||Nevada Univ. System, Reno. Desert Research Inst.;Coordinating Research Council, Inc., Atlanta, GA.;National Renewable Energy Lab., Golden, CO.;South Coast Air Quality Management District, Diamond Bar, CA.;North Carolina State Univ. at Raleigh. School of Forest Resources.
In 1995, as part of a study designed to locate and evaluate sites for quantifying emissions of ozone forming precursors (oxides of nitrogen (NOx) and speciated hydrocarbons), carbon monoxide (CO), and particles from the urban light-duty fleet, a series of on-road emissions studies were performed in the Van Nuys (Los Angeles, CA), Sepulveda (Los Angeles, CA), Deck Park (Phoenix, AZ), Lincoln (NY/NJ), and Callahan (Boston, MA) Tunnels. One confounding factor in the direct comparison with previous studies was the inability to separate LD and HD emissions. Taking into account the estimated HD emissions. Taking into account the estimated HD contribution to the observed emissions, the urban light-duty fleet emissions measured in the 1995 experiments do not differ greatly from the interstate fleet emissions observed in the 1992 Fort McHenry and Tuscarora Mountain Tunnel experiments. When comparing the observed emission factors with emission model predictions, EMFAC7F model tended to underpredict CO and hydrocarbon emissions, while correctly predicting NOx, in the Van Nuys and Sepulveda tunnels. For the non-California tunnels (Deck Park, Lincoln, and Callahan), the MOBILE5a model overpredicted the observed emissions.