Volatile Organic Compounds in the atmosphere of the Great Athens area: The case of a port site close to Piraeus, Greece

VOCs are key atmospheric constituents for both health and climate issues and further knowledge is still needed about their sources and fate. The presence of volatile organic compounds in ambient air is strongly dependent on the site characteristics and a harbor area undergoes many source typologies such as road transport, ship emissions and contaminants of commercial activities, the shipbuilding zone and other operating facilities. The current work was implemented at the recently established Atmospheric Pollution Monitoring Station of the Municipality of Keratsini-Drapetsona located in the close vicinity of the Piraeus port. Since December 2018 an automatic gas chromatograph with flame ionization detector (FID) continuously monitors at a 30 minutes time resolution non methane hydrocarbons (NMHCs) focusing on hazardous compounds (aromatics) and strong precursors (aromatics, monoterpenes) of secondary pollutants like ozone and secondary organic aerosols. High levels of benzene were observed, especially during the morning to noon period, and the mean concentration of both benzene and toluene were two-folded in summer (July and August 2019) compared to winter (January and February 2019). Ethylbenzene follows the same pattern, whereas xylenes presented comparable levels during the cold and warm periods. Preliminary results based on source apportionment techniques are presented. In general terms the NMHC levels present their maximum under the impact of low wind speed, addressing thus the role of local emission sources, which are further investigated by the ratios used as tracking tools of processes of different origin (e.g. the traffic related ratio of toluene/benzene).