What is the Substance in cigarette smoke that affects breathing?

The primary substance in cigarette smoke that affects breathing is tar, which contains numerous harmful chemicals, including nicotine, carbon monoxide, and various toxins. Tar accumulates in the lungs, leading to inflammation and damage to the respiratory tissues, which can cause chronic obstructive pulmonary disease (COPD) and other respiratory issues. Additionally, carbon monoxide reduces the oxygen-carrying capacity of the blood, further impairing lung function.