1.1''These test methods cover the bubbler collection and colorimetric determination of sulfur dioxide (SO₂) in the ambient or workplace atmosphere.

1.2''These test methods are applicable for determining SO₂ over the range from approximately 25 ''g/m³ (0.01 ppm(v)) to 1000 ''g/m³ (0.4 ppm(v)), corresponding to a solution concentration of 0.03 ''g SO₂/mL to 1.3 ''g SO₂/mL. Beer's law is followed through the working analytical range from 0.02 ''g SO₂/mL to 1.4 ''g SO₂/mL.

1.3''The lower limit of detection is 0.075 ''g SO₂/mL (1),2 representing an air concentration of 25 ''g SO₂/m³ (0.01'''ppm(v)) in a 30-min sample, or 13 ''g SO₂/m³ (0.005 ppm(v)) in a 24-h sample.

1.4''These test methods incorporate sampling for periods between 30 min and 24 h.

1.5''These test methods describe the determination of the collected (impinged) samples. A Method A and a Method B are described.

1.6''Method A is preferred over Method B, as it gives the higher sensitivity, but it has a higher blank. Manual Method B is pH-dependent, but is more suitable with spectrometers having a spectral band width greater than 20 nm.

1.7''The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.8''Warning'''Mercury has been designated by many regulatory agencies as a hazardous material that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet (SDS) for additional information. Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.

1.9''This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 8.3.1, Section 9, and A3.1.3.

1.10''This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.