Former EPA Method 202 (Charged Impinger)
Determination of Condensible Particulate Emissions From Stationary
Sources
Method Overview
- • Isokinetic.
- • In-stack filter (M17/201/201A) or heated out of stack filter
(M5).
- • "Condensible" particulates pass through the filter and
condense in impingers.
- • Impinger catch is extracted, gravimetrically analyzed,
and blank corrected to provide separate organic and inorganic condensible
particulate data.
- • Tester may adjust out-of-stack filter temperature to suit
source specific conditions.
Target Compounds
Condensible Particulate Matter (CPM) -- those substances that pass
through the heated filter to condense in the cold components of the
sample train.
Method Summary
- • During sampling a filter is maintained at the stack temperature
or at other specified temperature. Gas that passes through the filter
and then condenses in the chilled impingers in the back half is
counted as condensible particulate.
- • Three impingers are each charged with 100 mL of DI water.
- • 1st and 2nd impingers are Greenberg-Smith type.
- • Do not use silicone grease - it will be soluble in the
final train rinse and will bias the organic CPM value high.
- • Run the train isokinetically or pseudo-isokinetically if
combined with M201 or M201A.
- • SO2 can be collected in the impingers, convert to SO4 during
storage, and bias the inorganic CPM value high. SO2 can be removed
by purging the train with nitrogen immediately after the run for
1 hour at the DH&.
- • IMPORTANT - Purging procedure is essential when impinger
pH is less than 4.5, which will indicate the presence of acid gasses.
Keep the train iced during the purge to preserve moisture catch.
- • Oil fired boilers exhibit low collection efficiencies for
this method. At these sources, add an extra filter between the 1st
and 2nd impinger. Filter catch must be added to the total CPM.
- • Sources that contain chloride and ammonia may form NH4Cl.
A subtraction for NH4Cl based on Cl analysis is allowed.
- • After initial water rinses, the train is rinsed twice with
MeCl2. For storage or shipping convenience, the MeCl2 and water
can be added to the impinger contents after moisture catch is recorded.
- • IMPORTANT - Many resin type DI systems do not produce water
of a grade that meets the .001% criteria for blanks. So, blank-test
your water before M202 testing. If purchasing H2O, Enthalpy recommends
DI/UF grade.
- • The MeCl2 is separated from the water in a separatory funnel
and two additional MeCl2 extractions are performed.
- • The MeCl2 extract and the water are evaporated. The water
is evaporated at 90°C.
- • If water has a pH of ‹4.5 an aliquot is analyzed
by HPLC/IC for sulfate. The sulfate is not subtracted, but waters
of hydration may be subtracted.
Quality Assurance
- • Blank corrections required for water and for MeCl2 blanks.
- • To accurately calculate blank corrections the tester must
supply to Enthalpy the volume or weight of water condensed from
the stack - e.g. if the final volume for impingers 1 & 2 was
457 mL and the charged amount was 200 mL, the condensed volume was
257 mL. The final volume delivered to us might be 575 mL after rinses
are added. Of this, 257 mL is condensed and 318 mL came from the
tester's reagent water. Only the 318 mL of reagent water should
be blank corrected. So take a final volume before adding the rinses.
- • Specify which sulfate correction factor to apply: if waters
of hydration are to be counted as CPM, add 2.08% of the sulfate
catch to the inorganic catch weight. If waters of hydration are
not counted as particulate then subtract 35.4% of the sulfate catch
from the inorganic catch.
- • An Aliquot Factor must be applied for aliquots removed
if sulfate or ammonium chloride corrections are made.
Shipping Tips
- • MeCl2 must be shipped as a hazardous material. Please call
for IATA codes if you need them.
- • Samples may be shipped warm.
- • It may prove more economical to keep MeCl2 rinses separate,
ship the waters by normally, and the MeCL2 as hazardous.
- • Be sure to include a chain of custody for each shipping
container.
Enthalpy Experience
Enthalpy has conducted between 2000 and 3000 M202 analyses. About
1/3 of these included associated sulfate or chloride analysis for
subtraction from the CPM catch.
