient nicotine was 5-500ng per sampler tube.
The principal advantages of the personal monitoring system can be summarized as follows:
(1) The sensitivity is about 10-1000 times as high as those of ordinary methods utilizing wet process.
(2) The sampler is compact, portable, and can be used repeatedly.
(3) The direct thermal desorption of nicotine in the carrier gas flow saves much time and simplifies the analytical processes.
(4) Since no liquid is involved, analytical sample is free from possible contamination by nicotine from glass ware, solvent, etc.

View full abstract

The aerosol generation system was deviced for the studies on the exposure experiments of the mouse to nitrate and nitrite aerosols.
Aerosols were generated with an ultrasonic nebulizer (Acoma EN-2), and passed into an 80 liter exposure chamber.
Aerosol monitoring and characterization were performed by light scattering dust counter, cascade impactor, and electronmicroscope.
0.02M NaNO₃ aqueous solution was used for aerosol generations.
It was shown that concentrations of 15-89mg/m³ NaNO₃ aerosols were achieved by adjusting dilution air flow.
In the concentration range of 17 to 60mg/m³ and in the humidity range lower than the specific deliquescent humidity (NaNO₃: 77.7%, NaNO₂: 66%), log normal distributed aerosols with mass median aerodynamic diameter (MMAD) of 0.85-0.88μ and σg of 1.4-1.6 were obtained.
Aerosols in the chamber distributed homogeneously. Four hours operation at the concentration of about 50mg/m³ showed that the coefficient of variation was 2.7% and MMAD and σg were constant.
The aerosol flow rates of the system were of 11 to 49 litter/min.

View full abstract

In order to evaluate the possible deleterious effects of inorganic nitrate and nitrite aerosols, mice were exposed to 9-37mg/m³ NaNO₃ or 11-24mg/m³ NaNO₂ aerosols 3 hours a day for 5 days (short-term exposure) or one hour a day, 5 days a week for 2-4 weeks (long-term exposure) and the effects on the respiratory system and blood were compared with those of the mice exposed to similar concentration of NO₂ gas and NaCl aerosol.
The results were as follows:
1. Histochemically detected enzymatic alterations by light microscopy such as increased reactivities of acid phosphatase, alkaline phosphatase, and lactate dehydrogenase in the trachea and lung tissue and a decreased reactivity of cholinesterase in the smooth muscles of submucosal tissue in bronchi were observed following the exposure to NO₂. These alterations were also observed following the exposure to NaNO₃ and NaNO₂, but not to NaCl. The alterations were corresponded to the concentrations of the aerosols in the short-term exposure, but not corresponded to the duration of exposure in the long-term exposure.
2. Histopathological findings such as focal inflammation around the peripheral bronchioles were observed in the mice exposed to NO₂, but not in the mice exposed to NaNO₃ and NaNO₂.
3. Increased levels of reduced glytathione in lung or changes in the osmotic fragility of erythrocytes were observed following the short-term exposure to NaNO₂.
4. These results indicate that both NaNO₃ and NaNO₂ aerosols produce the biological effects similar to those of NO₂ and that these aerosols which coexist inevitably with NO₂ are also factors that are related to health effects of atmospheric nitrogen oxides.

View full abstract

By virtue of the search theory, a basic strategy has been developed how to itinerate mobile units to supplement or to substitute a routine air monitoring network system. The objective criterion is defined as to minimize the total error variance of monitored values throughout an objective area. An optimum itinerating schedule is decided under this criterion.
The followings are the results derived in this work;
1) itinerary of a mobile unit should be made in a constant interval to minimize total detection error along a given time span,
2) the interval can be decided depending upon a variance of the estimated values at each station in case of plural stations,
3) the evolved strategy was applied to a practical case of the air monitoring system in Osaka Prefecture and an interesting fact has been noted that the suburban stations has become of increasing importance to patrol in recent years.
The strategy above would be readily extended for more sophisticated situation by elaborating mathematical model and introducing more practical objective criteria.

