The widespread use of traditional tobacco products makes it important to understand their physical nature and the consequences they have on the human body. This article examines the structure and operation of the conventional cigarette, focusing on the chemical reactions that occur during burning. The resulting health impacts are discussed, specifically concerning the respiratory and cardiovascular systems, as well as broader systemic effects.
Defining Combustible Cigarettes
A combustible cigarette is a product designed to be burned, typically consisting of shredded tobacco filler, paper wrapping, and a filter. The physical act of lighting and puffing initiates combustion, which is the defining characteristic of this product category. Combustion involves the burning of tobacco at extremely high temperatures, differentiating these products from non-combustible alternatives.
During an active puff, the temperature at the burning end, or coal, can surge to between 900°C and 950°C. Even when the cigarette is merely smoldering between puffs, the temperature remains high, often around 400°C. This intense heat drives the chemical reactions that create the smoke inhaled by the user. The burning process is the mechanism responsible for generating the vast majority of toxic compounds found in the smoke.
Chemical Release During Combustion
The high-temperature combustion of the tobacco and paper triggers pyrolysis and chemical synthesis, creating an aerosol that is inhaled. This smoke is not simply vaporized material but a mixture of over 7,000 chemical compounds. Of these, at least 70 are known carcinogens, and nearly 100 are defined as toxic or poisonous to humans.
The physical components of the smoke are separated into a gas phase and a particulate phase. The particulate phase contains tar, a sticky, brown material that is a collective term for the solid particles suspended in the smoke. These particles carry many cancer-causing substances and collect within the lungs upon inhalation. The gas phase includes highly toxic compounds like carbon monoxide, a colorless and odorless gas.
Other dangerous chemical agents formed during this burning process include benzene, a known industrial solvent, and formaldehyde. Heavy metals like arsenic and cadmium are also released. The formation of substances like tobacco-specific nitrosamines (TSNAs) occurs during the curing and burning of the tobacco, establishing a direct link between combustion and the intake of potent carcinogens.
Respiratory System Damage
The respiratory system is the first point of contact for cigarette smoke, leading to immediate and long-term damage. Chronic Obstructive Pulmonary Disease (COPD) is a progressive condition, and smoking is responsible for approximately 8 out of 10 cases. COPD includes chronic bronchitis, which causes persistent airway inflammation and excessive mucus production, and emphysema, which destroys the air sacs (alveoli), leading to permanent breathlessness.
The microscopic, hair-like projections lining the airways, called cilia, are immediately affected by the smoke. Cilia are normally responsible for sweeping foreign particles and mucus out of the lungs, but the chemicals in the smoke paralyze and eventually destroy them. This impairment of the lungs’ natural clearance system allows toxic substances to accumulate, further irritating and damaging the lung tissue. Damage to the lung cells also increases the risk of lung cancer; smokers are about 20 times more likely to develop it than non-smokers.
Cardiovascular System Impact
The toxic agents from combustible cigarettes enter the bloodstream through the lungs, causing systemic damage that heavily affects the heart and blood vessels. Carbon monoxide, a component of the smoke, binds to hemoglobin in red blood cells more readily than oxygen does, reducing the blood’s capacity to deliver oxygen to organs and muscles. This forces the heart to work harder to supply the body with the oxygen it needs, leading to an immediate increase in heart rate and blood pressure.
Smoking contributes significantly to atherosclerosis, a condition where plaque builds up in the artery walls, causing them to thicken and narrow. The chemicals in the smoke also damage the cells lining the blood vessels, making the blood more prone to clotting. This combination of narrowed vessels and increased clotting risk elevates the likelihood of a blockage, which can result in a heart attack. Smoking also doubles a person’s risk for stroke by increasing the chance of blockages or hemorrhages in the blood vessels supplying the brain.
Broader Health Consequences
Beyond the respiratory and cardiovascular systems, smoking combustible cigarettes has numerous other negative effects across the body. The immune system is weakened by exposure to smoke components, making individuals more susceptible to infections like pneumonia and influenza. The toxic exposure also increases the risk of developing type 2 diabetes and complicates its management by affecting insulin response.
Oral health suffers significantly, with smoking increasing the risk of periodontal disease, a chronic condition that destroys the gums and jawbone, often leading to tooth loss. For women, smoking can lead to fertility issues and increases the risk of complications during pregnancy, including miscarriage, stillbirth, and low birth weight. Exposure of non-smokers to secondhand smoke carries a risk of similar diseases. Non-smokers exposed to this smoke have a raised risk of coronary heart disease and stroke, while exposed children are more likely to suffer from respiratory infections and sudden infant death syndrome.