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Real‐World Vehicle Emissions Measurements
Gary A. Bishop and Donald H. StedmanDepartment of Chemistry and BiochemistryUniversity of Denver, Denver, CO 80208
www.feat.biochem.du.edu
ARPA-E Powertrain Innovations in Connected and Autonomous Vehicles Workshop
Denver, ColoradoMay 14 – May 15, 2015
Acknowledgements• Colorado Office of Energy Conservation• Coordinating Research Council• California Air Resources Board• Envirotest Systems Corp. (commercial partner)• Numerous foundations, city, state, federal
agencies, international groups, many students and other professional co‐workers.
Our Data, Reports and Publication Repositorywww.feat.biochem.du.edu
Fuel Efficiency Automobile TestIn 1987, with a grant from the Colorado Office of Energy Conservation, the first successful remote sensor used to test light‐duty vehicle emissions was developed at the University of Denver and named FEAT (Fuel Efficiency Automobile Test).
Research concept was to measure the tailpipe emissions of in‐use vehicles and find the highest carbon monoxide emitting vehicles and repair them to improve their fuel efficiency.
More than 50 peer reviewed journal articles and an additional 100+ reports
Roadside Instrument Setup
Speed Bars
IR/UV Light Source
Calibration Cylinder
FEAT NDIR Detector
UV SpectrometersQuartz Fiber Coupled
IR Plume Signal vs. Time5
4
3
2
1
0
Vol
ts
5004003002001000Time (ms)
ReferenceCOCO2HC
Pollutant Readings vs Time1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Perc
ent i
n 8c
m
5004003002001000Time (ms)
HC
(ppm) in 8cm
CO2COHC
0.0
50
100
150
200
250
300
Pollutant Ratio Plots0.75
0.50
0.25
0.00
Perc
ent C
O in
8cm
2.01.51.00.50.0Percent CO2 in 8cm
HC
(ppm) in 8cm
CO/CO2 = 0.41 gCO/kg ~ 550
0.0
50
100
150
200
250
300
HC/CO2 = 0.0067 gHC/kg ~ 14
Current FEAT Remote Sensor• Measures absorptions using:
– Infrared (non‐dispersive)•CO @ 2170 cm‐1 / CO2 @ 2330 cm‐1
•HC @ 2940 cm‐1 / Reference 2560 cm‐1
– Ultraviolet (dispersive)•NO @ 226nm, SO2 @ 215nm and NH3 @ 205nm•NO2 @ 430 nm
•FEAT compares the pollutant ratios (CO/CO2, HC/CO2, NO/CO2 etc.) in the vehicle exhaust to the pollutant ratios in a certified gas cylinder.
Lion’s Gate Bridge, Vancouver BC
FEAT Record More than 1.6 million light‐duty car and truck measurements collected from more than 30 locations in the US and 21 countries worldwide.More than 27,000 Heavy‐duty truck measurements.Snowmobile and Snow‐Coach measurements in Yellowstone National ParkLocomotive measurements in NE and WACommercial Aircraft at Heathrow AirportOcean going vessels in Vancouver BCSmall water craft at a lock in Seattle
Colorado On‐Road Mean COEmission Trends
250
200
150
100
50
0
Mea
n gC
O/k
g of
Fue
l
20102005200019951990
Measurement Year
Colorado On‐Road Mean HC and NO Emission Trends
20
15
10
5
0
Mea
n g/
kg o
f Fue
l
20102005200019951990
Measurement Year
HCNO
Colorado is not Unique!Emissions are decreasing Everywhere
60
40
20
0
gCO
/kg
of F
uel
8
6
4
2
0
gHC
/kg
of F
uel
(Adj
uste
d)
ChicagoDenverLA LaBreaLA RiversidePhoenixTulsa
8
6
4
2
0
gN
O/k
g of
Fue
l
201420122010200820062004200220001998
Measurement Year
Vehicle Emissions Distributions are Extremely Skewed
600
500
400
300
200
100
0
gCO
/kg
of F
uel
0 1 2 3 4 5 6 7 8 9Decile
Los Angeles (Mean / Median)2013 (16 / 4)2003 (43 / 9)1991 (96 / 18)
Colorado 99th Percentile Trends1000
800
600
400
200
0
gCO
/kg
99th
Per
cent
ile
20102005200019951990
Measurement Year
200
150
100
50
0
gHC
or NO
/kg 99th Percentile
COHCNO
The Tail Wags the Dog
0.30
0.20
0.10
0.00Top
1% C
O F
ract
ion
2000199519901985
Mean Model Year
I/MNo I/M
Who are the 99th Percentile?
