Sulphur dioxide is the main cause of acid rain, since it turns into sulphuric acid in the atmosphere. It is released in many combustion processes since fuels such as coal, petrol, diesel or natural gas contain certain amounts of sulphur-bearing compounds.


What is SO2?

Sulphur dioxide (SO2) is a colourless, poisonous gas, heavier than air, which in high concentrations has an acrid, irritating and asphyxiating smell. Due to photo-chemical reactions in air, especially in high humidity conditions, it is slowly turned into sulphur trioxide (SO3), which dissolves in the water particles, becoming sulphuric acid (H2SO4), one of the strongest acids.

SO2 is a gas produced by the combustion of fossil fuels with a rich content in sulphur, such as petrol and coal, although it is also produced from many processes in the chemical industry.

The origin of high SO2 concentrations in the air in certain places, is generally related with the use of coal in coal-fired power plants or the use of diesel fuel in city vehicles.


How can SO2 affect us?

SO2 is hygroscopic, in other words, when it is in the atmosphere it reacts with the humidity and forms aerosols of sulphuric and sulphurous acid and goes on to form part of so-called acid rain. The intensity of the aerosol formations and the time remaining in the atmosphere depends on the prevailing meteorological conditions and the amount of catalytic impurities (substances that accelerate the processes) present in the air. However, in general, the average time of remaining in the atmosphere is 3-5 days, so that it can be carried great distances. Air pollution by SO2 causes the following effects: difficulty in breathing, inflammation of the respiratory tracts, eye irritation due to formation of sulphurous acid on the damp mucous membranes, psychological alterations, pulmonary oedema, cardiac arrest and circulatory collapse.

SO2 is also associated with problems of asthma and chronic bronchitis, increasing morbidity and mortality rates in the elderly and children. Sulphur is a highly noxious poison to people’s health. In the case of trees, they are even more sensitive to SO2. For example, a level of 0.3 µg per cubic metre of air is a value that represents a potential risk for human health, but for trees a value of 0.2 µg is already very serious.

Bionatur has developed an absorbent specifically for acidic gases such as SO2 that makes it possible to completely (100%) remove the emissions of this polluting gas.

For the first time worldwide the Bionatur integral solution has managed to remove 100% of the SO2 emissions from thermal power plants for electricity, as is recorded in the CIEMAT certificate on tests conducted in ENEL-ENDESA.

Bionatur has also managed to successfully solve the main problem in large foundries (copper, steel, aluminium, etc.) such as the emissions involved in emergency stoppages.