학술논문
The difference in effect of ambient particles on mortality between days with and without yellow dust events: Using a larger dataset in Seoul, Korea from 1998 to 2015.
Document Type
Article
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ISSN
0048-9697
Abstract
Yellow Dust (YD) is a natural source of particulate matter (PM) in Korea. It remarkably increases the concentration of PM. However, characteristics of PM in YD period are different from those of PM in non-YD period. To investigate whether the association of PM with mortality is different between all days and non-YD days in Seoul, Korea, 1998–2015. We applied time-stratified case-crossover design to estimate effects of PM 10 and PM 2.5 on non-accidental cardiovascular and respiratory mortality. Effect estimates of PM were compared for all days in the study period and days without YD events. To identify whether different effect estimates between all days and non-YD days were not merely caused by the exclusion of high PM concentrations but rather by YD itself, we estimated effects of PM by randomly excluding the same number of days as days of YD. A total of 4,509,392 deaths were observed during the study period. A 10 μg/m3 increase in PM 10 or PM 2.5 was associated with a 0.15% (95% CI: 0.06% to 0.24%) or 0.27% (95% CI: 0.07% to 0.47%) increase in risk of non-accidental mortality for all days, respectively. These associations were changed to 0.30% (95% CI: 0.18% to 0.42%) and 0.33% (95% CI: 0.10% to 0.55%) when YD days were excluded from analyses. We also found that effect estimates of PM were larger when YD days were excluded than those when high PM concentrations were randomly excluded. The effect estimates of PM differed between all days and non-YD days. Our study suggests that including YD days in the analyses is likely to attenuate the effect of PM in a usual urban environment. Unlabelled Image • Effects of PM were higher when yellow dust (YD) days are excluded from the analysis than when the all days are included • The higher PM effects in non-YD days may not simply be due to the exclusion of high-concentration PM days • PM emitted from urban environment seems to be more hazardous than the PM originated from YD • YD days are needed to be considered as outliers in order to properly assess the health effects of locally produced PM [ABSTRACT FROM AUTHOR]