The ambient air pollutant concentrations are known empirically to be longnormally distributed for any averaging time and frequency. The law of lognormal distribution of air pollutant concentrations are examined in the case of isolated point source, assuming that spatial concentrations of air pollutants are described by the Gaussian plume model.
The results show that the air pollutant concentrations are lognormally distributed at any receptor, and the parameter of the distribution can be estimated by the parameter of the distribution of the wind velocitiEs and the wind directions at the point source and by the distance from the point source to the receptor.

View full abstract

We recorded the livelihood time under the circumstances, those are: using gas cooking burner and gas stove going out and in the experiment room and to ventilate by opening the window. While taking these time recordings, the dose of exposure for nitrogen oxides (NOx) to volunteer was continuously measured by the chemiluminescent NO/NO² analyzer.
In order to investigate the relationship between each activity and the exposure dose of NOx, we applied statistical methods such as multiple regression analysis. After that we tried to consider the possibility of evaluating the exposure dose of NOx for general population based on daily activities by means of time budget survey.
The results were as follows:
(1) The statistically significant correlation was observed between the time of using gas stove and NO² concentration (daily average), and it also had the highest contribution ratio for predicting the dose of exposure for NO² by multiple regression analysis.
(2) The time of using gas cooking burner was not markedly related to the dose of exposure for NOx (daily average), contrary to the amount of NOx production.
(3) It seemed difficult to predict the dose of exposure for NO by multiple regression analysis when independent variable was the time spent under each activity.
(4) In order that different approach should be necessary to evaluate the dose ofexposure for NO from the way which can be used in evaluating NO² exposure, the most suggestive way to predict the dose of exposuresuccesfully should be using a personal monitor along with methods above noted.

View full abstract

In order to study the effect of air pollution on lung cancer mortality, the relationship between the level of air pollution and the mortality rate of lung cancer was examined by ward in Nagoya city with a population of about two million. The standardized mortality ratio (SMR) of lung cancer for each ward was calculated by using Vital Statistics in 1969-1974, and was related to the average level of air pollution for each ward. Furthermore, the relationship between the level of air pollution and lung cancer mortality was adjusted for the proportion of smokers and several socio-economical factors by using multiple regression analysis.
The simple correlation coefficient between the amount of dust fall and lung cancer mortality was +0.643 (p<0.05) for males and +0.653 (p <0.05) for females. The coefficient between the amount of sulfar oxides (SOx) and lung cancer mortality was, +0.650 (p<0.05) for males and +0.549 (p<0.05) for females.
The amount of dust fall was used as an index of air pollution for the multiple regression analysis because the amount of dust fall was related closely with the amount of SOx (r=+0.878) and the former was related slightly more closely to the lung cancer mortality. Besides dust fall the proportion of smokers, per capita amount of municipal taxes and proportion of persons receiving welfare aids were used as explanatory factors for the multiple regression analysis.
The partial correlation coefficient between the amount of dust fall and lung cancer mortality was+0.452 for males and +0.680 for females. It was shown that the rlationship between the level of air pollution and lung cancer mortality was still significant statistically among females even after the relationship was adjusted for several other factors. On the other hand, the partial correlation coefficient between the per capita amount of municipal taxes and lung cancer mortality was +0.527 for males and +0.532 for females. This suggests the importance of socio-economical factors in the etiology of lung cancer.

View full abstract

The effect of operating conditions of automobiles on polynuclear aromatic hydrocarbon (PAH) emissions was studied. The PAH emission rate for a car with a high engine oil consumption rate increased with an increase in the car speed. However, the change of the emission rate was not so noticeable for a car with a low oil consumption rate.
In the 10-mode city driving cycle, PAH emission rates, on a concentration basis, were highest during 40 km/h cruise, and on a mass basis were highest during accelerations. The lowest emissions were during idling.
The high PAH emissions for the operating conditions of high speeds and accelarations were mainly caused by the high oil consumption due to high engine speeds and by the increase in the rate of formation of PAH from consumed oil with the increase in the pyrolysis temperature of the oil.
No obvious change of PAH emissions with load condition under a steady speed of 40 km/h was observed.

View full abstract

Evaluating the concentration distributions of contaminants is indispensable to improving and controlling the urban atomospheric environments. Recently a law has been made in order to oblige local government of urban area, where the atomospheric environments turned remarkably bad, to enforce the climatological air pollutant predictions and establish a rule to decrease the contaminants. The climatological diffusion model consists of two submodels-the climatological plume model by Holland and the puff model whichis applicable in weakly windy and calm conditions. The former is a climatological model while the later is not. Hence it does need to develop a climatological diffusion model which is applicable in weakly windy and calm conditions.
In the present paper a simple climatological puff model (CPM, for short) derived from the stationary solution of puff equation which is called Frenkiel's solution is proposed. The following specific features of our model have been observed:
1) In case frequency of wind directions is uniform to every direction our equation exactly gives an analytical solution.
2) The form of our model is quite similar to Holland's one.
3) Maximum ground level concentration (Max. GLC) and the distance of Max. GLC from smoke source are obtained analytically.
4) The time required for computing the annual mean concentration by our model decreases to about 1/20-1/100 time that by Frenkiel's one.
5) Concentration distribution calculated by our model is quite similar to the superposition of concentrations calculated at each wind direction by Frenkiel's one.
From those observation we can conclude that our model is an efficient, practical climatological diffusion model for urban air pollutant prediction.

View full abstract