Dioxyde de soufre (SO2) : impacts sur la santé et l'environnement

Sulfur dioxide (SO2): sources and health impacts

Sulfur dioxide or SO2 is an air pollutant, considered a key indicator of pollution that is essential to monitor according to WHO recommendations to improve the quality of life and health of populations.

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What is sulfur dioxide (SO2)?
What are the sources of sulfur dioxide (SO2)?
What are the environmental and health impacts of sulfur dioxide?
How to protect yourself and reduce sulfur dioxide (SO2) emissions?

What is sulfur dioxide (SO2)? 

Sulfur dioxide (SO2) is a colorless gas with a pungent odor that is irritating to the eyes and respiratory tract above a certain concentration. This air pollutant is mainly produced by the combustion of fossil elements (coal, petroleum, fuel oil,) and the smelting of sulfur-containing ores, during which the impurities are oxidized to sulfur dioxide by oxygen (O2).

💡 Good to know: SO2 levels have declined alarmingly since the 1990s. This improvement is due to several factors: the gradual shift from sulfur-rich fuels (coal, fuel oil) to cleaner fuels (natural gas), thereby limiting the sulfur content of fuels.

Sulfur dioxide (SO2): what are the sources? 

Sulfur dioxide is a primary pollutant, i.e. directly emitted by human activities, unlike other pollutants such as ozone, particulate matter and part of NO2,which are secondary pollutants (produced by the chemical or photochemical reaction of one or several primary pollutants).

SO2 is mainly emitted during the combustion of fossil fuels, such as coal and oil.

More than half is emitted by industrial activities, including those related to power generation such as thermal power plants. But it is also released by residential and business heating.

Sulfur dioxide also comes from volcanic activity, which is the primary natural source. 🌋

Indoor sources of volatile organic compounds

Indoors, VOCs come from many products used daily in buildings, such as: perfumes, candles and fireplace x, cooking fumes, new furniture, cleaning products, children’s toys, etc.

Sulphur dioxide (SO2): impacts on health and the environment

💙 The impact of SO2 on health

Sulfur dioxide (SO2) is an irritant to the eyes and mucous membranes. In high concentrations, this pollutant can have health effects such as affecting the respiratory system and lung function in adults (coughing, respiratory discomfort, bronchitis…) and causing or aggravating respiratory diseases in sensitive people (asthmatics, smokers, chronic respiratory diseases…).

💡 Good to know:SO2 limit values for the protection of human health (Directive 2008/50/EC):

  • 350 μg/m3 as an hourly average, not to be exceeded more than 24 times per calendar year, to be met since January 1, 2005.
  • 125 μg/m3 as a daily average, not to be exceeded more than 3 times per calendar year, to be met since January 1, 2005.
Short-term effects

👉Maux de tête

👉 Inconfort olfactif

👉 Irritation de la peau et des muqueuses

👉 Fatigue

👉 Toux, respiration douloureuse

👉 Pneumonie, bronchite

Long-term effects

👉Le système nerveux central est altéré (maux de tête, anxiété)

👉 Maladies cardiovasculaires

👉 Maladies respiratoires (asthme)

👉 Cancers

👉 Impacts sur le foie, la rate, le sang

👉 Impacts sur l’appareil reproducteur

🌍 The impact of SO2 on the environment

Sulfur dioxide is an acidifying gaseous air pollutant that can cause environmental acidification when concentrations are too high.

Once released into the air and in the presence of water, SO2 is transformed into sulphuric acid H2SO4 causing the phenomenon of acid rain. The consequences of this precipitation are:

👉 Acid deposits on building materials, which can damage architectural and cultural heritage,

👉 Acidification of surface waters, which can kill some species and affect freshwater and marine aquatic food chains,

👉 Soil degradation which leads to adverse effects on vegetation and plants.

Therefore, acidifying substances are harmful to the ecosystems. Sulfur dioxide emissions also cause the formation of toxic fogs known as smog.

How to protect yourself and reduce sulfur dioxide (SO2) emissions?

Preventing or reducing direct sources of SO2 can be difficult, especially emissions from natural sources such as volcanic eruptions. But here are some solutions to implement:

👉 Switching from high-sulfur to low-sulfur fuels (natural gas),

👉 Flue gas desulfurization in industrial plants,

👉 Environmental monitoring


Measuring and monitoring sulfur dioxide (SO2) with Meersens solutions

To monitor outdoor air pollution and in particular sulfur dioxide (SO2), Meersens allows you to analyze the environment wherever you are, whenever you want thanks to the power of environmental intelligence.

Meersens’ modeling and our easy-to-deploy air quality sensors allow us to know the concentration of sulfur dioxide, in real time, anywhere in the world to ensure the health and well-being of populations.

Does your city face air quality issues?

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Meersens offre une vision et une surveillance multi-polluants à 360°, en temps réel, historique et prédictive, pour n’importe quel lieu, avec une grande précision, vous permettant d’atténuer les risques et de prendre de meilleures décisions.

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