Air Pollution and Increased Levels of Fractional Exhaled Nitric Oxide in Children with No History of Airway Damage

Abstract

Air pollution is associated with a wide range of adverse respiratory events. In order to study the mechanism associated with these effects, the relationships between fractional exhaled nitric oxide (FeNO), a potential marker of airway inflammation, and exposure to air pollution were examined in schoolchildren. FeNO was measured in 104 children (34 asthmatics and 70 non-asthmatics) drawn from the general population simultaneously with air pollution assessments (fine particles with an aerodiameter under 2.5 μm, nitrogen dioxide, acetaldehyde, and formaldehyde, with pumps and passive samplers) in schoolyards and classrooms. Asthmatics exhaled more FeNO than non-asthmatics. FeNO levels were significantly elevated in both asthmatic and non-asthmatic children exposed to high concentrations of formaldehyde, acetaldehyde, and PM_2.5. Differences between high versus low exposure in non-asthmatics resulted in an FeNO increase ranging from 45% for indoor acetaldehyde to 62% for indoor PM_2.5. Stronger associations were found in non-asthmatic children who were atopic, suggesting that atopic children may be more sensitive to air pollution than non-atopic children. Exposure to air pollution may lead to airway inflammation, as measured by FeNO, in schoolchildren. These associations occur even in children with no history of airway damage and seem to be enhanced in atopic subjects.

Acknowledgments

We are particularly indebted to the students and parents without whom the study would not have been possible. We thank Yvon Le Moullec and Anne-Marie Laurent from Laboratoire d'Hygiène de la Ville de Paris, who centralized air pollution assessments, and Gilles Perron, Joseph Kleinpeter, and Alain Target from ASPA in Strasbourg, who analyzed the reproducibility of air pollution assessment. We also thank the study field teams and staff at the participating air quality districts in the six cities, which helped to establish the air pollution monitoring, and particularly Serge Pellier and Lionel Rosset from ATMO Auvergne. Allergen extracts were kindly provided by Stallergenes Laboratoires (France). A special thanks to Vincenzo Cocheo (Fondazione Maugeri, Italy), who helped in NO₂ and VOC assessment, and to Education Nationale and the school doctors, school principals, and teachers. We thank Prof. Jean Mercier from Comité Contre la Tuberculose et les Maladies Respiratoires, under the aegis of which the survey was conducted, as well as the field personnel, Jean-Claude Calart and Ginette Dollat. Thanks to Pr Mario Bedu, who greatly contributed to the implementation of the FeNO assessment used in the survey. Finally the authors thank Anders Boyd for his helpful comments. The French Six City study was supported by National Institute for Health and Medical Research (INSERM) (Programme Déterminants de la Santé), Ministry of Health (DGS), Environmental Programme PRIMEQUAL-PREDIT, Agence de la Maîtrise de l'Energie (ADEME), Mutuelle Générale de l'Education Nationale (MGEN), Agence Française de Sécurité Sanitaire de l'Environnement et du Travail (AFSSET), and ANTADIR.