PMP-33-09
33d PMP Meeting Notes
30 September-01 October 2014
30 September 2014 @ 11:00H - CLIMA ROOM BU-24 0/036,
EUROPEAN COMMISSION DG CLIMATE ACTION
Avenue de Beaulieu 24/Beaulieulaan 24, 1160 Bruxelles
Doc list
33-01 – Agenda
33-02 – EU Com summary presentation on NRMM
33-03 – Regeneration, sub 23nm
33-04 – JRC calibration
33-05 – EU WLTP short trips driving behaviour
33-06 – PMP non exhaust items overview
33-07 – REBRAKE
33-08 – PM2.5 TRWP study
Meeting notes
Rev 1: corrections from Hans-Georg Horn (TSI)
Rev 2: corrections / clarifications from JRC to non-exhaust particles section
1. Welcome & Introductions
Minutes uploaded to the PMP website after the meeting for meetings 30 and 31 but were not
available for review before the meeting.
The Chairman opened with the following remarks:
NRMM was included in scope because of need to test range of engines over range of test
cycles. In mean time, EU Com made a proposal based on the Swiss data.
Ricardo prepared paper on regeneration of DPFs for NRMM relating to measurement and
guidelines for testing to ensure common approach to ensure data from testing is
comparable. The ECE-R-49 is the basis for the procedure and the guidelines were intended
to help companies with less experience in PN. EU Com therefore believes further work on
NRMM by PMP is not a priority, unless issues arise with the test procedures.
EU Com proposal was released this week summary presentation – document PMP-33-02
2.
Calibration
i.
ii.
PNC
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Input from the EMPR report
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Input from ISO 27891
VPR
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Input from VPR RR
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Input from EMRP report
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PMP-33-09
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Other input
iii.
Summary of important and minor open issues and suggestions, experimental
recommendations for future
iv.
Develop work plan for progressing updates to calibration documents
Calibration PMP- 33-04,
JRC presented on overview of the current calibration work items and status
Overview:
10-15% improvement is max that could be achieved by better calibration of CPC and VPR
(slide 9). PNC calibration appears to be greater part of this. Differences between
manufacturers’ instruments are smaller than between manufacturers.
2.1 PNC calibration issues (slide 13)
Some of these might be theoretical but should be closed / defined anyway. Eg cut-off of ref
CPC not specified – so could even be theoretically 23nm CPC – but all known providers are
calibrating against electrometer.
ISO 27891 - final standard ballot closed 15 Sept; standard it was approved and is in final
preparation before publishing. Of particular relevance to PMP – the standard makes clear
that a reference CPC must be calibrated on the material it is going to measure.
EMRP
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DMA size standards below 80nm are calculated from ISO 15900
Difficult to find a real soot like aerosol (high-variability)
Calibration material should be therefore monodisperse, single size
Primary calibration aerosol recommended as heterogeneous nucleated silver
particles (thermal treatment to ensure spherical).
There was prolonged discussion on how to get to the end user calibration – suggestion for a
secondary calibration aerosol, but discussed whether this would be allowed by ISO – agreed
by the group that it could be possible only if the secondary aerosol was measured via the
electrometer and had the same characteristics for reference CPC. Another approach could
be to have a master electrometer calibrated using a silver aerosol. The electrometer is not
silver dependent. Calibration for electrometer includes the measurement of charge per unit
volume. The disadvantage is that use of silver seems quite difficult for end user.
Action: Request for traceability chain charts from NMI to end user and additional
uncertainties for the options listed above. Agreed Hans-Georg Horn (TSI) would provide
examples for the next face to face meeting.
2.2 VPR
Considerable discussion regarding calibration materials. EMRP suggested tetracontane
might not be best material and did find Palast CAST was quite stable. Found that no material
could be preferred or rejected, however, for silver the upper size limited to 50nm.
Aviation has introduced more strict requirements on the removal of tetracontane particles
than in automotive specification and they also use a CS, with dilution factor (not PCRF) and
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PMP-33-09
losses are characterised in another way (not 100% finalised) – there are remaining open
questions about the methodologies.
Considerable discussion took place on the merits or not of diluting tetracontane with air or
N2. Need oxygen by the time you get to CS. Agreed that today’s oxidised C40 is well used
and appears to work. It might only be sufficient to say it must be oxidised and not diluted by
N2.
