3

WP3: Megacity Plume Case Study

Coordinated by M. Beekmann (CNRS) and U. Baltensperger (PSI)

MEGAPOLI Partners involved: FORTH, CNRS, PSI, UHel, IfT

Summary of progress toward objectives

Two intensive measurement campaigns were performed in the Ile de France region during a one-month summer and a one-month winter period (July 1 – 31, 2009 and January 15 to February 15, 2010, respectively). The campaigns aimed at better quantifying primary and secondary organic aerosol sources on the example of a big European Megacity (the Paris region), according to the WP3 objectives O3.1-O3.4. During the 1st year, the campaign was prepared, with a coordination meeting held in Paris in April 2009. The campaign design included 3 primary and 7 secondary fixed ground measurement sites, an aircraft and 5 mobile platforms (Figure 3.1). This set-up was much bigger than initially planned and funded by the Commission, due to a large number of additional volunteering contributions by the MEGAPOLI partners and other research groups, and due to additional national (French) funding. The campaign was coordinated by a coordinating committee (Table 3.1). In total, more than 25 research laboratories participated (Table 3.2). Major tasks included: activation of predefined aircraft flight plans (Figure 3.2), and decision on target sectors for mobile labs, organisation of intercomparison activities, organisation of scientific campaign meetings, communication to national French and international media. For campaign planning, the chemical forecast from the PREVAIR system (http://www.prevair.org) was provided by INERIS in a specific format defined for the campaign and uploaded each day at 6 a.m. of Local Time (LT) on the local WP3 website (http://megapoli.lisa.univ-paris12.fr). In addition, DMI produced forecast was also used. Regular, weekly science meetings were organized where all groups presented measurements performed so far, and common campaign issues were also discussed. A particular focus was put on specific intercomparison exercises covering all major instruments or parameters measured by different groups. This activity was coordinated by IfT (A. Wiedensohler and A. Held). A specific intercomparison workshop was organised after the summer campaign in Leipzig, Germany in November 2009. A report on this workshop can be found on the internal MEGAPOLI website (http://megapoliforum.dmi.dk, section “2009 11 --- MEGAPOLI Intercomparison Workshop (WP3: Paris Plume Study), Leipzig, Germany)”. Figure 3.1 shows the location of the primary and secondary ground based sites, mobile platforms and one aircraft. The MEGAPOLI project is very warmly thankful and acknowledgesd the Laboratoire d’Hygiène de Paris (LHVP), SIRTA/IPSL, Golf de la Poudrérie à Livry-Gargan for hosting campaign sites. Without this help, the campaign would not have been possible.

Table 3.1: Coordinating committee of the Paris campaign.

M. Beekmann (CNRS /LISA) - WP3 co-leader,

A. Borbon (CNRS / LISA) - airborne segment coordinator,

J. Sciare (LSCE/CNRS) - ground segment coordinator (aerosol),

V. Gros (LSCE/CNRS) - ground segment coordinator (gases, LHVP site responsible),

S. Pandis (FORTH), A. Baklanov (DMI), M. Lawrence (MPI), MEGAPOLI coordinators

(one of three present during the whole campaign),

M. Haeffelin (IPSL/CNRS) - SIRTA site responsible,

A. Schwarzenboeck (LaMP/CNRS) - airborne instruments PI,

L. Gomes (Game/CNRS) - airborne instruments PI.

Figure 3.1: The campaign design included 3 primary (in black) and 3 secondary (in blue) fixed ground measurement sites, an aircraft and 5 mobile platforms. Primary sites are devoted to aerosols and gas phase chemistry, secondary sites to active and passive remote sensing. A specific lidar network was set-up during the winter campaign at a central Paris site and at 4 cardinal points (red stars).

Table 3.2: European laboratories that participated in the 2009 and 2010 Paris campaigns.

FP7 funded research laboratories:

· GAME-CNRM (Météo-France/CNRS), France,

· Institut für Troposphärenforschung, Leipzig, Germany,

· LaMP (CNRS / Université Blaise Pascal), France,

· LGGE (Université Joseph Fourier / CNRS), France,

· LISA/IPSL (CNRS / Universités Paris-Est et Paris 7), France,

· LSCE/IPSL (CEA / CNRS / UVSQ), France,

· Paul Scherer Institute, Villingen, Switzerland,

· SAFIRE (CNRS / Météo-France / CNES), France,

· Université de Patras, Grece,

· Université d’Helsinki, Finnland.

