Air Pollution and Prevalence Rate of Cough as a Complaint for School Children in Osaka

Abstract

Every other year since 1971, the Osaka Prefectural Medical Association has conducted a series of investigations regarding sub jective symptoms resulting from air pollution.
The investigation were conducted on all public school children in Osaka Prefectureby the use of a specific questionnaire. In 1979 the fifth investigation was conducted. The total number of schools and students studied between 1971 and 1979 has reached 4, 173 and 3, 648, 550 respectively. In the Osaka area, the sulfur dioxide concentration and the quantity of suspended particulate matter decreased each year, and the nitrogen dioxide showed little change.
1) Osaka was divided into five regeons, according to the level of sulfur oxides. Every series studied illustrated that the more heavily the air was polluted, the higher the prevalence rate of cough as a complaint, and at the same time, the more markedly it decreased year by year. On the other hand, the frequency of cough as a complaint remained almost constant in the non-polluted area.
2) In schools near 9 monitoring stations where the nitrogen dioxide concentration remained at the same level, a decrease in the cough complaint was observed as well as a decrease in sulfur dioxide concentration. Based on these results, we could obtain a model equation showing the prevalence rate of cough and its relationship to the nitrogen dioxide concentration and sulfur dioxide concentration.