State Parks’ new Oceano Dunes dust reduction plan falls short of goal, ACPD says
California State Parks must go back to the drawing board on its 2023 plan for dust reduction measures at the Oceano Dunes, according to the San Luis Obispo County Air Pollution Control District.
The state agency did not propose any additional dust emission mitigations in Oceano Dunes State Vehicular Recreation Area for next year — saying it had met a goal proposed by the scientific advisory group that advises it on dust-related issues in the park.
But the air pollution control district said State Parks must continue to abide by the dust emission reduction goal outlined in the 2019 stipulated order of abatement. That goal specifies that thar dust emissions must be reduced by 50% from 2013 baseline levels by the end of 2023.
State Parks estimates that it has reduced dust emissions by 40.8%, according to its annual report and work plan for the popular off-roading park in southern San Luis Obispo County.
Earlier this year, the agency said it had reduced emissions from the dunes by 22%.
The jump to 40.8% is largely due to the permanent closure of nearly 300 acres of threatened and endangered bird habitat that was previously opened seasonally to allow camping and off-highway vehicle access, according to State Parks.
The bird habitat area must be closed year-round per a March 2021 California Coastal Commission vote that revised the park’s coastal development permit.
That 40.8% reduction just barely meets the scientific advisory group’s newly suggested dust reduction goal of 40.7%.
The group proposed revising the stipulated order of abatement to the lower emissions reduction goal in February.
That suggested revision is based on new research that shows the 50% reduction target was likely too aggressive because it compared emissions at an air quality sensor downwind of the riding area at the dunes to an air quality sensor downwind of an undisturbed dune area near Oso Flaco Lake.
The dunes near the Oso Flaco air quality sensor are significantly covered by an invasive weed species that naturally reduces emissions, therefore skewing the target.
The 40.7% reduction target would bring the Oceano Dunes back to estimate dust emission levels were like in 1939, before off-road riding became a popular activity on the dunes.
However, the target State Parks must meet has not been officially changed. Doing so would take a petition to the air pollution control district’s hearing board and approval by the local agency.
Furthermore, the scientific advisory group said in its response to State Parks’ 2023 work plan for the dunes that it is likely the state agency’s estimates for how effective its dust mitigations have been “overestimate the actual emissions reductions.”
“Any decision regarding the adequacy of the existing dust mitigation treatments should recognize this uncertainty, and it should acknowledge that model refinements, as well as other long-term PM10 (fine particulate matter) monitoring efforts, may reveal the need for deployment of additional dust mitigation treatments in the future,” the scientific advisory group wrote.
The air pollution control district pointed out in its response denying State Parks’ 2023 work plan that the 50% reduction goal in the stipulated order of abatement is “an ancillary goal” meant to “achieve state and federal ambient PM10 air quality standards.”
“With dozens of exceedances of the California PM10 standard still occurring downwind of the (Oceano Dunes) on windy days, it is apparent that State Parks is not in compliance with this part of the SOA,” the ACPD wrote. “We further note that the SOA was the outcome of a nuisance petition filed before the hearing board, and this nuisance is ongoing, with verified dust complaints still being received from residents downwind of the (Oceano Dunes).”
The local agency added that “more work remains to be done” until the Oceano Dunes is brought into compliance with local, state and federal air quality standards.
State Parks has until Oct. 1 to submit a final 2023 work plan to the air pollution control district and scientific advisory group.
This story was originally published September 2, 2022 at 9:00 AM.
