The Short-term Effects Of Air Pollutants On Hospitalizations For Respiratory Disease

The rapid development of the world's economy brings not only continuous im-provement in people's living standards but also an increasingly severe air pollution problem,especially in less-developed developing countries.Air pollution has adverse effects on human health,in particular on the respiratory system.Respiratory diseases are one of the leading causes of death among Chinese residents and are becoming more and more common among the population.In this context,this paper has three research goals:1)to study the distribution level and variation of respiratory disease-related hospital-izations,outdoor air pollution,and meteorological factors;2)to analyze the short-term effects of outdoor air pollution and respiratory disease-related hospitalizations;and 3)to discuss the population differences and seasonal differences of short-term effects.To achieve these goals,this paper uses monitoring data from Hefei as the study sample.From January 1,2014,to March 31,2016,there are 19465 hospitalized cases of respiratory diseases being reported,including 14929 cases of pneumonia,3579 cases of chronic obstructive pulmonary disease(COPD)and 957 cases of asthma.In this study,the epidemiological characteristics of three diseases were shown,and in particu-lar,the time and population distribution of each disease were analyzed.The descriptive analysis showed that the hospitalization rate of pneumonia and COPD was higher in the warm season(May-October),while the hospitalization rate of asthma was higher in the cold season(November-April).All of the three diseases were more common in male population than female population:take COPD for example,male patients accounted for 62.2%of all hospitalizations.For pneumonia and asthma,people below 65 years old were more likely to be hospitalized:among all the hospitalizations of pneumonia and asthma,patients below age 65 account for 87.6%and 89.1%,respectively.In contrast,COPD was more likely to affect the elderly:2843 hospitalized patients were over 65 years old,accounting for 79.4%of the total.In addition,this paper collected the daily average concentration information of six standard air pollutants(PM2 5,PM10,SO2,NO2,O3,and CO)in Hefei from January 2014 to March 2016.Descriptive statistical analysis reveals that air pollution existed in nearly half of all days during the study period.The average annual concentration of PM2 5 and PM10 far exceeds the national environmental air quality standard limit,while the other four standard air pollutants are within the national limit.In addition,obvious seasonal patterns have been found in PM2.5 and PM10:the concentration level of pollutants is low in the warm season,and relatively high in the cold season.The paper studies the short-term effects of PM2.5 and PM10 on hospitalization of respiratory diseases by combining the generalized additive model and distributed lag nonlinear model.After controlling the concentration of other air pollutants,meteoro-logical factors and time trends,this study found that the characteristics of air pollution on the incidence of pneumonia,COPD and asthma are different.The effect on pneumo-nia was the smallest,and the cumulative effect was not significant.The increase of air pollutant concentration is correlated with the increase of hospitalization in COPD and asthma,and there is a lag effect.The average daily concentration of PM2 5 increased by 10?g/m3,and the cumulative effect of PM2 5 on COPD hospitalization lagged 6-11 days.The cumulative effect of PM2 5 on COPD hospitalization 12 lag-days was the largest,with the relative risk of PM2.5 increased by 1.068(95%CI:1.017-1.121).The short-term effect of PM10 on COPD peaked on the 10th day with an increase of 10?g/m3,which increased the number of admissions by 3.1%(RR= 1.031,95%CI 1.002-1.060);the impact on asthma hospitalization continued from the 7th day to the 14th day with the highest risk of 12 lag-day(RR=1.057,95%CI:1.010-1.107).In order to investigate whether the relationship between outdoor air pollution and the number of hospitalizations for respiratory diseases is affected by the characteristics of the population and the seasons,this paper conducts a stratified study,dividing each disease data into six groups according to age,sex and season,and using generalized additive model combined with distribution lag non-linear model for each group to hos-pitalize air pollution and respiratory diseases.The relationship is estimated.The results showed that pollutants had obvious seasonal effect on COPD hospitalization,and the effect of warm season was higher than that of cold season;women were sensitive to the change of particulate matter concentration,which could easily lead to COPD;PM2 5 had a greater impact on COPD and asthma in people over 65 years old.The results of this study can help medical institutions to formulate management measures for respiratory diseases,provide the scientific basis for the government to allocate medical resources,and support local authorities to formulate targeted preven-tion and control measures to protect vulnerable groups from the adverse effects of air pollution.