Asthma is a chronic inflammatory airway disease that affects around 334 million individuals worldwide. Patients with severe asthma have persistent respiratory symptoms, reduced quality of life and frequent exacerbations. Despite important breakthroughs in the treatment of severe asthma, some patients remain uncontrolled and at risk of exacerbations. Exposure to external triggers such as allergens and air pollution can aggravate asthma by inducing inflammatory processes. In this project we will investigate the mechanisms leading to the aggravated response to air pollution in asthma at a single cell level. We will use a translational approach, in which we will combine studies in a murine asthma model, with analyses on samples from asthma patients and controls to identify the key molecular processes associated with air pollution exposure in severe asthma and to identify whether they can serve as biomarker for treatment response.