Additional research laboratories (or non-funded groups of funded laboratories):

§ ANDRA (ASL lidar network, winter),

§ AIRPARIF, France,

§ CEREA (Ecole des Ponts et Chaussés / EDF), France,

§ Département Chimie & Environnement (Ecole des Mines de Douai), France,

§ Finnish Meteorological Institute, Finland (ceilometer measurements),

§ INERIS, France,

§ INRA (ECG) (ASL lidar network, winter),

§ LATMOS/IPSL (CNRS / UVSQ / UPMC), France,

§ LCME (Université de Savoie), France,

§ LCP-IRA (CNRS / Université de Provence), France,

§ LEOSPHERE (ASL, lidar network, winter), Orsay, France

§ LMD/ IPSL (CNRS / ENS / Ecole Polytechnique / UPMC), France,

§ Max-Planck Institut für Chemie à Mayance, Germany, Aerosol group and MAX-DOAS group,

§ Paul Scherer Institute, Villingen, Switzerland, (mobile measurements),

§ SIRTA/ IPSL (CNRS, Ecole Polytechnique),

§ University Essen-Duisburg, Germany (summer only).

§ University College of Cork, Ireland (winter only)

At the three primary sites, a very complete set-up of instruments was deployed (Table 3.3) allowing for a detailed characterisation of aerosol properties, including their size distribution, volatility, hygroscopicity, optical properties, of aerosol chemical composition including fast measurements by Aerosol Mass Spectrometry (AMS, time resolution of several minutes, including also single particle measurements) and chromatographic measurements. They give the mass concentration of inorganic ions, and of primary and secondary organic carbon, respectively for PM1 and PM2.5 aerosol. In addition, filter measurements were taken to allow for individual analysis of up to 100 individual organic compounds. Detailed gas phase measurements were performed, especially of VOC’s as precursors of organic aerosol, using PTRMS, on-line and off-line chromatography, including derivative techniques for oxidised VOC (Table 3.4). During summer campaign, at SIRTA, also radical measurements (OH, HO₂) were performed by mass spectrometry, in addition to measurements of species and parameters interfering in the odd hydrogen radiacal budget (O₃, NOx, HONO, HCHO, J’s, etc.), At one primary site (SIRTA, Table 3.5), extensive dynamical measurements were performed, including especially wind profiles, and backscatter lidar measurements. At this site, and during the winter campaign, the cloud (fog) phase was also sampled. At two urban secondary sites (Jussieu in the center and Créteil in the south-east of the agglomeration) the spectroscopic column measurements and backscatter lidar measurements were carried out. During the winter campaign, an additional lidar network was set-up by LEOSPERE at an urban and at four suburban sites (red stars in Fig. 3.1), with aerosol lidars produced by this company (either provided directly by the company or by customers).

Table 3.3: Set-up of aerosol measurement at the three primary measurement sites.

Parameter	Instrument	Time resol.	Urban site	SOUTH-WEST Suburban site	NORTH-EAST Suburban site
			LHVP	SIRTA

