Air Pollution and Hospital Admissions for Respiratory Disease in Certain Areas of Korea

Recently studies reporting the incidence of diseases at air pollution levels below the recognized standard levels are increasing and the issue is becoming a matter of concern. We therefore examined the relationship between the level of air pollution in three areas of Korea and the incidence of respiratory diseases. Poisson regression models were used to account for day-of-the-week effects and nonparametric smoothing to make adjustments for season and weather in this time series analysis. The levels of air pollution across the three selected areas were characterized by the total suspended particle (TSP) concentration, which in Daejon was 61.28±29.22, in Ulsan 72.01±25.99, and in Suwon was 82.84±30.18. The total number of hospitalized cases due to respiratory diseases during the study period was 5,446. The relative risk of hospitalization due to respiratory diseases caused by air pollutants after accounting for seasonal and temperature effects were as follows：-CO (R.R.; 1.21, 95% C.I.; 1.02-1.44) in a residential area (Daejon), and NO_2 (R.R.; 1.47, 95% C.I.; 1.03-2.10) and CO (R.R; 2.51, 95% C.I.; 1.06-5.93) in a heavily industrialized area (Ulsan), and were statistically significant. When the TSP concentration was manipulated as a quintile dummy variable, the relative risk of admission increased by 2.48% (95% C.I.： 1.82%-3.15%) for every quintile increase. In conclusion, respiratory disease admissions are related to NO_2 , CO, and TSP concentrations below the environmental standard, but the significance of this relationship was area dependent.