### Background Information:

OTHER TEST METHOD 28 — April 15, 2009

DRY IMPINGER METHOD FOR DETERMINING CONDENSABLE PAR TICULATE

EMISSIONS FROM STATIONARY SOURCES

1. Scope and Applicability 1.1 Scope. The U.S. Environmental Protection Agency (U.S. EPA or “we”) developed this method to describe the procedu res that the stack tester (“you”) must follow to measure condens able particulate matter (CPM) emissions from stationary sources. This method includes procedures for measuring both organ ic and inorganic CPM. 1.2 Applicability. You can use this method to measu re CPM from stationary source emissions after filterable partic ulate matter
has been removed. CPM is measured in the emissions after removal from the stack and after passing through a filter. You can use Method 17 to collect condensable and filterable par ticulate material from sources operating at stack temperatur es and/or samples collected below 30°C (85°F) if the filter i s treated as
described in Sections 8.5.4.4 and 11.2.1 of this me thod. You may use this method only for stationary source emission measurements. 1.3 Responsibility. You are responsible for obtaini ng the equipment and supplies you will need to use this me thod. You must also develop your own procedures for following this method.

This category (Other Test Methods) includes test me thods which have not yet been subject to the
Federal rulemaking process. Each of these methods, as well as the available technical
documentation supporting them, have been reviewed b y the Emission Measurement Center staff
and have been found to be potentially useful to the emission measurement community. The types

of technical information reviewed include field and laboratory validation studies; results of
collaborative testing; articles from peer-reviewed journals; peer-review comments; and quality
assurance (QA) and quality control (QC) procedures in the method itself. A table summarizing the

available technical information for each method can be found at the link below. The EPA strongly
encourages the submission of additional supporting field and laboratory data as well as comments
in regard to these methods.



### Problem Statement: Substitute Toluene for Methylene Chloride as the organic rinse

solvent

Arguments to Support Actions Taken:

The use of a solvent for recovery of a “chemical com pound” is predicated on knowledge of
the chemical structure and characteristics of that com pound. A chemist uses theory and experience to select the solvent that is most suited for a reaction system. The simple rule for

### solvents and reagents is that “like dissolves like” – a non-polar reactant will dissolve in a

non-polar solvent; a polar reactant dissolves in a pola r solvent. The polarity of a solvent is determined by its dipole moment (measure of charge distribut ion in a molecule), dielectric constant (DeC; distance between the internal charges in a molecule) and its miscibility with

water.

Water is a highly polar compound (owing to the large charge differential between the oxygen and hydrogen atoms in the molecule; DeC of 80) and will mi x/dissolve high polarity compounds such as alcohol. There are other high polarit y compounds such as acetone that have a high DeC value owing to the carbonyl (carbon-oxygen double bond; C=O) structure in the molecule. Hexane has a low DeC of 2.02 (dipole mome nt is 0.0) and is very non-polar. Toluene has a dipole moment of 0.36 so it is relatively no n polar. Water (polar) and hexane (non-polar) are not-like compounds and are not miscible ( oil and water don’t mix). Methylene chloride (MeCl 2 

### ) has a DeC of 9.08 and is a relatively non-polar solvent that is
not miscible in water.

There are a number of aliphatic and aromatic organic co mpounds that may potentially be present in combustion effluents (alkanes – Cn-H2n; ketones – RR’C=O; aldehydes – RCOH; phenols – R n 

### -C 6 

### H 5-n 

### -OH). There is an unknown mixture of these compounds in the organic fraction of the OTM28 sample train. Method OTM 28 includes MeCl 2 

### as the rinse solvent for cleaning the glassware used in the sampling sys tem as described below.

“8.5.4 Sample Recovery. 8.5.4.1 Recovery of Filterable Particulate Matter. Recovery of filterable particulate matter involves the quantita tive transfer of particles according to the filterable particulat e sampling method (i.e., Method 5, 17 or 201A). 8.5.4.2 CPM Container #1, Aqueous Liquid Impinger C ontents. Quantitatively transfer liquid from the dropout and the impinger prior to the CPM filter into a clean sample bottle (glass or plastic). Rinse the probe extension, condenser, eac h impinger and the connecting glassware, and the front half of the CPM filter housing twice with water. Recover the rinse water, and add it to the same sample bottle. Mark the liquid level on th e bottle. CPM Container #1 holds the water soluble CPM captured i n the impingers. 8.5.4.3 CPM Container #2, Organic Rinses. Follow th e water rinses of the probe extension, condenser, each impinger an d all of the connecting glassware and front half of the CPM filt er with an acetone rinse. Then repeat the entire procedure
with two rinses of MeCl

2 , and save both solvents in a separate

glass container identified as CPM Container #2. Mar k the liquid level on the jar.”



### . This solvent has a “middle of the road” polarity. It is possible that MeCl 2 

### may not dissolve all organics that may cling to the sampling system glasswa re.

### The sampling trains were initially rinsed with water, followed by acetone and toluene. This

sequence and nature of solvents actually provide a variety o f polarities to assure all types of organics present on the glassware of the sampling train are recovered for the analysis of the OTM28 parameters. The initial water rinse removes aqueous drops adhering to the glassware. The high polarity acetone that follows is miscible with water dissolves the ketones, aldehydes and phenolic compounds. The toluene rinse dissolves the CnH2n compounds. This is an exhaustive cleaning of the glassware that exceeds the simple rinse
with MeCl 2 

### may miss some of the oragnics targeted by OTM28.