Appears to be group consensus to look at 99.9% efficiency for tetracontane as Horiba
reported everyone gets over 99% already.
Open issue summary - slide 40
The open issue list was presented, noting that further updates are required. Group agreed
we can continue without inviting additional experts unless we get stuck at open questions
Dr Carli (VW) mentioned some work with silicone which revealed differences relating to
temperature and pressure of the
Action:
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3.
Comments on the open issue document are requested with an indication whether
issues relate to measurement at 10 and / or 23 nm. (ALL)
Final EMRP presentation at next face to face meeting (when EMPR final report
available) (Paul Quincey (NPL) or Hanspeter Andres (METAS))
Update of data /experimental campaigns (ALL)
Sub-23nm particles
v.
Status of monitoring >10nm particles (and >3nm for comparisons)
vi.
Open issues
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Euro 6 cars are necessary for further investigations
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More precise quantification of ‘error’ at sub23nm level (investigation of
different PN systems)
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CS are needed / investigations with CS
a)
Definition of key characteristics of catalytic strippers.
b)
Input from PN-PEMS program
c)
Input from CS manufacturers
Sub-23nm, when DPF fitted and therefore nearly no soot, investigations showed that even
small amounts of sulphuric acid could cause renucleation post DPF. Seems to be ok down to
10nm but not for smaller sizes.
FVV study with evap tube showed sub 23nm of average 20% (diesels lower, GDI higher).
Needs investigation with catalytic stripper because appears that nuclei need HCs to grow up
to 10nm.
Discussion on E85 fuels – JRC recalled a study which showed absolute level lower but ratio
of sub-23 higher – attributed to ethanol being good detergent and liberating the lubricant
from the cylinder walls.
Concluded to monitor future technologies for 10nm to check sub 23nm ratio doesn’t change
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PMP-33-09
A next step for measurement method is to better investigate CS characteristics /
performance.
Measuring with 2 CPCs in parallel gave 35-55 % difference on PFI and up to 102% on a 4stroke moped but caution needed for this specific result as may be artefact – further
investigation is needed.
FVV noted that depending on what material you use (sulphuric acid vs tetracontane) you get
different counting efficiencies and different response to volatiles.
Also how to ensure CS is not saturated with sulphur? FVV found up to 2 mg sulphur could
be stored without impacting performance (this was an MAN truck aftertreatment device used
as a CS)
One study on DISI engines showed that CS + evap tube had a better effect than either
separately below 10nm (slide 25) – group discussion suggested residence time would be the
key point here.
Strongly recommended CS should have sulphur trap, takes sulphur removal from g to mg
level.
JRC has launched a tender for PMP system with CS with 10 and 23nm CPCs. Study will
focus only on vehicle exhaust measurements, not on characterisation of CS
ET seems ok to measure down to 10nm with high PCRF around 1000. More investigation
needed at the extreme cases and need to characterise losses of VPR or make a new set of
clear criteria.
Below 10nm CS would be more critical. Particles nucleating need HCs to grow and with high
PCRF they seem to stop at 5nm.
Actions:
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input on CS devices / specifications needed from CS manufacturers
JRC requesting Euro 6 cars to test during early 2015.
JRC to prepare a list of the open points for the investigations (both routes)
Next steps:
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4.
Use ET with 1000 PRCR
Or use another approach like CS (seems to add more issues and complexity)
Review aero industry 10 nm CPC regulation
Regeneration (document PMP-33-03)
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Presentations from JRC on regeneration – many issues were discussed and the
document updated.
Currently JRC is planning the regeneration study using WHTC – hot start for
regeneration and continued cycles if not complete. JRC will manually continue with
the PN measurement after one cycle in order to avoid stopping the vehicle.
Project kick off expected early 2015 – request for Euro 6 cars to check new potential
issues
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PMP-33-09
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WLTP regeneration procedure remains an open question on how to handle if a
regeneration is not finished within 1 WLTC - whether to stop or not the vehicle after 1
WLTP due to number of bags JRC can check Euro 5 DPF vehicles in these
conditions (minor issue, input is needed by WLTP to define if experimentation is
necessary) WLTP should decide on this in the WLTP Pune meeting mid November
2015.
Reminders :
o At Euro 5, CPCs appeared ok to measure regeneration at 10nm but concerns
noted with 3nm.
o Current understanding is with high PCRF that 23nm has no issues for diesel
regeneration.
