It
is important to understand that the US-EPA does not designate monitors. The US-EPA designates “methods”, which monitors are a part of.
A “method” consists of a monitor
equipped a number of specified accessories operated in a very specific way. Which
accessories are required and how they are operated is written into US Federal
Regulation.
The
EPA publishes and regularly updates a list of designated “reference” and “equivalent”
methods. For each designated method, specific details are provided as to what additional
equipment must be operated with the analyzer and how the analyzer must be
configured in order for it to be a designated method.
Reference
methods were the original methods by which pollutants were measured. Equivalent
methods are additional methods that have been demonstrated to the satisfaction
of the US-EPA to provide equivalent measurements and are treated the same way
legally as the reference method. For example, a manual low volume sampler, such
as the BGI PQ-200, equipped with certain accessories and operated according to
the user manual, is the reference method for PM2.5 measurement. The
Met One Instruments BAM-1020, equipped with its PM2.5 FEM standard
accessories, and operated as a PM2.5 equivalent method, produces results
that are considered by the US-EPA to be “equivalent” to those produced by the
reference method.
As
an example, let us consider the BAM-1020 beta attenuation mass monitor. This
analyzer has three EPA methods associated with it: one for PM10, one for PM2.5 and one for PM-Coarse. All three
designations involving the BAM-1020 as well as for other instruments such as
the TEOM are located on the US-EPA’s website:
Each
designated method has a designation number. The designation number for the
BAM-1020 operated as a PM10 equivalent method is EQPM-0798-122. The
designation number for the BAM-1020 operated as a PM2.5 equivalent
method is EQPM-0308-170. The designation number for the BAM-1020 operated as a
PM-Coarse equivalent method is EQPM-0709-185.
As
an example, we’ve shown the official US-EPA designation for the PM2.5
method involving the BAM-1020 below:
Met One BAM-1020 Monitor –
PM2.5 FEM Configuration or Horiba APDA-371– PM2.5 Configuration
Automated Equivalent Method:
EQPM-0308-170
“Met One Instruments, Inc.
BAM-1020 Beta Attenuation Mass Monitor - PM2.5 FEM Configuration, Horiba
Instruments APDA-371 Beta Attenuation Mass Monitor – PM2.5 FEM Configuration,
configured with a BGI VSCCTM Very Sharp Cut Cyclone particle size
separator,” operated for 24 1-hour average measurements with firmware revision
3.2.4 or later, with or without an inlet tube extension (BX-823), with or
without external enclosures BX-902 or BX-903, in accordance with the BAM 1020
Particulate Monitor operation manual, revision F or later, or the Horiba
APDA-371 Monitor operation manual, and VSCCTM supplemental manual and equipped
with BX-596 ambient temperature and barometric pressure combination sensor,
internal BX-961 automatic flow controller operated in Actual (volumetric) flow
control mode, the standard BX-802 EPA PM10 inlet head and a BGI VSCCTM
Very Sharp Cut Cyclone (VSCC-A), BX-827 (110V) or BX-830 (230V) Smart Inlet
Heater, with the heater RH set to 35% and the temperature control set to
"off", the 8470-1 revision D or later tape control transport assembly
with close geometry beta source configuration, used with standard glass fiber
filter tape, COUNT TIME parameter set for 8 minutes, the SAMPLE TIME parameter
set for 42 minutes, BX-302 zero filter calibration kit required and with or
without BX-970 touch-screen display with USB interface.
Federal Register: Vol. 73, page 13224, 03/12/2008 Latest
modifications: 7/2010; 8/2010
Notice in the
PM2.5
method
description above that the US-EPA defines the method as having to be “configured with a BGI VSCCTM Very
Sharp Cut Cyclone particle size separator.” Additional required accessories
such as the BX-827 “smart heater” and the BX-596 temperature/barometric
pressure sensor are also listed in the designation wording for the method. This
means that a BAM-1020 operated without these accessories is not a designated
US-EPA equivalent method for PM2.5.
In conclusion, it is important to understand that the US-EPA
designates methods – not analyzers. US-EPA methods are defined by an
analyzer (such as the BAM-1020), required accessories (such as the BGI VSCC), and
strict adherence to the operating manual. Analyzers operated without the required
accessories and in strict accordance with the operating manual are not
EPA-designated methods!