What is the dune dust and what causes it?

The   dust   plume,   which   consists   of   particulate   matter,   blows   up   on   to   the   Nipomo   Mesa   from   the   off-highway   vehicle   park   on   the   Oceano Dunes.   The   dust   is   particulate   matter   (PM),   also   known   as   particle   pollution,   and   is   created   when   vehicle   riding   breaks   the   dune   crust, allowing the dust to be picked up in the wind and carried inland, blanketing the Nipomo Mesa and directly affecting local residents.

What are the health risks from breathing dune dust?

Fine   particulate   matter   that   is   10   micrometers   (PM10)   or   less   in   size   is   classified   as   pollution   because   it   is   known   to   cause   health   risks.      Fine silica   PM   air   pollution   is   an   especially   serious   public   health   hazard.      When   particulate   matter   is   inhaled,   it   is   trapped   in   the   lungs,   and   some of   it   becomes   embedded   in   the   lining   of   the   lung,   where   over   time   it   causes   scar   tissue   that   damages   lung   function.      The   effects   of   this   are cumulative.      The   more   PM   that   is   inhaled,   the   more   of   the   lung   can   be   affected.      The   smallest   particles   can   be   absorbed   by   the   lungs   into   the blood   stream   and   cause   heart   problems.      There   are   thousands   of   studies   linking   exposure   to   particulate   matter   exposure   with   increased risk of respiratory and cardiac disease.  Inhaled crystaline silica dust is known to cause lung cancer.   ( learn more… ) While   the   State   and   Federal   authorities   have   set   maxium   PM   concentration   exposure   standards   to   protect   public   health,   there   is   no      safe level   of   exposure.      What   matters   is   how   much   PM   has   been   inhaled   over   time.      The   health   risks   increase   with   the   cumulative   amount   of   PM inhaled    in    a    person’s    lifetime.        Long    term    exposures    to    low    levels    of    PM10    or    smaller    particles    and    short    term    exposures    to    higher concentrations can both have serious health effects.  

What level of dust emission is considered excessive?

The California Air Resources Board (CARB) has established standards for outdoor exposure to PM10 and PM2.5.  These are as follows: Annual Average 24 Hour Average PM10    20 µg/m3         50 µg/m3 PM2.5             12 µg/m3        none (µg stands for microgram) In California emissions greater than these are by law considered excessive. However,   these   standards   are   based   on   a   24-hour   average   and   thus   do   not   truly   reflect   the   health   risks   caused   by   dune   dust   from   the Oceano   SVRA.      On   the   Nipomo   Mesa,   PM   concentration   peaks   occur   when   people   are   most   likely   to   be   active   outdoors   –   between   the   hours of   10   a.m.   and   about   4   p.m.      During   these   hours,   PM10   concentrations   often   exceed   hundreds   of   ug/m3.         A   person   outdoors   at   this   sime   can receive   in   a   few   hours   many   times   the   exposure   they   would   have   experienced   had   PM10   levels   been   a   constant   50   µg/m3   over   24   hours.     Remember, there really is no completely safe level of exposure.  

What can Nipomo Mesa residents do to protect themselves?

The   only   way   to   protect   against   PM   exposure   is   to   avoid   it   as   much   as   possible.   On   the   Nipomo   Mesa,   this   means   avoiding   outdoor   activity in   areas   affected   by   the   dust   pollution   during   the   time   of   day   when   the   PM   concentrations   are   high.      Residents   can   also   protect   themselves by   monitoring   the   air   quality   forecasts   in   the   local   paper   and   on   the   Air   Pollution   Control   District   web   site   links.      Time   outdoors   should   be limited   on   days   when   high   pollution   levels   are   forecast,   generally   between   10   a.m.   and   4   p.m.      Furthermore,   the   pollution   can   often   be   seen. If the wind is blowing and you can actually see dust in the air, stay out of it.  Very   fine   particulate   matter   can   infiltrate   indoors.   Make   sure   window   and   door   seals   are   in   good   order   and   windows   are   closed   during   high wind   days.      Consider   using   high   performance   air   purifiers   for   the   places   in   your   home   where   you   spend   most   of   your   time.      Running   central air fans can also help reduce airborne indoor PM levels, however, high efficiency return air filters work best.

From where is excessive dust being emitted?

Dune dust emissions that exceed State of California PM standards primarily come from the Oceano Dunes State Vehicle Recreation (SVRA) areas where off-highway vehicle activity is allowed.  Emissions are greatest in the area known as the LaGrande Tract, a 585-acre parcel within the off-highway vehicle park, in the northern part of the SVRA riding area.
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Nipomo Mesa - Concerned Citizens for Clean Air

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