Fine particle and toxic emissions from InService Diesel Vehicles

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Fine particle and toxic emissions from In-Service
Diesel Vehicles

• Peter Nelson
• Graduate School of the Environment
• Macquarie University

2
Risk factors and diesel emissions

• USEPA
• Diesel exhaust is characterized as likely to be
  carcinogenic to humans by inhalation at any
  exposure condition in their 2000 review
• But no quantified cancer unit risk factor for
  diesel exhaust
• Existing exposure-response data in animal studies
  inappropriate for human cancer risk
• Exposure-response data in human studies too
  uncertain to derive a confident quantitative
  estimate of cancer unit risk
• California Air Resources Board
• has adopted an official cancer unit risk factor
  for diesel particulates
• Scientific Review Panel's (SRP) recommended unit
  risk factor of 300 excess cancers per million per
  microgram per cubic meter of diesel PM 3 x
  10-4(mg/m3)-1 based on 70 years of exposure

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Particle Epidemiology Reanalysis Project

• Health Effects Institute (HEI) reanalysed
• 6 Cities Study (Dockery et al)
• American Cancer Society Study (Pope et al)
• First attempt to apply spatial analytical methods
  to data
• Results confirmed earlier findings
• Robust associations between mortality and FPs,
  sulphate and SO2

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Fine particles

• Revised risk factors
• May 2003 Health Effects Institute revised health
  effects estimates
• Across the 90 cities the revised mean effect on
  mortality decreased substantially
• from 0.41 (increase per 10 µg/m3 increase in
  PM10 concentration) to 0.27
• 34 decrease
• The overall decreases in effect estimates for
  hospitalisation for cardiovascular diseases were
  smaller ( approximately 8 to 10)
• The effect estimate on pneumonia hospitalisation
  was substantially reduced

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Work on Causes

• Size
• size ranges fine is PM1 NOT PM10
• generally larger particles less implicated in
  health effects
• Composition
• potential role of metals in the induction of
  PM-related effects
• Ghio et al (2001) particles collected during a
  period in which metal levels were high induced a
  greater inflammatory response in the lung
• Ann Aust (2002) iron can detach from coal fly
  ash taken into airway epithelial cells and induce
  inflammatory responses
• EPRI
• Carbonaceous material most highly associated with
  adverse health outcomes
• Neither sulfates nor nitrates significantly
  associated with adverse health outcomes

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(No Transcript)
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Motor Vehicle Emissions -Contribution from
Diesels (MAQS inventory)
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Diesel Emissions

• Diesel emissions are complex mixture of organic
  and inorganic compounds
• present in gaseous, liquid and solid phases
• consist of
• major combustion gases
• NOx, HC, CO
• trace compounds
• trace compounds have health impacts
• benzene and other compounds known to cause cancer
  in humans
• particulate material (recently classified by CARB
  as toxic)
• PAHs
• gt 40 compounds listed as HAPs by USEPA

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Some Toxic Compounds in Diesel Exhaust
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Diesel NEPM Project

• Project 1
• Characterise Australian Diesel Fleet
• Develop Drive Cycles
• Project 2
• Measure Emissions of 80 Vehicles Under Realistic
  Driving Conditions
• Examine Effect of Fuel Quality on Emissions
• Performed for NEPC / EA in collaboration with
  Parsons Australia

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Toxics Sampling System
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Auburn Diesel Test Site
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Dynamometer Test Cell
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Instrument Room
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Particle Instrumentation
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Vehicle Test Schedule

• Vehicle Matrix
• Passenger 4WD
• Light Commercial lt3.5 t
• Medium Commercial 3.5 - 12.5 t
• Rigid Truck 12.5 - 25 t
• Articulated Truck gt25 t
• Bus gt5 t
• Driving Modes
• Congested Traffic
• Minor roads
• Arterial Roads
• Highway Operation
• Short Tests

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Drive cycles (short tests)

• Short tests
• 6 tests (D550, DT80, AC5080, 2 speed, snap idle
  and lug down)
• D550 used for SMPS particle sampling.

