Overview

Sulphur dioxide is colourless gas with an irritating pungent odour. It is a common air pollutant.

Uses of sulphur dioxide

One of the main uses of sulphur dioxide is as a chemical intermediate in the production of sulphuric acid. It is also used as a fumigant, a food preservative and as a bleaching agent. Sulphur dioxide has also been used in the purification of petroleum products.

How sulphur dioxide gets into the environment

Sulphur dioxide is released into the environment during the burning of coal and oil. Power plants, oil refineries, some motor vehicles and domestic boilers and fires are all sources of sulphur dioxide. It is also produced naturally by active volcanoes.

Exposure to sulphur dioxide

The general public can be exposed to sulphur dioxide by breathing in air that contains it. Exposure can also occur in the workplace where it is produced as a by-product during the burning of coal or oil or in industries where it is used.

How exposure to sulphur dioxide could affect your health

The presence of sulphur dioxide in the environment does not always lead to exposure. In order for it to cause any adverse health effects you must come into contact with it. You may be exposed by breathing, eating, or drinking the substance or by skin contact. Following exposure to any chemical, the adverse health effects you may encounter depend on several factors, including the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.

Breathing in sulphur dioxide causes irritation to the nose and throat. Exposure to high levels can cause nausea, vomiting, stomach pain and corrosive damage to the airways and lungs.

Skin contact causes stinging pain, redness of the skin and blisters. Skin exposure to compressed gas or liquid can cause frostbite.

Contact with eyes can cause watering and in severe cases blindness can occur.

Long-term inhalation exposure to sulphur dioxide may cause long-term breathing problems.

Sulphur dioxide and cancer

Due to the lack of human data and the limited data in animals, the International Agency for Research on Cancer (IARC) determined that it is not known whether sulphur dioxide causes cancer so considered it as not being classifiable.

Pregnancy and the unborn child 

There are are very limited data available to assess the reproductive and developmental effects of sulphur dioxide. Children may be more sensitive to the effects of sulphur dioxide due to their smaller size.

What to do if you are exposed to sulphur dioxide

It is very unlikely that the general population will be exposed to a level of sulphur dioxide high enough to cause adverse health effects.

Email chemcompendium@ukhsa.gov.uk if you have any questions about this guidance or enquiries@ukhsa.gov.uk if you have any other questions.