By Daniel Weintraub
California’s top air quality regulator and the head of a major construction industry trade group announced Thursday that they have reached agreement on a plan to reduce diesel emissions from construction equipment.
The agreement, if approved by the full Air Resources Board in December, would end years of dispute between the board and the Associated General Contractors of America, which has fought California’s diesel emission regulations for construction equipment since they were adopted in 2007.
The deal will postpone until 2014 any mandatory changes the industry will have to make, and will essentially rely on the replacement of aging equipment with newer vehicles that come with cleaner-burning engines, rather than the forced installation of expensive and potentially dangerous retrofit filters to capture diesel exhaust.
Since the beginning of this year the contractors have been pushing the ARB to recognize and correct flaws in a computer model the state used to estimate emissions from construction equipment at the time the original rule was adopted. The industry claimed, and the board’s staff later confirmed, that actual sales of diesel fuel to construction companies was far lower than the computer model was predicting.
Part of the discrepancy was due to the recession’s toll on construction. With fewer projects underway, fewer vehicles were in use, less fuel was being consumed and thus emissions were lower than projected.
But a big part of the difference was also due to flaws in the ARB’s computer model, which had overestimated how much each piece of equipment was being used and the intensity of that use.
Michael Kennedy, general counsel for the contractors’ association, praised the ARB staff for being open to criticism about its computer model and willing to consider changes. He called today’s agreement “a victory for good data and good science.”
ARB Chairwoman Mary Nichols downplayed the model’s problems, instead attributing the change in direction to the board’s desire to react to the effects of the recession. Although the board’s staff unveiled a proposal just last week that delayed implementation of the regulations until 2012, Nichols said she was comfortable pushing that date back another two years.
Even with the delay in the regulation’s mandatory provisions, Nichols said, she expects California to meet federal requirements for reducing diesel emissions by the end of 2014.
Nichols said that one of the few good things to come out of the recession was that the downturn, by depressing construction activity, “gave us a little more time to address this problem.” A recent ARB study attributed 9,200 premature deaths per year to diesel emissions known as “fine particulate matter.”
“This is a good agreement,” Nichols said.