number + mass conc
size distribution - submicron aerosols	DMPS/SMPS	5 min	IfT	UHEL	MPI
CN	AIS	5 min		UHEL
size distribution after TD	V-DMPS/SMPS	5 min		FORTH
size distribution	APS	5 min	FORTH	PSI	MPI
Size distribution	GRIMM	1min	LSCE	LSCE	MPI
Hygroscopic growth factor	HTDMA	5 min	IfT	PSI
CCN	CCN counter	5 min	FORTH	PSI
PM1	TEOM-FDMS	15 min	I		MPI
PM2.5	TEOM-FDMS	15 min	INERISIS	LSCE
Fast chemistry (<1h)
size resolved chemistry in PM1	AMS	7 sec	IfT	PSI	MPI
size resolved chemistry in PM1 after TD	AMS	2.5 min		PSI
Inorganic salts in PM2.5	PILS-IC	15 min	LSCE	LSCE
WSOC in PM2.5	PILS-TOC	4 min	LSCE
EC-OC in PM2.5	Sunset Field Inst.	60 min	LSCE
PM2.5	TEOM-FDMS	6 min	LSCE
size resolved elements in PM2.5	RDI / SRXFR	60 min	PSI	PSI
Individual particles	ATOF-MS or SPLAT	Some min	U CORK ATOF-MS (winter)		MPI SPLAT
Integrated chemistry (1h-24h)
C-OC + WSOC + ions + sugars in PM2.5	Filters (Partisol)	3 h	LSCE	LSCE
EC-OC + ions in PM1	Filters	12h			LSCE
Carbon-14 in PM1	Filter (daily sampling)	48h	PSI	PSI
Organic tracers in PM2.5	Filter (DA80 in PM_2.5)	12h	LCP - LGGE	LCP - LGGE
size resolved chemistry	13-stage Cascade Impactor	24-48h	LSCE	LCP - LGGE
Optical properties
Absorption coeff (BC)	Aethalometer 7-L	5 min	LSCE	LSCE
Absorption Coeff (BC)	MAAP	1-5 min	IfT	PSI	MPI
Black carbon	SP2	1 sec		PSI
Light scattering coefficient	TSI 3wavelength	5 min	IfT	PSI
Aerosol Optical Depth	Cimel sunphotometer			SIRTA
Aerosol Vertical profile	Lidar (LEOSPHERE)			SIRTA

Table 3.4 : Set-up of gas phase measurement at the three primary measurement sites.

Parameter	Instrument	Time resolution	Urban site	SOUTH-WEST Suburban site	NORTH-EAST Suburban site
			LHVP	SIRTA
in-situ measurements
O3	UV analyser	1 min	LSCE	LISA	MPI
CO	IR /GC analyser	1 min	LSCE	LSCE	MPI
NOx	Chemiluminescence	1 min	LSCE	LISA	MPI
NOy	Chemiluminescence	1 min		*LISA*
HONO	Gas-liquid conversion - HPLC-UV	5 min		LISA
PAN	GC-ECD	5 min		LISA
light NMHC (C2-C6)	GC-FID	30 min	LSCE	LISA
NMHC (C6-C10)	GC-FID	30 min	LSCE	LISA
VOC	PTR-MS	2.5 min	LCP
SO2	Fluoresecence UV	1min			MPI
OH/HO2	CIMS only summer	5 min		LATMOS
oxygenated VOC	GC-FID-MS only winter	90 min	EMD
OH reactivity	PTR-MS only winter	2 min	LSCE
CO-CO2	PICARRO only winter	1 min	LSCE

Integrated chemistry
HCHO	AMOVOC/HPLC	1h	LISA	LISA/EMD
Oxygenated VOC	cartridges/HPLC-UV	3h		LISA/EMD
VOC	cartridges/GC-MS	3h	LSCE	LISA/EMD
CO2 isotopes	flasks / GC only winter	variable	LSCE

Table 3.5: Meteorological profiling measurements operated at the suburban IPSL/SIRTA site at Ecole Polytechnique, Palaiseau (France).

arameter	Instrument	Time resolution	Vertical range and resolution	Laboratory	Remarks
Temperature, pressure, relative humidity, precipitation	Surface weather station	1 min	Surface	LMD	Continuous
Solar and Infrared irradiances	K&Z pyranometer, pyrheliometer, pyrgeometer	1 min	Surface	LMD	Continuous
Horizontal and vertical wind components	Sonic anemometer	10 min	10 and 30 m above ground	LMD + CEREA	Continuous
Turbulent Fluxes	Sonic anemometer	10 min	10 and 30 m above ground	LMD + CEREA	Continuous
Vertical profile of horizontal wind module and direction + vertical wind component	PA2 SODAR (Remtech)	20 min	100 – 600 m 50 m resolution	CEREA	Continuous
Vertical profile of horizontal wind module and direction + vertical wind component	WLS7 LIDAR (Leosphere)	10 min	40 – 300 m 50 m resolution	Leosphere SAS	Continuous
Vertical profile of horizontal wind module and direction + vertical wind component	CURIE X-band RADAR	5-10 min	40-700 m 24m resolution	LATMOS	Continuous
Mixing layer depth	ALS450 LIDAR (Leosphere)	5 min	200 – 5000 m	LMD	Continuous

Table 3.6: Airborne measurements on the ATR42 aircraft operated by SAFIRE during the summer campaign.

