Conflict of interest: M-I. Kourid reports no conflict of interest. S. Couillard has received non-restricted research grants from the NIHR Oxford BRC, the Quebec Respiratory Health Research Network, the Association Pulmonaire du Québec, the Academy of Medical Sciences, AstraZeneca, bioMérieux, Circassia Niox Group and Sanofi-Genyme-Regeneron; is the holder of the Association Pulmonaire du Québec's Research Chair in Respiratory Medicine and is a clinical research scholar of the Fonds de Recherche du Québec; received speaker honoraria from AstraZeneca, GlaxoSmithKline, Sanofi-Regeneron and Valeo Pharma; received consultancy fees from FirstThought, AstraZeneca, GlaxoSmithKline, Sanofi-Regeneron, Access Biotechnology and Access Industries; has received sponsorship to attend/speak at international scientific meetings by/for AstraZeneca and Sanofi-Regeneron; is an advisory board member and retains stock options for Biometry Inc., a company which is developing a FeNO device (myBiometry); advised the Institut national d'excellence en santé et services sociaux (INESSS) for an update of the asthma general practice information booklet for general practitioners; and is a member of the asthma steering committee of the Canadian Thoracic Society.