diesel engines: environmental impact and control alan c. lloyd, ph.d. and tom a. cackette

Diesel Engines: Environmental Impact and Control

Alan C. Lloyd, Ph.D. and Tom A. CacketteCalifornia Air Resources Board

IntroductionIntroduction

Land and sea transport

Electrical power

Farming, industrial, and construction activities

Diesels are an ImportantPart of the World’s Economy


The Number of Commercial Diesel Vehicles Will Grow in Many Countries

U.S.289

Canada20

Middle & South

America21

Africa9

Western Europe57

Eastern Europe34

Russia34

China6

Japan175

Australia116

India6

Sources: World Road Statistics (1999) and World Bank Atlas (1998)Commercial Vehicles per 1000 Inhabitants


0%

5%

10%

15%

20%

25%

30%

35%

1980 1985 1990 1995 2001

Sales Year

Percent of New Car Sales

Diesels Make Up One-third of Diesels Make Up One-third of Passenger Car Sales in EuropePassenger Car Sales in Europe

Source: Walsh (2001) SAE paper 2001-01-0183


Diesel Truck VMT is Growing in the U.S.

0

20

40

60

80

100

120

140

<10,000 10,001 to 19,500

19,501 to 26,000

>26,000

Truck Average Weight Category (pounds)

19921997

Annual VMT (billions)

Source: U.S. Department of Commerce


30% less fuel than comparable gasoline engine

More durable

DisadvantagesDisadvantages

AdvantageAdvantage

Single largest source of NOX

Toxic emissions

Less power per unit displacement

Advantages and Disadvantages of Diesel

EmissionsEmissions

Harmful Components of Diesel Exhaust

Gases Particles

Carbon Dioxide Elemental CarbonCarbon Monoxide SulfateNitrogen Oxides HydrocarbonsSulfur Dioxide PAHsHydrocarbonsAldehydesPAHs

EmissionsEmissions

A Diesel Particle

Diesel is a Major Source of NOX in California

Other Mobile Sources

42%

Off-Road Diesel23%

Stationary20%

On-Road HDD15%

California in 2000

Emissions

Source: EMFAC2000

Diesel is a Majority of Air Diesel is a Majority of Air Toxic Risk in Los AngelesToxic Risk in Los Angeles

0200400600800

10001200140016001800

Ris

k (e

xces

s per

mill

ion)

1990 2000

Other Toxics

Diesel PM

Greater Los AngelesEmissions

U.S. Diesel Vehicle NOX Inventory

NOX (million tons/year)

Heavy-duty Vehicles

Non-road Vehicles

Light-duty Vehicles

YearEmissionsEmissionsU.S. EPA Nat’l Air Pollution Trends, 1900 - 1998 Office of Air Quality

0

50

100

150

200

250

300

350

1970 1980 1990 2000Year

EmissionsEmissions

U.S. Diesel Vehicle PM10 Inventory

PM10 (thousand tons/year)

Non-road Vehicles

Heavy-duty Vehicles

Light-duty Vehicles

U.S. EPA Nat’l Air Pollution Trends, 1900 - 1998 Office of Air Quality

Emission ModelingEmission Modeling

Improvements Needed in Emission Inventory

More emission and activity data

Conversion factors for units of work per mile

Test cycles do not represent all driving conditions

Emission deterioration characterization

Uncertainties not great enough to question need to reduce emissions

Atmospheric Atmospheric Diesel PM ConcentrationsDiesel PM Concentrations

Location Year(µg/m3)

Reference Concentration

Los Angeles 1982 4.4 - 12 Schauer et al., 1996

Tokyo 1987 24 Yoshizumi, 1990Phoenix 1989 - 90 3.0 - 20 Chow et al., 1991

Phoenix 1994 - 95 2.4 - 5.3 Maricopa, 1999Denver 1996 - 97 1.1 - 2.4 Fujita et al.,1998

