[Effect of Air Pollution on Emergency Room Visits for Respiratory Diseases in Lanzhou].

Objective To explore the effect of air pollution on the number of emergency room visits for respiratory diseases in residents at different ages and its seasonal changes in Lanzhou,so as to provide a scientific basis for the early prevention of respiratory diseases in Lanzhou. Methods The daily number of emergency room visits for respiratory diseases in three class A hospitals in Lanzhou from January 1,2013 to December 31,2017,as well as the air pollutants and meteorological data of Lanzhou in the same period,was collected.After controlling the confounding factors including long-term trend of time,meteorological factors and day-of-week effect using a generalized additive model,we analyzed the relationships between air pollutants and the daily number of emergency room visits for respiratory diseases,and explored whether there was a lag effect of air pollutants.Results From 2013 to 2017,the emergency room visits for respiratory diseases in Lanzhou had a total number of 124 871,with an average of 69(1-367)visits per day.The single pollutant model showed that among the six conventional air pollutants monitored in Lanzhou,PM ,PM,NO,SO and O8h had a lag effect on the number of emergency room visits for respiratory diseases.For every 10 μg/m increase in the concentration of PM (lag02:=4.792, =0.001), PM (lag2:=3.421, <0.001), NO (lag6:=3.654, =0.003), SO(lag06:=4.712, <0.001)and O8h (lag07:=3.021, =0.012), the number of emergency room visits for respiratory diseases increased by 0.900%(95% :0.573%-1.249%), 0.083%(95% :0.012%-0.153%), 1.293%(95% :0.867%-1.720%), 3.851%(95% :2.675%-5.041%)and 0.737%(95% :0.129%-1.348%), respectively.For every 1 mg/m increase in the concentration of CO(lag0:=3.564,<0.001),the number of emergency room visits for respiratory diseases increased by 2.556% (95%: 1.493%-3.629%). In gender stratification, PM(male:=3.124, =0.019;female:=3.418, =0.007), PM(male:=2.980, =0.160;female:=2.997, =0.013)and CO(male:=4.117, =0.001;female:=4.629, <0.001)in winter had stronger effects on the emergency room visits for respiratory diseases in females than that in males, while the effects of NO(male:=3.020, =0.107;female:=3.006, =0.128), SO(male:=4.101, <0.001;female:=3.820, <0.001)and O8h(male:=3.660, =0.022;female:=3.517, =0.018)in winter showed an opposite trend.In age stratification, the increase in the daily average concentration of PM(0-14 years old:=3.520, =0.008), PM(0-14 years old:=3.840, <0.001), SO(0-14 years old:=4.570, <0.001), CO(0-14 years old:=4.102, =0.002)in winter would increase the emergency visits for respiratory diseases in the 0-14-year-old population.The daily average concentration of O8h(0-14 years old:=4.210, <0.001;15-64 years old:=3.807, =0.001)in summer only affected the visits of the 0-14-year-old and the 15-64-year-old populations, and the air pollutants had no significant effect on the visits of those≥65 years old.The double pollutant model analysis revealed that after introducing 5 other pollutants respectively, PM, PM, NO, SO and O8h significantly increased the emergency room visits for respiratory diseases, and CO had a more obvious effect than that predicted with the single pollutant model. Conclusion The rises in the concentrations of six air pollutants in Lanzhou will increase the emergency room visits for respiratory diseases, and the patterns vary with different genders, ages and seasons.