Many epidemiological studies have shown the association between daily mortality and daily average of PM10 level. Daily average of PM 10 has been used for regression type time-series analysis. This article suggests that daily mean mortality is not only a function of daily mean but also a function of daily standard deviation of PM10. We used generalized additive Poisson regression model with overdispersion parameter to investigate this hypothesis using the data from Seoul, Korea, from 1997 to 2001. One interquartile range (IQR = 42.11 μg/m3) increase of daily mean level of PM10 was found to be associated with 2.1% increase of additional daily mortality (RR = 1.021, 95% CI = 1.009-1.035) after controlling for other confounders. Similarly, we also found that one IQR (11.93 μg/m 3) increase in daily standard deviation of PM10 is associated with 2.5% increase of additional risk of death (RR = 1.025, 95% CI = 1.000-1.028) when other covariates remained the same. These findings may provide new insight into the possible explanation of health effect of PM10 and support the hypothesis that PM10 deviation is also an important risk factor after controlling for daily mean PM10 level.
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis