REMOTE-SENSING MEASUREMENT OF REAL WORLD VEHICLE
HIGH-EXHAUST EMITTERS
CRC Project No. E-23
Leaders: M. Natarajan
S. H. Cadle
Scope and Objective
The objectives of this project are to follow vehicle conditions and emissions
using remote-sensing measurements of on-road vehicles at selected sites to
identify trends over a multi-year period and to use the information to estimate
high-exhaust emitter populations.
Current Status and Future Program
Investigators have used remote sensing of
on-road emissions to find the fraction of vehicles that are high hydrocarbon
(HC) and carbon monoxide (CO) emitters, and have shown that a small fraction of
on-road cars contribute most of the mobile emissions. Until the start of this
project, there was little information from one site over a period of years to
examine trends. CRC is interested in long-term monitoring at several sites to
examine the influence of new technology, use of enhanced Inspection/Maintenance
(I/M) programs, and the use of on-board diagnostic systems.
CRC negotiated a
contract with the University of Denver (DU) to observe sites over a period of
several years where CO, HC, and oxides of nitrogen (NOx) emissions
were measured. CRC also arranged for cooperative efforts with states and other
agencies. The plan called for collecting information on about 20,000 vehicles
each year at each site. Later the frequency of measurements was changed to
every two years. Investigators made measurements during the same time of year
at the selected sites. EPA supplied data collected in Raleigh/Durham, NC.
Georgia Institute of Technology supplied data from Atlanta and other locations
in Georgia. CRC established a five-year phased contract to collect data in Los
Angeles, Phoenix, Denver, and Chicago. Final Reports for E-23-4 ("On-Road Remote
Sensing of Automobile Emissions") have been completed in the Chicago Area: Years
1-7, Los Angeles-Riverside: Years 1-4, Los Angeles-La Brea Years 1-4, Phoenix
Area: Years 1-6, and Denver Area: Years 1-5. The data collection effort in an
EPA addition to E-23 was completed for Omaha in September 2002 and 2004 and for
Tulsa in September 2003 where the impacts of OBD in a non-I/M area will be
analyzed.
CRC has an agreement with
consultant Dr. Robert Slott (retired from Shell) to integrate and analyze the
data collected under E-23. Dr. Slott has developed a data collection guidance
document for consistent reporting in the program. This document has also been
adopted by EPA and will be used as a key component in EPA's effort to evaluate
the effectiveness of I/M programs. Dr. Slott completed a data analysis report
on data collected by EPA in North Carolina. Dr. Slott has also completed
several interim reports for use by the Real World Vehicle Emissions and
Emissions Modeling Group summarizing data from the Georgia remote sensing
program and approaches for making city-to-city comparisons.
Dr. Slott prepared an interim program report, which provided a comprehensive
overview of progress in the E-23 program in 2003. This report is posted on the
CRC website, as are the several site reports. EPA added the non-I/M city study
(Omaha, NE & Tulsa, OK) to the E-23 project in 2002 through direct funding to
CRC via a competitive solicitation. A journal article summarizing some results
from the E-23 program was published in Environmental Science & Technology
(2003)37, 5097-5101. Dr. Slott's report, "Analysis of Remote Sensing
Data to Determine Deterioration Rates for OBDII Equipped Vehicles," was issued
September 2006 and is posted on the CRC website.
Data
collection has been completed. Dr. Robert Slott's final overall report is in
review by the Real World Group.
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