Assessing the impact of non-exhaust emissions on the asthmatic airway (IONA) protocol for a randomised three exposure crossover study

This paper describes the design of a randomized three-condition crossover study that will evaluate the acute impacts of non-exhaust emissions on lung function and airway immune status in 48 adults with asthma residing in London, England. The primary outcome of the study is change in FEV1, which will be assessed using a portable desktop spirometer (Vitalograph Alpha). Secondary endpoints will include changes in FVC, FEV1/FVC ratio, FeNO, oscillometry, asthma symptoms, and nasal mucosal immune response.