In the video below, I provide a comment and simple explanation why smoking is one of the main causes of poor asthma control.
If you have asthma and continue to smoke it is likely that your medication will be less effective. This is because asthma is an inflammatory disease of the airways. Since these airways are already very sensitive and irritated, inhaling smoke will trigger more inflammation and the medication will be less effective at controlling it. If the inflammation is not controlled, there is higher risk of getting more asthma attacks. You will likely require more medication and more frequent emergency treatment.