End of Day 1 @ 17:00H
01 October 2014 @ 09:30H - ENTR MTG ROOM BREY 11/A
EUROPEAN COMMISSION ENTERPRISE AND INDUSTRY DG
Avenue d'Auderghem 45, 1040 Bruxelles
5.
Non-Exhaust Emission Particles
Introduction
The chairman welcomed the group and briefly introduced the history of the non-exhaust
emissions in relation to the PMP group, the work and findings so far, the open questions –
particle number, size distribution, chemical composition etc. Although many studies exist,
different methodologies and measurement methods were used. The knowledge today is not
sufficient relating to health effects and direct emissions. As PMP we can contribute with
knowledge on measurement methods / drive cycles.
At June GRPE 2014, the work outline was accepted with the request to develop a more
detailed plan.
JRC presented a brief overview of the 4 working items including related open questions and
possible actions to be taken in the future:
1. Driving data
a. (Heinz Steven)
2. Brake and Tyre wear related projects
a. REBRAKE
b. TIP PM 2.4
c. Networking – Enlargement of the PMP group with experts
3. Sampling methods and measurement techniques
7: Working Item 1: Investigation of typical driving patterns and in particular of typical
accelerations/decelerations. Possible actions:
vii.
Definition of typical driving conditions. Data set(s) to be considered?
viii.
Would a single “harmonized” approach be appropriate or several definitions
depending on the region are needed?
Driving Database for WLTP (presented by consultant Heinz Steven)
Real world” driving data from different regions around the world was collected in the
framework of the WLTP (World Light-duty Test Procedure) project. “Real world” traffic data
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PMP-33-09
was collected from 441 vehicles equipped with on-board data acquisition systems able to
collect the speed, and the acceleration of a vehicle. The activity data was collected from five
regions: Europe, India, Japan, Korea and USA. Within Japan, Korea and India “instructed
drivers” were used, while in EU and Switzerland “customer data” (data from vehicles with
drivers without any particular instruction to drive their cars) was collected. Finally, USA
submitted both “customer data” and “instructed drivers” using the “chase car” method.
 Database contains 815.000 km, 450.000 km from Europe (10 EU Member States)
 A journey consists of many short trips – stop phase to stop phase.
 Data divided into short trips and stop phases (1 km above and below). The statistical
analysis started on the basis of the road type category (urban, rural, motorway) as
defined in each region. However, to achieve the desired harmonization it became
necessary to develop the WLTC on speed classes rather than on road categories and
the concept of low (L), medium (M), high (H) and extra-high (Ex-H) speed phases
replaced the urban, rural and motorway classification.
 Presentation focusses on EU data but US data was almost identical for driving dynamics,
but different for India (nothing in extra high phase) and Japan / South Korea has more
stop-go traffic. Asia has more stop/go situations, and lower speed but otherwise the
driving dynamics are quite similar to EU.
 Accelerations over 1 km h-1 s-1 (0.278 m s-2), cruise and decelerations above 1 km h-1 s-1
(0.278 m s-2) were differentiated
 Cruise percentage of driving increases with increasing speed (e.g. low to mid etc.)
 Decelerations – data available on duration, distance, min, max but not whether brake
pedal was applied. It’s clear for decelerations greater than 3 m s-2 and maybe at lower
levels the brakes would have been used.
 In low speed the majority of short trips last less than 2 minutes and less than 1 km.
 Strongest acceleration phases are quite short.
 Even in low speed the cruise phase is not often longer than 130 s.
 No deceleration longer than 65 s (> 1 km h-1s-1) appeared in the entire database
 The border of 1 km h-1s-1 deceleration is historical from WMTC and WHTC convention
and for the WLTP development is not so important.
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Some questions of how WLTC was weighted across the regions for the different
phases. In the end WLTC is representative globally but not any more for a special
situation in regions.
Heinz Stevens also mentioned the FIAT eco-drive database on 2.4 million km and
more focused on urban areas. He is not aware of other databases because of the
high effort made in WLTP to get data from all regions.
Data in WLTP has date and time attached. Could be possible to define a short
journey.
Discussion:
 To investigate an idea that brakes emit more particles when warm – what’s the
typical number of braking events - interrogate database to find how many
decelerations?
