According to WHO estimates, over 8 million people die due to tobacco consumption across the world every year. In spite of so many awareness initiatives and repeated warnings, and even with rising death tolls, the use of tobacco goes on unabated. The lungs are already exposed to the outside world of dust and pollution, which is increasing day by day, and since the lungs bear the brunt of the effects of smoking, cancer, lung failure, and heart attacks are common outcomes.

How does smoking disrupt lung function?

Lungs are a pair of organs with very small air-filled alveoli, which act like a balloon in the chest cavity made up of elastic tissues. When we breathe, the air we intake passes through the trachea, a pathway in the lung and reaches the bronchioles and ultimately to the alveoli - the lung units. Oxygen-rich air is carried to the lungs, and carbon dioxide is ejected. Cilia, a hair-like structure along the trachea and lungs, help remove dust and rubbish that the air drags in. The lungs and the entire body then use the oxygen-rich blood. Smoking can derail the entire process.
A single puff of smoke is said to contain over 7,000 chemicals, of which at least 70 are known to cause cancer.

This is what happens when you smoke:

Coughing and respiratory injuries: Coughing is the most common problem a smoker experiences. This is caused by the smoke toxins, which go deeper and inflame the lungs. This leads to the production of excess mucus, causing not just coughing, but also bronchitis and pneumonia.
Blackening of the lungs: The tiny airways inside the lungs get inflamed due to smoking, causing tightness in the chest, shortness of breath and wheezing. Over time, the swelling of the airways turns into scar tissue, and the sticky tar builds up dangerously in the lungs. The colour of the lungs gradually turns from pink to black.
Damage to cilia: Cilia, the hair-like structures on the lungs, are temporarily paralysed due to nicotine present in cigarette smoke. It can no longer filter dust and debris from the air one breathes, often inviting respiratory infections and colds.
Damage to alveoli: Alveoli in our lungs are tasked with bringing oxygen to the body, and smoking damages them. This damage is irreversible, which means once they are destroyed, they can’t grow back. As a result, the ability of your lungs to carry oxygen-rich blood to the body suffers with an increase in the carbon monoxide present in cigarette smoke. All these seriously disrupt the functioning of the lungs and vital organs.

Dangers of smoking :

Shortness of breath
Coarse coughing
Impaired athletic performance
Degraded lung health
Bad breath
Yellow teeth
Body odour
High chances of developing cancer
Possibility of developing COPD, pneumonia
Diseases of the kidney, liver, pancreas, mouth, bladder, oesophagus
Heart attack
Stroke
Coronary artery disease
Damaged blood vessels