EPA Method 8 - Sulfur Dioxide and Sulfuric Acid Emissions

Method Overview

  • Isokinetic sampling train
  • Filter separates particulate sulfates from gaseous sulfates
    • Typically, only the gaseous sulfates are quantified
  • Analyses by Barium Chloride Titration.

Target Compounds

  • Sulfuric acid (H2SO4) including sulfur trioxide (SO3);
  • Sulfur dioxide (SO2).

Performance Tips

  • Probe liner should be pre-rinsed with DI Water and then with isopropanol (to dry water);
  • Hot Condensor should be rinsed with DI Water after each test run (then with isopropanol to dry water);
  • Charge the first two impingers with 100 mLs of 3% H2O2 each
  • Charge the last impinger with 300 g silica gel.
  • Filter holder must be teflon;
  • Separation of Analytes:
    • Sulfuric acid mist should be vaporized in the hot filter/probe and be collected in the hot condensor;
    • Sulfur trioxide should condense and be caught in the hot condensor;
    • Sulfur dioxide should be absorbed in the peroxide absorbing solution;
  • If high moisture content is expected, an optional pre-impinger can be inserted prior to the first two. This impinger should be charged with 50 mL of the hydrogen peroxide absorbing solution.
  • Please provide high volume blanks when low concentrations are expected such as in the Acid mist and/or sulfur trioxide (SO3) fraction.


  • Samples may be shipped at ambient temperatures.
  • Be sure to include a chain of custody for each shipping container.


  • This method was originally designed for sulfuric acid plant exhausts (dry gas stream);
    • Sulfuric Acid Mist Emissions;
    • Sulfur Trioxide Emissions; and
    • Sulfur Dioxide Emissions.
  • Difficulties can be experienced in adaptations to coal-fired power plants (contact us for further information).


  • Yes, please contact us if you are interested!
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