651 research outputs found
Does California’s EMFAC2017 Vehicle Emissions Model Under-predict California Light-duty Gasoline Vehicle NOx Emissions?
On-road remote sensing measurements of light and medium-duty gasoline vehicles collected within California’s South Coast Air Basin since 1999 generally fall within the range of observed summer ambient molar NOx/CO measurements collected during morning rush hours. Compared with ambient and on-road emissions, the California Air Resources Board EMFAC model under predicts 2018 gasoline vehicle NOx emission factors by more than a factor of 2.6. Contributing to these differences is that vehicles older than model year 2006 have NOx emission deterioration rates that are up to 4 time’s higher on-road than predicted by the EMFAC model. A fuel-based inventory using the 2018 on-road gasoline emission factors for CO and NOx results in total CO emissions similar to the basin inventory but NOx emissions that are 74% higher than the inventory. The higher NOx emission estimates from on-road gasoline vehicle measurements makes their contribution to the inventory slightly larger than heavy-duty diesel vehicles. We have found LEV I (1994 - 2003) gasoline vehicles are a major source of these on-road emissions and that significant NOx reductions in the South Coast Air Basin are being overlooked by not targeting the high emitters for removal
United States Light and Heavy -Duty Fuel Specific On -Road NO and NO x Emission Factor Trends and Their Importance in Inventory Calculations (Presentation)
The Art of Poetry and Its Place in the History of the Coordinating Research Councils Real World Emissions Workshop {poster}
On-road Vehicle Emission Measurements and Their use in Evaluating Emission Control Effectiveness {presentation}
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