1987 Volume 22 Issue 1 Pages 57-71
Between 1973 nad 1985 the Osaka Medical Society conducted surveys by means of questionnaires every other year for public school children in the Osaka Prefecture concerning the subjective symptoms of “usually coughing”(a total of 5, 480, 443 children in 6, 449 schools).
The results of these surveys were analysed and the following results obtianed:
(1) Between 1973 and 1981 the concentration of sulfur dioxide was found to decrease significantly throughout the Osaka Prefecture, while the concentration of nitrogen dioxide remained unchanged. Regional differences related to the prevalnce of cough complaint between polluted and control areas also decreased in parallel to the fall in sulfur doixide concentration. After 1981, however, the regional differences in the rate of cough complaint remained constant, despite a continued fall in sulfur dioxide concentration which is in contrast to the previously observed trend. The lower limit of the yearly mean sulfur dioxide concentration which appeared to influence the prevalence of cough complaint was 0.013-0.015 ppm.
(2) The correlation coefficient between the rate for complaint of cough and for the nitrogen dioxide concentration was+0.708 (p<0. 001) in those schools located within 1 km of the 27 air pollution monitoring stations (the number of children surveyed, 89, 866). The lower limit for the yearly mean nitrogen dioxide concentration which influenced the complaint of cough was 0.020-0.025 ppm.
(3) Based on these results, a formula for a model was proposed which shows the relationship between the rate for cough complaint and the degree of air pollution.
