Seasonal effect of PM(10) concentrations on mortality and morbidity in Seoul, Korea: a temperature-matched case-crossover analysis.
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.


METHODS
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.
Yi
Okhee
O
Department Epidemiology and Biostatistics, School of Public health and the Institute of Environment and Health, Seoul National University, Seoul, Republic of Korea.
Hong
Yun-Chul
YC
Kim
Ho
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality*; D016022:Case-Control Studies; D002947:Cities; D018592:Cross-Over Studies; D005260:Female; D006760:Hospitalization / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009026:Mortality / Q000639:trends; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis*; D056910:Republic of Korea / Q000453:epidemiology; D012140:Respiratory Tract Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality*; D012621:Seasons; D013696:Temperature; D055815:Young Adult
D052638:Particulate Matter