Michael St. Denis, D.Env., Joe Roeschen - Revecorp Inc.
I/M Solutions
May 20 – 24, 2012 Sacramento, California

To estimate the cost effectiveness of a high evaporative
emitter identification and repair program in Denver by
combining remote sensing data (used for high emitter
identification), evaporative emission rates from MOVES,
on-road hydrocarbon emissions distributions and repair
data
Revecorp Inc.
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The field data used in this study came from a
cooperative effort of US EPA, Colorado Department of
Public Health and Environment, Eastern Research Group,
Envirotest, Applied Analysis, many others

This analysis was sponsored by Envirotest

This presentation has not be reviewed by any of the
above and is not endorsed by any of the above

The opinions expressed are solely those of Revecorp
Revecorp Inc.
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It is estimated that approximately half of all mobile source
hydrocarbon emissions are from evaporative sources
Few I/M programs test for evaporative emissions (besides gas
cap and OBDII) and therefore may not identify gross leakers
Current evaporative testing methods (purge and pressure
testing) are difficult, intrusive, expensive
Few I/M programs performing these checks, failure rates are
low for pressure testing in CA and not performed on 1996+
vehicles
Can you find and repair these vehicles cost effectively?
Identify – Test – Repair - Retest
Revecorp Inc.
 Study data are from work conducted over two summers in
Colorado at an Air Care Colorado test station and on an
adjacent highway
 Remote Sensing was used to screen vehicles for high
evaporative emissions
Revecorp Inc.
160
1600
140
1400
120
1200
80
800
60
600
HC
400
CO2
40
20
200
0
0
2
CO % cm
CO2 % cm
100
1000
7
12
17
22
27
Plume Sample #
32
37
42
47
0.4
160
0.4
140
0.3
120
0.3
100
0.2
80
0.2
CO
60
CO2
0.1
40
0.1
20
0.0
0
2
7
12
17
22
27
Plume Sample #
32
37
42
47
CO2 % cm
HC ppm cm
1800
 Study data are from work conducted over two summers in
Colorado at an Air Care Colorado test station and on an
adjacent highway
 Remote Sensing was used to screen vehicles for high
evaporative emissions
 A representative sample of screened vehicles were tested for
evaporative emissions in a portable SHED (g/15 min)
Revecorp Inc.
 Study data are from work conducted over two summers in Colorado at an
Air Care Colorado test station and on an adjacent highway
 Remote Sensing was used to screen vehicles for high evaporative
emissions
 A representative sample of screened vehicles were tested for evaporative
emissions in a portable SHED (g/15 min)
 Remote Sensing performed
▪ Two measurements each on road at approximately 34 and 55 mph
▪ Three measurements at entrance gate at approximately 12 mph
 Higher emitters were sent out for repair:
▪ Year 1 – Local repair shops performed repairs
▪ Year 2 – CDPHE performed repairs and additional SHED testing
 Retest on-road and in P-SHED
Revecorp Inc.
 Repairs made by local shops and CDPHE had nearly
identical repair reductions and repair costs
 Difference in repair effectiveness between 1997-/1998+
 In general - repairs were inexpensive and effective
Revecorp Inc.
 Average remote sensing speed in Colorado is 44 mph
 Averaged capture rates for 34 and 55 mph for gross liquid
leakers ~ 66%
Percent of Group Emissions Identified
100%
% of Hot Soak Emissions Identified by RSD
90%
12 mph
80%
70%
34 mph
60%
50%
40%
55 mph
30%
20%
10%
0%
0.0 - 0.2
grams
0.2 - 1.0
grams
1.0 - 4.0
grams
4.0 - 8.0
grams
>8 grams
(GLLs)
15-Minute Hot Soak Groups
Revecorp Inc.
 Used MOVES to model evaporative emissions for the metro
Denver fleet, by model year for June 2010 – average emissions by
model year
 Used 9 million on-road remote sensing measurements from
Denver to determine the distribution of on-road fleet population
by model year (1981 to 2010) and on-road HC emissions by model
year (100 bins for each model year)
Revecorp Inc.
Revecorp Inc.
 Used MOVES to model evaporative emissions for the metro
Denver fleet, by model year for June 2010 – average emissions by
model year
 Used 9 million on-road remote sensing measurements from
Denver to determine the distribution of on-road fleet population
by model year (1981 to 2010) and on-road HC emissions by model
year (100 bins for each model year)
 Normalized each model years emissions rates
Revecorp Inc.
Revecorp Inc.
 Used MOVES to model evaporative emissions for the metro
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Denver fleet, by model year for June 2010 – average emissions by
model year
Used 9 million on-road remote sensing measurements from
Denver to determine the distribution of on-road fleet population
by model year (1981 to 2010) and on-road HC emissions by model
year (100 bins for each model year)
Normalized each model years emissions rates
Applied the average modeled emission rate for each model year to
the distributions of on-road emissions by model year to develop
by model year distributions of evaporative HC emissions
Multiplied the emissions rates by the population for each 1/3000
of the fleet to get it’s overall emissions contribution:
Average emission rate x fraction x population = contribution
Revecorp Inc.
 Determined the emissions for the whole fleet – tons/year
 Determined the emissions of highest emitters - top 0.5%,
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1%, 2%, 4%, 6%, 8%, 10% of the fleet = EX%
Multiplied by the identification rate = 66%
Multiplied by the repair effectiveness rate by model year
group (1997 and older = 88.2%, 1998 and newer = 98.7%)
= EXReduced
Multiplied the number of vehicles “repaired” by the average
cost of repair = $353
Cost effectiveness = Total cost / EXReduced
Revecorp Inc.
 Assume repairs last three years
 In Colorado, identification is no cost since there is an
existing Remote Sensing Program which clean screens
vehicles – revenue could be used to pay for repairs
 The use of Remote Sensing to identify high evaporative
emitters for repair and the repair of these vehicles appears
to be a cost effective emissions control strategy
Revecorp Inc.
Contact:
Revecorp Inc.
Michael St. Denis
5732 Lonetree Blvd
Rocklin, CA 95765
(916) 786-1006
www.Revecorp.com
Revecorp Inc.