In October, air quality expert and local resident Thomas Cahill testified before the Planning Commission that “the threats from air pollution (diesel and ultra-fine metals) are so grave that it should be modified to eliminate all residential housing.” He attributes the severity of the problem to the fact that the “Nishi property is pinned between two major diesel sources, so that no matter which way the wind blows, the property will be impacted.”
The city has recognized this issue through the Environmental Impact Report, where they believe that they can reduce the impact by planting tress to create a barrier of sorts.
Planning Commissioner Cheryl Essex pointed out at last week’s planning commission hearing that tree planting “is not something that’s going to work right away, so the outdoor air quality may take some time to improve. It may never improve – it’s not a proven mitigation measure.” She noted that this might be possible if they delayed for-sale housing until the tree mitigation is proven effective.
Brett Lee asked Gary Jacobs about the air quality concerns in the report and, in particular, Professor Cahill’s suggestion that putting a biological barrier of trees could reduce the impacts of the ultra-fine particulate matter in the air.
Mr. Jacobs stated that “trees are extremely effective” in reducing ultra-fine particulates, “the question is at what point does it become effective?” Dr. Cahill, he said, found that in some places “they have virtually no effect because there is a well-developed canopy of trees, the ultra-fine particulates just don’t make their way down to people.”
The research is not there to determine at what point trees have an effect in the reduction of that matter. He said, “This has been theoretical over the years, Dr. Cahill has been a leader in this research. He has recommended certain tree types – pine needle conifers, also broad leaf trees that are sticky.”
Mr. Jacobs told Councilmember Lee that this is one of the suite of measures from the document to be reduced, but “exactly what risk it reduces is not quantifiable, there is no data that allows us to do this.”
Brett Lee asked how thick the barrier needs to be. The plan appears to call for a thin, single-file line of trees. He asked if it would be more effective if it were 50 feet.
Mr. Jacobs responded that the key is having the barrier. “Creating a line of trees that creates a buffer is the intent here. Having a wider buffer isn’t necessarily going to create a so-called ‘safe zone’ if there’s not the line of site blockage.”
Instead, he said what they really need “is just creating a barrier between the freeway and the project site with trees,” he said.
The draft EIR identifies the air quality impacts, even with mitigation measures that “are expected to result in substantial reductions to exposure levels of UFPs [ultra-fine particulates] and diesel PM [particulate matter].” The DEIR warns that “the level of effectiveness cannot be quantified.”
They conclude, “For this reason, and because ‘safe’ levels of UFP exposure and diesel PM exposure have not been identified by any applicable agency, or by a consensus of scientific literature, this analysis assumes that resultant levels of UFP exposure and diesel PM on the project site could potentially be associated with a substantial increase in health risks. Therefore, this impact would be significant and unavoidable.”
This led Dr. Cahill in his report in October to conclude, “in present conditions, it is my opinion that causing people, and especially vulnerable populations spending much of their time on the Nishi property, to move into a situation of such great potential harm is simply not supportable.”
Mayor Pro Tem Robb Davis, however, pushed back on the issue, stating, “I’m really frustrated about this one.” He argued that “we need a basic course in risk analysis.”
For instance, he noted that 1 in 3500 farmworkers in this country will die on the job this year. “That’s an acceptable risk to us,” he stated. “We live with that. We consume the food that they produce.”
The mayor pro tem explained, “What we’re hearing about this property is 1 in 4500 people will over the course of an entire lifetime contract a certain form of cancer. That’s not annually, that’s 1 in 4500 over the course of lifetime. We’re talking about magnitudes of difference.”
He said, “These are miniscule risks compared to the risks that we face every day in our lives.” He noted that people who drive their car their entire lives will have three accidents on average. “That’s the risk we live with,” he said.
Mayor Pro Tem Davis said he is not claiming there is no risk, but he believes that going out of the way to mitigate a small risk is not going to make a real difference for most people.
One in 10 people, he said, will contract some form of a respiratory cancer in their lifetime. And now “we’re talking about an incremental risk that will be 1 in 4500. I think we need some perspective on this. I don’t think it’s a major issue.”
Ultimately the planning commission, while clearly concerned about the air quality issues, recommended that the council move forward with the project. The question is now what the council will decide to do.
—David M. Greenwald reporting