There is growing evidence that asthma symptoms can be aggravated or events triggered by exposure to indoor NO2 emitted from un-flued gas heating. The NO2 impact on respiratory health of children with asthma was examined as a secondary analysis of a randomised community trial involving 409 households in winter in 2006 (June-September). Geometric mean indoor NO2 concentrations were 11.4 íg/m3; outdoor NO2 concentrations were 7.4 íg/m3. Higher indoor NO2 concentrations (per logged unit increase) were associated with greater daily reports of lower (mean ratio 14, 95% confidence interval [CI], 1.12-1.16) and upper respiratory tract symptoms (mean ratio 1.03, 95% CI, 1.00-1.05), more frequent cough and wheeze, and more frequent reliever use during the day; it had no effect on preventer use. Higher indoor NO2 concentrations (per logged unit increase) were associated with a decrease in morning (-17.25 mL, 95% CI, -27.63 to -6.68) and evening (-13.21, 95% CI, -26.03 to -0.38) forced expiratory volume in 1-s readings. Outdoor NO2 was not associated with respiratory tract or asthma symptoms, medication use, or lung function measurements. The authors concluded that the findings from the present study indicated that reducing indoor NO2 exposure is important to improve the respiratory health of children with asthma.
Authors: Gillespie-Bennett, J.; Pierse, N.; Wickens, K.; Crane, J.; Howden-Chapman, P. ;Full Source: European Respiratory Journal 2011, 38(2), 303-309 (Eng) ;