How and When can a mask be NOT be effective?

Wearing it wrong if it is ripped torn made the wrong way not cdc approved wearing a disposable mask more than once and other people just not wearing it right

Air goes past the epiglottis and into the trachea when you breathe in. from there, it goes to your vocal cords in the larynx until it reaches the bronchi. from the bronchi, air passes into each lung.