Sulphur Dioxide
- Sources
- Impacts
- Testing
Sources of Sulphur Dioxide (SO2)
SO2 is a colourless corrosive acidic gas with a pungent odour, similar to burnt matches. Its prominence occurs from the combustion of unrefined fuels, such as coal or crude oil. Its emission has significantly reduced over the past decades as the burning of these fuel types (and the sulphur content of fuels) has declined within the UK. Emissions have lowered 97% from 1990 to 2005. SO2 can also interact with NOx and NH3 to form secondary particulate matter, causing reduced visibility. For context SO2 and this process was a key contributor to the London smog episode in 1952.
SO2 is a contributor to the formation of acid rain. Natural sources may include forest fires or volcanic eruptions. Major anthropogenic sources of SO2 include industrial combustion processes, energy industries, domestic combustion of household heaters and the burning of heavy fuel by ships.
Typical Sources of SO2
- Industrial combustion processes
- Energy industries
- Domestic combustion heaters
- Ship engine combustion
Impacts of Sulphur Dioxide (SO2)
Short term exposure to SO2 can irritate the respiratory system, causing inflammation of the lungs. Those already with respiratory conditions or vulnerable individuals such as children in the elders may be particularly susceptible. It can also irritate the eyes and ENT systems. High concentrations can worsen respiratory and cardiovascular conditions and cause the development of bronchitis. SO2 acting as a precursor pollutant can deposit secondary particulate matter in the airways.
Common Impacts of N20
- Irritation of the respiratory system
- Irritates the eyes and ENT systems
- Worsens respiratory and cardiovascular conditions
- Bronchitis
Testing for Sulphur Dioxide (SO2)
Testing for SO2 is done through passive monitoring. A fluorinated ethylene polymer tube contains absorbent which attracts sulphate ions. Exposure time takes 2-4 weeks. Tube is sent to lab after exposure for analysis. Industrial grade air quality monitors exist for SO2, but are not normally aimed at domestic use.
- Passive Diffusive Monitoring
- Some Industrial Air Quality Monitors
The WHO states a 24-hour average of SO2 should be below 40µg/m3. EH40/2005 gives a limit of 1300µg/m3 for an average 8-hour exposure time. The Air Quality Directive (2008/EC/50) has a limit of 125µg/m3, an average not to be exceeded 3 times a year.
- EH40/2005 limit is 1300µg/m3
- The WHO 2021 limit is 40µg/m3
- The Air Quality Directive (2008/EC/50) has a limit of 125µg/m3
Nitrous Oxide FAQs
How Do I Remove SO2 From My Indoor Air? ↓
SO2 will very likely infiltrate from outdoor sources such as industrial/ chemical processes. Therefore having adequate ventilation, and filtration measures with activated carbon filters would ensure exposure is kept to a minimum in indoor spaces.
What UK Legislation Refers To SO2 Limits? ↓
EH40/2005, National Emission Ceilings Regulations (2018)
Is SO2 Prevalent in The UK? ↓
There was a dramatic reduction of 97% from 1990-2005. Domestic burning of coal and crude oil has reduced significantly in the UK. Sulphur content of fuels actively reduced over the years. Ships not permitted to burn heavy fuel near coastlines through the MARPOL act. Less developed countries still have significant SO2 pollution and exposure effects.
Can I Perceive SO2? ↓
In What Areas of Industry May People Be Exposed to SO2? ↓
Workers involved in power generation, oil refineries, metal smelting and the manufacture of sulphuric acid.
Why Choose ARM?
SO₂ exposure from industrial activity can compromise indoor air. ARM offers passive sampling and filtration guidance to keep environments safe.
We are SafeContractor certified and a member of BESA. With our CEO Adam Taylor chairing the BESA Indoor Air Quality Group, our approach is backed by expert insight and aligned with national guidance for regulatory compliance and occupant wellbeing.
