Carbonaceous particles and aerosol mass closure in PM2.5 collected in a port city

• Diagnostic ratios were used to assess carbonaceous particle sources.
• POC, SOC were estimated in two wind direction: harbour and urban-industrial area.
• Mass closure approach was used to estimate the OC to OM conversion factor.
• SIA, SOA, carbonaceous fractions, sea salts and crustal fraction were determined.

Mass concentrations of PM2.5, mineral dust, organic carbon (OC) and elemental carbon (EC), water-soluble organic carbon (WSOC), sea salts and anthropogenic metals have been studied in a city-port of south Italy (Brindisi). This city is characterized by different emission sources (ship, vehicular traffic, biomass burning and industrial emissions) and it is an important port and industrial site of the Adriatic sea. Based on diagnostic ratios of carbonaceous species we assess the presence of biomass burning emissions (BBE), fossil fuel emissions (FFE) and ship emission (SE). Our proposed conversion factors from OC to OM are higher than those reported in the literature for urban site: the reason of this could be due to the existence of aged combustion aerosols during the sampling campaign (WSOC/OC = 0.6 ± 0.3).