View full abstract

The object of this study is to simulate the dispersion of pollutants from flat roadways in urban area. The utilized dispersion model satisfies the condition that wind profile is expressed by power law and is a non-Gaussian type for vertical spreading of plume. The model and its parameters were considered by using the field experimental data of cross wind case. The results are as follows:
(1) The parameters relating to dispersion were found for three locations of different roughness near roadways. Those parameters are exponent for power law of wind speed (m), shape factor showing the vertical profile of pollutants (s), initial diffusion width of pollutants (σ_zo) and ratio of Lagrangian and Eulerian time scale (β).
For flat area: m=0.25, s=1.3, σ_zo=2.6 meters
For residential area (4-storied building, noncrowded): m=0.75, s=2.4, σ_zo=3.1 meters
For residential area (2-storied house, crowded): m=1.0, s=3.0, σ_zo=4.4 meters
The mean value of β was 3.8. The value of s for flat area has the tendency of increasing with the down wind distance from roadways.
(2) The peocess was defined by which vertical diffusion parameter can be estimated directly from turbulent wind data.

View full abstract

The following simple method was devised for analyzing N-nitrosamines in the side-stream smoke from cigarette. N-Nitrosamines in the side-stream smoke are collected by passing it through an impinger containing 0.5 M sulfamic acid, a desiccant tube (Na₂CO₃) and Thermo Sorb/N tube, successively. N-Nitrosamines collected are extracted from each port of the collection system by dichloromethane, and the extracts are gathered together. After adding a known amounts of N-nitrosodi-n-butylamine as an internal standard, the extracts are concentrated to about 0.5 ml by the K-D condenser and by gentle evaporation under nitrogen stream. NNitrosamines in the concentrate are analyzed by a gas chromatography with TEA analyzer.
The collection efficiency and its coefficient of variation in this method were 100% and 7.2% for N-nitrosodimethylamine (NDMA) and 100% and 8.1% for N-nitrosopyrrolidine (NPYR).
This method was applied to NDMA and NPYR analysis in the side-stream smokes from 15 Japanese and 15 foreign brands of cigarettes. N-Nitrosamines contents were largely depended on its brands, and ranged from 113 to 544 ng/cigarette for NDMA and 40 to 332 ng/cigarette for NPYR. Chinese cigarettes emmited fairly lower N-nitrosamines than those of the other countries. NDMA and NPYR emmited from American cigarettes tested were larger than those from Japanese cigarettes.

View full abstract

Photochemical reactivities of 23 kinds of organico compounds, which were used for organic solvent and so on, were clarified by the ultraviolet ray irradiation test, using the laboratory smog chamber (6.64 m³) controlled in light intensity 7 mw/cm², initial concentration HC 2 ppm, NO 1 ppm, temperature 30°C and relative humidity 50%. Irradiation time was 4 hours (max.) and analytical items were HC, NO, NO₂ and O₃.
From the result, diethylether, tetrahydrofuran, p-cymen and isophorone showed very high reactivity like propylene, and diisobutylketone, di-n-propylketone, isobutylacetate and so on showed relatively high reactivity like toluene. For alkylether compounds, dimethylether showed the lowest reactivity, but it tended to be the larger molecular weight the higher reactivity.

View full abstract

A new plume rise model and dispersion parametcrs are proposed for the stack gas emitted from a large-scale source, e. g. a thermal power plant.
The plume rise model was derived from plume rise measurement data obtained by Central Research Institute of Electric Power Industry, and Tennessee Valley Authority in U. S. A. respectively, referring to previously published plume rise models. The dispersion parameters σy and σz for the Gaussian plume model were determined by tracer dispersion measurement data obtained by Central Research Institute of Electric Power Industry and National Research Institute for Pollution and Resources in Japan respevticely.
The calculated results with the proposed atmospheric dispersion models were in good agreement with the observed SO₂ ground-level concentrations in the area around a thermal power plant in Japan.

