North
Carolina
Recommendation
for
Union
County
The
purpose
of
this
paper
is
to
discuss
the
rationale
for
recommending
the
rural
eastern
portion
of
Union
County,
an
MSA
county
and
part
of
the
Mecklenburg/
Union
County
Metropolitan
Planning
Area
Boundary,
to
be
excluded
from
the
nonattainment
recommendation
for
the
8
hour
ozone
standard.
The
Monroe
monitor
is
located
in
the
County.

 
First,
this
area
has
a
marginal
8­
hour
ozone
problem
for
the
three
years
spanning
2001­
2003
season
with
a
current
Design
Value
(
DVC)
of
0.088
ppm.
More
recent
8­
hour
ozonemodeling
results
show
the
future
Design
Value
(
DVF)
in
2007
as
0.077
ppm,
which
is
well
below
the
standard.
The
control
measures
included
in
the
future
year
modeling
are
the
NOx
SIP
call,
new
mobile
source
engine
standards,
low
sulfur
gasoline,
and
the
phase
in
of
North
Carolina's
OBD
I/
M
program
implemented
in
July
2003.
 
Second,
Union
County
has
few
industrial
sources
with
only
0.15
tons
of
NOx
emissions
per
day
coming
from
point
sources
out
of
a
county
total
of
15.01
tons
per
day
(
Anthropogenic).
The
non­
road
and
highway
mobile
adds
up
to
represent
the
bulk
of
the
NOx
emissions
(
14.45
tons
per
day)
for
the
county's
total
of
15.01
tons
per
day.
The
8
hour
modeling
results,
which
takes
into
account
for
future
growth
in
Daily
VMT
and
Population,
clearly
shows
the
Monroe
monitor
attaining
the
ozone
standard
in
2007.
 
Third,
Union
County
ranks
number
1
out
of
the
6
commuting
counties
into
Mecklenburg
County,
contributing
5.2
percent
of
commuters
driving
to
work
each
day.
The
eastern
portion
recommended
for
attainment
has
a
low
population
density
and
accounts
for
only
15.7
percent
of
the
total
residents
in
the
county.
By
following
the
MPO
boundary,
North
Carolina
believes
the
majority
of
the
commuters
from
Union
to
Mecklenburg
would
be
captured
in
this
nonattainment
boundary.
Additionally,
Union
County
already
has
an
inspection
and
maintenance
program
to
address
the
vehicle
maintenance.
 
In
conclusion,
because
the
future
year
8­
hour
ozone
modeling
demonstrate
that
the
monitor
in
Union
County
will
be
well
below
the
stand,
North
Carolina
believes
this
is
an
important
consideration
for
setting
nonattainment
boundaries
that
exclude
the
less
populated
eastern
region.
Also
important
to
consider
is
the
effect
of
the
Federal
engine
and
fuel
standards
and
the
expanding
new
I/
M
program
requiring
on­
board
diagnostic
testing
in
48
counties
(
nearly
half
of
North
Carolina's
100
counties),
which
will
continue
to
control
mobile
source
emissions
in
counties
regardless
of
the
nonattainment
designations.
