What is passive smoking?

  • Passive smoking is breathing in other people’s tobacco smoke (second hand smoke)
  • It can increase the risk of cancer, heart disease and many other health conditions
  • All passive smoking is unsafe, and it is particularly dangerous for children

What is passive smoking?

Passive smoking, or second hand smoking, means breathing in other people’s tobacco smoke.

Second hand tobacco smoke comes from cigarettes, pipes, cigars and shisha pipes (hookah). Smoke is breathed out by a person who is smoking, and it also comes from the lit end of a tobacco product. Most tobacco smoke is invisible but it spreads easily and it can stay in the air for hours. It can also build up on surfaces, furniture and clothes. This is called third hand smoke.

Passive smoking is harmful and it can cause many of the same health effects as smoking does. Breathing in smoke while pregnant can also affect the unborn baby.

If you smoke, stopping completely is the best thing you can do to protect the people around you and benefit your own health.

Our tips and support to help you quit smoking for good


Health risks and effects of passive smoking

All passive smoking is unsafe. Tobacco smoke contains over 5000 chemicals.  Many of these chemicals are harmful and some can cause cancer.

Passive smoking puts people at higher risk of smoking-related diseases. It can cause lung cancer, heart disease and stroke. It may also increase the risk of some other types of cancer, such as breast cancer, and a serious lung condition called chronic obstructive pulmonary disease (COPD).

Coughing, headaches, a sore throat and eye and nose irritation are some of the short-term effects of passive smoking.


Second hand smoke and pregnancy

Breathing in second hand smoke during pregnancy can have serious risks for the baby during pregnancy and after birth. This includes an increased risk of low birth weight and cot death.

It is not clear yet if there is a link between exposure to second hand smoke before birth and childhood cancer.

Whether you’re about to become a parent, grandparent, or live with someone who’s pregnant, the best thing you can do to protect the unborn baby is to stop smoking completely.


Passive smoking and children

Passive smoking is particularly dangerous for children as their bodies are still developing.

Children and babies exposed to second hand smoke are at higher risk of health conditions including:

  • Asthma
  • Bacterial meningitis
  • Cot death
  • Middle ear infection
  • Respiratory infections

But the dangers of smoking around children go beyond damaging their health through second hand smoke. Children who have family members who smoke, or live with people who smoke, are more likely to start smoking themselves.


How can I protect myself and people around me from passive smoking?

Most exposure to second hand smoke happens in the home. Smoke can spread throughout the home from room to room and stay in the air for hours, even if you open the windows.

The only way to protect your loved ones from passive smoking is to keep the environment around them smoke free. The best way of doing this is to stop smoking completely.

We know that stopping smoking can be hard. There are things you can do to help reduce second hand smoke exposure until you, or the people you live with, are able to stop completely.

  • Always smoke outside and away from the house, and ask visitors to do the same.
  • Never smoke in the car or let anyone else smoke in the car.

Second hand smoke can reach very high levels inside a car, even with the windows open, because it’s a small, enclosed space. In the UK, it’s against the law to smoke in a vehicle with anyone under the age of 18 inside.

Our tips and support to help you quit smoking for good


Gee IL, Semple S, and Watson A, C. A. Nearly 85% of tobacco smoke is invisible - a confirmation of previous claims. Tob. Control . 22, 429 (2013).

International Agency for Reseach on Cancer. Personal Habit and Indoor Combustion: Second-hand Tobacco Smoke. Vol  100 E (2012).

Tobacco Advisory Group of the Royal College of Physicians. Passive Smoking and Children. (2010).

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