Is secondhand smoke or vaping around my baby safe?

The verdict

No, and this is one of the strongest positions in UK public health.

The NHS states that passive smoking is especially harmful for children because they have less-well-developed airways, lungs and immune systems, and that children who live in a household where at least one person smokes are more likely to develop asthma, chest infections such as pneumonia and bronchitis, meningitis, ear infections, and coughs and colds.

The Lullaby Trust adds the sudden infant death dimension: the risk of SIDS is higher if you or your partner smokes while you are pregnant, or after your baby is born.

On vaping the honest answer is different in kind. The Lullaby Trust states that there is no research available on vaping and SIDS yet, that giving up vaping is therefore the best option, and that if you do choose to use a vape you should keep your baby away from vapes and their vapour.

Why smoking outside is not a complete answer

This is the part most smoking parents have not been told clearly.

The NHS states that opening windows and doors, or smoking in another room in the house, does not protect people, because smoke can linger in the air for hours after a cigarette is finished even with a window open, and because smoke limited to one room spreads to the rest of the house.

It also addresses the residue problem directly: even if you smoke outside, chemicals from the smoke can stay on your clothes and affect the people around you. For a baby held against a chest, that clothing is the interface.

None of which is an argument against smoking outside - it is much better than smoking indoors. It is an argument against believing the problem is solved by it. The NHS's stated position is that the only way to protect friends and family from secondhand smoke is to keep the environment around them smoke-free, and the best way to do that is to quit completely.

The car is the worst place

The NHS says children are particularly vulnerable in the family car, where secondhand smoke can reach hazardous levels even with the windows open. This is why the UK legislated: smoking in cars and other vehicles carrying children was banned in 2015, and it is against the law to smoke in a private vehicle if there is a young person under 18 present.

That is a legal prohibition with a fixed penalty attached, not advice.

Vaping: what is and is not known

Vaping is not equivalent to smoking, and it is not established as safe around a baby. Both halves matter.

For an adult who smokes, switching to vaping reduces their own exposure to the products of combustion, which is why UK public health policy supports vaping as a quitting aid. The Office for Health Improvement and Disparities' evidence updates on nicotine vaping in England set out that position for adults.

None of that is a statement about infant exposure. Vape aerosol is not water vapour: it carries nicotine, propylene glycol, glycerol and flavouring compounds, and there is far less evidence about what sustained exposure means for an infant airway than there is for tobacco smoke.

The Lullaby Trust's guidance is the most useful because it is explicit about the uncertainty rather than papering over it. There is no research yet on vaping and SIDS; stopping is best; if you vape, keep your baby away from vapes and their vapour; and because there is no research on bedsharing and vaping, do not share a bed with your baby if you vape.

There is also an acute poisoning hazard that has nothing to do with vapour. E-liquid is concentrated nicotine in a small, brightly coloured, often sweet-smelling bottle, and nicotine is toxic to infants in small quantities. Store liquids and devices where a baby or toddler cannot reach them.

What to do if you or someone in the house smokes

Make the home and car completely smoke-free, without exception and including visitors. The Lullaby Trust's phrasing is to keep your baby out of smoky areas, and the NHS's is to always smoke outside and to ask visitors to do the same.

Change or cover clothing before holding the baby if you can. It is imperfect but it reduces what is transferred.

Take the offer of help. The Lullaby Trust lists national stop smoking services - 0300 123 1044 in England, 0800 84 84 84 in Scotland, 0800 085 2219 in Wales - and NHS stop smoking services are free. Support roughly triples the odds of a quit attempt succeeding compared with willpower alone.

Do not bedshare if you or your partner smokes. This is a well-established interaction: the risk associated with bedsharing is substantially higher where a parent smokes, which is why the Lullaby Trust singles it out.

Where guidance differs

On tobacco there is no disagreement anywhere. On vaping there is a real difference in how much each country is willing to say.

The UK is the most permissive about adult vaping as a quitting route, through the Office for Health Improvement and Disparities' evidence reviews, while the Lullaby Trust is careful to separate that from infant exposure and to say the evidence base for babies does not exist yet.

The American Academy of Pediatrics writes primarily about tobacco smoke exposure, setting out the increased risk of respiratory infections, ear infections, asthma and SIDS in exposed infants, and takes a more restrictive line on e-cigarettes generally than UK policy does.

Ireland's HSE runs the same quit-focused public health approach as the NHS, with free stop smoking support.

The practical answer that satisfies all of them: nothing that produces smoke or vapour anywhere near the baby, and nowhere in the home or car at all.