IMPATTO DELLA DIFFUSIONE DI VEICOLI ELETTRICI E A IDROGENO SULLE CONCENTRAZIONI DI PM10 IN EMILIA-ROMAGNA

PM10 is a critical pollutant for the air quality in Emilia Romagna, a Northern Italy region that includes a large part of the Po Valley. The atmospheric levels of PM10 are strongly affected by vehicular traffic emissions, due to fuel exhaust and also to tires, brake and road surface wear, and to road dust resuspension (non-exhaust emissions). This study presents atmospheric PM10 scenarios deriving from vehicular traffic emissions in Emilia Romagna as resulting in 2030 from the growth of the Fuel Cell Electric Vehicle (FCEV) and battery electric vehicles (BEV) fleet in the region. Both exhaust and non-exhaust vehicular emissions are considered, evaluated according to the most up-to-date regional bottom-up emission inventory, which attributes about 60% of total primary PM10 traffic emissions to wear processes. PM10 concentration maps for actual (2019) and 2030 scenarios are obtained by a Lagrangian dispersion model (PMSS). Preliminary results highlight the future impact on atmospheric PM10 from tires, brake and road surface wear produced by battery electric vehicles, due to their larger mass compared to FCEVs, which have smaller batteries and mass. These emissions will partially offset the lack of PM10 exhaust emissions for electric vehicles. Finally, the daily primary PM10 levels by traffic emissions simulated by PMSS and CHIMERE models were compared at specific sites relevant for the studied domain, i.e. the regulatory air quality monitoring stations, only for actual (2019) scenario

µ-MO assessing the contribution of NOXtraffic emission to atmospheric pollution in modena by microscale dispersion modelling

Based on the air pollutant emission inventory data (INEMAR – Arpa Emilia-Romagna 2010) road traffic in Modena, a city in the central Po valley (Northern Italy), contributes up to the 60% of the total emission in terms of NOx, followed by Domestic Heating (15%) and Industrial Combustion (14%). Goal of the -MO project is to assess the road traffic impact on air quality in the urban area of Modena by a combined experimental and modelling approach. Dispersion of vehicular NOxwas simulated by Parallel Micro Swift Spray (PMSS, Arianet srl, Italy and Aria Technologies, France) over a domain of 6 km x 6 km, including most of the urban areas of Modena, with a horizontal resolution of 4 m. The atmospheric emission sources were estimated by merging local fleet composition data, traffic flux at rush hours simulated by PTV VISUM mobility software and direct measurements collected by radar traffic counters, provided by the Municipality of Modena. The modelling system, implemented on a 16 cores cluster (64 GB of total memory), includes PSWIFT, a parallelized mass-consistent diagnostic wind field model, and PSPRAY, a three-dimensional parallel lagrangian particle dispersion model, both able to take into account obstacles (buildings). A run of the system on an entire day has been performed and is presented. In the next step of the work, NOxatmospheric concentration measurements will be provided by the two urban air quality monitoring sites and by a set of 10 monitoring boxes distributed over the domain and featured by small sensors for NO, NO2and particulates. Among the final goals of the -MO project there is the tentative source-apportionment of urban atmospheric NOxbetween traffic emissions, domestic heating and regional background, to support epidemiological studies and finally future urban development strategies

Vehicular exhaust impact simulated at microscale from traffic flow automatic surveys and emission factor evaluation

Vehicular emissions are a large NOx and CO source in Italian urban areas. In order to assess the impact of heavy traffic roads on local air quality a micro-scale simulation of pollutant concentration fields was produced. The investigated areas are in downtown of Reggio Emilia and Modena, two cities in central Po valley, Italy, and focused on high traffic intersections. An urban traffic station of the regional air quality monitoring network is present in both investigated areas, where traffic is expected to be the main local source of atmospheric pollutants. The simulation has been performed by the micro-scale model suite Micro-Swift-Spray (Aria Technologies, France and ARIANET, Italy) a Lagrangian particle dispersion model directly derived from the SPRAY code, able to account for buildings and obstacles. Simulated pollutants are NOx and CO, as main tracers of combustion emissions. Direct measurements of traffic flow have been continuously collected for 12 day survey periods (in Reggio Emilia from January 13 to 24, 2014 by a two channel doppler radar traffic counter and in Modena from October 28 to November 8, 2016 by four one channel doppler radar traffic counters) and used for the hourly modulation of vehicular emissions. Specific emission factors were obtained by the combination of radar counts with vehicular fleet composition for each municipality: these depend on vehicle type, fuel type, speed and EURO category and were calculated according to the EMEP/EEA guidelines for air pollutant emission inventory. Simulated concentration fields were evaluated over the period with direct traffic counts for the two studied areas: for both areas the results were compared to local air quality measurements collected at the traffic urban monitoring stations and also at the respective urban background stations. The simulated NOx hourly concentrations show a very large agreement with the observations, even if they result underestimated compared to the observed atmospheric concentrations at the traffic site. Simulated and observed concentrations show a fair agreement for CO. The results outline the representativeness of air quality stations in characterizing the sites for pollution level and for dominant pollutant sources

