Isn’t dune dust emission a natural phenomenon?
Some
dust
emission
from
coastal
dunes
does
occur
naturally,
but
at
levels
that
do
not
threaten
public
health.
However,
the
level
of
dune
dust
emissions
from
the
off-highway
vehicle
riding
area
is
many
times
greater
than
the
emissions
from
non-riding
areas.
This
is
clearly
proven
by
comparing
monitored
PM10
and
PM2.5
concentrations
downwind of the riding areas versus emission measurements downwind of non-riding areas.
How
do
we
determine
how
much
of
the
dust
emission
is
caused
by
OHV
activity
versus natural background emission?
Various
studies
and
monitoring
programs
have
verified
and
quantified
how
much
more
dust
is
emitted
from
the
SVRA
riding
areas
compared
with
the
non-riding
areas.
Both
areas
are
similar
in
terrain
and
the
winds
are
comparable.
In
the
riding
area,
the
foredunes,
which
tend
to
break
the
offshore
wind,
have
disappeared
due
to
vehicle
activity.
Also,
significant
amounts
of
natural
vegetation
have
been
destroyed
by
vehicle
activity.
The
natural
crusting
of
the
dunes
is
constantly
disturbed
by
vehicle
tracks.
These
conditions
are
all
known
to
increase
dust
emissions.
In
the
non-riding
areas,
the
foredunes
and
natural
vegetation
exist,
and
the
natural
sand
crust
is
not
disturbed.
These
facts
point
strongly
to
the
conclusion
that
most,
if
not
all,
of
the
difference
in
PM
emissions
is
caused
by
off-highway
vehicle
activity in the SVRA.
Since
the
dune
dust
is
from
sand,
is
there
a
PM10
pollution
problem
elsewhere
along the California coast?
The
simple
answer
is
no
.
PM10
emissions
do
not
exceed
state
standards
anywhere
on
the
coast
of
California
other
than
from
the
Oceano
Dunes
SVRA
riding
areas.
This
has
been
determined
through
two
separate
surveys
of
Air
Pollution
Control
Districts
along
the
entire
coast
of
California.
No
other
coastal
APCD
experiences
this
phenomenon
and
none
of
them has off-highway vehicle riding on their beaches.
Who is responsible for mitigating the excessive emissions?
The
Off-Highway
Motorized
Vehicle
Recreation
(OHMVR)
Division
of
the
California
Department
of
Parks
and
Recreation
(DPR)
is
responsible
for
managing
the
Oceano
Dunes
State
Vehicle
Recreation
Area
(SVRA).
Part
of
this
responsibility
is
ensuring
that
the
SVRA
is
operated
in
accordance
with
California
environmental
laws
and
regulations,
including
the
State’s
own
PM
emission
standards.
The
OHMVR
has
acknowledged
its
responsibility
for
mitigating
the
PM
pollution
from its off-highway park.
What mitigation measures would be most effective?
The
OHMVR
Division
has
commissioned
studies
of
the
dune
dust
sources
and
possible
dust
control
measures.
In
an
effort
to
reduce
the
PM
emissions
upwind
of
the
monitoring
station
located
at
the
Cal
Fire
Station
on
Highway
1,
the
OHMVR
Division
has
deployed
hay
bales
and
wind
fences
to
disrupt
surface
wind
patterns.
These
measures
have
been
largely
ineffective.
According
to
the
Air
Pollution
Control
District,
the
most
effective
measures
would
be
to
allow
the
natural
foredunes
and
vegetation
to
return
between
the
ocean
and
the
more
inland
part
of
the
riding
area.
This
occurred
in
the
southern
part
of
the
Oceano
Dune
Natural
Preserve,
adjacent
to
the
off-highway
vehicle
park,
when
OHV
activity
was
stopped
to
protect
Snowy
Plover
reproduction
habitat,
and
accounts
for
the
significant
difference
in
PM emissions between the protected area and the riding area.
Why not plant trees to trap or filter the dust?
Trees
can
be
effective
in
slowing
down
wind
and
causing
turbulent
air
flows,
which
allows
the
heavier
dust
particles
to
precipitate
from
the
dust
plume.
However,
the
smaller
and
lighter
particles
largely
pass
through
and
over
trees.
PM10
and PM2.5 pollution on the Nipomo Mesa would not be significantly reduced.
Why has effective mitigation not been done already?
A
primary
mission
of
the
State
Parks
OHMVR
Division
is
to
operate
off-highway
recreation
areas,
including
the
Oceano
Dunes
SVRA.
The
operation
of
the
SVRA
is
also
subject
to
State
Parks’
obligation
to
maintain
and
restore
the
dunes
environment.
The
Division
has
historically
resisted
implementing
any
dust
mitigation
measures
that
would
permanently
reduce
the
riding
area.
Instead,
it
has
elected
to
install
ineffective,
temporary
mitigation
measures
outside
of
the
most
emissive
areas.
In
its
Oceano
Dunes
SVRA
Dust
Control
Program
FINAL
Program
Environmental
Impact
Report
(March,
2017),
and
in
its
Updated
Dust
Control
Program
Description
(July,
2017),
the
Division
describes
a
dust
mitigation
plan
that
would
take
five
years
to
implement
a
series
of
measures
that
are
similar
to
those
employed
unsuccessfully
in
the
past.
It
has
rejected
a
more
effective
alternative
because
it
would
reduce
the
riding
area.
Over
the
years,
the
OHMVR
Division
has
consistently
given
preference
to
off-highway
vehicle
riding
over
protecting
public
health.
Continued…
Mesa Air Facts!