Risk Assessment Of The Impact Of Main Air Pollutant Concentrations On Daily Outpatient Volume Of Respiratory In Shijiazhuang City

Objective:In this study,the air pollution data,meteorological data,and respiratory disease day outpatient data of Shijiazhuang were used to identify outliers of the atmospheric pollutants,analyze the time-varying correlation between atmospheric pollutants and meteorological factors and assess the respiratory risk of the atmospheric pollutants,and to explore their application in air pollution prevention and control,providing favorable strategies for air pollution supervise and preventive measures for the impact of air pollutants on health.Methods:This study describes the data in summary,draws distribution histograms and time trend graphs,identifies the outliers of atmospheric pollution based on time series models,analyzes the time-dependent correlations between atmospheric pollutants and meteorological factors based on ARIMA+GARCH+Copula model,and assesses the risk of air pollutants on the respiratory system based on generalized additive model+piecewise regression model and quasi-accumulation effect model.Results:Description results in summary:The average values of atmospheric pollutants NO₂（ug/m³）,SO₂（ug/m³）,PM₁₀（ug/m³）,CO（mg/m³）,and PM_2.5（ug/m³）were:53.871,50.498,74.862,1.497,and 104.827,the number of days（percentage）exceed the Ambient Air Quality Standard（GB 3095-2012）were 185（16.9%）,53（4.8%）,504（46%）,62（5.7%）and 573（52.3%）,respectively.Time trend showed peaks in winter.For the meteorological factors,the average of daily pressure,daily temperature,daily relative humidity,daily rainfall,daily wind speed and the hours of sunshine were 1012.6hpa,14.818°C,72.125%,1.19 mm,1.582 m/s and 5.027 hours respectively.The time trend of the average daily barometric pressure peaked in winter,others all peaked in summer.The time trend of respiratory disease outpatient data peaked in winter.Outlier results analysis:There were more CO innovation outliers（IOs）in winter and there was an increasing trend;SO₂ had more IOs in early and end of 2014;particulate matter(PM₁₀,PM_2.5)had more IOs at the end of 2016.The time-varying correlation results showed that the daily average air pressure was negatively correlated with various atmospheric pollutants,SO₂ was more obvious in summer;the daily average temperature was positively correlated with atmospheric pollutants in summer;the daily average relative humidity was positively correlated with various pollutants,PM₁₀ and PM_2.5 had a larger correlation coefficient;the daily average wind speed negatively correlated with atmosphere pollutants,NO₂,SO₂ and CO were more obvious in winter and the correlation coefficient with PM₁₀ and PM_2.5 was larger;the hours of sunshine was positively correlated with pollutants SO₂ in summer and negatively correlated in winter,and negatively correlated with other pollutants.In the upper tail correlation analysis,PM_2.5 was related to the daily average relative humidity in winter.In the lower tail correlation analysis,the daily average temperature was related to the air pollutants in the summer;the daily average relative humidity was related to the air pollutants other than SO₂.Risk assessment of respiratory disease:When the NO₂ concentration was 0-100μg/m³,the relative risk and 95%confidence interval（HR（95%CI））was 1.0023（1.0018-1.0032）for every 1μg/m³ increase,there was no statistical significance in the segment exceed100ug/m³;when SO₂ concentration was in the range of 0-100ug/m³,the HR（95%CI）was0.9985（0.9978-0.9991）,when exceed 150ug/m³,the HR（95%CI）was 1.0014（1.0000-1.0027）for every 1 ug/m³ increase.For every 1 mg/m³ increase of CO,HR（95%CI）was 1.0686（1.0442-1.0935）.Neither PM₁₀ nor PM_2.5 had Statistical differences.In the quasi-cumulative effect analysis,the data for three consecutive days were analyzed.We defined that HR3 represented the risk of respiratory system all higher in three days than normal,HR2 represented the risk of respiratory system was higher in two days and HR1represented the risk of respiratory system was higher in one day.The HR1（95%CI）of PM₁₀ was 1.0458（1.01-1.083）;the HR1（95%CI）,HR2（95%CI）,and HR3（95%CI）of CO)were 1.1211（1.0741-1.17）,1.1226（1.053-1.1967）and 1.2057（1.108-1.3119）respectively;HR2（95%CI）and HR3（95%CI）for PM_2.5 were 0.9533（0.9201-0.9877）and 0.9557（0.9143-0.9989）,respectively.ConclusionThis study assesses the risk of respiratory disease from air pollution in Shijiazhuang,and concludes that CO has a statistical significance and needs to be given priority to supervising.CO has IO in both 2015 and 2016 winters,indicating that there is an outbreak in winter and should be monitored in the winter;considering that winter CO is negatively related to atmospheric pressure,wind speed and sunshine respectively,it has no obvious relationship with temperature,It is positively correlated to relative humidity.However atmospheric pressure is relatively high,relative humidity,wind speed and sunshine duration are all relatively low in winter.Therefore,except for relative humidity,they are not conducive to the reduction of CO concentration in winter.Therefore,the prevention and control of CO needs to be strengthened in the winter.