Sulphur dioxide

Starting date: 20-3-2014
Status: Running
Instrumentation and calibration: Sulphur dioxide is measured by using a UV-fluorescence analyser (Thermo 43i-TLE). Daily zero check are executed by using an external zero air source (scrubber with active charcoal), while daily span check are performed using a permeation tube with set point at 48 ppb
Project affiliation (s) Present: NextData Past: -
Related research programmes

  • Tropospheric background condition
  • Pollution transport
  • Long-range transport
  • Volcanic plume detection

Why is this research important? Sulphur dioxide (SO2) is the main precursor to the sulphate aerosol which exerts a large influence on climate and air quality. It is a well know precursor to acid rain. SO2 is also one of the main tracers for detecting the occurrence of ash plumes from volcanic eruption. In Europe, SO2 concentrations have been declining due to efficient restrictions on emissions. As highlighted by GAW-WMO (GAW Report No. 172) there are very few SO2 measurements in the background atmosphere where SO2 concentrations are often at sub-ppb levels, thus making accurate measurements a very challenging task. As reported by GAW-WMO, background SO2 measurements are also important in order to create a database suitable for the validation of models used to predict global sulphate aerosol distribution, and its present and future influence on cli
mate. Quick look The first SO2 measurements carried out at the ICO-OV during summer 2014, showed average levels below the detection limit with highest peak (hourly value) of 0.88 ppb, which is well below the air quality threshold value (350 microg m-3, equivalent to 133.6 ppb) indicated by European legislation. Nevertheless, during specific days (e.g. 16 – 17 July), a diurnal cycle clearly appear in the central part of the day, thus highlighting the role of thermal transport processes in transporting air-masses richer in SO2 from the lower troposphere.

Time-series of sulphur dioxide values (blue: 1-minute averaged values; red: 60-minute averaged values) at ICO-OV on July 2014.

Organization (s): ISAC-CNR Via Gobetti 101, I-40129, Bologna
Contact persons: Dr. Paolo Cristofanelli e-mail: p.cristofanelli [at] phone: +39 051 6399597
Where can I find the data? by direct request to: p.cristofanelli [at]