Background: Explorations of interactions between air pollution and seasonal changes have represented one approach in examining the consequences of global warming. However, only a few studies have focused on evaluating the effects of seasonal air pollution using data on both morbidity and mortality in Asia.
Method: We examined the associations between PM(10) concentrations and mortality and hospital admissions in Seoul, Korea for the periods 2000-2006 and 2001-2006. We employed a temperature-matched case-crossover design, where reference periods matched case days in regard to temperature (same rounded to degrees celsius ( degrees C)), month, and year.
Results: A total of 238,826 deaths were identified, along with 98,570 and 93,553 inpatient admissions for cardiovascular and respiratory diseases, respectively. We found that the association with PM(10) and mortality/morbidity increased during the summer. During the study period, 10microg/m(3) increase in PM(10) was associated with the increase in mortality by 0.28% (95% confidence interval: 0.12, 0.44), 0.51% (0.19, 0.83), and 0.59% (-0.08, 1.26) for non-accidental, cardiovascular, and respiratory causes. 10microg/m(3) increase in PM(10) was also associated with increase in hospitalization from cardiovascular and respiratory causes by 0.77% (0.53, 1.01) and 1.19% (0.94, 1.44). In the summer, the increase in mortality and hospitalization was 0.57% (0.20, 0.93), 0.64% (-0.10, 1.38), 0.50% (-1.02, 2.05), 1.52% (0.89, 2.16), and 1.55% (0.87, 2.22).
Conclusions: This study provides evidence that the effect of PM(10) on mortality and morbidity varies with season and increases during the summer season.