MASS EMISSION RATES AND CHEMICAL CHARACTERIZATION OF PM2.5 EMISSIONS FROM TWO

MOTORCYCLES

Deniz Karman and Colin WelburnDepartment of Civil and Environmental Engineering, Carleton University

1125 Colonel By Drive, K1S 5B6 Ottawa, Ontario, Canada

Lisa A. Graham Environmental Technology Centre, Environment Canada

3439 River Road, K1A 0H3 Ottawa, Ontario, Canada

11TH CRC ON-ROAD VEHICLE EMISSIONS WORKSHOP San Diego, CaliforniaMarch 26-28, 2001

Overview

• Considerations for PM2.5 sampling from vehicle exhaust

• Motorcycle emission measurement program• Results & Discussion

– PM2.5 Mass emission rates– Chemical characterization

• Comparison with diesel bus emissions• Conclusions

Sample Collection Goals

• Dilute and cool the hot exhaust gases simulating the actual dilution process that occurs at the tailpipe or exhaust stack of a vehicle on the road

• Capture sufficient sample on a filter without causing changes in the physical and chemical composition of the particulate matter

Requirements of Dilution System

• Easily cleaned between tests.• Useful for light duty gasoline and diesel vehicles

and heavy duty diesel vehicles.• Residence time appropriate for collecting primary

particle emission samples• Adequate conditioning of dilution air • Provide complete mixing of dilution air and hot

exhaust before samples are collected

Requirements of Dilution System

• Simulate as much as possible real world dilution process

• Present dilute samples to the collection media at a temperature and relative humidity consistent with ambient conditions.

• Must be able to collect multiple, simultaneous samples using different sample collection methods and different sample media.

ERMD Dilution System

• Located in cold temperature test cell to simulate all seasons (25 to -20 °C)

• Exhaust transfer line from vehicle to tunnel is heated and relatively straight to reduce PM loss.

• Constructed of flanged pipe segments for easy cleaning.

• All samples collected under iso-axial, isokinetic conditions.

DISTANCE / SPEED

LOAD (force)

Critical Flow Venturi

Dilution Air

Dilution Air Filter

Particulate Sampling

Particulate Pump

Unregulated Emissions Sample

Regulated Emissions Sample

Dilute Exhaust

Filter Box

Heated NOxHeated Fid (NDIR)

Carbon Monoxide

(NDIR)

Carbon DioxideNitrogen OxidesTotal Hydrocarbon

Analyzer Bench

Concentrations

Temperature, Abs. Pressure

grams/mileCO CO2NOx HC

Vehicle Exhaust

LIGHT DUTY VEHICLE TESTING

Critical Flow Venturi - Constant Volume Sampler

Critical Flow Venturi

Dilution Air

Dilution Air Filter

Particulate Pump

Unregulated Emissions Sample

Regulated Emissions Sample

Dilute Exhaust

Filter Box

Heated NOxHeated Fid (NDIR)

Carbon Monoxide

(NDIR)

Carbon DioxideNitrogen OxidesTotal Hydrocarbon

Analyzer Bench

• Multiple PM2.5 samples collected in parallel from 2 isokinetic sampling probes in dilution tunnel

Motorcycle testing

• 2 motorcycles: – Suzuki 750 – Honda 600

• 2 gasoline fuels: – Summer Grade Commercial (SGC) – Low-sulfur (2 ppmw)

• 3 driving cycles– LA4, US06, NYCC

Collecting Sufficient Mass

• More repeats of a test, same filter is exposed longer– 2 X LA4 ; first one cold start, followed by

second one – 3 X US06– 3 X NYCC

PM2.5 Sample Analysis

• Gravimetric mg/mile

• Chemical– Organic / Elemental Carbon – Ion Analysis – Ammonia – Sulphur Dioxide

PM2.5 Emission Rates

0.00

10.00

20.00

30.00

40.00

50.00

60.00

CS LA4 HS LA4 Comp US06 NYCC

Em

issi

on

Rat

e (m

g/m

ile)

Suzuki SGC

Suzuki Lo-S

Honda SGC

Honda Lo-S

Results of Motorcycle Testing - Gravimetric Analysis

• High degree of uncertainty in PM emission rates (5-94% RSD).

• Uncertainty linked to low mass of PM collected on filters.

• Cold Start emission rates not significantly different from Hot Start emission rates

• US-06 and NYCC produce significantly higher emission rates compared to FTP

OC/EC Analysis

Quartz

Quartz Quartz

Teflon

Traditional Method Supplemental Method

T1

Q3

Q 1

Q2

Organic Carbon in PM2.5 - corrected for filter adsorption

R2 = 0.733

R2 = 0.2141

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00PM2.5 Rate (mg/mile)

OC

ra

te (

mg/

mile

)

OC-Q3 correctedOC-Q2 corrected

Linear (OC-Q3 corrected)

Linear (1:1)

Linear (OC-Q2 corrected)

1:1

Organic/Elemental Carbon Analysis

• Need to correct for sampling “artefacts”• Correction method critical for accurate

results• Number of invalidated tests directly

linked to mass of sample collected.• EC emission rates below detectable

limits

Measured Sulphur (SO4 and SO2) vs. Fuel S

y = 0.2728x

0

5

10

15

20

25

30

35

40

45

0 10 20 30 40 50

Fuel Sulphur Consumption Rate (mg/mile)

Tot

al S

ulph

ur E

mis

sion

Rat

e (m

g/m

ile)

1:1

Sulphur Balance - Motorcycles

• Fuel sulphur consumed >> sulphur collected as SO2 and PM-bound SO4.

• Causes:

– SO2 by-pass?

– Gaseous sulphur species not identified?.

PM2.5 Emission Rates - Diesel Bus on CBD

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

WarmBaseline

ColdBaseline

WarmCatalyst

ColdCatalyst

Em

iss

ion

Ra

te (

g/m

ile)

EC

OCPM2.5

• Conclusions– PM2.5 mass emission rates from motorcycles are

1/1000 of emissions from bus - approaching limit of gravimetric method of measurement

– the effect of aggressive driving cycles is noticeable – Motorcycle PM2.5 virtually all organic carbon

• Current work:– Particle size distribution with SMPS and ELPI,

potential for observing effect of driving conditions on emission rate and size distribution

Acknowledgement

• Contributions from the following programs are gratefully acknowledged:

• PERD (Government of Canada Panel on Energy Research and Development)

• TSRI - Health Canada (Toxic Substances Research Initiative)

• NSERC -PGS (Natural Sciences and Engineering Research Council of Canada, Post Graduate Scholarships)