0.08
0.06
0.04
0.02
0.00
Flee
t Fra
ctio
n
1993 2000 2001 2005 2009 2013Model Year
2008 Recession Repercussions seen in the Denver On-Road Fleet
Bishop and Stedman, The recession of 2008 and it impact on light‐duty vehicle emissions in three western US cities. Environ. Sci. Technol. 2014, 48, 14822‐14827.
Comparison with pre‐Recession 2007 Denver On‐Road Fleet
0.08
0.06
0.04
0.02
0.00
Flee
t Fra
ctio
n
25 20 15 10 5 0Vehicle Age (years)
2007 Denver Fleet2014 Denver Fleet
Recession Effects on Fleet Age in Denver and Los Angeles
10
8
6
4
2
0
Mea
n Fl
eet A
ge (y
ears
)
201520102005200019951990
Measurement Year
Denver I-25/6th Ave.Other Denver SitesWest Los Angeles I-10/La Brea Ave.Other LA Basin Sites
Recession Impacts on On‐Road Fleet Fuel Specific Emissions in Denver
30
25
20
15
10
5
0
Mea
n g/
kg
CO HC x 10 NO x 10 NH x 10Emission Species
2014 MeasuredModeled (2007)
28%11%
31%
16%
3
Certification Does not Always Work
50
40
30
20
10
0
gNO
x/kg
of F
uel
2014201220102008200620042002
Model Year
2L Pass. Engines> 2L Pass. EnginesTrucks All Engines
2013 LD Diesel Data from Denver, LA and Tulsa
2013 LD 2 Liter Diesel NO2/NOx Ratios2013 Data from Denver, LA and Tulsa
Bishop and Stedman, Reactive Nitrogen Species Trends in Light/Medium Duty U. S. Fleet Emissions. In preparation for ES&T.
50
40
30
20
10
0
gNO
x/kg
of F
uel
2014201220102008200620042002
Diesel Model Year
NONO2
0.3 0.6Mass
NO2/NOx
2012 Heavy‐duty NOx EmissionsPeralta Weigh Station California
50
40
30
20
10
0Mea
n gN
Ox/
kg o
f fue
l
20102005200019951990Chassis Model Year
2004 Cert.2007 Cert.
2010 Cert.
Bishop et al., Heavy‐Duty Truck Emissions in the South Coast Air Basin of California. Environ. Sci. Technol. 2013, 47, (16), 9523‐9529
On‐road Heavy‐duty Measurement System
Bishop et al., On‐road Heavy‐duty Vehicle Emissions Monitoring System. Environ. Sci. Technol. 2015, 49, (3), 1639‐1645.
2013 Heavy‐duty PM EmissionsCottonwood Weigh Station California
SummaryWe’ve made lots and lots of vehicle emission measurements with FEAT!
The “Great News” is that the US transportation fleet continues to have lower and lower emissions.
The not so great news is that because of the skewed nature of emissions distribution a minority of vehicles (broken ones) holds the fleet back from realizing even lower emission levels.
Since broken vehicles dominate emission distributions special emission certifications and so‐called “clean fuels” are generally irrelevant.
Regulations that reward the user usually meet great success.Those that don’t are usually nullified by human nature.
References• Bishop, G. A.; Starkey, J. R.; Ihlenfeldt, A.; Williams, W. J.; Stedman, D. H., IR
long‐path photometry, A remote sensing tool for automobile emissions. Anal. Chem. 1989, 61, 671A‐677A, DOI: 10.1021/ac00185a746.
• Bishop, G. A.; Stedman, D. H., A decade of on‐road emissions measurements. Environ. Sci. Technol. 2008, 42, (5), 1651‐1656, DOI: 10.1021/es702413b.
• Bishop, G. A.; Schuchmann, B. G.; Stedman, D. H.; Lawson, D. R., Multispecies remote sensing measurements of vehicle emissions on Sherman Way in Van Nuys, California. J. Air Waste Manage. Assoc. 2012, 62, (10), 1127‐1133, DOI: 10.1080/10962247.2012.699015.
• Bishop, G. A.; Schuchmann, B. G.; Stedman, D. H., Heavy‐Duty Truck Emissions in the South Coast Air Basin of California. Environ. Sci. Technol. 2013, 47, (16), 9523‐9529, DOI: 10.1021/es401487b.
• Bishop, G. A.; Stedman, D. H., The recession of 2008 and it impact on light‐duty vehicle emissions in three western US cities. Environ. Sci. Technol. 2014,48, 14822‐14827, DOI: 10.1021/es5043518.
• Bishop, G. A.; Hottor‐Raguindin, R.; Stedman, D. H.; McClintock, P.; Theobald, E.; Johnson, J. D.; Lee, D.‐W.; Zietsman, J.; Misra, C., On‐road Heavy‐duty Vehicle Emissions Monitoring System. Environ. Sci. Technol. 2015, 49, (3), 1639‐1645, DOI: 10.1021/es505534e.