Table 3.7: Airborne measurements on Piper Aztec aircraft operated by SAFIRE during the winter campaign.

Species	Instrument	Technique	LD	Frequency	Operated
O₃	MOZART	Absorption UV	2 ppb	4 s	SAFIRE
CO	MOZART	Absorption IR	5 ppb	5 s	SAFIRE
NO/NO₂	Termo electron 42S	Chimiluminescence O3	0.15 ppb	300 s	SAFIRE/LISA

Figure 3.2: Typical ATR-42 flight pattern during the summer campaign (for the Western sector).

Figure 3.3 : Flight plans during the MEGAPOLI winter campaign.

Figure 3.4: Instrumental set-up of the PSI mobile lab.

Figure 3.5: Measurements on the MPI MOLA mobile lab.

Table 3.8-3.9: Flight days, flight characteristics and conditions during the summer and winter campaigns.
Table 3.10: PSI mobile lab - dates of measurements for the summer and winter campaigns.

Table 3.11: MoLa Measurements during summer 2009.

Table 3.12: MoLa Measurements during winter 2010.

Table 3.13A: Driving patterns with the mobile MAX-DOAS instrument (Summer 2009).

Table 3.13B: Driving patterns with the mobile MAX-DOAS instrument (Winter 2009).

Table 3.14: Driving patterns of mobile CEA lidar, with indication of plume sector (Winter 2009).

Figure 3.6: Example of mobile lidar measurements, on July 1, in the SW sector.

An extensive instrumentation was set-up on the ATR-42 aircraft during the summer campaign (Table 3.6) combining aerosol property and chemical composition measurements (by AMS) and gas phase measurements (NOx, NOy and VOC). In total, 11 successful flights in the Paris agglomeration pollution plume were performed (Table 3.8). A typical flight pattern is given in Figure 3.2. The plume is crossed by aircraft several times to document its evolution up to distance of 150 km from the town center. Flying around the agglomeration also allows for characterising air masses entering the agglomeration.
During the winter campaign, a smaller aircraft (Piper Aztec) was flown with instrumentation allowing to characterise basic properties/constituents of the aerosol (total number, number of aerosol > 0.3 µm diameter, diffusion, absorption, gross chemical composition on filters) and gas phase (O₃, CO, NOx) levels (Table 3.7). Flight conditions were much more difficult than during summer, but three flights around the agglomeration and three flights into the plume could be performed with success (Table 3.9, Figure 3.3).

During the summer campaign, a fleet of 5 mobile vans was deployed in the plume or for characterising upwind air masses:

PSI van and MOLA van with extensive aerosol and gas phase measurement facilities (respectively Figures 3.4 and 3.5); Measurements days and driving patterns are indicated respectively in Tables 3.10 and 3.11. In general, one van was deployed in the plume while the other measured upwind conditions.
MPI MAX-DOAS van allowing for column measurements of NO₂, HCHO and other VOC’s typically with a minute time resolution; these results are derived from slant columns measurements at different angles in a wavelength range from 320-460 nm. Driving patterns, in circles of varying distance from the town center, are indicated in Table 3.13.
CEA van with backscatter lidar measurements including a polarized channel; this van was deployed into the pollution plume for days with aircraft measurements (Table 3.14). An example of measurements, showing decreasing of aerosol levels along the plume axis is shown for July 1, is shown in Figure 3.6.
University Duisburg van allowing for aerosol mass and gas phase measurements, mostly in the plume sector.

During the winter campaign, three vans participated (PSI, MPI-MOLA and MPI-MAX-DOAS) and performed again extensive measurements within the Paris pollution plume and in upwind conditions, sampling continental pollution advected to the region.
The campaigns have been clearly a success, with measurement coverage above 90%. Now the measurements are analyzed and quality checked by partners. Measurement quick-looks have already been submitted to the campaign database at LISA or have been presented at scientific seminars (http://megapoli.lisa.univ-paris12.fr/).