Impact of NOx and NH3 Emission Reduction on Particulate Matter across Po Valley: A LIFE-IP-PREPAIR Study

Air quality in Europe continues to remain poor in many areas, with regulation limits often exceeded by many countries. The EU Life-IP PREPAIR Project, involving administrations and environmental protection agencies of eight regions and three municipalities in Northern Italy and Slovenia, was designed to support the implementation of the regional air quality plans in the Po Valley, one of the most critical areas in Europe in terms of pollution levels. In this study, four air quality modelling systems, based on three chemical transport models (CHIMERE, FARM and CAMx) were applied over the Po Valley to assess the sensitivity of PM2.5 concentrations to NOx and NH3 emission reductions. These two precursors were reduced (individually and simultaneously) from 25% up to 75% for a total of 10 scenarios, aimed at identifying the most efficient emission reduction strategies and to assess the non-linear response of PM2.5 concentrations to precursor changes. The multi-model analysis shows that reductions across multiple emission sectors are necessary to achieve optimal results. In addition, the analysis of non-linearities revealed that during the cold season, the efficiency of PM2.5 abatement tends to increase by increasing the emission reductions, while during summertime, the same efficiency remains almost constant, or slightly decreases towards higher reduction strengths. Since the concentrations of PM2.5 are greater in winter than in summer, it is reasonable to infer that significant emission reductions should be planned to maximise reduction effectiveness

Sviluppo di un sistema ad alta risoluzione spaziale per la previsione della qualit\ue0 dell'aria urbana tramite approccio modellistico multi-scala e sua applicazione alla citt\ue0 di Modena

