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.
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OCEANO DUNES SVRA DUST EMISSIONS FACTS