Lee J T, Kim H, Hong Y C, Kwon H J, Schwartz J, Christiani D C
Department of Preventive Medicine and Public Health, College of Medicine, Yonsei University, Seoul 120-752, Korea.
Environ Res. 2000 Nov;84(3):247-54. doi: 10.1006/enrs.2000.4096.
The relationship between ambient air pollution and daily mortality in seven major cities of Korea for the period 1991-1997 was examined. These cities account for half of the Korean population (about 22 million). The observed concentrations of sulfur dioxide (SO(2), mean=23.3 ppb), ozone (O(3), mean=23.7 ppb), and total suspended particulates (TSP, mean=77.9 microg/m(3)) during the study period were at levels below Korea's current ambient air quality standards. Generalized additive models were applied to allow for the highly flexible fitting of seasonal and long-term time trends in air pollution as well as nonlinear associations with weather variables, such as air temperature and relative humidity. In city-specific analyses, an increase of 50 ppb of SO(2) corresponded to 1-12% more deaths, given constant weather conditions. The risk of all-cause mortality was estimated to increase by 0.5-4%, with an increase in the 2-day moving average of TSP levels equal to 100 microg/m(3). In multipollutant models with pooled data, we found that the estimated risk of death by SO(2) was notably unaffected by adding the other two pollutants (TSP and O(3)) to the model and was statistically significant in various regression models. The rate ratio (RR) for SO(2) remained elevated, indicating an excess mortality of 3% 50 ppb (RR=1.03; 95% CI, 1.01-1.05). TSP's effect on mortality maintained its significance with O(3), but not with SO(2). This implies that there may be collinearity problems where TSP and SO(2) are included in the same model or that TSP may function less than SO(2) as a surrogate for fine particles in the ambient air of Korea. In conclusion, increased mortality was associated with air pollution at SO(2) levels below the current recommendation for air quality. Further research is needed to clarify the relationship between SO(2) and fine particles in Korea.
研究了1991 - 1997年期间韩国七个主要城市的环境空气污染与每日死亡率之间的关系。这些城市的人口占韩国总人口的一半（约2200万）。研究期间观测到的二氧化硫（SO₂，均值 = 23.3 ppb）、臭氧（O₃，均值 = 23.7 ppb）和总悬浮颗粒物（TSP，均值 = 77.9 μg/m³）浓度均低于韩国当前的环境空气质量标准。应用广义相加模型来灵活拟合空气污染的季节性和长期时间趋势，以及与气温和相对湿度等气象变量的非线性关联。在特定城市分析中，在天气条件不变的情况下，SO₂浓度每增加50 ppb，死亡人数就会增加1% - 12%。TSP水平的两日移动平均值每增加100 μg/m³，全因死亡率风险估计会增加0.5% - 4%。在汇总数据的多污染物模型中，我们发现添加其他两种污染物（TSP和O₃）到模型中，对SO₂导致的死亡风险估计值没有显著影响，并且在各种回归模型中具有统计学意义。SO₂的率比（RR）仍然升高，表明50 ppb时超额死亡率为3%（RR = 1.03；95% CI，1.01 - 1.05）。TSP对死亡率的影响在与O₃共同存在时保持显著，但与SO₂共同存在时则不然。这意味着在同一模型中纳入TSP和SO₂时可能存在共线性问题，或者在韩国环境空气中，TSP作为细颗粒物替代物的作用可能不如SO₂。总之，在SO₂浓度低于当前空气质量建议水平时，死亡率增加与空气污染有关。需要进一步研究以阐明韩国SO₂与细颗粒物之间的关系。
