## 2 Site Description and Techniques for Data Analyses  
### Experimental Site and General Methodology  
The experimental site was set in the Brindisi port-industrial area (Figure 1). The experimental campaign was part of the CESAPO project as largely described in [PERSON] et al. [21]. Here, we report only those aspects relevant to the scope of this paper. Brindisi is a city with about 86,000 inhabitants located in the Apulia Region, Southern Italy. The area is characterized by a complex scheme of emission sources which need to be identified with respect to the PM\({}_{2.5}\) sampling site located on the roof of the ASI (Consorzio per l'Area di Sviluppo Industriale) building at 13 m above the ground level. Broadly speaking, emissions can be categorized as urban emissions, port-related emissions with port traffic accounted for more than 9.5 million tons, 520,000 passengers, and 175,000 vehicles and industrial emissions. With respect to the sampling site, the port is located at NNE to WNW, airport emissions are located at NW, while petrochemical emissions, power-plant emissions, and several artisan activities are located at SSW. To estimate the impact of the port area on the city, an evaluation of the existence of a statistical difference among PM\({}_{2.5}\) samples collected in the port area according to the prevailing winds has been performed using a linear discriminant analysis. Given the specific layout of the port of Brindisi (Figure 1), and in accordance with [PERSON] et al. (2011), for winds in the sector NNE to WNW (22.5\({}^{\circ}\)-292.5\({}^{\circ}\)) the sampling site was directly affected by the urban and industrial areas, while for winds in the sector WNW to NNE (292.5\({}^{\circ}\)-22.5\({}^{\circ}\)), the sampling site was affected directly by the port area. In the first case (referred to as Urban-Industrial) a total of 38 days were considered in the analysis (8 days in June, 8 days on July, 5 days in August, 10 days in September, and 7 days in October); in the second case (referred to as Port) 55 days were considered (15 days in June, 11 days in July, 10 days in August, 8 days in September, and 11 days in October). Please note that PM\({}_{2.5}\) samples were collected for 24 h, starting from 00:00 to 24:00. Each sample was representative of the sampling day and the prevailing wind direction was obtained from meteorological data measured close to the study site by calculating the median of measured wind directions. It is known that organic matter and elemental carbon account for a relevant part of PM\({}_{2.5}\), ranging between 20 and 45% ([PERSON], 2011). With this in mind, the chemical characterization of pollution sources on the PM\({}_{2.5}\) samples collected in the port of Brindisi, previously reported in [PERSON] et al. (2011), has been extended to organic carbon and elemental carbon and in this respect this work completes the analyses previously reported. Principal Component Analysis has been applied to a larger and more comprehensive data set with respect to [PERSON] et al. (2011) with the aim of deriving more realistic source profiles through factor loadings of the variables affecting the receptor site. Further, chemical mass closure has been used for sources quantification. Chemical characterization of PM\({}_{2.5}\) has been then completed with numerical investigations by combining the mesoscale model BOLCHEM ([PERSON], 2011; [PERSON], 2012) and the local scale advanced-Gaussian dispersion model ADMS-Urban ([PERSON], 2011). BOLCHEM simulations were performed  
Figure 1: Map of the southern part of Italy showing the position of Brindisi (**left**) and satellite image showing the experimental site in yellow (ASI) and the monitoring stations managed by ARPA-Puglia (**right**). for the whole measurement campaign period (June-October 2012) to reproduce hourly pollutants concentration, both for gaseous and particulate and to calculate mean concentration over the area, at regional scale.