Facts about secondhand smoke | Smoke Free Families

What is secondhand smoke?

Secondhand smoke is a mix of the smoke from the lit end of your cigarette and the smoke you breathe out. Non-smokers who breathe in secondhand smoke take in toxic chemicals the same way smokers do (American Cancer Society).

Smoke from the end of a cigarette is even more toxic and has smaller particles which make their way into the lungs and the body’s cells more easily (American Cancer Society).

Evidence shows nearly 85% of secondhand smoke is invisible and odourless, which means it lingers long after you can see it or smell it.

Why is it harmful?


Some of these chemicals are found naturally in tobacco, some are absorbed by the plant from the soil, air or fertilisers, others are formed when tobacco leaves are processed, while others form when the cigarette burns (Cancer Research UK).

Many of these chemicals are poisonous and more than 70 may cause cancer (International Agency for Research on Cancer/ IARC).

Courtesy of Cancer Research UK

How can it hang around for five hours?

Opening a window or restricting smoking to a specific room does little to protect against exposure to secondhand smoke. This means it will still be there when your kids come home from school.

And because it's made up of particles that are smaller than household dust, it moves easily from room to room, as you move around and open doors.

Watch our film to discover whether it is ever safe to smoke indoors..

How can it affect my child?

Children are more vulnerable to secondhand smoke. They have smaller airways, breathe faster, and their lungs and immune systems are still developing.

Secondhand smoke can affect children of all ages. The Royal College of Physicians report Passive Smoking and Children detailed the harm this causes to families across the UK:

  • Children exposed to secondhand smoke at home are more at risk of coughs, colds, ear problems, chest infections, wheezing, asthma, phlegm, breathlessness and poorer lung function. Children exposed to smoke are also more at risk of meningitis and sudden infant death.
  • Secondhand smoke in the UK accounts for over GP 300,000 consultations a year with children
  • Every year, 9,500 children in Britain are admitted to hospital because of the effects of secondhand smoke.
  • Secondhand smoke accounts for 40 cot deaths in the UK every year.
  • Smoking during pregnancy raises risks of miscarriage, stillbirth, prematurity, low birth weight, stillborth, neo-natal or sudden infant death.
  • Children growing up with a parent or others who smoke around them are more likely to become smokers themselves.

Can it affect adults' health too?


Exposure to secondhand smoke has immediate adverse effects on the cardiovascular system and can cause coronary heart disease and stroke. Even brief exposure to secondhand smoke can damage the lining of blood vessels and cause your blood platelets to become stickier (US Centres for Disease Control and Prevention).

Exposure to secondhand smoke also increases risk of lung cancer and heart disease in non-smokers (International Agency for Research on Cancer).

What can I do?

Even if you open a window, smoke in a different room or smoke at the open back door it's not enough to protect your family .

And when you consider the harmful effects that secondhand smoke can have on your child's developing lungs, it's not worth the risk to smoke indoors.

Everyone's situation is different - we can help you find ways to keep your home smokefree.

The best way to protect your family from the hidden dangers of secondhand smoke is to find ways of quitting or take it right outside, making sure you shut windows and doors behind you so the smoke doesn't drift back in.

Find out more about the hidden dangers of secondhand smoke

Or, for help quitting visit ways of quitting