La Pianura Padana, situata nella parte settentrionale dell'Italia, \ue8 una delle aree pi\uf9 critiche del paese per livelli d\u2019inquinamento. La ragione di questo problema non \ue8 solo legata all'elevata densit\ue0 di popolazione con relative attivit\ue0 antropiche, ma \ue8 anche dovuta alla conformazione orografica del territorio, delimitato dalla catena alpina ad ovest e a nord e dagli Appennini a sud. Queste caratteristiche geografiche determinano condizioni meteorologiche sfavorevoli alla dispersione atmosferica, quali: velocit\ue0 medie annue del vento inferiori a 2 m s-1, inversioni termiche ricorrenti nei primi strati di atmosfera a contatto con il suolo, ridotte altezze dello strato rimescolato e persistenti nebbie durante il periodo invernale. Uno degli inquinanti atmosferici pi\uf9 rilevanti per effetti critici sulla salute umana \ue8 il biossido di azoto (NO2), i cui livelli negli ultimi anni hanno superato i limiti nazionali e dell\u2019OMS in molte aree urbane della Pianura Padana, esponendo la popolazione al rischio di patologie legate all\u2019inquinamento. L\u2019obiettivo principale di questo studio \ue8 stato lo sviluppo di un sistema di modellazione multi-scala in grado di fornire campi di concentrazione oraria di NOx (NO + NO2) sulla citt\ue0 di Modena ad una scala spaziale in grado di risolvere gli effetti dovuti alla presenza degli edifici, al fine di supportare politiche ambientali, studi epidemiologici e di aiutare la pianificazione della mobilit\ue0 urbana. Il sistema di modellazione si basa su due diversi tool: il modello euleriano di chimica e di trasporto WRF-Chem, in grado di calcolare campi di concentrazione su un dominio regionale considerando specifici scenari di emissione, e Parallel Micro SWIFT e SPRAY (PMSS) suite modellistica sviluppata per risolvere i fenomeni di dispersione all'interno di ambienti urbani. PMSS \ue8 stato utilizzato per simulare la dispersione di NOx prodotta dai flussi di traffico urbano nella citt\ue0 di Modena, mentre il modello WRF-Chem \ue8 stato applicato per stimare le concentrazioni di NOx di fondo su pi\uf9 domini innestati fra loro, utilizzando emissioni a scala regionale ed escludendo allo stesso tempo le fonti di emissioni da traffico entro la citt\ue0 di Modena. Nella prima parte del lavoro il sistema di modellazione \ue8 stato impiegato per riprodurre le concentrazioni comprese nell\u2019arco temporale tra il 28 ottobre e l'8 novembre 2016, corrispondente al periodo in cui \ue8 stata condotta una campagna di rilevazione dei flussi di traffico, attraverso radar Doppler su una strada di Modena a quattro corsie, al fine di riprodurre una modulazione temporale delle emissioni il pi\uf9 possibile realistica. Nella seconda parte dello studio lo stesso sistema di modellazione \ue8 stato utilizzato per produrre previsioni orarie delle concentrazioni di NO2 e NO, fino ad un giorno in avanti, per tutto il mese di febbraio 2019 sulla citt\ue0 di Modena. Le concentrazioni orarie simulate e osservate mostrano un andamento molto concorde fra loro, specialmente per il sito di traffico urbano, dove le stime dettagliate sulle emissioni del traffico si sono dimostrate molto efficaci nel riprodurre la tendenza osservata. Nella stazione urbana di fondo, nonostante una generale sottostima delle concentrazioni osservate, la combinazione di WRF-Chem con PMSS ha fornito comunque un andamento medio giornaliero in linea con le osservazioni. Infine, l'analisi statistica ha mostrato che il sistema di modellazione, in entrambi i siti urbani (di traffico e di fondo), soddisfa i criteri di accettazione standard per la valutazione dei modelli di dispersione urbana, confermando che tale sistema pu\uf2 essere impiegato come strumento per verificare gli effetti delle politiche locali riguardanti il traffico e a supporto di valutazioni di impatto sulla salute umana.In Europe, emissions of many air pollutants have decreased substantially over the past decades, resulting in improved air quality across the region. However, air pollutant concentrations are still too high, and air quality problems persist. The Po Valley, located in the northern part of Italy, is one of the most critical area of the country in terms of pollution level. The reason to this problem is not only related to the high population density with its related activities, but it is also due to the orographic conformation of the territory which appears surrounded by mountains on three sides: the Alps to the west and to the north and the Apennines to the south. These geographical characteristics lead to meteorological conditions unfavorable to the atmospheric dispersion: average annual wind speed less than 2 m s-1, recurrent thermal inversions at low altitude, low mixing layer heights and persistent foggy and hazy events during winter time. One of the main critical air pollutants in terms of health effects is nitrogen dioxide (NO2), whose levels in the last years exceeded national and WHO (World Health Organization) standards in many urban areas across the Po Valley, exposing urban population to the risk of pollution-related diseases and health conditions. The main goal of this study was to develop a multi-scale modelling system able to provide hourly NOx (NO + NO2) concentration fields at a building-resolving scale in the urban area of Modena, a city in the middle of the Po Valley, in order to support environmental policies, epidemiological studies and urban mobility planning. The modelling system relied on two different models: the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), which is able to compute concentration fields over regional domain by considering specific emission scenarios, and the Parallel Micro SWIFT and SPRAY (PMSS) modelling suite accounting for dispersion phenomena within the urban area. The PMSS modelling suite was used to simulate at building-scale resolution the NOx dispersion produced by urban traffic flows in the city of Modena. Conversely, the WRF-Chem model was selected to estimate the NOx background concentrations on multiple domains with a nesting technique, in order to take into account emissions both at regional and local scale by excluding traffic emissions sources over the city of Modena. In the first part of the work the modelling system was performed for the period between 28 October and 8 November 2016, the same period whereby a direct vehicle flow measurement campaign was carried out continuously with 4 Doppler radar counters in a four-lane road in Modena, in order to reproduce emission hourly modulation rates. In second section of the study the modelling system was set-up with the aim of produce hourly forecast of NO2 and NO concentrations, up to one day ahead, for the city of Modena for the entire month of February 2019. Simulated and observed hourly concentrations exhibited a large agreement in particular for urban traffic site where detailed traffic emission estimations proved to be very successful in reproducing the observed trend. At urban background stations, despite a general underestimation of the observed concentrations, the combination of WRF-Chem with PMSS provided daily pattern in line with observations. Finally, the statistical analysis showed that PMSS combined with WRF-Chem at both traffic and background sites fulfilled standard acceptance criteria for urban dispersion model evaluation, confirming that the proposed multi-modelling system can be employed as a tool to support human exposures and health impact assessments as well as the effects of local traffic policies on urban air quality