Effects Of Air Pollutants On Hospital Admission For Respiratory Diseases Under Different Weather Types In Shenyang City

ObjectiveAir pollution has become a serious public environmental health problem,seriously affecting the health of the population,especially respiratory diseases.Shenyang,as the central hub city in Northeast China,has cold weather in winter and serious air pollution with complex sources.It is of great significance to explore the health hazards of air pollutants based on the weather characteristics of Shenyang.The purpose of this study is to classify the weather in Shenyang by using the Spatial Weather Classification(SSC),and further analyze the characteristics of the weather and atmospheric pollutants in Shenyang;By constructing a distributed lag nonlinear model(DLNM)of the time series,we analyze the risk of admission of respiratory diseases caused by air pollutants,and further analyze the risk of admission caused by pollutants in different weather types,as well as the characteristics of different populations,to provide a basis for prevention and control decisions and health warnings.MethodsThis study collected and collated the air pollutants and meteorological data of a district in Shenyang from 2015 to 2021,as well as the data of patients admitted to the respiratory department of a Grade Ⅲ Grade A hospital during the same period.Air pollutant data include daily average concentrations of PM2.5,PM10,SO2,NO2,O3 and CO;Meteorological data include daily average temperature,humidity,sea level pressure and wind speed;The data of admitted patients include demographic basic data,admission date,diagnosis of diseases,smoking and drinking status,and complications.In this study,the space weather classification(SSC)is used to classify the weather in Shenyang,describe and analyze the weather types in Shenyang,and explore their characteristics;Compare the concentration characteristics of different pollutants under different weather types in combination with different weather types;The distributed lag nonlinear model(DLNM)of time series was used to analyze the incidence risk of respiratory diseases caused by air pollutants in Shenyang under different weather types,and the characteristics of different populations were stratified.Results1.During 2015-2021,13878 patients with respiratory diseases were admitted,including 7008 men(50.49%)and 6869 women(49.51%);5723 patients(41.24%)were under 65 years old,8155 patients(58.76%)were over 65 years old;6936 patients(50%)were diagnosed with pneumonia,3883 patients(28%)with COPD,1712 patients(12.34%)with asthma,652 patients(4.7%)with pulmonary interstitial fibrosis,and 695 patients(4.96%)with bronchiectasis;5412 smokers(39%)and 8466 non-smokers(61%);1550 patients(11.17%)drank alcohol and 12328 patients(88.83%)did not drink alcohol;There were 2001 patients with diabetes history(14.42%),4937 patients with hypertension(35.57%),and 4781 patients with coronary heart disease(34.45%).2.During 2015-2021,the median(interquartile interval)of daily average concentrations of air pollutants PM2.5,PM10,SO2,NO2,O3and CO in a district of Shenyang were39μg/m3(40μg/m3),79μg/m3(64μg/m3),20μg/m3(19μg/m3),34μg/m3(24μg/m3),57μg/m3(47μg/m3),0.83μg/m3(0.54μg/m3).The atmospheric pollutants in this area show a certain time trend and seasonal fluctuation.Except for O3,other pollutants are generally higher from October to April of the next year,and fall to a lower level in June of each year,with higher concentrations in autumn and winter;The O3level showed the opposite seasonal change trend,and the warm season was higher than the cold season.According to the national pollutant limit standard,during the study period(2557 days),the number of days(days)exceeding the standard for PM2.5,PM10,SO2,NO2and O3was 20.03%(512 days),14.75%(377 days),3.48%(89 days),3.44%(88 days)and 1.29%(33 days),respectively,and CO did not exceed the standard.3.In Shenyang,the dry and mild DM weather type appeared the most,accounting for 30.27%,followed by the dry and cold DP weather type,accounting for 24.09%.The results showed that the average concentrations of SO2,NO2 and PM2.5 were the highest under the dry and cold DP type.There was no significant difference in CO under different weather types.The concentration distribution of O3 was significantly higher in hot conditions(DT,MT)than in cold conditions(DP,MP).4.Grey correlation analysis is used to further explore the relationship between pollutant concentration and meteorological factors.Among all meteorological factors,the concentration of other pollutants except O3 has the largest correlation with air pressure and the smallest correlation with temperature.O3is most affected by temperature,and has the least correlation with wind speed.5.With the increase of pollutant concentration,the risk of admission to hospital for respiratory diseases,COPD diseases and asthma gradually increases,with a lag effect.The increased concentrations of PM2.5,PM10,SO2,NO2,and CO had a statistically significant impact on the risk of admission of respiratory diseases,with RR(95%CI)of 1.0057(1.002,1.009),1.0113(1.006,1.016),1.003(1.001,1.005),1.0172(1.006,1.028),and 1.0172(1.009,1.025),respectively;The increased concentration of PM2.5 and PM10 had a statistically significant impact on the admission risk of COPD.The RR(95%CI)was 1.0066(1.001,1.013),1.0112(1.002,1.02),respectively;The increase of CO concentration has an impact on the increase of asthma admission risk,RR(95%CI)is 1.0223(1.001,1.044).6.The risks of hospitalization caused by various pollutants are different in different weather types.For respiratory diseases:PM2.5,PM10,NO2,CO,O3are more likely to be affected in dry and cold DP weather;In dry and moderate DM weather types,it is more vulnerable to PM2.5and PM10;For COPD:admission risk is more likely to be affected by PM2.5,PM10 and CO under the type of dry and cold DP;For asthma:O3has a greater impact on the risk of admission in dry and mild DM weather types.7.The stratified analysis results showed that the male group and the age group<65 years old were more likely to be affected by pollutants in dry and mild DM weather types,thus increasing the risk of admission RR(95%CI)was 1.0152(1.0019,1.0288),1.0705(1.0125,1.1319),respectively;On the contrary,the RR(95%)of women and the age group ≥65 years old is 1.0490(1.001,1.0993),1.0196(1.0005,1.039)respectively,which is more likely to be affected by pollutants in dry and cold DP weather types,thus increasing the risk of respiratory diseases admission.Conclusions1.Dry mild weather(DM)is the main weather type in Shenyang,followed by dry cold weather(DP).Under DP type,the average concentrations of PM2.5,SO2,NO2are higher,and PM10and O3are higher under hot weather type.2.The increased risk of admission to hospital for respiratory diseases is affected by the increased concentration of PM2.5,PM10,SO2,NO2and CO;The increased risk of admission to COPD is related to the increased concentration of PM2.5,PM10and SO2;The increased risk of asthma admission is related to the increase of SO2and CO concentration.3.The risk of hospitalization due to respiratory diseases increased under the weather types of dry and cold DP,dry and mild DM,and humid and hot MT.The risk of COPD admission increased under dry and cold DP,humid and mild MM weather types.The risk of admission for asthma is increased under dry and mild DM,wet and cold MP,and dry and hot DT weather types.4.The susceptible population in all age groups had a high risk of admission due to respiratory diseases in cold weather;Especially in the weather type of dry and cold DP,women and the elderly aged 65 years and older are at risk for respiratory diseases.