Dangers of second-hand smoke

Breathing in other people’s smoke is known as exposure to second-hand smoke or passive smoking. When you smoke, it’s not just your health that’s put at risk, but the health of anyone around you.

Most second-hand smoke comes from the tip of a burning cigarette or from what the person smoking breathes out. This makes it almost impossible to direct smoke away from those around you.

If you only smoke in one area of your home, the harmful chemicals will spread rapidly from room to room. It can linger for up to 5 hours.

If you smoke in a confined space like a car, you’re exposing your passengers to even more harmful chemicals. This is why smoking in cars with children on board has been banned in Scotland since December 2016.

Risks to other people

People exposed to second-hand smoke face the same dangers as people who smoke themselves. They too inhale the same poisonous gases and thousands of toxic chemicals found in tobacco smoke. Their risk of developing smoking-related diseases will also increase.

Pregnant women exposed to second-hand smoke will pass on harmful chemicals to their babies.

Second-hand smoke is also particularly harmful for:

  • children
  • anyone with long-term heart and/or breathing conditions

Short-term effects

Some short-term effects from exposure to second-hand smoke include:

  • coughing
  • headaches
  • eye and nasal irritation
  • sore throat

Long-term effects

Long-term effects from exposure to second-hand smoke include increased risk of:

  • coronary heart disease (risk increased by 25 to 30%)
  • lung cancer (risk increased by 20 to 30%) and other cancers
  • stroke (risk increased by 20 to 30%)
  • increased risk of chronic obstructive pulmonary disease (COPD) and other breathing problems

Breathing in second-hand smoke makes the blood stickier. This means there’s an increased risk of blood clots forming, even with brief exposure. A blood clot can block an artery and cause:

In pregnant women there’s an increased risk of complications during the pregnancy and after the birth. The most likely risk is that your baby could weigh less than expected.

Do

  • smoke outside – this won’t completely protect others but it will reduce the risk
  • clean and steam carpets regularly to reduce the toxic particles at home

Don’t

  • do not leave cigarette butts or ashtrays in easy access of children, other people or pets

Risks to children

Children breathe faster than adults. This means they take in more of the harmful chemicals in second-hand smoke. They’re even more sensitive to smoke than adults because their bodies are young and still developing.

Babies and children exposed to a smoky atmosphere are likely to have increased risk of:

  • breathing problems
  • illnesses and infections
  • reduced lung function
  • wheezing illnesses and asthma
  • sudden and unexpected death in infancy (SUDI)
  • certain ear, nose and throat problems, in particular middle ear disease

There’s also an increased risk of developing:

  • bacterial meningitis
  • bronchitis
  • pneumonia
  • acute respiratory illnesses

Risks to pets

Second-hand smoke can be damaging to pets health too.

Family pets are at a high risk of disease and illness due to second-hand smoke. This can result in higher vet costs and emotional distress on families.

Over 7,000 harmful chemicals are found in smoke, with 70 known to directly cause cancer. These pose a threat to all kinds of pets including dogs, cats, birds, guinea pigs and even fish.

There are small steps you can take to reduce harm from exposure to second-hand smoke.

Take it Right Outside

Visit our Take it Right Outside campaign for quizzes, hints and tips on second-hand smoke.

Quit Your Way Scotland

Contact Quit Your Way Scotland for additional support and advice.

Last updated:
20 December 2022

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