Spatio-temporal Analysis Of The Impact Of PM_2.5 On Primary School Absenteeism Due To Illness In Jiangsu Province

Ambient air pollution is a global problem.With the progress of urbanization,China is suffering from severe air pollution.Multiple epidemiological studies have proven adverse health effects of ambient air pollutants on public health,especially fine particulate matter(PM2.5).PM2.5 is tightly associated with morbidity and mortality derived from cardiopulmonary diseases.Children are the sensitive people with ambient air pollution.Primary school absenteeism,especially the primary school absenteeism due to illness,is recognized as a practical and sensitive disease monitor indicator for healthy school-age children.It not only plays an important role in exploring the relationship between air pollution and children’s health,but also means a lot for the students’ future growth and the benign operation of the social education system.However,the number of relevant studies is still limited to date,eapecially in China.The existing relevant studies have largely used the average value of measured pollutant concentrations at fixed monitors to represent the exposure of large population which ignored the spatial variations of air pollutants.In addition,existing studies have insufficient consideration of the spatial heterogeneity of socio-economic conditions.This paper takeing Jiangsu province as the study area,based on the spatio-temporal model predicting results of PM2.5 concentration,explored the relationship between PM2.5 and the primary school absenteeism of 2551 primary schools in Jiangsu province in 2016 school year(2016.9-2017.6)both from time dimension and space dimension.Then the acute effects of primary school absenteeism due to illness and high-risk areas exposed to PM2.5 can be identified.The main conclusions of this paper are included in the following aspects:(1)Exposure assessment of PM2.5This paper established land use regression spatio-temporal model(ST Model)for PM2.5 based on national monitoring network and simulated the two-week average concentration and long-term average concentration of PM2.5 based on the addresses of primary schools in Jiangsu province.As was shown in the 10-fold cross-validation results,the time explained variance of the spatio-temporal model was 82%(RCVobs2=0.818),the spatial explained variance of the spatio-temporal model was 73%(RCVaverage2=0.730).The predicted concentrations of PM2.5 for long-term average and four seasons in 2016 school year average in Jiangsu province were all exceed the secondary limit of the ambient air quality standards in China(35μg/m3).(2)Time series analysis of the impact of PM2.5 on primary school absenteeism due to illnessFrom the perspectives of primary school students’ overall,gender,grade level(12,3-4,5-6)and respiratory diseases,generalized additive model(GAM)of poisson regression was employed for analyzing the effect of PM2.5 on primary school absenteeism due to illness.The analysis showed that:For each increase of 33.12μg/m3 in PM2.5,the RR(Relative Risk)(95%CI)of total daily primary school absenteeism,respiratory diseases were 1.026(1.023-1.030)、1.025(1.021-1.029)respectively;The RR(95%CI)of boy,girl were 1.029(1.024-1.034)、1.023(1.017-1.028)respectively;The RR(95%CI)of grade level(1-2,3-4,5-6)were 1.027(1.022-1.032)、1.025(1.0191.03 1)、1.025(1.017-1.033)respectively.Under the exposure of ambient PM2.5,the primary school absenteeism due to illness risk of boy was higher than that of girl;the primary school absenteeism due to illness risk was reduced from lower grade to higher grade;There was a lag effect of PM2.5 on primary school absenteeism.Overall,the best lag day were the 3rd day.(3)Spatial analysis of the impact of PM2.5 on primary school absenteeism due to illnessBased on the PM2.5 predicting concentrations of primary schools in Jiangsu province,considering the influencing factors of social,economic and environmental geography,geographically weighted regression(GWR)was employed to explore spatial varicance of the relationship between ambient PM2.5 and primary school absenteeism from four perspectives of primary school students’ overall,gender,grade level(1-2,3-4,5-6)and respiratory diseases respectively.The analysis showed that:Ambient PM2.5 was significantly positive correlated with the primary school absenteeism in areas with low economic development,low population density,and low urbanization rate,which was concentrated in Huai’an City and Suqian City in Jiangsu Province.From these four perspectives of primary school students’ overall,gender,grade level(1-2,3-4,5-6)and respiratory diseases,the t test results of the local regression parameter of PM2.5 showed a geographical consistency for the distribution of positive correlation at 0.01,0.05,and 0.1 level.To a certain extent,it suggests that the spatial distribution regularity of the relationship between ambient PM2.5 and primary school absenteeism due to illness may exist under different social and economic environment.The above results will help the government identify the acute effects of atmospheric PM2.5 exposure on primary school absenteeism due to illness and high-risk areas where primary school students may be absent from school due to exposure to ambient PM2.5,then more targeted policy can be undertaken.