IFAC PapersOnLine 51-5 (2018) 61–66 ScienceDirect ScienceDirect Available online at www.sciencedirect.com 2405-8963 © 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Peer review under responsibility of International Federation of Automatic Control. 10.1016/j.ifacol.2018.06.211 © 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Improving Air Quality in Lisbon: modelling emission abatement scenarios J. Monjardino* N. Barros** F. Ferreira* H. Tente* T. Fontes*** P. Pereira* C. Manso** * Center for Environmental and Sustainability Research, Department of Environmental Sciences and Engineering, Faculty of Sciences and Technology, Universidade NOVA de Lisboa (CENSE-DCEA/FCT/NOVA), Campus de Caparica, 2829-516 Caparica, Portugal (e-mail: jvm@fct.unl.pt; ff@fct.unl.pt; htente@fct.unl.pt; pr.pereira@fct.unl.pt) ** Energy, Environment and Health Research Unit (FP-ENAS), Universidade Fernando Pessoa, Porto, Portugal (e-mail: nelson@ufp.edu.pt; cmanso@ufp.edu.pt) *** INESC-TEC, Faculty of Engineering, Universidade do Porto (FEUP), Porto, Portugal (e mail: tania.d.fontes@inesctec.pt) Abstract: Lisbon is one of the European cities where NO2 and PM10 legal limit values are still exceeded, leading to an Air Quality Plan applicable up to 2020. The developed work combined a detailed emission inventory, monitoring data, and modelling in order to assess if the proposed emission abatement scenarios, focused on the road transport sector, were able to tackle exceedances. A maximum decrease of 14% for PM10 concentrations was achieved, and of 21% for NO2, providing compliance. PM10 smallest reduction is related with higher weight of regional background sources, while for NO2 local traffic has more influence on concentrations. Keywords: Air pollution, Urban air quality, PM10, NO2, Modelling, TAPM, Emission scenarios, Air Quality Plan, Lisbon 1. INTRODUCTION Air pollution is the major environmental cause of premature deaths in Europe. Air quality in European Union (EU) is slowly improving. However, in 2015 a significant proportion of EU urban population was exposed to air pollutants concentrations above the EU limit or target values. For particulate matter (PM10), the respective exposure estimates were 16-20% and, for nitrogen dioxide (NO2), were 7-9%, representing an increase over the previous year (EEA, 2017). Lisbon (Portugal) is one of the European cities where NO2 and PM10 are the most critical air pollutants, with limit value exceedances being frequently recorded. This municipality integrates the agglomeration of Northern Lisbon Metropolitan Area (NLMA) for which is still legally compulsory to develop an Air Quality Plan (AQP) to meet the required limit values. The definition of efficient and relevant action plans to avoid such situations is often a challenge. In urban environments with high annual NO2 concentrations the main source has been attributed to the considerable fleet proportion of diesel vehicles, namely due to the influence of modern diesel-fuelled passenger cars, with increased NO2/NOx ratio, caused by equipment used in the after-treatment of exhaust emissions (Keuken et al., 2012). Regarding urban PM, road traffic is also considered a major source, leading air quality managers to focus on this sector for specific emission control measures. In Europe diesel vehicle use prevails, leading to higher ambient burdens of black carbon particles (Lee et al., 2017). Road traffic emissions comprise not only tailpipe exhaust emissions but also non- exhaust emissions derived mostly from the vehicle-induced dust resuspension deposited on the road and in part 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 reduced (Amato et al., 2010). Recent improvements have been recorded in NLMA PM10 urban concentrations. Part of observed PM10 changes can be explained by the impact of the economic crisis, the implementation of abatement strategies over specific areas (Ferreira et al., 2015), to the occurrence of favourable meteorological conditions related to the atmospheric circulation over the northern Atlantic, and a decrease in African dust contributions (APA, 2017). Although this have been explained by Cerro et al. (2015) for other region (NW Mediterranean) it has a similarity with LTV region situation. In the Lisbon region, the mesoscale circulation is, in general, reinforced by north-northwest synoptic circulation associated with the Azores anticyclone promoting a strong circulation from the Atlantic sea (Barros et al., 2003). This coastal and estuarine area has a complex orography creating specific land/sea interfaces. The present study describes the modelling activities carried out for Lisbon and Tagus Valley region (LTVR). The developed work combined emission data, air quality monitoring data, and modelling in order to provide a more comprehensive knowledge of air quality dynamics at urban scale, and allowing to assess if policies and measures and emission reduction scenarios will be able to significantly improve air quality.