People who do not smoke but breathe air polluted by tobacco (passive smoke) have also been shown to be at risk.

Breathing in air polluted by tobacco smoke increases the risk of the same heart and lung diseases as smokers. 

In addition, if they suffer from allergic, asthmatic or cardiovascular problems, their symptoms may be aggravated.

These risks are especially significant for pregnant women and children. During pregnancy there is an increased risk of miscarriage, premature birth or low birth weight.

In children, exposure to tobacco smoke increases the risk of sudden infant death and increases the risk of respiratory infections, asthma, pneumonia and otitis.

A worsening of asthmatic children exposed to tobacco smoke has also been shown.

The International Agency for Research on Cancer detected in 2002 the presence of 69 carcinogens in air contaminated by tobacco smoke, so breathing this air can also cause cancer.

According to the International Agency for Research on Cancer, after the combustion of tobacco, carcinogenic particles remain suspended in the air which, due to their small size, can reach deep corners of the respiratory system and be very harmful.