The crackling or popping sounds are generally refered to as "rales"....more often when inhaling than exhaling, however, it is very little concern unless there are other symptoms. But crackles are often associated with inflammation or infection of the small bronchi, bronchioles, and alveoli. Individuals in heart failure mode with congestion of the lungs (edema) will experience rales. I experienced rales that with congested heart failure. I occasionally have crackles but a cough clears the bronchi airways.
Thanks for your question. Take care,
Ken