Asian dust and daily mortality in Korea and Japan

Abstract

Background: Asian dust spreads to wide areas of Asian countries. The chemical components of the dust are not fully understood, and may be complex, including pollutants from urban emissions. Desert dust is considered to have a potential toxicity and such toxicity can change during long-range transportation. The independent effects of desert dust in different location, however, have still been less clear in Asian countries. Aims: We evaluated adverse-health effects of Asian dust event on cause-specific mortality independent of particulate matter in Korea and Japan. Methods: We obtained daily mean concentrations of Asian dust as well as particulate matter between 2005 and 2010. Asian dust was obtained from Light Detection And Ranging (LIDAR) by National Institute for Environmental Studies, Japan. We then evaluated city-specific [Seoul (Korea), Matsue, Osaka, and Tokyo (Japan)] associations of Asian dust with daily mortality for all age groups using a time-series analysis. Study periods were different between each city due to data availability. Results: The mean (and maximum) concentration of Asian dust in Seoul, Matsue, Osaka, and Tokyo were 15.4 ?g/m3 (max 444.4 ?g/m3), 26.6 (458.7), 7.7 (121.6), and 9.5 (123.8), respectively. The positive associations of Asian dust with all-cause or cause-specific mortality were observed even after we adjusted for particulate matter in the same model. The excess risk following 10 ?g/m3 increase of Asian dust was 0.5% (95% CI 0.1–0.1) for all-cause mortality in Seoul (mean of lag 0–4). In addition, the excess risks for cerebrovascular disease mortality (lag 1) following 10 ?/m3 increase of Asian dust were 0.6% (95% CI -0.1–1.4) in Seoul, 4.0% (95% CI 0.1–8.0) in Matsue, 3.8% (95% CI 0.3–7.4) in Osaka, and -1.3% (95% CI -3.6–1.1) in Tokyo, respectively. Conclusions: Adverse health effects on all-cause and cerebrovascular disease mortality were observed in Seoul and Western part of Japan.