Hourly Difference in Air Pollution, Demographic Characteristics, and Emergency Department Visits for Asthma in Seoul, Korea

Abstract

Hourly Difference in Air Pollution, Demographic Characteristics, and Emergency Department Visits for Asthma in Seoul, KoreaAbstract Number:2294 Jayeun Kim and Ho Kim* Jayeun Kim School of Public health, Seoul National University, Korea, E-mail Address: [email protected] Search for more papers by this author and Ho Kim* School of Public Health,Seoul National University, Korea, E-mail Address: [email protected] Search for more papers by this author AbstractObjective This study aimed to quantify the adverse association between air pollutant and asthma emergency department(ED) visits and to verify vulnerable demographic characteristics on short time scales.Methods 8,188 asthma related ED visits which have asthma diagnose on discharge over the period 2008-2011 in Seoul, Korea. Time stratified case crossover study linking ED data from the National Emergency Department Information System with PM10, PM2.5, Coarse PM, ozone, CO, NO2, and SO2 data. Pollution effects were investigated with delays(lags) of 1-6, 7-12, 13-18, 19-24, 25-48, and 25-72 hours in single pollutant model, adjusted for ambient temperature, relative humidity, air pressure, and weekly proportion of influenza outpatients. Age group [youth (age<=19), adults (20<=age<=64), elderly (65<=age)], sex (male, female), SES; using a proxy of the status of National health insurance; were reviewed.Results In the single pollutant model, PM10 and Coarse PM showed adverse association on 1-6 hours later with youth [excess risks 1.2% (95% CI 0.1 to 2.2)], [4.2% (0.9 to 7.5)] while coarse PM and PM2.5 are associated with male dominantly [3.3% (0.4 to 6.4)], [4.7 %( 0.6 to 9.0)] respectively per 10 unit increase. Ozone level was associated with asthma related ED visits for both male and female [4.2% (0.7 to 7.9)],[4.0% (0.2 to 8.0)] and SES did not modify the ozone effect but lower SES seems to brining events forward in time rather than increasing overall risk. In contrast, NO2 and CO levels showed larger protective effect to adults, the elderly, and the upper SES populations on mostly 19-24 hours later.Conclusions Higher levels of PM10, Coarse PM, and PM2.5 seem to be associated with increased risk of asthma related ED visits 1-6 hours’ exposure and longer hours for ozone alone. Although defined vulnerable populations are not same as previous studies, individual demographic characteristics modified risk of asthma related ED visits on short time scales.