It was recently announced that the California Air Resources Board (ARB) miscalculated pollution levels by 340 percent in a scientific analysis that prompted harsher clean air standards for the state. Regulations adopted by the board in 2007 particularly affected the construction industry, since businesses were required to cut diesel emissions by replacing or making upgrades to heavy-duty diesel off-road vehicles.
The announcement was made in an article in the San Francisco Chronicle, which reported that a faulty method of calculation was used. However, the board attributed the error to calculations that were taken before the recession.
“The 2007 estimate of emissions from construction equipment was recently cut in half due to reduced activity and fewer vehicles in the fleet during the recession,” said Karen Caesar, information officer for the ARB. “This had nothing to do with faulty science or calculations — the equipment wasn’t being used or had been sold due to lack of business, thus emissions were lower by half.”
Caesar explained that the emission estimate was cut in half again because new data became available that suggested equipment was used less aggressively (at lower power) than data available in 2007 had indicated.
“Lower power means lower emissions,” she said. “It is correct that if ARB had checked fuel usage (a different way of estimated emissions) this problem could have been identified in 2007. ARB will use this cross-check in future inventories to better ensure their accuracy.”
A statement from the Associated General Contractors of America acknowledged the challenge in estimated emissions and the effort ARB staff made to update its estimates.
“At the time CARB put together its original forecasts, it had a limited amount of data available to it,” said Mike Kennedy, general counsel for AGC. “The process of estimated and forecasting emissions from offroad construction equipment is a very difficult and complex process…It would be a mistake to point to any one thing and say ’Yes the original numbers were off.’ This is a very complex process. In the end CARB and its staff made a serious good faith effort to come up with the right results.”
Caesar noted that the ARB staff also has reviewed new data regarding diesel trucks, the largest source of diesel emissions in the state, and has confirmed the validity of its previous calculations.
In light of the findings, the ARB has announced a proposal to delay the deadline to meet the emissions requirements until 2014. In addition, more vehicles would be exempt. A vote on the new proposal is planned for December.
A statement from the AGC noted that they and the ARB “have reached an agreement on proposed changes to the state’s off-road diesel rule designed to give the local construction industry time to recover from the recession while protecting air quality.”
The AGC reported that the proposal would provide help for an industry that has lost 4 out of every 10 jobs since the start of the downturn.
“The proposed changes promise relief for struggling construction workers and improvements for the state’s air quality,” Kennedy said. “The new estimates provided a common starting point for changes that everyone agreed the data should drive.”
Kennedy also noted that the association will continue to work with the ARB on some of the details of the proposal.
According to a statement from the ARB, the proposed changes call for the board to delay its emissions standards until 2014, to ease the annual burden employers have to bear, and to give contractors greater flexibility in determining how to comply. The changes also call for the board to give contractors credit for their efforts that have already been made to reduce emissions and to reward contractors for voluntarily reducing emissions before 2014.
“…the board staff demonstrated the courage and wisdom to propose significant changes to the rule,” Kennedy said. “It was not easy, but we found a way to protect workers and air quality at the same time.”
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