MEGAPOLI Campaign in the Paris Region
during Summer 2009 and Winter 2009/2010

Contacts:

Campaign coordination
Matthias Beekmann (Matthias.Beekmann@lisa.univ-paris12.fr), LISA/IPSL Team, France
Urs Baltensperger (urs.baltensperger@psi.ch), PSI Team, Switzerland

See MEGAPOLI WP3 details/ results at the http://megapoli.lisa.univ-paris12.fr

Taking into account the data gathered during the campaign, it is clear that the WP3 objectives will be met, i.e.:

O3.1: To characterize atmospheric aerosol and relevant precursors at two urban and suburban sites in Greater Paris area;
O3.2: To provide a source apportionment of PM (separately for ultrafine particles, PM1, and the coarse mode);
O3.3: To examine the evolution of aerosols and gas-aerosol interactions in the urban outflow of Paris;
O3.4: To provide additional data for the evaluation of Chemical Transport Models.

Summary details for each relevant WP deliverables, milestones, and tasks

Task 3.1: Characterization of the atmospheric aerosol and relevant precursors (lead: CNRS-LSCE, contributions from PSI, IfT, FORTH, UHel, CNRS-LISA + LaMP, NERSC)

Aerosol and gaseous species measurements gathered during the summer and winter campaigns will directly serve as input for this task and will allow an extensive characterisation of urban aerosol and precursors. As said before the geographical coverage and detail of aerosol and gaseous precursors were much beyond of what has initially been proposed in MEGAPOLI DoW, due to many additional contributions from volunteers.

Task 3.2: Source apportionment of PM (lead: PSI, contributions from FORTH, CNRS, IfT, UHel)

Data gathered during the summer 2009 and winter 2010 campaigns will serve as input for source apportionment studies. A preliminary analysis of results obtained during the summer campaign shows a large secondary fraction among the organic aerosol. Due to advection of rather cleaner marine air masses during most of July, the origin of organic aerosol was often local. On the contrary, for winter, continental PM advection is also important. Among local sources, the wood burning contribution was particularly important.

Task 3.3: Examination of the evolution of aerosols and gas-aerosol interactions in the urban outflow of Paris (lead CNRS-LAMP, contributions from CNRS-GAME, LGGE, and LISA, and PSI, FORTH, CNRS-LSCE, IfT, UHel for flight planning and exploitation)

Data gathered during the summer and winter campaigns will serve as input for this task. Especially data gathered by the French ATR-42 aircraft in the plume and by mobile platforms, but also at fixed sub-urban sites when downwind of the agglomeration will give a huge database allowing the examination of the evolution of aerosols and gas-aerosol interactions in the urban outflow of Paris.

Task 3.4: Set-up of an integrated data base and use for model evaluation (lead: CNRS-LISA, contributions from UHel, FORTH, CNRS-LISA+LSCE+GAME+LGGE, PSI, IfT, NERSC)

A first data base of measurements quick looks and chemical weather forecast simulations has been set-up at CNRS LISA (http://megapoli.lisa.univ-paris12.fr).

Milestone 3.1: Preparing the measurement programme, instrumental base, equipment calibration and test measurements (month 12)

has been achieved by successfully performing the summer 2009 intensive campaign.

Deliverable 3.1 - Database of Chemical Composition, Size Distribution and Optical Parameters of Urban and Suburban PM and its Temporal Variability (Hourly to Seasonal)

is ready and available from the MEGAPOLI public website. Beekmann M., Baltensperger U., and the MEGAPOLI campaign team (2010): Database of Chemical Composition, Size Distribution and Optical Parameters of Urban and Suburban PM and its Temporal Variability (Hourly to Seasonal). Deliverable D3.1, MEGAPOLI Scientific Report 10-15, MEGAPOLI-18-REP-2010-10, 21p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr10-15.pdf

Deliverable 3.2 - Source Apportionment of Major Urban Aerosol Components Including Primary and Secondary PM Sources

is ready and at current moment is available only at the MEGAPOLI internal website (note, the report will became publicly available after the project ends). Baltensperger U., Beekmann M., and the MEGAPOLI campaign team (2011): Baltensperger U., Beekmann M., and the MEGAPOLI campaign team (2011): Source Apportionment of Major Urban Aerosol Components Including Primary and Secondary PM Sources. Deliverable D3.2, MEGAPOLI Scientific Report 11-05, MEGAPOLI-31-REP-2011-05, 20p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr11-05.pdf

