Association between daily mortality from respiratory and cardiovascular diseases and air pollution in Taiwan

Background: Many studies have investigated the effects of air pollutants on disease and mortality. However, the results remain inconsistent and inconclusive. We thought that the impact of different seasons or ages of people may explain these differences. Methods: Measurement of the five pollutants (particulate matter < 10 mu m in aerodynamic diameter (PM10), SO2, NO2, O-3, and CO) was monitored by automated measuring units at five different stations. Monitoring stations were provided by the Taiwan Environmental Protection Agency (EPA) from 1997 to 1999. The subjects in the study were classified in two groups: those 65 years of age and older, and those of all ages (including the subjects in the >= 65 group). Data on daily mortality caused by respiratory disease, cardiovascular disease, and all other causes including the two aforementioned was collected by the Taiwan Department of Health (DOH). A time-series regression model was used to analyze the relative risk of respiratory and cardiovascular diseases due to air pollution in the summer and winter seasons. Results: Risk of death from all causes and mortality from cardiovascular diseases during winter was significantly positively correlated with levels of SO2, CO, and NO2 for both groups of subjects and additionally with PM10 for the elderly (>= 65 years old) group. There were significant positive correlations with respiratory diseases and levels of 03 for both groups. However, the only significant positive correlation was with O-3 (RR = 1.283) for the elderly group during summer. No other parameters showed significance for either group. Conclusion: Our findings contribute to the evidence of an association between SO2, CO, NO2, and PM10 and mortality from respiratory and cardiovascular diseases, especially among elderly people during the winter season. Crown Copyright (C) 2008 Published by Elsevier Inc. All rights reserved.