Micro–scale simulation of atmospheric emissions from power–plant stacks in the Po Valley

The atmospheric dispersion of the NOX plume that will be emitted from a new power–plant, at present under installation, was simulated at micro–scale with Micro–Swift–Spray (MSS) Model. The plant will be constructed in a residential urban area in the town of Modena (Po Valley, Northern Italy), where low wind speeds and thermal inversions are quite frequent. Simulation results point out a different behavior of urban canopy in influencing the 3D dispersion patterns among urban obstacles, according to atmospheric mixing conditions: in case of moderate wind events, urban canyon phenomena may occur with a consequent increasing of NOX concentration gradients among buildings, while with low winds the near–field influence of the buildings emphasizes pollutant accumulation. The MSS simulated NOX concentrations result always much lower than the regulatory limits for air quality. The comparison of simulation results with measured concentration data for NOX shows the importance of micro–scale dispersion modeling to perform an accurate and reliable assessment of meteorological condition effects on pollutant distribution, and the ability of MSS in providing reliable simulations of atmospheric dispersion

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

Dispersione atmosferica a microscala di emissioni veicolari da flussi di traffico rilevati automaticamente e confronto con misure di qualità dell’aria

La stima del contributo del traffico veicolare all’inquinamento atmosferico urbano è una informazione fondamentale per la popolazione e le amministrazioni. A questo scopo è stata condotta una simulazione microscala della dispersione delle emissioni da traffico veicolare presso un incrocio trafficato lungo la circolare interna a Reggio Emilia, una città di medie dimensioni nella parte centrale della pianura Padana (Italia settentrionale). L’area studiata include una stazione della rete regionale di monitoraggio della qualità dell’aria: la stazione è classificata come sito urbano di traffico, ovvero ci si attende che la stazione sia principalmente influenzata dalle emissioni da traffico veicolare. I modelli di simulazione a microscala sono maggiormente adatti alla modellizzazione della dispersione in aree urbane, dove la concentrazione in gran parte dipende anche dalla stagnazione di aria dovuta ad edifici ed ostacoli. Micro-Swift-Spray (Aria Technologies, Francia), un modello di dispersione lagrangiano a particelle derivato direttamente dal modello Spray a scala locale, è stato utilizzato per simulare al dispersione delle emissioni da traffico veicolare (in particolare NOx e CO), tenendo conto anche della volumetria degli edifici e degli ostacoli. Un radar conta traffico installato localmente ha fornito velocità e lunghezza dei veicoli in continuo per un periodo di 12 giorni (13 – 24 gennaio 2014). Questi dati, assieme ai dettagli della composizione della flotta, sono stati usati per calcolare fattori di emissioni su misura in base alla tipologia, alimentazione, velocità e classe EURO di emissione. Sono stati prodotti dei campi 3D di concentrazione e i risultati sono stati confrontati con le misure locali di qualità dell’aria: la correlazione tra le concentrazioni orarie di NO x simulate ed osservate è risultata estremamente soddisfacente (r = 0.86). Il confronto con le misure di qualità dell’aria in condizioni di fondo urbano ha permesso di stimare meglio la performance del modello e la quantità di NO x primario e secondario al sito di studio

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

Leukemia risk in children exposed to benzene and PM10 from vehicular traffic: a case-control study in an Italian population.

Benzene, a recognized occupational leukemogen in adults, has been implicated by sparse and conflicting epidemiologic evidence in the etiology of childhood leukemia. We carried out a population-based case-control study in a northern Italy population involving 83 cases with childhood leukemia diagnosed in the years 1998-2009 and 332 matched controls. We assessed residential exposure to benzene and to particulate matter ≤10 µm (PM10) from motorized traffic using geocoded residences and detailed emission and dispersion modeling. Exposure to benzene, and to a lesser extent to PM10, appeared to be independently associated with an excess leukemia risk. When we stratified the study population by age, the relative risk associated with benzene exposure was higher among children aged less than five years. Overall, these findings suggest that low levels of benzene exposure released from motorized traffic may increase the risk of childhood leukemia, and do not rule out an independent effect of PM10