S/I-VOC issues from vehicle emissions for

Secondary Organic Aerosol modellingBertrand BESSAGNET – bertrand.bessagnet@ineris.fr

Florian COUVIDAT – florian.couvidat@ineris.fr

INERIS – FR – National Institute for Industrial Environment & Risks

ERMES Plenary Meeting - November 14th, 2017

EMPA - Swiss Federal Laboratories for Materials Science and Technology

Ueberlandstrasse 129, 8600 Dubendorf (Switzerland)

2

Simulation at the global scale (PM2.5) with

CHIMERE - March 2014

Important contribution of SOA to PM2.5

CHIMERE – the french national chemistry transport developped by CNRS & INERIS used

for the official air quality forecasting PREV’AIR: www.prevair.org

3

➢ Organic matter (OM) represents 20 to 30% of the particulate matter in Europe, this fraction is

dominated by the secondary organic fraction produced by chemical reactions of organic precursors

(Freutel et al., 2013, Crippa et al., 2013)

➢ Official primary PM emissions decrease (e. g. use of filtering techniques for the case of diesel

vehicles, improvement of efficiency of wood stoves, etc…)

➢ Air quality models usually underestimate PM, and the lack of some emissions is considered as one of

the explanations (particularly in winter due to wood burning)

➢ The secondary fraction and/or the organic fraction are underestimated by models

➢ In smog chambers, the aging of diesel vs gasoline exhausts show the importance of SOA formation.

In some experiments, gasoline vehicles produce more aerosols than diesel vehicles after several

hours in the chambers → role of VOC and S/IVOC

➢ WG on emissions decided during the 2015 TFMM in Krakow

➢ Semi volatile Organic Compounds (SVOC) are partly included in emission inventories

▪ How to complement these emissions inventories?

The S/I-VOC issue

4

➢ Denier Van der Gon et al. (2014) shows that PM emissions are underestimated by

a factor 2-3 due to the missing SVOC emissions

➢ Missing emissions from other sources? Road trafic? Maritime trafic?

Nussbaumer et al. (2008)

Total organic carbon emissions for selected

countries according to the EUCAARI and the

TNO-newRWC emission inventories.

The S/I-VOC issue

5

Dilution profiles

➢ Most organic compounds are semi volatile

➢ Their partitioning between gas & particles

depends on:

▪ Temperature

▪ The organic mass loading

▪ Example: dilution profile obtained from a diesel

vehicle (Robinson et al., 2010)

Dilution curve

OA

SVOCg

Equilibribum

6

➢ SVOC (Semi Volatile Organic compounds): compounds present in the

gas and particle phases with non negligible weights

➢ IVOC (Intermediate Volatility Organic Compounds) too volatile to be

SVOC but not enough volatile to be identified by GC-MS. Could be a

significant source of SOA.

Definitions

SOA formation from diesel emissions

Zhao et al., Environ. Sci. Technol., 2014,

2015

7

Conceptual scheme of SOA formation

8

PM EF measurements – focus on the organic fraction

Elemental

Carbon

Metals-dust

Inorganics

IVOC

Not adsorbedon filters

POA in dilution samplers +

Total SVOC without IVOC+ +

Adsorbedvapors on filters

12 16 20 24 28 32 36

2

4

6

8

10

12

14

Em

issio

n F

acto

r in

mg

km

-1

Ambient POA

Molecule Carbon number

VOC

Adapted from Robinson et al. (2010)

IVOC SVOC LVOC ELVOC

9

IVOC emissions in recent literature

Gasoline

(IVOC between 3 to 19% of NMHCs)

Diesel

(IVOC = 60% of NMHCs)

IVOC vs VOC

IVOC vs POA

Zhao et al., Environ. Sci.

Technol., 2015

Zhao et al., Environ. Sci.

Technol., 2014

10

POA : Primary Organic Aerosol

BC: Black Carbon

PF SOA: Potential formation factor (equilavent for EF for secondary compounds)

DOC : Diesel Oxidation Catalyst

FAP : Particle Filter

In the case of Diesel DOC+FAP, SOA may be underestimated. If there is no absorbing

mass, SOA may not form.

Synthesis of emission factors (EF) from

simulation chambers (in mg/kg of fuel)

11

Contribution to SOA

GasolineDiesel

Zhao et al., Environ. Sci. Technol., 2015

12

➢ Based on trafic fleet from COPERT and emission factors (with details on

the speciation of emissions) from EMEP guidebooks

➢ IVOC :

▪ 60% of IVOC in VOC for diesel vehicles

▪ 19% of IVOC in VOC for gasoline vehicles

▪ 50% of IVOC in VOC for Motorcycles

➢ SVOC estimated with equilibrium assumption to estimate the missing

SVOC gaseous part:

▪ By linking an emission factor to an organic aerosol loading (by using a dilution

factor, a fraction of POA in PM, engine size)

▪ By computing the gas/particle partitioning at a specified temperature (>39°C)

A first estimate of S/I-VOC emissions

13

Estimation of IVOC/SVOC emissions for France

Vehicles emit less and less organic aerosol

Increase of gaseous SVOC

Contribution of gasoline emissions decreases

Increase of IVOC emissions

A SIGNIFICANT PART OF SVOC ARE IN THE GAS PHASE

14

3D simulations with the CHIMERE model

IVOC = 30% of VOC

Assume that IVOC are linear

alcanes from C14 to C18

NL06445 :Cabauw Netherlands

SIRTA : Nearby Paris

Simulated SOA

composition

15

More and and more papers on the

contribution SOA from gasoline versus diesel vehicles

Platt et al. 2017 (Nature)

16

➢ IVOC can be a significant source of SOA but their emissions can be difficult to

estimate.

➢ Need to better estimate SVOC and IVOC emissions from traffic

▪ Missing VOC emissions? Problems of wall losses during sampling?

➢ Need to better understand the SOA formation from IVOC

➢ French project EVORA (PRIMEQUAL ADEME) with INERIS-IFSTTAR-CITEPA

to identify IVOC by volatility bin for modern EU vehicles (gasoline and diesel)

emissions based on Zhao’s work

Conclusions

17

IFSTTAR / INERIS interested to participate in H2020 projects

➢ LC-MG-1-4-2018 - InCo flagship on reduction of transport impact on air quality

▪ A) Low-emission oriented driving, management and assistance

• Driving measurement campaigns to assess driver behavior and correlate real emissions

• Impact of poor maintenance and tampering

▪ B) From recently defined emissions indicators (RDE NOx and PN max values, WLTP CO2 emissions)

• Develop a holistic testing and scoring mechanism to assess all vehicles (green vehicle index)

▪ C) Sensing and monitoring emission in urban road…

• Remote sensing of road vehicle emissions

• Data infrastructure around vehicle registration databases, traffic management measures and air

quality monitoring

➢ LC-MG-1-9-2018: Hardening vehicle environmental protection systems against tampering

Possible contribution to H2020 projects