Los Angeles 1998 - 99 3.4 SCAQMD, 2000

CA (pop-wt'd) 2000 1.8 Cal/EPA, 1998Indirect Nitrate 2000 0.81 ARB, 2001

ExposureExposure

Health EffectsHealth Effects

Yearly Deaths Attributable Yearly Deaths Attributable to Particulate Matterto Particulate Matter

Europe Europe 40,600* due to PM10 (About 6% of all natural deaths in Austria, France, and Switzerland)

Nationwide Nationwide ~70,000** due to PM2.5 (About 3% of all natural deaths)

CaliforniaCalifornia 1,380- 4,250*** due to Diesel PM2.5(1.3% of all natural deaths in 1999)

* Kunzli, 2000 **Schwartz, 2000 ***Krewski, 2000 and DHS records


0

1000

2000

3000

4000

5000

6000

Long-Term Exposure Short-Term Exposure

95th Percentile, Mean, and 5th Percentile percentile

Yearly Deaths Attributable to Diesel Particles in California

Annual Mortality


Cancer Effects of DieselCancer Effects of Diesel

Increased lung cancer incidence supported by 30+ population studies

WHO, U.S. EPA, NIOSH, and HEI acknowledge the cancer potential in humans

ARB identified diesel exhaust PM as TAC

Unit Risk Range: 130 - 2,400 per million


Potential Near-Source Added Cancer Potential Near-Source Added Cancer Risks for Diesel-Related ActivitiesRisks for Diesel-Related Activities

0 200 400 600 800 1,000Potential cancers / million based on 70 years exposure

Truck Stop

Idling School Buses

High Volume Freeway

Prime Engine

Emergency/Standby Engine

1,700

Distribution Center

Low Volume Freeway

Association Between Lung Function of Association Between Lung Function of Children Living <300 Meters From Children Living <300 Meters From

Motorway and Intensity of Cargo TrafficMotorway and Intensity of Cargo Traffic

1.961.98

22.022.042.062.082.1

5000 7000 9000 11000 13000 15000 17000 19000

Number of Heavy Duty Vehicles Per Working Day

Lung FunctionFEV1 (Liters)

Health EffectsHealth EffectsSource: Brunekreef B, et al, Air Pollution from truck traffic and lung function in children living near motorways

Increased Symptoms for Increased Symptoms for High Truck TrafficHigh Truck Traffic

1

1.2

1.4

1.6

1.8

2

2.2

asthma hayfever phlegm HD allergy pet allergy wheeze last year


Odds Ratio

Environmental EffectsEnvironmental Effects

Black carbon absorbs light efficiently

Diesels largest source of black carbon

10-75% of light extinction in urban areas

Diesels and Visibility Reduction


Smoggy Los Angeles

Los Angeles On a Clear Day

Many Diesel Exhaust Components Many Diesel Exhaust Components Contribute to Global WarmingContribute to Global Warming

Source: IPCC 2000; Summary for Policymakers



The Galapagos Island Diesel Fuel Spill


Fuel spills and leaks

Deposition to water bodies and soils

Diesel Contributes to Water and Soil Pollution

Reducing Emissions Reducing Emissions of Dieselsof Diesels

New EnginesEngine modificationsPost-combustion clean-upAlternatives to Diesel

FuelsCleaner dieselAlternatives

Current fleetProper maintenanceRetrofit

Emission ControlsEmission Controls


Turbocharging

Aftercooling

Optimize combustion

Chamber design

Oxidation Catalysts

Retard injection timing

High pressure fuel injection

Electronic/computer control

Engine Technologies that Reduce Diesel Emissions


Lower Sulfur Reduces PM Less engine wear 350 ppm on-road 3500 ppm off-road

Lower Aromatics Reduces NOX 7%

Diesel Fuel Improvements

NOx Emission Standards for New On-road Engines

Current and Future TechnologiesCurrent and Future Technologies

NOX (g/bhp-hr)

Source: DieselNet. Emissions Standards: European Union, 2001.

PM Emissions Standardsfor New On-road Engines

Current and Future TechnologiesCurrent and Future Technologies

PM (g/bhp-hr)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

U.S./CAEU

98+% lower

Source: DieselNet. Emissions Standards: European Union, 2001.