 Will need to find a way to quantify which decelerations are braking
 Is data available from GPS data from sat navigation companies – German national
project trying to get this but not so successful.
 There might be one database for when brake signal was monitored which might give
information on a screening / protocol.
 Data can be interrogated re detailed behaviour on the decelerations as data available
second by second.
 How to define extreme vs normal braking events? Important to avoid ‘extreme’ cases
which are not ‘really real’
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PMP-33-09
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Audi mentioned they calculated an expected 160°C from brake disc during WLTP
and in final WLTP braking event at 220°C (calculations based on standard pass car)
and aero cooling of car would also have an influence.
Noted that the WLTP data also important for tyre/road wear – in this case the
important data relates to accelerations as well as decelerations.
What parameters do we need?
o Severity of braking
o Number of braking
o Speed from which deceleration starts? (speed multiplied by deceleration – for
brake energy)
o WLTP uses RPA but this could be defined for negative accelerations (i.e.
decelerations) – not yet calculated but is possible. Short trip RPA = (sum of
(speed * acceleration)) / distance travelled
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Action: List draft by end October and finalise by Jan 2015 to complete comprehensive
analysis which could be delivered by Heinz Steven then by June 2015 separately for brakes
and tyre/road.
8 Working Item 2: Compilation and monitoring of the on-going research projects on
non-exhaust traffic related particle emissions.
Possible actions:
ix.
Overview of on-going research activities
Intention is to have a compilation of the other projects in existence and to keep updated
on the latest findings
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BREMBO – brake project (REBRAKE)
www.rebrake-project.eu
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Objectives to reduce PM10 (mass) by 50% (EU 2020 thematic strategy of 47%
reduction of PM by 2020) by providing a new braking system (by new materials /
coatings etc)
Deeper comprehension of the physical and chemical phenomena underlying the
brake wear process, including higher comprehension and analysis of characteristics
coarse, fine and UFP particles.
Partners: Brembo S.p.A., KTH (simulation / testing), Department of Materials
Engineering and Industrial Technologies (DIMTI) of the University of Trento (UniTN)
(industry and academic partners)
48 months from 01 Mar 2013
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Work packages –
o WP1 – Management
o WP2 – Tribological tests
o WP3 – Wear and particle simulation
o WP4 – Particles characterisation
o WP5 – Novel pad and disc formulation
o WP6 – Dissemination
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Quick testing route – pin and disc in clean chamber with a HEPA filtered intake
air flow exchange rate 7.7 m3 h-1. In 10 min have clean air in chamber. Design of
the pin found to be critical.
Next steps more in depth testing of real pads / discs on dyno set up over wide
range of PN / PM sizes 6nm to 10 m. Isokinetic sampling.
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Noted that bedding in of the brakes is contained in the ‘burnish procedure’ to get
a stable behaviour and these particles are also collected.
Appears to be a kind of ‘cold start’ emissions with higher particle emissions at the
start
Measurement during ELPI which can’t distinguish between volatile / solid (same
as CPC) so possible that condensation of material is contributing here especially
as no heating in ELPI.
PM measurement by ELPI with collection and additionally on pin on disc FMPS
and OPS (OPS is a very small instrument – optical particle counter 0.3 um
upwards – fine and coarse)
NEDC wasn’t suitable - too slow and not enough braking – SAE protocol used.
Particle collection via polycarbonate and aluminium filters (former for chemical
analysis, later is optical analysis (SEM))
Chemical analysis shows Fe, CU Zn Mn Titanium in broad size range from UFP
to coarse range
Different results arise from the 3 different measurement instruments (noted by
some experts as not surprising)
Will be adding a formal PM mass method, but today calculating mass from
standard particle density from the PN.
Noted that coarse particles relate to inflammatory effect and UFP to cardiovascular
effects. If look at number, UFP is dominant, whereas in PM the coarse fraction is
dominant.
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Study conclusions / projections further complicated because of ECE-90 regulation on
brake disc – entry into force 2014 for trucks and 2015 for pass car with will have
likely different material compositions.
Investigations required whether the particles are composed from disc or pad or both
materials. Experts suggested there might be interesting mechanisms re vaporisation /
condensation.
REBRAKE is not separate characterisation of organics
Further discussion occurred regarding the PMP measurement process for exhaust
emissions – focus on solid vs volatile.
