Levels Of Fractional Exhaled Nitric Oxide In Children In Relation To Air Pollution In Chinese Day Care Centres

OBJECTIVE: To study fractional exhaled nitric oxide (FeNO) levels among pre-school children in day care centres (DCCs) in relation to indoor and outdoor air pollution in northern China.DESIGN: This was a cross-sectional study among children aged 5 years from 34 classrooms at 10 randomly selected DCCs in Taiyuan, China. A total of 507 (99%) children participated. Air pollution and carbon dioxide (CO2) levels were measured in the classroom and outside the school. Linear mixed models were applied for statistical analysis.RESULTS: The geometric mean FeNO was 9.1 +/- 1.5 parts per billion; 11.6% of children had wheeze, 6.0% had dry cough, 26.4% rhinitis symptoms, 1.6% ever physician-diagnosed asthma and 29.2% ever physician diagnosed pneumonia. FeNO levels were associated with current wheeze (P = 0.04) and ever physician diagnosed pneumonia (P = 0.05). The mean indoor concentrations were particulate matter with a diameter of <2.5 pm (PM2,5) 268 mu g/m(3), sulfur dioxide (SO2) 40.5 mu g/m(3), nitrogen dioxide (NO2) 43.0 pg/m(3) and CO2 827 parts per million. Outdoor concentrations were PM2.5 244 mu g,/m(3), SO2 106.6 mu g/m(3) and NO2 40.9 pg/m(4). PM2,5 levels inside (P= 0.002) and outside DCCs (P = 0.05) were associated with FeNO levels.CONCLUSION: PM2.5 levels inside and outside DCCs in China can contribute to airway inflammation in preschool children. Children with current wheeze and ever physician-diagnosed pneumonia may have higher FeNO levels.