According to a group of collaborating researchers from the Lawrence Berkeley National Laboratory, University of California at Berkeley, and the Bay Area Air Quality Management District, emissions at the Port of Oakland, Calif., have decreased dramatically due to more stringent California Air Resources Board (CARB) regulation.

The increasing inclusion of diesel particle filters and selective catalytic reduction on heavy-duty diesel trucks in California has led to “dramatic reductions of nitrogen oxides and black carbon PM,” according to the group. The measurements for this research were taken by monitoring drayage trucks at the Port of Oakland in 2009, before a new emissions rule was in place; in 2011 during the rule’s phase-in; and in 2013, after it was implemented.

“Our study is an important verification of the impacts of California’s air quality regulations,” said Lawrence Berkeley National Laboratory scientist Thomas Kirchstetter. “California tends to lead the way in air quality. The technologies we’re evaluating will eventually dominate truck fleets nationwide, so the significance of our study extends far beyond California.”

The groups has plans to continue measuring possible reductions next summer and again in 2017, when close to all heavy-duty trucks will have diesel particle filters installed.