California Construction Trucking Association (CCTA)

By Jesse Lanum -  Martinez News-gazett

On February 26, the California Air Resources Board (ARB) held a symposium in Sacramento on the effects of PM2.5, a form of pollutant that is in part caused by diesel exhaust, on premature deaths. The symposium was intended to debate the science that buttresses the diesel regulations that truckers complain have cost many of them their jobs.

ARB scientists faced off against critics of their work, facilitated by Jonathon Samet. Arden Pope, Daniel Krewski, Michael Jerrett and Aaron Cohen came in the side of the ARB’s diesel regulations, presenting their findings to the ARB board and the attendees. The critical analysis came from James Enstrom, Robert Phalen and Fred Lipfert.

Dr. Enstrom began by presenting his credentials to the board. He received his PhD from Stanford from Nobel Laureate Melvin Schwartz and was the first fellow admitted to the American College of Epidemiology.

“I can’t find any employees of CARB from the College of Epidemiology or even with a PhD in Statistics,” said Enstrom. “In fact, I’m not sure they have a single PhD in epidemiology.”

He claimed that their studies fall victim to the ecological fallacy in not being able to directly measure a person’s ingestion of air pollutants. Instead, they rely on data from testing sites that pick up air pollution in the area. These test sites, as Dr. Phalen said, pick up an aggregate of pollutants that are dubbed PM2.5, which can include road dust. The scientists then measure the mass as an indicator of concentrations of air pollution.

“There are thirty properties other than mass that can drive the health effects,” said Phalen. “Figure it out and control that, because it will upset the economy a lot less.”

Phalen went on to say that PM2.5 in California is related to its dry climate and dust. This was, in part, to illustrate his problems with the EPA nationalizing regulations rather than localizing them with respect to specific ecological factors. “We can’t control the dust, so we have to go after diesel trucks,” said Phalen. 

Enstrom lamented the lack of diversity in the ARB panel of toxicologists. He claimed that the rules set out for appointment to the panel included appointment for three years. Instead, he said, three scientists have dominated the panel for twenty-six years. Gary Friedman has sat on the panel for sixteen years without appointment, according to Enstrom.

Enstrom noted that when national studies were broken into region specific data, the West came in with a -9 percent health risk, which he said supports the notion that there is no correlation between PM2.5 and premature death. The three largest California studies, Enstrom showed, have found no correlation between PM2.5 and premature death.  The 1.014 effect that was found in 1999 and 2000 is not considered statistically significant.

“California is the sixth highest in the nation in life expectancy,” said Enstrom. “California is a very healthy state.”

Enstrom asked that there be an objective reassessment of the relationship between premature death and PM2.5 in California by independent reviewers not funded by the ARB. Additionally, he asked that all researchers be given funding, including the critics. And, finally, he asked why all of the board members were not informed of the credential fraud of one of their lead researchers on PM2.5. He was referring to Hein Tran, who lied about having earned a PhD from UC Davis.

Dr. Lipfert reiterated that PM2.5 is simply an aggregate of air pollutants. “There is nothing that emits PM2.5,” said Lipfert.

He added that on-road measurements have found that seventy percent of total fleet emissions are coming from just ten percent of the vehicles. “These are not the regulated vehicles,” said Lipfert.

Phalen addressed the validity of bringing all pollutants down to zero. “If I put any of you in a clean room for two weeks, you would lose the ability to fight off infection. When you came out, you wouldn’t even be able to be around people.”

Phalen ended his comments with a suggestion that ARB scientists look into the offsetting health risks of their proposed regulations. “If you drive up the cost of electricity, people will die with air conditioning. If you drive up the cost of diesel, you have fewer goods, you have the indirect health effects caused by joblessness.”

Dr. Jerrett, who has done a large portion of the research for the ARB, responded to the critics by clarifying his research. He summed his findings up by saying, “The pattern we see is that there’s a significantly higher risk for premature deaths with air pollution.”

The meeting transitioned into a back-and-forth between the two teams. Roger McClellan lambasted the American Cancer Society for only giving its data to a small sect of scientists, calling it deplorable and despicable. Suresh Moolgavkar said that he was tired of what he called “trust me science” from the ARB.

The next meeting will be held on March 26.