EPA Method 6 - Sulfur Dioxide Emissions

Method Overview

  • Non-Isokinetic Constant Rate Sampling
  • Titrimetric Analysis

Target Compounds

  • Sulfur Dioxide

Performance Tips

  • Charge first collection impingers with 15 mL 80% Isopropanol;
  • Charge next two collection impingers (2 & 3) with 15 mL 3% H2O2 each;
  • Fourth impinger should remain empty;
  • Charge fifth impinger with silica gel.
  • Separation of Analytes:
    • Acid mist and/or sulfur trioxide (SO3) are soluble and collected in the Isopropanol (IPA) solution;
    • Sulfur Dioxide is insoluble in the IPA solution. It will pass through this impinger and be collected in thehydrogen peroxide absorbing solution.
  • If water droplets are expected, large impingers along with EPA Method 8 should be used.
  • If high moisture content is expected, an optional pre-impinger can be inserted prior to the first two. This impinger should be charged with 15 mL of the 0.1 N H2O2 absorbing solution.
  • Please provide high volume blanks when low concentrations are expected such as in the Acid mist and/or sulfur trioxide (SO3) fraction.


  • The isopropanol fraction may be a hazardous good (flammable) for shipping purposes. Please call for IATA codes if you need them.
  • Samples may be shipped at ambient temperatures.
  • Be sure to include a chain of custody for each shipping container.


  • Emissions measurements of sulfur dioxide
  • We've even used this method on suflur burners (upwards of 8% SO2 in the gas stream).


  • Yes, please contact us if you are interested!
    • Texas
    • New Jersey
    • Louisisana

White Papers