Caring about the future

URBE - Source apportionment of URBan Emissions of primary particulate matter
Coordinator - Célia Alves
Programme - PTDC/AAC-AMB/117956/2010
Execution dates - 2012-04-01 - 2015-09-30 (42 Months)
Funding Entity - FCT
Funding for CESAM - 164682 €
Total Funding - 164682 €
Proponent Institution - Universidade de Aveiro

Project Description

Atmospheric particles are of major scientific interest due to their demonstrated role in climate change and their effect on human health, local visibility and soiling of monuments. Current European Directive on Air Quality 2008/50/CE targets the mass concentration of airborne particulate matter under 10 and 2.5 um (PM10 and PM2.5). The threshold values are frequently being exceeded in many urban centres throughoutEurope. Emissions from road traffic comprise a substantial fraction of primary PM within urban areas and an even larger proportion at roadside. Road traffic emissions include not only tailpipe exhaust but also non-exhaust emissions derived mostly from the vehicle-induced dust resuspension and from the direct emissions from vehicle wear (brakes, tyres, discs, etc.). Non-exhaust emissions are often of the same order or even greater than exhaust emissions, especially when rainfall rates are low and the wash-off of the road is scarce. Source apportionment results indicate that biomass burning (particularly in winter) and cooking are the two main nonroad primary sources of PM in urban areas. Quantitative knowledge of individual source concentrations in the air is crucial to devise cost-effective abatement strategies. Receptor modelling techniques are used to identify and quantify the contributions from emission sources to the levels of major components of PM. In theUnited States, the Chemical Mass Balance (CMB) model has been widely used, while inEurope receptor modelling has mainly been based on methods that do not require chemical profiles of previously identified source emissions (e.g. multivariate statistical techniques, such as Positive Matrix Factorisation, PMF). The CMB method has been very little applied inEurope due to the lack of EU chemical composition of particles emitted from specific sources. Concerning the application of PMF, the major weakness in Europe in comparison toNorth America is the scarcity of suitable high quality ambient datasets in which multiple components of PM have been measured over a long period. A particularly novel feature of URBE is its strategy to tackle the identified problem via the development of hitherto unavailable European source emission profiles and long-term environmental datasets.

A systematic approach will be used to sample and quantify the organic and inorganic components present in PM2.5 and PM10 from a variety of sources associated with both non-traffic (cooking) and traffic-related emissions. Aerosols from EU cooking styles will be collected in the exhaust of restaurants. Particle sampling from on-road motor vehicles will include tailpipe emissions (from both gasoline and diesel vehicles operated on a chassis dynamometer under realistic driving cycles), dust from brake and tyre wear, and roadway dust. In addition, total roadway emissions will be measured in two roadway tunnels. Use of sensitive analytical techniques such as thermo-optical analysis for organic and elemental carbon (OC/EC), gas chromatography-mass spectrometry (GC-MS) for a vast array of organic compounds, ion chromatography for water soluble ions and inductively coupled plasma-mass spectrometry (ICP-MS) for a variety of elements will allow detailed measurements in these emissions and subsequent development of profiles for each source. The same chemical constituents will be characterised in ambient air from urban sites. The ambient monitoring will be performed in cooperation with the SAPHIM Marie Curie Training Network, leaded by theUniversity ofBirmingham, within which collaborative measurement campaigns will be carried out in several EU cities. The University of Aveiro (UA) will participate in a long term campaign (18 months) inBarcelona coordinated by the Spanish Research Council (CSIC). The source profiles developed for emissions from cooking and from on-road vehicles will be used as input data to the CMB model, allowing a much enhanced estimation of source categories contributing to PM in EU urban sites. Biomass burning profiles, whose characterisation was not included in URBE, will be derived from an ongoing project hosted at UA. Sensitivity studies will be carry out on CMB modelling to understand the influence of substituting European source profiles for the original US source profiles upon quantitative source attribution. A comparative evaluation of the CMB and PMF models using tracer compounds will also be done.

URBE is an initiative of UA in cooperation with CSIC and the French Institute of Science and Technology for Transport, Development and Networks (IFSTTAR). UA and CSIC are widely recognised as centres of excellence in aerosol research. Over the last two decades, both institutions have developed aerosol sampling and analytical techniques, and source apportionment methodologies, which nowadays are applied successfully in several studies. IFSTTAR has long-standing recognition in both Franceand abroad in the area of evaluating pollutant emissions from road transports.

CESAM members on this project
Casimiro Pio
Célia A. Alves


Teresa Nunes

CESAM Funding: UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020