Sulfur dioxide
![](/Images/godic/202502/14/Sulfur-dioxide-3D-vdW1133.png")
![The blue auroral glows of Io's upper atmosphere are caused by volcanic sulfur dioxide.](/Images/godic/202502/14/Io_Aurorae_color1133.jpg")
![A sulfur dioxide plume from the Halemaʻumaʻu vent, glows at night](/Images/godic/202502/14/Sulfur_dioxide_emissions_from_the_Halema`uma`u_vent,_glows_at_night1133.jpg")
![A collection of estimates of past and future anthropogenic global sulphur dioxide emissions. The Cofala et al. estimates are for sensitivity studies on SO2 emission policies, CLE: Current Legislation, MFR: Maximum Feasible Reductions. RCPs (Representative Concentration Pathways) are used in CMIP5 simulations for latest (2013–2014) IPCC 5th assessment report.](/Images/godic/202502/14/Estimates_of_past_and_future_SO2_global_anthropogenic_emissions1133.png")
Sulfur dioxide (also sulphur dioxide) is the chemical compound with the formula SO
2. At standard atmosphere, it is a toxic gas with a pungent, irritating smell. The triple point is 197.69 K and 1.67 kPa. It is released naturally by volcanic activity.