Source Emission Testing
Taking a sample of pollutants from a stack or vent is usually
the most direct, and often the only, way of determining if
a source's emissions comply with regulations or with the limits
set in a permit. Emission, or "stack", testing may
be required when a new piece of equipment is installed, or
when a new or revised permit is issued. Or, a facility may
be required to routinely perform emission testing every two
or three years. Stack tests are complex: test equipment and
procedures vary widely depending on the pollutants being measured.
Due to the difficulty of the procedures and expense of the
equipment, stack tests are normally performed by a professional
consultant who specializes in this type of work and is hired
by the facility doing the test. Occasionally, the AQCD conducts
research projects to determine the contribution of emissions
from a particular type of source to the overall levels of
pollution in Vermont. In this case the AQCD hires the testing
consultant and the facilities involved in the test are volunteer
In a typical stack test program, the AQCD first reviews a
"pretest report" that lists the equipment and procedures
the consultant intends to use to perform the test. The AQCD
recommends any changes needed to ensure that the results of
the test will be acceptable for comparison to the emission
limits. An AQCD staff member will then visit the site during
the testing to observe the operation of the equipment being
tested and the testing procedures actually used by the consultant.
Finally, a report of the test results is filed with the AQCD,
typically within about 30 days after completion of the test.
regarding the use of stack test procedures and data handling conventions
required by the AQCD for compliance testing are available.
last updated 8/23/13