| 1. |
- Boikos, Christos, et al.
(författare)
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Validating CFD modelling of ship plume dispersion in an urban environment with pollutant concentration measurements
- 2024
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Ingår i: Atmospheric Environment. - 1873-2844 .- 1352-2310. ; 319
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution in urban areas constitutes a global environmental problem, with shipping being one major contributor to hazardous pollutants in harbour areas. This work concerns the application of a method using CFD modelling to study how ships affect the air quality of port areas at a microscale level. A steady RANS-CFD approach was applied to simulate the dispersion of shipping-emitted pollutants, and a spatial sensitivity analysis of the CFD modelling results was conducted. The port of Marseille was used as a case study, and the CFD predictions were compared with on-site observations from two monitoring stations for CO2, CO, NOx, SO2 and PM concentrations. Representative modelled and measured concentrations were considered at the location of the monitoring stations to facilitate one-by-one comparisons for all pollutants in three different test cases of departing vessels. The modelling predictions presented an 8.2% (95% CI: -9.3%, 25.7%) average deviation from the measurements. Validation metrics were included to conduct a statistical comparison between predicted and measured concentrations, with almost all metric values indicating acceptable agreement between the CFD model and measurements. From a technical perspective, this study demonstrates the reliability of the applied CFD modelling method in estimating shipping plume dispersion, while from a societal perspective, this model can serve as an advisory tool for port authorities and policy makers to reduce the impact of shipping emissions on urban air quality.
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| 2. |
- Cyrys, Josef, et al.
(författare)
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Variation of NO2 and NOx concentrations between and within 36 European study areas : Results from the ESCAPE study
- 2012
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 62, s. 374-390
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Tidskriftsartikel (refereegranskat)abstract
- The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates long-term effects of exposure to air pollution on human health in Europe. This paper documents the spatial variation of measured NO2 and NOx concentrations between and within 36 ESCAPE study areas across Europe.In all study areas NO2 and NOx were measured using standardized methods between October 2008 and April 2011. On average, 41 sites were selected per study area, including regional and urban background as well as street sites. The measurements were conducted in three different seasons, using Ogawa badges. Average concentrations for each site were calculated after adjustment for temporal variation using data obtained from a routine monitor background site.Substantial spatial variability was found in NO2 and NOx concentrations between and within study areas; 40% of the overall NO2 variance was attributable to the variability between study areas and 60% to variability within study areas. The corresponding values for NOx were 30% and 70%. The within-area spatial variability was mostly determined by differences between street and urban background concentrations. The street/urban background concentration ratio for NO2 varied between 1.09 and 3.16 across areas. The highest median concentrations were observed in Southern Europe, the lowest in Northern Europe.In conclusion, we found significant contrasts in annual average NO2 and NOx concentrations between and especially within 36 study areas across Europe. Epidemiological long-term studies should therefore consider different approaches for better characterization of the intra-urban contrasts, either by increasing of the number of monitors or by modelling.
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