Mihaela Mircea 1, Georgiana Grigoras3, Massimo D’Isidoro1, Gaia Righini1, Mario Adani1, Gino Briganti1, Luisella Ciancarella1, Andrea Cappelletti1, Giuseppe Calori2, Irene Cionni1, Giuseppe Cremona1, Sandro Finardi2, Bo R. Larsen4, Giandomenico Pace6, Cinzia Perrino5, Antonio Piersanti1, Camillo Silibello2, Lina Vitali1, Gabriele Zanini1
Cite this article: Mircea, M., Grigoras, G., D’Isidoro, M., Righini, G., Adani, M., Briganti, G., Ciancarella, L., Cappelletti, A., Calori, G., Cionni, I., Cremona, G., Finardi, S., Larsen, B.R., Pace, G., Perrino, C., Piersanti, A., Silibello, C., Vitali, L. and Zanini, G. (2016). Impact of Grid Resolution on Aerosol Predictions: A Case Study over Italy.
Aerosol Air Qual. Res.
16: 1253-1267. https://doi.org/10.4209/aaqr.2015.02.0058
Grid impact on inorganic and organic aerosols, of primary and secondary origin.
Grid impact long-term study on aerosols in a complex orographic and climatic area.
Grid influence evaluation in different seasons and daily and nightly during summer.
This study investigates the effect of grid resolution on the particulate matter (PM10, PM2.5) mass concentrations and its chemical composition simulated with the AMS-MINNI modelling system. The air pollution was simulated over Italy with grid resolutions of 20 and 4 km, for a whole year. The gridded emissions were produced performing speciation and space-time disaggregation of aggregated inventory data, using both land use information and anthropogenic activity-based profiles. Often, the fine grid simulations, based on high resolution gridded emissions, improved the agreement between model and measurements. In particular, the use of a fine grid improved predictions of primary species such as elemental carbon (EC), PM10 and PM2.5 mainly at urban stations. An improvement of predicted PM components and mass concentration at high altitudes sites was also observed, especially during winter. However, a general overestimation of nitrate (NO3–) and of secondary inorganic species, more evident at night than during the day, was increased by employing a finer grid. Organic carbon (OC) was more affected by the grid resolution than the other species. At urban and kerbside stations, the use of a finer grid resulted in an overestimation of primary organic carbon aerosol (POC) but had a negligible effect on secondary organic carbon aerosol (SOC). The overestimation of carbonaceous aerosol (defined as the sum of EC, POC and SOC), at an urban station, opposite to general underestimation of this component by air quality (AQ) models, indicates that the anthropogenic emissions can contribute as much as organic model formulation at the success of simulation in reproducing experimental data.
The modelling results obtained under stable meteorological conditions characterised by weak winds, which are often encountered in the Po Valley, did not improve substantially by the increase of the modelling system resolution.
Keywords: Horizontal grid resolution; Aerosol chemical composition; PM10; PM2.5; Air quality modelling