Associations of ambient air pollutants with airway and allergic symptoms in 13,335 preschoolers in Shanghai, China.

Findings are inconsistent in studies for impacts of outdoor air pollutants on airway health in childhood. In this paper, we collected data regarding airway and allergic symptoms in the past year before a survey in 13,335 preschoolers from a cross-sectional study. Daily averaged concentrations of ambient sulphur dioxide (SO 2), nitrogen dioxide (NO 2), and particulate matter with an aerodynamic diameter ≤10 μm (PM 10) in the past year before the survey were collected in the kindergarten-located district. We investigated associations of 12-month average concentrations of these pollutants with childhood airway and allergic symptoms. In the two-level (district-child) logistic regression analyses, exposure to higher level of NO 2 and of PM 10 increased odds of wheeze symptoms (adjusted OR, 95%CI: 1.03, 1.01–1.05 for per 3.0 μg/m3 increase in NO 2 ; 1.22, 1.09–1.39 for per 7.6 μg/m3 increase in PM 10), wheeze with a cold (1.03, 1.01–1.06; 1.22, 1.08–1.39), dry cough during night (1.05, 1.03–1.08; 1.23, 1.09–1.40), rhinitis symptoms (1.11, 1.08–1.13; 1.32, 1.07–1.63), rhinitis on pet (1.11, 1.05–1.18; 1.37, 0.95–1.98) and pollen (1.12, 1.03–1.21; 1.23, 0.84–1.82) exposure, eczema symptoms (1.09, 1.05–1.12; 1.22, 0.98–1.52), and lack of sleep due to eczema (1.12, 1.07–1.18; 1.58, 1.25–1.98). Exposures to NO 2 and PM 10 were also significantly and positively associated with the accumulative score of airway symptoms. Similar positive associations were found of NO 2 and of PM 10 with the individual symptoms and symptom scores among preschoolers from different kindergarten-located district. These results indicate that ambient NO 2 and PM 10 likely are risk factors for airway and allergic symptoms in childhood in Shanghai, China. • We surveyed 13,335 preschoolers from five districts of Shanghai, China. • We studied effects of ambient NO 2 , SO 2 and PM 10 on airway and allergic diseases. • Periods of pollutant exposures and disease appearances were same in one year. • NO 2 and PM 10 was associated with increased risks of most studied diseases. [ABSTRACT FROM AUTHOR]