These test methods describe the evaluation of the total
sulfation activity in the atmosphere. Because of its oxidizing
power, lead dioxide (PbO2) converts not only sulfur dioxide (SO2),
but other compounds, such as mercaptans and hydrogen sulfide, into
sulfate. It fixes sulfur trioxide and sulfuric acid mist present in
the atmosphere (see Note 1).
Test Method A describes the use of a PbO2 candle, and
Test Method B describes that of a PbO2 sulfation
These test methods provide a weighted average effective
SO2 level for a 30-day interval.
The results of these test methods correlate approximately with
volumetric SO2 concentrations, although the presence of
dew or condensed moisture tends to enhance the capture of
SO2 onto the candle or plate.
The values stated in SI units shall be regarded as the standard.
The values given in brackets are for information only and may be
NOTE 1—It has been shown that the rate constant of the chemical
reaction between SO2 and PbO2 is independent
of the concentration of SO2 up to levels of 1000 ppm(v),
if 15 % or less of the PbO2 has been reduced
(1).3 15 % of the PbO2 is equivalent to 11 to
12 mg of SO2/cm2 per day.
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 and
health practices and determine the applicability of regulatory
limitations prior to use. For specific precautionary
statements, see Section 8.
2 Test Method B has been adapted from Test Method
G91, which is under the jurisdiction of ASTM Committee D22 on Air
Quality and is the direct responsibility of Subcommittee D22.03 on
Ambient Atmospheres and Source Emissions.
Order online or call: Americas: +1 800 854 7179 | Asia Pacific: +852 2368 5733 | Europe, Middle East, Africa: +44 1344 328039