Introduction to Sulfur Dioxide (SO2)

Sulfur Dioxide (SO2) is a toxic gas with a pungent, irritating, and rotten smell. It is released in various industrial processes and also naturally through volcanic eruptions. Fossil fuels and mineral ores often contain sulfur compounds and their combustion generates Sulfur Dioxide. The emission of Sulfur Dioxide is a major air pollutant, with the concentration of the gas in the atmosphere influencing the habitat suitability for plant communities and animal life. However, Sulfur can be removed from coal and fuel during the burning process to prevent the formation of Sulfur Dioxide.

Exposure to high concentrations of Sulfur Dioxide can be life threatening. Inhaling the toxic gas is associated with increased respiratory symptoms and disease, difficulty in breathing, and premature death. People working in industries where Sulfur Dioxide is produced and those who live near industrial sources are exposed on a regular basis. It is essential to have proper monitoring at all times to ensure the safety of the workers and the neighborhood surrounding the industry.

Health Hazards

When present in high concentrations, Sulfur Dioxide may produce these symptoms:

  • Eye, nose, throat irritation
  • Rhinorrhea (discharge of thin nasal mucus)
  • Coughing
  • Choking
  • Bronchoconstriction

Exposure Limits

When researching SO2 gas detection solutions, facility managers should be aware of the following SO2 exposure limits:

Exposure Limits Agency
5 ppm TWA OSHA PEL (General Industry)
5 ppm TWA OSHA PEL (Construction Industry)
5 ppm TWA OSHA PEL (Maritime)
0.5 ppm STEL ACGIH TLV
2 ppm TWA; 5 ppm STEL NIOSH REL
100 ppm NIOSH IDLH

Technology for SO2 Gas Detection

Electrochemical Sensors

Electrochemical sensors are fuel cell-like devices consisting of an anode, cathode, and electrolyte. The components of the cell are selected so that a subject gas, allowed to diffuse into the cell, will cause a chemical reaction and generate a current. The cells are diffusion-limited, meaning that the rate of the gas entering the cell is solely dependent on the gas concentration. The current generated is proportional to the rate of consumption of the subject gas in the cell.

Learn more about the advantages of using Sierra Monitor's electrochemical gas sensor modules »