Spatiotemporal variation of odor-active VOCs in Thessaloniki, Greece: implications for impacts from industrial activities

A yearlong study of odor-active VOCs was carried out in the northwestern district of the city of Thessaloniki, Greece, which is in close vicinity to a large-scale petroleum refining and petrochemical process complex, as well as other activities such as power generation from natural gas burning and liquefied petroleum gas (LPG) shipping. Odor nuisance has been a major concern in the district often rising complaints from local residents. A total of 312 samples of VOCs were collected at three sites during a 12-month period (May 2018-May 2019) on thermal desorption cartridges and analyzed by thermal desorption gas chromatography interfaced with mass selective detector (TD-CG/MS). Fifty-five odorous compounds including 8 mercaptans, 5 thiophenes, 7 sulfides, 22 aromatics, and 13 aldehydes were measured, and their spatial and temporal variations were assessed. Concentrations found were compared with those measured at other sites within the urban agglomeration Thessaloniki. Correlations with meteorological conditions (ambient temperature, relative humidity, wind direction/speed, and frequency/depth of temperature inversions) were investigated. Bivariate polar plots of the concentrations of Σ₈Mercaptans, Σ₅Thiophenes, Σ₇Sulfides, Σ₂₂Aromatics, and Σ₁₃Aldehydes as a function of wind speed and wind direction were constructed for source localization.