Fig. 4From: Association between gaseous pollutants and emergency ambulance dispatches for asthma in Chengdu, China: a time-stratified case-crossover studyAssociation between EADs for asthma and IQR increases in SO2, NO2, CO, and O3 levels with lag 0 to lag 7 days. The results derive from controlled analyses after altering the lag structure for each pollutant by restricting three fixed controls to one caseBack to article page