Ozone pollution: what is it, danger, what to do?

Extreme heat and lack of wind favor the ozone pollution. In France, the Prev’Air website offers a map showing the concentration of ozone in the air. “You don’t have to not confuse the “ozone layer”, that can be found at an altitude of more than 10km and protects the Earth from UV radiation emitted by the sunand theozone, which is found closer to the surface and can become toxic when its concentrations are too high”, points out Augustin Colette, head of the Atmospheric Modeling and Environmental Mapping Unit at Inéris.

Definition: what is ozone?

Ozone is a air pollutant says “secondary” because it is not directly released into the atmosphere by an activity (industry, transport, agriculture, residential, etc.) but it is formed by chemical reactions between several different pollutants. “Its formation can therefore take a few hours, especially since it also depends on the weather conditions (temperature and sunshine). Once formed, it is able to disperse on a continental scale. explains Augustin Colette.

What is the composition of ozone?

Ozone is made up of many chemical compounds including:

• nitrogen oxides (NOx),
• volatile organic compounds (VOCs) including methane (CH4)
• carbon monoxide (CO).

“THE nitrogen oxides come mainly from road traffic, but also industry and heating. VOCs are hydrocarbons emitted by industrial and refining activities, by road traffic and certain domestic activities. Finally, methane comes mainly from agricultural activities”, explains our expert.

​​​​​​​What are the causes of ozone pollution?

“In the majority of cases, the peak of ozone pollution is due to strong heat, I’lack of wind and significant pollutant emissions. This trio is unparalleled in raising concentrations of this toxic gas.” explains Augustin Colette.

What are the symptoms of ozone pollution?

• Cough
• Eye, nose and mouth irritation
• Difficulty breathing and marked shortness of breath
• Headache
• chest pain

What solutions to protect yourself?

“The first of these is the reduction of road traffic and industrial emissionswhich is why as soon as pollution increases, the differentiated circulation is setup. Measures to restrict industrial activities also exist, even if these are less visible to the general public” says our expert. During ozone pollution peaks, it is recommended :

• ofavoid going out in the afternoon,
• of do not practice intense physical and sporting activities in the open air,
• in case of respiratory discomfort or cardiac symptoms, make an appointment with your doctor without delay.

What are the health hazards of ozone pollution?

ozone poses a problem when its concentrations in the air are high and there is no wind to scatter them. It can then cause numerous inflammatory reactions of the bronchi but also cardiac. It particularly disturbs the elderly, those who suffer from asthma and young children. Repeated ozone concentrations may also be responsible for a rebound in mortality. According to a study published by Santé Publique France, “Chronic exposure to ozone would be responsible for nearly 500 deaths from respiratory causes each year” In France. “Ozone also has significant effects on ecosystems, leading for example to substantial losses in agricultural yields”, adds the expert.

Does ozone have an odor?

Yes, ozone has a acrid odor and a bluish color. “But it is only at very high concentrations that its smell and color are remarkable.“, specifies Augustin Colette.

Thanks to Augustin Colette, Head of the Atmospheric Modeling and Environmental Mapping Unit at Inéris.