Single-day and cumulative effects of ambient particulate matter exposure on emergency department visits for respiratory disease in South Korea

Background: Along with the industrialization, the air pollutants have gained more attention and studies especially about respiratory diseases were conducted. Emergency visit reflects acute aggravation of disease rather than chronic exacerbation. Objectives: The objective of this study was to evaluate the relationship between the ambient particulate matter and the emergency visits with respiratory disease in South Korea. Methods: Patients diagnosed with respiratory disease in the emergency department in 2018 were enrolled. The data of meteorological factors and air pollutants between 4 December 2017 and 31 December 2018 were acquired. Poisson regression was used with daily emergency visits as the response variable and single-day particulate matter concentration as the explanatory variable. Results: A total of 4207 patients were enrolled. In Poisson regression analysis of all respiratory diseases, the effects of PM10 and PM2.5 were strongest at day before 8 and 26. Age older than 65 group and chronic respiratory disease group had earlier lag effect than the all-diseases group. Cumulative effect was peaked at 14 lag day. The split point of prediction was 87 mu g/m(3) before 3 days for PM10 and 37 mu g/m(3)before 8 days forPM2.5. Conclusion: The results can be used to predict the increase of emergency visits and need for medical resources when the ambient particulate matter concentration rises.