| Objectives Filling in missing polycyclic aromatic hydrocarbons?PAHs?concentration on unmonitored date;To explore the relationship between PAHs in atmospheric fine particulate matter(PM2.5)and children's chronic lower respiratory tract diseases in Tangshan City;Quantitative analysis the effect of PAHs on the daily outpatient volume of children with chronic lower respiratory tract disease and its lagging effect.Methods Collecting PAHs concentration from two monitoring sites in Tangshan City from 2015 to 2017,meteorological data for the same period and PM2.5.5 concentration and daily outpatient volume of children with chronic lower respiratory tract diseases?J40-J47?;Perform a Box-Cox transformation on the data and use a multiple linear stepwise regression method to establish an equation to fill the PAHs concentration on the unmonitored date;Analysis of the relationship between the concentration of PAHs in PM2.5 and the daily outpatients of children with chronic lower respiratory tract disease using Spearman correlation coefficient;Using multivariate linear stepwise regression method to establish the equation of daily outpatient volume and 16 kinds of PAHs components in children with chronic lower respiratory disease;Establish a time-series generalized additive model analyze the effect of PAHs concentration on the daily outpatient volume of children with chronic lower respiratory disease and its hysteresis effect,and quantitatively evaluate the effect of PAHs concentration on children's health.Results 1 After the Box-Cox transformation,the regression equations of PAHs and average temperature,wind speed and PM2.5 established by the two monitoring points were statistically significant?P<0.001?,the equations are Y1'=4.898-0.084X1-0.195X2+0.002X3 and Y2'=4.756-0.089X4-0.195X5+0.003X6 respectively;The mean and standard deviation of residuals between measured and predicted values of PAHs of the two monitoring points in 2017 were 3.69±0.65 and 2.95±0.48,respectively;the average relative errors were 0.06 and 0.05 respectively,There is no statistical difference?P>0.05?.2 Correlation analysis showed that PAHs was negatively correlated with the average temperature,wind speed and hours of sunshine,and positively correlated with daily outpatient volume and mean barometric pressure and PM2.5.3 The average concentration of PAHs in atmospheric PM2.5 in Tangshan City was 78.76 ng/m3,and the monthly average concentration of PAHs is"U"type distribution throughout the year,which was similar to the monthly mean change of the number of outpatients with chronic lower respiratory tract disease in children.4 Correlation analysis showed that polycyclic aromatic hydrocarbons such as Any,BaP,Phe,BaA,Flu and Chr elta were positively correlated with the amount of chronic lower respiratory disease in children.5Multivariate linear stepwise regression equations showed that high-ring?4-6 rings?PAHs had a greater impact on children's chronic lower respiratory disease daily outpatient visits.6 The results of the generalized additive model showed that the PAHs in the atmospheric PM2.5 were positively correlated with the daily outpatients of children with chronic lower respiratory tract diseases and lag behind for a certain period of time.The effect of the PAHs on the day and the lag of 3 days?lag03?was most significant.For every 10 ng/m3increase in PAHs concentration,the number of outpatients with chronic lower respiratory tract disease increased by 0.56%?95%CI:0.44%?0.69%?.7 According to the results of gender stratification analysis,PAHs were positively correlated with the daily outpatients of chronic lower respiratory tract diseases of different genders and lag behind for a certain period of time.The effect of the PAHs on the day and the lag of 3 days?lag03?was most significant.For every 10 ng/m3 increase in PAHs concentration,the daily outpatient volume of chronic lower respiratory disease in boy and girl increased by0.58%?95%CI:0.41%?0.75%?and 0.55%?95%CI:0.35%?0.74%?respectively.8According to the stratified analysis of age groups,PAHs were positively correlated with the daily outpatients of chronic lower respiratory tract diseases in different age groups and lag behind for a certain period of time.For every 10 ng/m3 increase in PAHs concentration,chronic lower respiratory tract disease number for children of different ages Outpatient volume increased by 0.38%?95%CI:0.14%?0.61%?,0.23%?95%CI:0.12%?0.33%?,0.96%?95%CI:0.74%1.18%?,and 1.28%?95%CI:0.94%?1.63%?.Conclusions After the box-cox transformation of the dependent variables,the equation of PAHs concentration and average temperature,average wind speed and PM2.5 of the two monitoring points fitted by multiple linear stepwise regression method has a good prediction effect;The concentration of PAHs in atmospheric PM2.5 in Tangshan City and the trend of outpatients in children with chronic lower respiratory tract diseases were similar,with obvious seasonality,highest in winter and lowest in summer.The high-ring?4-6 ring?PAHs component has a greater impact on the daily outpatient volume of children with chronic lower respiratory disease;Increased concentration of PAHs in atmospheric PM2.5 will lead to an increase in the number of outpatients with chronic lower respiratory tract disease in children.The generalized additive model of time series analysis showed that the effect of PAHs concentration on the daily outpatient volume of chronic lower respiratory disease in children may have a lag effect of 1-3 days.Figure 15;Table 9;Reference 130... |
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