January
2004
preliminary
­
VOC
Measurement
Approach
for
Barns
The
development
of
cost
effective
continuous
real
time
VOC
emissions
information
from
animal
feeding
operations
requires
establishing
a
correlation
between
one
or
several
continuous
monitoring
instruments
and
the
mass
emissions
of
the
compounds
comprising
these
emissions.
To
establish
this
correlation,
the
following
processes
are
required:

A
comprehensive
screening
program
needs
to
be
performed
on
a
few
samples
collected
form
each
typical
production
operation.
The
major
purpose
of
this
screening
is
to
identify
the
organic
components
that
comprise
the
majority
of
the
total
mass.
From
this
comprehensive
list
of
organic
compounds,
the
tester
will
select
those
compounds
that
make
up
at
least
90%
of
the
total
VOC
emissions
on
a
mass
basis.

The
screening
program
must
include
multiple
sampling
techniques
to
ensure
that
all
the
different
classes
of
VOC=
s
that
may
be
present
in
the
sample
are
detected
and
reported.
Samples
must
be
collected
by
all
integrated
sampling
techniques
allowed
by
Method
18
(
adsorbent
tube
and
Tedlar
bag
sampling).
The
adsorbent
tube
sampling
must
include
a
mixture
of
absorbents
(
or
a
series
of
adsorbent
tubes
each
containing
a
different
adsorbent)
designed
to
effectively
collect
and
recover
the
different
classes
of
organic
compounds.
In
addition
to
collecting
samples
by
the
procedures
in
Method
18,
samples
must
also
be
collected
in
a
summa
cannister,
by
a
procedure
such
as
TO­
15.
All
of
these
samples
must
be
collected
concurrently.
All
gas
samples
must
be
analyzed
by
gas
chromatography
(
GC)
separation
with
identification
and
measurement
by
mass
spectrometry
(
MS).
Any
condensate
samples
must
be
analyzed
by
GC/
MS
and
by
high
performance
liquid
chromatography.

From
those
compounds
comprising
90%
of
the
VOC
mass
identified
in
the
screening
program,
key
compounds
shall
be
identified
for
use
as
calibration
standards
and
development
of
QA
audit
materials.
The
primary
selection
criteria
for
these
key
compounds
will
be
their
percentage
of
the
total
mass
and
whether
pure
calibration
standards
are
available
or
can
be
created
for
them.
Secondary
selection
criteria
are
their
atmospheric
photochemical
reactivity
and
they
are
a
specific
reportable
organic
compound
or
class
of
compounds
under
either
the
CAA
or
CERCLA.
Based
upon
this
list
organic
compounds
comprising
90%
of
the
VOC
mass
and
the
key
calibration
compounds,
specifications
for
a
less
complex
compound
specific
sampling
and
analytical
method
will
be
developed.

During
the
monitoring
study,
a
continuous
methane
monitor
and
a
continuous
hydrocarbon
analyzer
will
be
used
as
indicators
of
total
VOC
emissions.
Daily
calibrations
of
the
continuous
hydrocarbon
monitor
will
be
performed
with
propane
and
a
standard
consisting
of
the
key
calibration
compounds.
At
least
once
per
month
at
each
monitoring
site,
the
less
complex
compound
specific
sampling
method
will
be
used
to
collect
three
two
to
three
hour
samples
representing
potential
temporal
differences
in
the
composition
of
the
emissions.
Although
laboratories
will
have
only
the
limited
number
of
compounds
available
for
calibration
standards,
semi­
quantitative
concentrations
of
all
compounds
comprising
90%
of
the
VOC
mass
in
the
screening
study
are
to
be
reported.
The
concurrent
results
of
the
continuous
monitors
during
the
sampling
periods
will
be
obtained.
The
ratio
of
the
mass
determined
by
the
less
complex
compound
specific
sampling
and
analytical
method
and
the
results
of
the
continuous
monitoring
methods
will
establish
the
correction
factor
for
the
monitoring
performed
during
the
15
days
prior
to
and
following
day
the
samples
were
obtained.
At
the
completion
of
the
monitoring
study,
the
information
from
the
compound
specific
sampling
and
analytical
method
will
provide
the
basis
for
measurement
uncertainty
of
the
continuous
monitoring
methods.