Deliverable 3.3 - Effective Emission Factors for OC and BC for Urban Type Emissions

is ready and available from the MEGAPOLI public website. Petetin H., M. Beekmann, V. Michoud, A. Borbon, J.-F. Doussin, A. Colomb, A. Schwarzenboeck, H. Denier van der Gon, C. Honore, A. Wiedensohler, U. Baltensperger, and the MEGAPOLI Campaign Team (2011): Effective Emission Factors for OC and BC for Urban Type Emissions. Deliverable D3.3, MEGAPOLI Scientific Report 11-08, MEGAPOLI-34-REP-2011-06, 30p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr11-08.pdf

Deliverable 3.4 - Database of the Impact of Megacity Emissions on Regional Scale PM Levels

is ready and available from the MEGAPOLI public website. Beekmann M., Baltensperger U., and the MEGAPOLI campaign team (2010): Database of the Impact of Megacity Emissions on Regional Scale PM Levels. Deliverable D3.4, MEGAPOLI Scientific Report 10-16, MEGAPOLI-19-REP-2010-10, 29p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr10-16.pdf

Deliverable 3.5 - Evaluation of Links between Sec-ondary VOCs and Secondary Organic Aerosols of Anthropogenic and Biogenic Origin

is ready and available from the MEGAPOLI public website. Borbon A., E. Freney, N. Marchand, M. Beekmann, E. Abidi, W. Ait-Helal, A. Colomb, J. Cozic, N. Locoge, S. Sauvage, K. Sellegri, B. Temine-Roussel, J. Sciare, V. Gros, J.L. Jaffrezo, U. Baltensperger, and the MEGAPOLI campaign team (2011): Evaluation of Links between Sec-ondary VOCs and Secondary Organic Aerosols of Anthropogenic and Biogenic Origin. Deliverable D3.5, MEGAPOLI Scientific Report 11-16, MEGAPOLI-42-REP-2011-09, 42p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr11-16.pdf

Deliverable 3.6 - Evaluation of State-of-the-Art CTMs Using New Experimental Datasets

is ready and available from the MEGAPOLI public website. Beekmann M., C. Fountoukis, Q.J. Zhang, S. N. and the MEGAPOLI campaign team (2011): Evaluation of State-of-the-Art CTMs Using New Experimental Datasets. Deliverable D3.6, MEGAPOLI Scientific Report 11-17, MEGAPOLI-43-REP-2011-09, 28p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr11-17.pdf

Deliverable 3.7 - Implementation of Improved Parameterizations of BC, OC Emissions and Secondary PM Formation in CTMs

is ready and available from the MEGAPOLI public website. Beekmann M., C. Fountoukis, R. Timmermans, Q.J. Zhang, S. N. Pandis, H.D. van der Gon , A. Segers, C. Honoré, O. Perrussel, P. Builtjes , M. Schaap and the MEGAPOLI Campaign Team (2011): Implementation of Improved Parameterizations of BC, OC Emissions and Secondary PM Formation in CTMs. Deliverable D3.7, MEGAPOLI Scientific Report 11-18, MEGA-POLI-44-REP-2011-09, 30p, http://megapoli.dmi.dk/publ/MEGAPOLI_sr11-18.pdf

Significant results: Methodologies and scientific achievements related to WP including partners' contributions