Emission Standards forEmission Standards forNew Off-road EnginesNew Off-road Engines

0

1

2

3

4

5

6

7

8

g/bh

p-hr

1996 2003 2006

HC+NOxPMx10

175-300 hp

Model YearEmission Controls

Technologies to Meet Future Technologies to Meet Future Emission StandardsEmission Standards

NOX

Exhaust gas recirculation (EGR) - 2002/4Combustion improvementAfter-treatment (2007)

PMFilter

Ultra-Low Sulfur Fuel 15 ppm (2006)

Future TechnologiesFuture Technologies

Diesel Particulate Filter

Emission Modeling Emission ModelingEmission Modeling Emission Modeling



Diesel FuelsLow Sulfur FuelLow Sulfur FuelU.S. - 15 ppm (on-road) by mid-2006CA/TX - 15 ppm (on and off-road) by mid-2006EU - 50 ppm by 2005 (possibly 10 ppm)

Alternative Diesel FuelsAlternative Diesel FuelsFischer Tropsch - zero sulfur and aromatics

Water emulsions - reduce PM and NOX

14 new control measures75% risk reduction by 2010Retrofit on- and off-road diesel engines with filters (80% of plan’s benefit)


California Diesel PM Risk Reduction Plan

Trap

Trap

Diesel PM Traps Are EffectiveDiesel PM Traps Are Effective

Trap



Roadside smoke inspections

Reduced smoky trucks from 30% to 8%

Expand to include NOX and PM testing (by 2003)

Maintaining Low Emissions In-use


Alternative Fuels

Natural GasNatural Gas

Lower NOX and PM

Nanoparticle formation being investigated

Methanol and EthanolMethanol and Ethanol

Poor durability and frequent overhauls

Ultimate replacement for diesel engines Zero Emissions High efficiency Cost reduction needed

Initial transit buses in 2003

Near-term promise as truck APU

Fuel Cells


Conclusions and RecommendationsConclusions and Recommendations

Environmental regulations result in reduced emissions

Equal focus on off-road engines and fuels needed

Monitoring of in-use emission performance must continue

Progress Means Regulations and Monitoring

SummarySummary

Widespread use of diesels throughout the world

Number of diesels continues to grow

Diesel PM associated with premature death, lung cancer, and asthma

NOX emissions are PM and O3 precursors

Black carbon soils, reduces visibility, and affects earth’s radiation balance

SummarySummary

Emissions reduced through improved engine design and fuel reformulation

After-treatment effectively reduces emissions to near-zero levels

Ultra-low sulfur fuels necessary

Alternative fuels (NG) making in-roads now

Fuel cells and other alternatives will begin to replace or complement diesels this decade

AcknowledgmentsAcknowledgments

Steve Church, P.E.

Shaelyn Raab Strattan

Carmen Harms

Mike Baker

Dr. Shannon Baxter

Mark Carlock

Donald Chernich, P.E.

Bart Croes, P.E.

Eric Decetis

Dr. Deborah Drechsler

Mark Edwards

Fereidun Feizollahi

Scott Fruin

Jim Guthrie

Robert Ianni

Dr. Norm Kado

Jack Kitowski

Robert Krieger

Gloria Lindner

Joann Lu

Dr. Dongmin Luo

Steve Mara

Dr. Eileen McCauley

Elizabeth Miller

Dr. Diane Mitchell

Dr. Nehzat Motallebi

Susan O’Connor

Dr. Shankar Prasad

Tony Servin, P.E.

Dr. Willam Vance

Tony VanCuren

Dr. Melanie Marty

Dr. Bart Ostro

Dr. Michael Lipsett

Dr. Stan Dawson

Dr. John Budroe

Air Resources Board Office of Environmental Health Hazard Assessment

Professor Judy Chow

Professor John Watson

Norman Mankin

Desert Research Institute

diesel engines: environmental impact and control alan c. lloyd, ph.d. and tom a. cackette

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