SMPS & ELPI both work on electrical charge but measure different size properties –
ELPI is aerodynamic type (morphology and density influence behaviour). Correlation
is possible in principle if you know metals vs organics then the models can be
corrected. Recommended to be an easier adjustment if volatile particles first
removed via catalytic stripper or evaporation tube.
Suggested by the PMP exhaust measurement experts to review the original PMP
measurement instrument list which has descriptions of working principles to
understand where valid correlations /comparisons can be made.
Tyre / Road Wear Particles (TRWP)
Julie Panko – consultant to ETRMA (USA)
Technical specification for TRWP in ambient air made to ISO TC 146 (SC3) using a
deuterated standard. New SC3 working group focussing on transportation sources PM in
general and TRWP would be one of the first items.
PM2.5 TRWP
- Found 0.8% of PM10 was tyre wear (some comments from PMP participants that
seems really low – response was that normal quantification is an over estimate
based on data from 1970)
- Quantify in ambient air (contribution to total PM2.5 and variability)
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Focus US (Los Angeles), EU (London), Japan (greater Tokyo)
In LA sampling for 10 days from July 15, 2014 in 6 locations (near road).
Sampling 4 events at 48-86 hours per event. Worked with air quality
management to identify suitable sampling locations.
In Tokyo, sampling 20 days from Sept 10, 6 roadside locations @ 10m, also 4
sampling events
London study not yet started – in collaboration with Kings College, expected
Spring 2015.
Goal for publishing in peer reviewed study in 2016
Discussion
 PMP participants asked whether study would be repeated in winter, because for example
in Milan big difference between summer and winter PM10. Clarified only one event per
city.
 Discussion on why only cities with Low Emission Zones were selected. The rationale
was not clear.
 Discussion on PM10 vs 2.5 – pyrolysis methods and markers (polymers very specific to
tyre tread) rather than using other organic markers.
 Height and distance of samplers from road for PM2.5 – at roadside maybe 10m away,
some 100 m from road. In Japan all on roadside. Height – not more than 3m.
 Average concentration of 20 g m-3 needed to detect but actually measured samples 13
g m-3
 Question whether possible to analyse existing samples: only if on quartz filters – daily
quartz filters are taken at many sites in London including traffic and background.
 Still some discussions ongoing about source apportionment – more detail on
measurement techniques could be provided next time.
9: Additional experts
Necessary to connect with other experts – some additional have been identified, the
PMP network should continue to expand
10: Working Item 4: Methodologies to generate particles:
Development of a set of recommended measurement techniques and sampling
procedures.
Actions for discussion:
x.
Clarification of metrics which should be considered (mass, number or both)?
xi.
Chemical characterization of wear particles?
xii.
Laboratory based methodologies and techniques or also on-road measurement
procedures?
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Some questions about internal lab testing vs real world. Rainer Vogt
mentioned the Ford study and also a new study from South Korea on tyre and
brake wear and also on resuspension particles (with a trailer). They found
resuspension particle concentration depends entirely on road – some hot
spots in the city etc.
Discussions identified the need for a guideline document with correct
sampling methodologies, and guidance on handing / avoiding various issues
Eg trailer = isokinetic sampling might be needed for fine particles in m but
potentially not required for Ultra-Fine Particle measurements.
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Air quality – source apportionment – need experts – to avoid that methods
over or under estimate – location of sampling is critical. Essential to identify
best practice to avoid unnecessary errors and to optimise comparability of
studies.
Chemical methods eg looking at markers should be included in the guideline Eg a modern error could be looking for antimony as a marker for brake
particles, a material which has not been used for many years.
In PMP started from carbonaceous particles were harmful to health and
needed to find a sensitive measurement method – from there to instruments
and methodologies. Agreed to ask health experts (NL) if there is any
guidance about what should be measured / used as markers. Suggestion of
an additional health expert could be requested to join PMP to advise on
composition
11: Schedule and milestones for the above described working items
Contributions by GRPE Jan 2015
12: Arrangements for the next meeting:
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PMP 34th session GRPE session 13 Jan ½ day. Geneva 14:30-17:30 with Audio web
in advance if necessary
PMP 35th session : 4-5 March 2015 face to face Brussels (1st day EU Com meeting
room and 2nd day at CONCAWE offices)
End of Day 2 @ 15:00H
Caroline Hosier
Technical Secretary PMP
Jan 2015
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