One of the interesting results from airborne primary pollutant measurements was that the pollution plume was still well defined at more than 100 kilometres downwind from the agglomeration. This will give a "safe" framework for later studying secondary organic aerosol build-up in the plume.
The mobile measurements (using mobile ground-based laboratories) including the concept of assessing upwind and downwind conditions of the Paris plume worked well. The setup of the stationary instrumentation allowed for a successful separation between internally and externally mixed particles.
Significant new particle formation events were observed in the Paris area during the whole summer month of the campaign. These events were assisted by the relatively low particulate matter concentration levels and resulting low surface area during most of July 2009.
During the summer campaign, very preliminary attribution of organic aerosol (OA) from AMS mass spectrometer urban and peri-urban measurements shows a large fraction of oxidised organic aerosol (OOA), comprising both chemically processed (oxidized) primary organic aerosol and classical secondary organic aerosol (from aromatic and biogenic VOC precursors), and a smaller fraction of un-oxidised organic aerosol (HOA) of primary origin. Another aspect is water solubility of OA available from PILS-TOC measurements. At the urban LHVP site, about half of OA is water soluble, corresponding probably to classical secondary organic aerosol, another half is water insoluble, corresponding probably to primary and chemically processed primary OA.
During the winter campaign, particulate matter levels were much larger than during summer, reaching up and beyond 100 µg/m³ PM2.5 at several occasions. Both local sources with a major OC fraction, and continental sources with a large nitrate fraction, contributed to these levels. A surprise was the major contribution of wood burning to local OC.

Socio-economic relevance and policy implications

The campaign fostered a large public awareness of urban pollution problems and scientific needs and activities to tackle them. Large national and regional, but also international televisions, radios, and newspapers provided reports on the campaign (see some details in MEGAPOLI NewsLetters and public web-site).

Discussion and conclusion

The WP1 is well on its way to deliver the needed output for other WPs. Contacting of local authorities and data exchange with 1^st level MCs is successful. This is an important achievement as this is critical to the project success. The first version of the regional scale inventory is already being used by the MP modellers, a first heat flux inventory has beeen made, and natural emissions are available for the year 2006. . The main problem to be solved during the 2^nd year is the delayed global emission inventory. Despite the failure of the original plan, a state of the art emission inventory is currently available to the global modellers within MP. We will further process this inventory to make it suitable for scenario development according to the MP work plan. It is important to note that although the deliverable report D 1.1 has not yet been submitted no further delays are foreseen in the global modelling due to the availability of the emission inventory. There is a good communication with the (global) modelling WPs and they have (re)planned some of their work accordingly.

List of WP3 reports, publications, presentations

Beekmann M., U. Baltensperger, A. Borbon, J. Sciare, V. Gros, A. Baklanov, M. Lawrence, S. Pandis, and the MEGAPOLI Paris-campaign team (2009): The MEGAPOLI Paris campaign for urban aerosol characterisation, EGU General Assembly, Vienna, April 2009.
Beekmann M, U. Baltensperger, A. Borbon, J. Sciare, V. Gros, A. Baklanov, M. Lawrence, S. Pandis, and the MEGAPOLI Paris-campaign team (2009): The MEGAPOLI Paris campaign for urban aerosol characterisation, first results, EMS General Assembly, Toulouse, September 2009.
Gros V., N. Marchand, M. Lopez, C. Gaimoz, N. Bonnaire, B. Bonsang, B.Termine, A. Colomb, A. Borbon , (2009): Atmospheric VOCs variability and sources in Paris: results from the AEROCOV campaign (May-June 2007) and preliminary results from the MEGAPOLI campaing (July 2009), invited oral communication, Workshop “Multiphase reactivity of atmospheric VOCs and its impact on climate, Health and materials”, Paris, Oct 6-8, 2009.
Sciare, J., R. Sarda-Esteve, & J. Nicolas, (2010): Hourly-resolved mass closure of fine aerosols (PM2.5) in Paris (France) during summertime: First results of the EU-FP7-MEGAPOLI program, Geophysical Research Abstracts, Vol. 12, EGU2010-7069, EGU General Assembly, Vienna, Austria, May 2010.
Sciare, J., R. Sarda-Esteve, L. Poulain, K. Kamilli, M. Merkel, A. Held,J. Nicolas, A. Wiedensohler, (2010): Time-resolved characterization of organic aerosols in Paris (France) during summertime: First results from the EU-FP7- MEGAPOLI project, IAC, Helsinki, Finland, September 2010.
Poulain, L., K. Kamilli, M. Merkel, A. Held, J. Sciare, R. Sarda-Estave, E. Larmanou, A. Wiedensohler, (2010): Particle characterization using two on-line instruments (PILS and AMS) during MEGAPOLI intensive campaigns in Paris, IAC, Helsinki, Finland, September 2010.