View full abstract

A methyl ester is hydrolytically cleaved to methanol, the latter is oxidized to formaldehyde. The formaldehyde determined spectrophotometrically with pararosaniline is an estimation of the methyl ester.
It was previously found that the oxidation of methanol to formaldehyde by potassium permanganate was accelerated in the presence of aldehyde compounds such as propionaldehyde, and increased in sensitivity of spectrophotometrical determination of methanol. The excess of potassium permanganate is reduced with sodium sulfite to be colorless. A sodium tetrachloromercurate II (TCM) solution was used as the stabilization reagent of sodium sulfite. But the TCM solution containing mercury compound is high poisonous, and propionaldehyde gives an offensive odor. As chemical analysis trends to be clean analysis, (1) the Na₂SO₃ was dissolved in distilled water, and (2) acetaldehyde-ammonia ([CH₃CH (NH₂) OH] ₃) was replaced by propionaldehyde.
The recommended analytical procedure for methyl ester by the pararosaniline method is as follows:
Acidify a 20 ml portion of the 0.5 As sodium hydroxide solution containing 20-300μg of methyl ester by adding 2 ml of 2.8 M sulfuric acid. Swirl, add 1ml of 1% potassium permanganate solution and 1 ml of 0.3% acetaldehyde-ammonia solution. Swirl, keep the mixture at room temperature for 10 minutes. Reduce the excess oxidizing reagent by adding 2 ml of 1.2% sodium sulfite aqueous solution. Swirl, add 2 ml of p-rosaniline hydrochloride solution (dissolved 0.16 g of the reagent completely in 24 ml of conc. hydrochloric acid, and dilute to 100 ml) and 1ml of 2.8 M sulfuric acid. Swirl, and let stand for 30 minutes at room temperature. Measure the absorbance at 585 nm against the reagent blank obtained by the same procedure.
The calibration curve is linear for 20-300μg/20 ml of methyl ester. The coefficient of variation is 3.6%, the molar extinction coefficient being 4.1×10³ mol^-1·cm^-1·dm³. A sample of vapor of methyl ester is passed at a rate of 0.5l/min through a midget impinger (with flitted glass beads attached to the tip of bubbler) containing 20ml of 0.5M sodium hydroxide solution. The solution is allowed to stand for 20 minutes or longer at room temperature until the ester is hydrolyzed to methanol. With a sample period of 1 hour, a concentration as low as 0.1 ppm in atmosphere can be determined.

View full abstract

There are many types of the cyclone dust collectors which are used for the various kinds of the industries in the Soviet Union. And also the interesresting and fragmentary reports concerning the flow patterns, the pressure drops, the concentration distributions of the fine solid particles, the fractional collection efficiencies and the total collection efficiencies were published in the many literatures and in the many engineering books by the Soviet Union. But it may be regarded that those profitable materials were not recognized or were not become familiar with the many engineers in our country. Therefore the author darlingly wants to describe the characteristics of the collection efficiencies η_c (%), the fractional collection efficiencies η_x (X_p), the pressure drops Δp_c (Pa) and the main sizes for the various types of the cyclone dust collectors by extra-cting from the many literatures.
In this first report, the author explained one example of the typical types of the cyclone dust collectors (_??_-cyclone systems) which were adapted in the many industries in the Sovit Union.
In addition to this, one exapmle of a curve of the fractional collection efficiency, η_x (X_p) of _??_-15 cyclone for the driving conditions as ρ_p=1.93g/cm³, Δp_c=882Pa, η_c=90.2%, X_c50=4.0μm was compared with the theoretical formula of η_x (X_p) by_??_et al., _??_ (1982), c. 551/c. 553.
Further the author included the more detailed experimental results of the collection efficiencies of the multi-cyclone system of _??_ No.7 (1064) c. 11/c, 15.

View full abstract