Smoking refers to the process of burning a substance and inhaling the smoke into the lungs. The smoke of a cigarette contains not only volatile parts but also liquids and micro-particles. In total 4.800 different compounds are in the smoke and many are classified as dangerous to human health. A closer look shows that smoke consists mainly of nitrogen (N2), oxygen (O2), carbon monoxide (CO) and carbon dioxide (CO2). Carbon monoxide is very toxic due to its high affinity to haemoglobin, which is a protein in our blood. Normally it is responsible for carrying oxygen molecules to all parts of our body, but since the affinity to carbon monoxide is higher, it will carry less oxygen. This leads to a shortage of essential O2 and subsequent damage to other tissues such as the brain.
The harmful effect of tobacco smoke cannot be attributed only to the gas phase but also to the micro particles. For example, aromatic particles appear to be the reason for smoking related bladder cancer. Even non-pathogenic particles can harm our lungs, since they irritate the alveoli, making them more susceptible to infection.
In addition, tobacco smoke is considered dangerous because of the component nicotine, to which people become addicted. It binds to a receptor in our nerve-system and is highly addictive. Hence, it is making it difficult for people to quit.