The Association Between Health Among Preschool Students And Environment In Day Care Centers In Taiyuan

In recent years,with the rapid development of industrialization and urbanization in China,the type and quantity of pollutant discharged in the production process and people's life is increasing,air pollution is increasingly serious.Health problems arising from air pollution has become the focus of attention.Day care centers are important indoor environment for children,and there is evidence that indoor air quality and ventilation may affect their health.Therefore,study on the characteristics of the indoor air pollution in day care centers and its' relationship with children's health has important theoretical and practical significance for the prevention measures formulation of relevant department,improving indoor air quality and health of students.In this study,a cluster sampling method was used to randomly select ten day care centers in Taiyuan.All children?N=4500?in selected day care centers were conducted a questionnaire survey,and FeNO were measured among some children?N=507,245 girls and 262 boys?.The relationship between air pollutions in day care centres and the health status as well as clinical signs of airway inflammation in preschool children were investigated.Associations between FeNO,respiratory symptoms,and environmental data were examined by linear mixed models.Association between FeNO and fungal DNA was analyzed by the linear regression.Associations between fungal DNA and symptoms were examined by logistic regression.The results were as follows:?1?Mean indoor concentrations of CO₂,SO₂,NO₂,PM2.5,formaldehyde were 827 ppm,40.5 ?g/m3,43.0 ?g/m3,268 ?g/m3 and 22.8 ?g/m3 respectively.Mean outdoor concentrations of SO₂,NO₂,O3,PM2.5,formaldehyde were 106.6 ?g/m3,40.9 ?g/m3,22.4 ?g/m3,244 ?g/m3 and 4.1 ?g/m3,respectively.Indoor/outdoor ratio of SO₂,NO₂,PM2.5 and formaldehyde were 0.38,1.05,1.10 and 0.38 respectively,therefore,outdoor source of SO₂ was the main contribution of the indoor SO₂.At high indoor temperature,relative humidity was low,and indoor formaldehyde level was high.When the indoor relative humidity was high,the indoor CO₂ and PM2.5 levels were higher.Indoor NO₂ and SO₂ were closely related,formaldehyde and PM2.5 had significant negative correlation;?2?Geometric mean of FeNO was 9.1±1.5 ppb.In total,11.6% reported wheeze,6.0% dry cough,26.4% rhinitis and 29.2% pneumonia.There were positive associations between FeNO and wheeze?OR=1.10,95% CI: 1.00¹.22?and pneumonia?OR=1.09,95% CI: 1.00¹.19?.FeNO was positively associated with PM2.5 in the classrooms?OR=1.72,95% CI: 1.35².19?as well as outside the day care centers?OR=1.48,95% CI: 1.13¹.95?;?3?FeNO was negatively associated with dust total fungal DNA?P=0.030?,Penicillium DNA?P=0.026?,Versicolor DNA?P=0.012?and Streptomyces DNA?P=0.018?.Ever wheezing was negatively associated with dust total fungal DNA?P=0.037?,Penicillium DNA?P=0.041?,Versicolor DNA?P=0.028?.Wheezing 12 months was associated with dust Versicolor DNA?P=0.041?.Eczema last 6 months negatively correlated with petri dish total fungal DNA?P=0.002?,Penicillium DNA?P=0.005?,Versicolor DNA?P=0.046?and Streptomyces DNA?P=0.002?.Eczema in 12 months negatively correlated with Penicillium DNA?P=0.016?.Ever eczema negatively correlated with total fungal DNA?P=0.008?,Penicillium DNA?P=0.018?,and Streptomyces DNA?P=0.013?.The results of this study showed that the concentration of PM2.5 in the kindergarten environment in Taiyuan was higher,and was positively correlated with FeNO,wheezing and pneumonia.This suggests that PM2.5 may cause respiratory inflammation in preschool children.At the same time,it was suggested that the protective effect of fungal DNA on wheezing and eczema,consistent with the "hygiene hypothesis" theory.This result remains to be further demonstrated.