During an air pollution alert, your baby can still go out, but for less time, away from major roads and outside rush hour. That is the guidance from the French health ministry for infants, who are classed as vulnerable alongside young children and pregnant women. Keep airing your home at the least polluted times of day, and don't seal yourself in: staying shut indoors is only justified in the event of an industrial accident.
This article goes through the official recommendations point by point: what a pollution alert is, how to find out about one, and what changes for a baby under one and for a child who is walking. It also covers windows, the car and the signs that mean you should see a doctor. It draws on the “Recommandations en cas d'épisode de pollution” (recommendations during a pollution episode) fact sheet from Santé.fr, on the ATMO index and on two publications from Santé publique France (the French public health agency).
Air pollution alert and baby: can you go out?
Yes. For infants, the ministry's fact sheet says outings can go ahead, but for a shorter time, especially near major roads and at peak pollution hours. For young children, intense physical activity should be limited; low- or moderate-intensity activities are still fine, for a shorter time near sources of pollution.
In other words, the twenty-minute stroll in a small park away from traffic goes ahead. The hour-long walk along a busy boulevard at 6 pm gets postponed or cut short. The guidance is about the dose, not a ban.
What is an air pollution alert, and how do you find out?
An air pollution alert, or episode, means a regulatory threshold has been exceeded, or is forecast to be, for one of the four monitored pollutants: PM10 particles, ozone, nitrogen dioxide or sulphur dioxide. There are two levels: the information and recommendation threshold, then the alert threshold. Exceeding them triggers procedures by the local prefecture, including the release of the health recommendations set out in the French ministerial order (arrêté) of 13 March 2018.
Day to day, the simplest reference is the ATMO index, published every day for each municipality by the approved air quality monitoring associations. Since its 2021 revision it has six classes, from ‘good’ to ‘extremely poor’, and covers five pollutants, including PM2.5 fine particles. A forecast for the same day and the next is published every day at around 2 pm on atmo-france.org. Particle episodes are more frequent in winter, in cold, still weather; ozone episodes happen in summer, in strong sunshine.
Why are infants considered vulnerable?
The ministry's fact sheet lists infants and young children among the vulnerable groups. The list also includes pregnant women, people over 65 and people with heart or respiratory conditions. The long-term effects are well documented. Santé publique France estimates that around 40,000 deaths a year among adults aged 30 and over are attributable to PM2.5 fine particles, over the 2016-2019 period. For children, the agency stated in October 2025 that bringing PM2.5 down to WHO guideline values would prevent nearly 30,000 new cases of childhood asthma a year.
Relative to their weight, an infant breathes faster than an adult, and their airways are still maturing. In a pushchair, they sit at the height of exhaust pipes. These two points come from physical common sense rather than an official measurement, but they explain the caution asked for near traffic.
The official recommendations, age by age
Under one
Outings continue, but shorter. Avoid major roads and rush hour. The signs to watch for are breathing difficulty, an unusual cough or wheezing: the fact sheet then says to see a health professional. For the very first months, the guidance in our article on going out with a newborn also applies.
Between one and three
A child who walks and runs is covered by the limit on intense activity. In practice, the game of chase in a park next to a ring road waits for a better day; quiet play in the local park is still fine, shorter than usual. With ozone, intense outdoor activity should be limited but indoor activities can carry on. A playground chosen away from traffic makes all the difference on those days.
During pregnancy
Pregnant women are on the list of vulnerable people, but the fact sheet has no specific guidance for them. The general rules apply: shorter outings, less intense activity, avoiding busy roads, seeing a doctor if you feel unwell.
What time should you go out during an air pollution alert?
The ministry's fact sheet gives the hours to avoid, and they depend on the pollutant. For particles, the peaks are often early in the morning and in the evening, at traffic hours. For ozone, it is the middle and end of the afternoon, when the sun is strongest; the fact sheet then advises avoiding afternoon outings. In practice, during a winter particle episode, late morning is often the best slot for a walk. During a summer ozone episode, it is the morning.
Unavoidable journeys, to nursery or an appointment, still go ahead: choose the least exposed route, side streets rather than the main road, and don't linger. Our article on public transport with a baby helps you plan these trips.
Should you keep the windows shut?
No. The ministry is clear: keep up your usual airing and ventilation habits, and air your home at the least polluted times of day. Staying shut in is not justified during an ordinary pollution episode; it is reserved for special cases such as an industrial accident. A closed-up home builds up its own pollutants, humidity, carbon dioxide and compounds given off by furniture or cleaning products, which weigh more heavily on an infant who spends their days there.
Two habits complete the airing: don't add indoor sources of particles on those days, such as candles, incense or an open fire, and use the extractor hood when cooking. Our article on indoor air pollution and babies' health covers these sources in detail. Outdoor naps, as practised in the Nordic countries, are put off during an episode: our article on Nordic outdoor naps gives the usual conditions.
Does the car protect your baby from pollution?
No, and it is a stubborn myth. The ministry's fact sheet states that the inside of a car does not protect against outdoor pollution. It advises against ventilating the car near heavy traffic or in tunnels, especially at rush hour. In a traffic jam, the air in the car is the air of the road. If a car journey is necessary, keep it short, with the windows closed in the most polluted areas, and air the car afterwards away from traffic.
What about a mask?
The health recommendations for pollution episodes do not mention wearing a mask, for adults or for children. None of the sources we read suggests one for an infant. The official answer comes down to three points: for less time, less intensely, less close to traffic.
Planning a shorter day outside
When the walk shrinks to twenty minutes, the rest of the day happens at home. Floor play time replaces the outing. A clear space on a baby play mat, a few objects swapped during the day and a parent sitting alongside are enough, at six months as at two years. Books, an earlier bath in the late afternoon and water play at the sink round off the programme. A pollution episode usually lasts from one to a few days: it is about adapting, not reorganising your life.
Signs that mean you should see a doctor
The ministry's fact sheet focuses first on breathing or heart difficulties, at any age. In an infant, this shows up as fast or wheezy breathing, a cough that sets in, difficulty feeding, a less responsive child. These signs are not specific to pollution: in autumn and winter, a particle episode often coincides with the season of respiratory viruses, including bronchiolitis. Our article on bronchiolitis 2026-2027 sets out the expected timeline. A fever in an infant is assessed by its own rules, regardless of air quality. A child with asthma or a respiratory condition needs medical advice on adjusting their treatment, which the fact sheet explicitly provides for vulnerable people.
Key takeaways
- Air pollution alert and baby: outings are still possible, shorter, away from major roads, outside rush hour.
- Particles: avoid early morning and evening. Ozone: avoid the afternoon.
- Keep airing your home, at the least polluted times; don't shut yourself in.
- The car does not protect; a mask is not recommended.
- Breathing difficulty, an unusual cough, wheezing: see a doctor.
Sources
- Ministère chargé de la Santé (French ministry of health), Santé.fr, “Recommandations en cas d'épisode de pollution”, published 9 August 2024, page updated 6 July 2026. The fact sheet reproduces the order (arrêté) of 13 March 2018 amending the order of 20 August 2014.
- Atmo France, “L'indice ATMO”, presentation of the index revised in 2021 (order of 10 July 2020).
- Santé publique France, “Pollution de l'air ambiant : nouvelles estimations de son impact sur la santé des Français”, press release of 14 April 2021.
- Santé publique France, “La pollution de l'air : des progrès pour notre santé nécessaires et possibles”, news item of 13 October 2025.
- The remarks on an infant's breathing rate, the height of the pushchair and how to organise the day are based on practical reasoning, not on an official recommendation.
