A scientific study has concluded that off-highway-vehicle riding at Oceano Dunes State Vehicular Recreation Area is a major cause of unhealthy air quality on the Nipomo Mesa.
Larry Allen, county air pollution control officer, announced the findings of the study at a recent meeting of the San Luis Obispo County Air Pollution Control District.
“The results in the study do conclude that there is a strong link between OHV activity on the SVRA and particulate levels on the Mesa,” Allen told the board, referring to Oceano Dunes.
The air district hopes to release the study to the public before Christmas, Allen said. The district has also tentatively scheduled two public workshops, on Jan. 5 and 6, at the South County Regional Center in Arroyo Grande to discuss the findings.
The study does not contain recommendations about how to reduce dust pollution from the park, Allen said. Members of the air board will begin discussing what to do with the study when they meet Jan. 27.
Andrew Zilke, Oceano Dunes superintendent, said he accepts the findings of the study and promised to work with air officials to find ways to minimize the problem.
“We can’t ignore it,” he said. “I think we are still a ways out from being able to determine what we need to do.”
Allen’s announcement prompted a debate among the air board directors, including all five county supervisors and one council member from each of the county’s seven incorporated cities.
Kris Vardas, Pismo Beach’s representative on the panel, said the board needs to protect public health but keep in mind that Oceano Dunes is economically important to nearby cities.
Ed Waage, another Pismo Beach city councilman, suggested that dust screens might be a solution to the problem. Zilke said his department is likely to look at what other jurisdictions with high particulate levels have done to address the problem.
For example, in the Owens Valley east of the Sierra Nevada, revegetation and watering were used to control dust, Zilke said. However, it is questionable whether those solutions are practical in a dune environment, he said.
The study is likely to add fuel to the debate about the environmental consequences of off-highway-vehicle riding in the park. Nell Langford, a longtime critic of the park, said the county and air officials should use their authority to shut the park down.
“If there was ever an opportunity to protect public health, this is it,” she said.
Public health impact
The study is the result of more than three years of data collection and analysis, Allen said. An initial phase of the study showed that the Nipomo Mesa, which is downwind of Oceano Dunes, has much higher particulate levels than any other part of the county and frequently exceeds state and federal health standards.
“This is a significant public health issue,” Allen said. “People on the Mesa are breathing very high levels of particulates.”
A second phase of the study sought specifically to determine whether the vehicular recreation area was exacerbating the problem. Monitoring stations compared the amount of particulates coming off parts of the Dunes where OHV riding is allowed with areas where they are not allowed.
The findings that dune buggies are contributing to the particulate pollution on the Mesa were peer-reviewed and confirmed by some of the top particulate scientists in the nation, Allen said. He told air board members that they should reject any effort to undercut the scientific validity of the study.
“Our only agenda is protecting public health,” he said.
Particulates are airborne particles small enough to be inhaled deeply into the lungs. Smoke and dust are two common forms of particulates.
At a public workshop in San Luis Obispo in September, Melanie Marty, chief of air toxicology and epidemiology at the state Environmental Protection Agency, said multiple studies have shown a link between high particulate levels and increased sickness and mortality.
Health problems caused by particulates include decreased lung capacity, asthma, chronic bronchitis, irregular heartbeat and heart attacks, Marty said. The elderly and children are at greatest risk.
Allen declined to elaborate specifically on how OHV riding increases particulate levels pending the release of the study later this month. However, there are three possible causes.
Dirt bikes and other vehicles often send plumes of sand into the air, increasing the likelihood that it will be blown away by prevailing winds that come from the northwest.
Vehicles can also crush the sand into smaller particles, similarly increasing the chance of them becoming airborne.
Finally, under natural circumstances, a crust forms on top of sand dunes and holds the particles in place. OHV riding breaks up this crust.
Reach David Sneed at 781-7930.