Multispecies remote sensing measurements of vehicle emissions on Sherman Way in Van Nuys, California

• Published in: Journal of the Air & Waste Management Association (1995) 2012-10, Vol.62 (10), p.1127-1133
• Main Authors: Bishop, Gary A., Schuchmann, Brent G., Stedman, Donald H., Lawson, Douglas R.
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Ammonia - analysis; Applied sciences; Atmospheric pollution; Automobiles; Automotive engineering; California; Carbon; Carbon monoxide; Carbon Monoxide - analysis; Cities; Emissions from vehicles; Environmental Monitoring - instrumentation; Environmental protection; Exact sciences and technology; Hydrocarbons - analysis; Light; Mass ratios; Models, Theoretical; Nitrogen dioxide; Nitrogen Oxides - analysis; Oxides; Pollution; Ratios; Remote sensing; Remote Sensing Technology - instrumentation; Studies; Tunnels (transportation); Vehicle emissions; Vehicle Emissions - analysis; Vehicles
• ISSN: 1096-2247; 2162-2906
• DOI: 10.1080/10962247.2012.699015

As part of the 2010 Van Nuys tunnel study, researchers from the University of Denver measured on-road fuel-specific light-duty vehicle emissions from nearly 13,000 vehicles on Sherman Way (0.4 miles west of the tunnel) in Van Nuys, California, with its multispecies Fuel Efficiency Automobile Test (FEAT) remote sensor a week ahead of the tunnel measurements. The remote sensing mean gram per kilogram carbon monoxide (CO), hydrocarbon (HC), and oxide of nitrogen (NO x ) measurements are 8.9% lower, 41% higher, and 24% higher than the tunnel measurements, respectively. The remote sensing CO/NO x and HC/NO x mass ratios are 28% lower and 20% higher than the comparable tunnel ratios. Comparisons with the historical tunnel measurements show large reductions in CO, HC, and NO x over the past 23 yr, but little change in the HC/NO x mass ratio since 1995. The fleet CO and HC emissions are increasingly dominated by a few gross emitters, with more than a third of the total emissions being contributed by less than 1% of the fleet. An example of this is a 1995 vehicle measured three times with an average HC emission of 419 g/kg fuel (two-stroke snowmobiles average 475 g/kg fuel), responsible for 4% of the total HC emissions. The 2008 economic downturn dramatically reduced the number of new vehicles entering the fleet, leading to an age increase (>1 model year) of the Sherman Way fleet that has increased the fleet's ammonia (NH 3 ) emissions. The mean NH 3 levels appear little changed from previous measurements collected in the Van Nuys tunnel in 1993. Comparisons between weekday and weekend data show few fleet differences, although the fraction of light-duty diesel vehicles decreased from the weekday (1.7%) to Saturday (1.2%) and Sunday (0.6%).