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CUEDC Drive Cycles.
NA Light goods vehicles ? 3.5 t
NB Medium goods vehicles ? 3.5 t and ? 12 t
MC Off road passenger ? 8 seats
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CUEDC Drive Cycles.
ME Heavy bus ? 5 t
NC Heavy goods vehicles ? 12 t and ? 25 t
NC-H Heavy goods vehicles gt 25t
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Example of time series data (NB mode 2).
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Particulate results (Filter)

• No clear trend with vehicle mass.
• Emission rates increasing with age.

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Particulate results (APS)

• No clear trend with vehicle mass.
• Emission rates increasing with age.

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Particulate results (method comparison)

• High correlation of APS, TEOM and LLSP with
  reference filter method.
• Opacity poorly correlated with all measurements.

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Particulate Mass Emission

• Emission rates for 80 vehicles
• Correlations between filter and instrumental
  methods
• Base line data for Australian fleet
• Aim to develop inspection and maintenance (IM)
  program

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Particulate results (LLSP - Filter comparison)

• Moderate-High correlation _at_ 55 filter mass.

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Particulate results (APS)

• Most particles in sub 1 ?m range.

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Particulate results (APS)

• Size fractions varied between vehicles.
• Source of large particles uncertain.
• Overall, PM1PM10 95, PM2.5PM10 96.

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DIESEL PM

• Diesels produce many fine particles
• size is determined by dilution rate,
  agglomeration, condensation, existing atmospheric
  particles
• elemental C
• organic C (PAHs, lubricating oil)
• S impacts
• toxicity

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Particle Size

• gas to particle conversion processes
• nucleation
• adsorption/condensation
• coagulation
• Processes are influenced by
• Dilution ratio,
• Cooling,
• Residence time,
• Temperature,
• Humidity,
• Ambient aerosols

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Sampling effects on size
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Fine particle size distribution

• Large number of very fine particles (10- 200 nm)
• Size distribution changes due to agglomeration
• Primary diesel particles are largely fine
  particles

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Targeted Toxic Species

• Volatile Organic Compounds
• Benzene
• Toluene
• Xylenes
• 1,3-butadiene
• Aldehydes
• Formaldehyde
• Acetaldehyde
• Polycyclic Aromatic Hydrocarbons
• 16 species ranging from 2 to 6 ring compounds
• Metals

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Fuel Properties Which Affect Emissions

• Sulphur Content
• Particulates
• Aromatic Content
• Particulates
• NOx
• PAH
• Cetane Index
• NOx
• Hydrocarbons

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PAH Results
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PAH Results
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On-line PAH Analysis
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VOC Results
FID1 A, (F\HPCHEM\1\DATA\DIESEL\VEH6-001.D)
ethene
propene
acetylene
propane
ethane
1,3-butadiene
FID2 B, (F\HPCHEM\1\DATA\DIESEL\VEH6-001.D)
benzene
toluene
m- p-xylene
o-xylene
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Aldehyde Results
DNPH
Formaldehyde
Acetone
DNPH-NO2
Butanone
Acetaldehyde
Benzaldehyde
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Previous work and need for Australian data

• Large amount of work done, particularly on PAHs
• mostly qualitative
• difficult to obtain quantitative information as a
  function of fuel burnt or distance travelled
• CARB (1998) notes deficiencies in measurements of
  gaseous and particulate toxic species
• Health Effects Institute (HEI, 1995)
• composition varies considerably
• depends on engine type and operating conditions
• fuel
• lubricating oil
• emissions control system
• changes over recent years (due to technology,
  fuel formulation, emissions controls)

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Conclusions

• Diesel NEPM project provides most extensive data
  on Australian diesel fleet
• gases (CO, HCs, NOx)
• particle mass emissions
• particle size distributions
• toxic emissions (VOCs, aldehydes, PAHs)
• fuel property effects (Euro 2, 3, 4)
• Basis for IM program
• Risk assessment problematic

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TEAM

• L.Bernaudat, J.N.Carras, S.Day, J.L.Gras,
  B.Halliburton, W.Lilley, P.F.Nelson, A.Quintinar,
  D.B.Roberts, F.Szemes, T.Trieu and D.J.Williams
  (CSIRO)
• S.Brown, P.Anyon, D.Pattison, J.Beville-Anderson,
  G.Walls and M.Mowle (Parsons Australia)