A million and a half of FFP2 masks rushed to Gironde: on paper, the measure is reassuring. In practice, it only addresses part of the problem. The smoke hanging over Bordeaux tonight is not simply wood smoke, and the FFP2 filters solid particles, not the toxic gases that accompany them. Nobody really explained this to residents queueing at pharmacies.
The announcement came directly from the Prime Minister. “To protect the personnel involved and the populations exposed to health-damaging fumes,” 1.5 million FFP2 masks were to be sent to Gironde, he announced in the evening. A strong gesture in the face of a convective fire, something unseen in the region: an unprecedented convective fire ravaging Gironde, with 30,000 hectares burned and 170,000 residents evacuated. On the Pont de Pierre in Bordeaux, the scene is striking: a widely diffused haze resembles winter fog, and some pedestrians cover their faces with scarves, for lack of a better option.
Key takeaways
- Why are authorities distributing masks that only address part of the problem?
- Which carcinogenic compounds does the FFP2 let through without protection?
- What figure should really make you seal doors and windows at home?
Two threats, one protection
The combustion of maritime pine resin does not produce a uniform smoke. It generates a cocktail in which solid particles and gases mingle, two families of pollutants that do not affect the body in the same way. On one side, fine particles PM2.5, small enough to penetrate the airways and lodge in the alveoli where gas exchange with the blood takes place. On the other, volatile organic compounds, benzene and formaldehyde at the forefront, which remain gaseous and directly attack the respiratory mucosa. A study relayed by a media outlet called Vert reminds us bluntly: VOCs like benzene or formaldehyde, both classified as “known carcinogens” by the International Agency for Research on Cancer (IARC).
Carbon monoxide completes this rather grim picture. A specialist quoted by Vert explains that this gas reduces the blood’s ability to carry oxygen, which can lead to fainting and death from poisoning during a fire. And the magnitude of the peaks is far from negligible: according to several studies, plumes from wood combustion can raise the concentration of fine particles in the air, by 150 to 300 micrograms per cubic meter, and up to 500 µg/m3 during the most severe episodes. This far exceeds usual vigilance thresholds, even in urban areas remote from the fire.
What the FFP2 does not do
Here is the point that few official communiqués detail clearly. An FFP2 mask is designed to filter suspended particles, not gaseous molecules. Its fibre structure captures solid and liquid aerosols through a combination of mechanical sieving and electrostatic capture, a mechanism that has no effect on a benzene or formaldehyde molecule, which passes through the filter as easily as air itself. Wearing an FFP2 protects against half of the toxic cocktail—the particulate portion—but lets through the other half, the irritant and carcinogenic gases. This is not a deception of the device: it is simply a technical limit that emergency communications rarely have time to explain amid a crisis.
Faced with this gap, the real remedy is not on the face but on the windows. Keeping the home closed, limiting outdoor air intake, and avoiding mechanical ventilation that draws in ambient air are the measures that reduce exposure to gases, where the mask remains powerless. Regional public health authorities confirm this for the most vulnerable groups: people with respiratory histories such as asthma, chronic respiratory failure, or heart failure should wear an FFP2 mask in case of direct exposure, but this is part of a broader set of precautions, not a standalone solution.
15 micrograms, the figure to watch
Now, when should one act? The scientific reference exists and is public. The World Health Organization has set, in its updated guidelines, a precise safety threshold: 15 µg/m3 as an average over 24 hours for PM2.5, versus an annual average recommended of only 5 µg/m3. This is the figure to look for on Atmo Nouvelle-Aquitaine readings before deciding to seal doors and windows or to cut ventilation. The regional monitoring body has already sounded the alarm: the fires in Gironde and Landes are heavily degrading air quality over a large part of the region, a deterioration linked to rising concentrations of particulate matter carried by the smoke.
In neighboring departments, the prefecture has already activated the first alert level. In Charente-Maritime, for example, the prefect decided to trigger the first level of the pollution episode management dispositif, a procedure of information and recommendations active across the department. On the ground, the effect is immediate among chronically ill patients: a Charente pharmacist reported that as soon as shops opened, asthmatics came to buy FFP2 masks, proof that the reflex exists, even if it remains incomplete.
A detail to keep in mind for the coming days: gases such as formaldehyde do not have an odor strong enough to reliably alert the nose, unlike the unmistakable burnt smell of particles. A room may smell almost normal while showing concerning concentrations of gaseous pollutants, which makes consulting Atmo Nouvelle-Aquitaine data more reliable than olfactory cues when deciding to stay indoors.
Sources: vert.eco | feuxdeforet.fr
