Secondhand smoke

Secondhand smoke is the smoke that comes from: 

• the burning of cigarette
• the smoke exhaled by the person smoking.

Smoke from cigarettes contains many chemicals that are harmful to health including cyanide, DDT, ammonia, and carbon monoxide. Learn more about what chemicals are in a cigarette.

There is no safe level of exposure to secondhand smoke. Secondhand smoke increases the risk of:

• heart disease
• lung cancer
• stroke
• nasal sinus cancer (cancer near and around the nose).

Before indoor smoking bans were in place in Aotearoa, it was estimated that about 350 people died every year because of exposure to secondhand smoke.

Effects on children

Babies and children can get particularly sick if they breathe in secondhand smoke. This is because their lungs are smaller, they have a faster breathing rate and their immune systems are still developing. They also often have no way of getting away from the smoke.

They are more likely to go to hospital, wheeze, and get coughs and colds. School-aged children are likely to need more time off school. Children whose parents smoke have twice the risk of lower respiratory illnesses like bronchitis and pneumonia compared to children of parents who do not smoke. 

Children need to be protected from secondhand smoke because it can increase the risk of:

• ear infections, like glue ear
• lung and breathing illness, like croup, bronchitis, bronchiolitis and pneumonia
• asthma, and it can make asthma worse
• delays in lung growth 
• Sudden Unexpected Death in Infancy (SUDI) or cot death
• meningitis.

In Aotearoa, we have a strong focus on maintaining smokefree environments, including homes, cars, schools, and outdoor spaces. 

Secondhand smoke and pets

Cats, dogs, birds, and other pets are at risk if they live with people who smoke. Like humans, animals can breathe in the toxins from secondhand smoke. 

Pets will also be exposed to toxic particles in the room, on the surfaces around them, and from being in contact with their owners. Toxins can get on their fur or feathers, which can be consumed when they are grooming themselves, or absorbed directly through their skin. 

Animals can develop breathing and respiratory problems, allergies, asthma, and cancer from being exposed to tobacco smoke.

Thirdhand smoke

The toxic chemicals from smoking are also absorbed into fabrics, walls, furniture, clothing and household dust where they can stay for a long time. This is called thirdhand smoke. 

Thirdhand smoke is linked to poorer health, especially in children. Children can even end up with poisons in their digestive system from touching contaminated objects and putting their hands in their mouth.