A 19-year-old university student with a history of physician-diagnosed asthma uses his salbutamol inhaler 3-4 times per week for daytime wheeze. He wakes with asthma symptoms twice a month and has no activity limitation. He has never been hospitalised for asthma. According to the 2021 Canadian Thoracic Society asthma guideline focused on mild asthma, what is the most appropriate change to his management?