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In this study we focus on the retrieval of aerosol and trace gas vertical profiles from multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations for the first time over Thessaloniki, Greece. We use two independent inversion algorithms for the profile retrievals: the Mexican MAX-DOAS Fit (MMF) and the Mainz Profile Algorithm (MAPA). The former is based on the optimal estimation method (OEM), while the latter follows a parameterization approach. We evaluate the performance of MMF and MAPA, and we validate their retrieved products with ancillary data measured by other co-located reference instruments. The trace gas differential slant column densities (dSCDs), simulated by the forward models, are in good agreement, except for HCHO, where larger scatter is observed due to the increased spectral noise of the measurements in the UV. We find an excellent agreement between the tropospheric column densities of NO2 retrieved by MMF and MAPA (slope=1.009, Pearson's correlation coefficient R=0.982) and a good correlation for the case of HCHO (R=0.927). For aerosols, we find better agreement for the aerosol optical depths (AODs) in the visible (i.e., at 477 nm) compared to the UV (at 360 nm), and we show that the agreement strongly depends on the O4 scaling factor that is used in the analysis. The agreement for NO2 and HCHO near-surface concentrations is similar to the comparison of the integrated columns with slightly decreased correlation coefficients. The seasonal mean vertical profiles that are retrieved by MMF and MAPA are intercompared, and the seasonal variation in all species along with possible sources is discussed. The AODs retrieved by the MAX-DOAS are validated by comparing them with AOD values measured by a CIMEL sun photometer and a Brewer spectrophotometer. Four different flagging schemes were applied to the data in order to evaluate their performance. Qualitatively, a generally good agreement is observed for both wavelengths, but we find a systematic bias from the CIMEL sun photometer and Brewer spectrophotometer measurements, due to the limited sensitivity of the MAX-DOAS in retrieving information at higher altitudes, especially in the UV. An in-depth validation of the aerosol vertical profiles retrieved by the MAX-DOAS is not possible since only in very few cases is the true aerosol profile known during the period of study. However, we examine four cases, where the MAX-DOAS provided a generally good estimation of the shape of the profiles retrieved by a co-located multi-wavelength lidar system. The NO2 near-surface concentrations are validated against in situ observations, and the comparison of both MMF and MAPA revealed good agreement with correlation coefficients of R=0.78 and R=0.73, respectively. Finally, the effect of the O4 scaling factor is investigated by intercomparing the integrated columns retrieved by the two algorithms and also by comparing the AODs derived by MAPA for different values of the scaling factor with AODs measured by the CIMEL sun photometer and the Brewer spectrophotometer.

Spectral measurements of the aerosol optical depth (AOD) and the Ångström coefficient were conducted at Thessaloniki, Greece (40.5° N, 22.9° E) between January 1997 and December 2005 with a Brewer MKIII double-monochromator spectroradiometer. The dataset was compared with collocated measurements of a second spectroradiometer (Brewer MKII) and a CIMEL sun-photometer, showing correlations of 0.93 and 0.98, respectively. A seasonal variation of the AOD was observed at Thessaloniki, with AOD values at 340 nm of 0.52 and 0.28 for August and December respectively. Back trajectories of air masses for up to 4 days were used to assess the influence of long-range transport from various regions to the aerosol load over Thessaloniki. It is shown that part of the observed seasonality can be attributed to air masses with high AOD originating from North-Eastern and Eastern directions during summertime. The analysis of the long-term record (9 years) of AOD showed a downward tendency. A similar decreasing tendency was found in the record of the PM$_{10}$ aerosol measurements, which are conducted near the surface at 4 air-quality monitoring stations in the area of the city of Thessaloniki.

Celebrity athletes are the most prominent achieved celebrity brands with well-noted effects in consumer behaviour. Still, current research is characterised by terminological polyglossia and conceptual overlaps, which results in a lack of clarity regarding the brand structure and content. Moreover, there is no consideration of the brandscape; the team or sports club the player belongs to or has most closely associated his name with. This paper addresses the current limitations by adopting an exploratory approach. Through qualitative research, namely five focus groups, we empirically investigated the celebrity footballer brand associations as they are being perceived by keen football fans. The data demonstrate that the celebrity footballer brand comprises two distinct components proposed by Keller (1993): 1) the professional one, to include product-related associations, further distinguished into individual, organisational and contextual associations; 2) the personal one, which corresponds to non-product-related associations and reflects the balance of a person's perceived virtues and vices. The role of the brandscape emerges as affecting his professional and personal associations both positively and negatively. [ABSTRACT FROM AUTHOR]

The present study refers to experimental ambient air hydrocarbon measurements in the city of Thessaloniki, Greece, during June and July 2006. The measurements were performed at two sites of the Municipal Air Quality Network of Thessaloniki, at the commercial city center (11.4 m asl) and at an urban peripheral site (174.0 m asl). The two locations, city center and peripheral site, have been selected because they represent the maximum and minimum levels of pollutants measured in Thessaloniki, respectively. The measurements concern two hydrocarbon groups, C2-C5 and C6-C 10 and were performed with three automatic gaschromatographs, selected for their suitability to measure in the field, equipped with FID and PID detectors. The daily and hourly variations of these measurements are presented and a comparison between the two sites is performed. Moreover an additional comparison is made with the permanent measurements of BTEX and of other relevant air pollutants which are performed at the urban area of Thessaloniki. [ABSTRACT FROM AUTHOR]

This study reports systematic ambient PM2.5 measurements during 2004–2005, for the first time in urban Thessaloniki area. PM10 concentrations have been also measured in Thessaloniki from 1989 until today. The measurements are performed at a central site, in the Thessaloniki area, using tapered element oscillating microbalance (TEOM) and beta-absorption methods. The annual average concentrations of PM2.5 and PM10 were 36.0 and 58.7μg m-3, respectively. The PM2.5/PM10 daily mean ratio was calculated equal to 0.64±0.17. The mean coarse particle concentration, PM10-PM2.5, was 22.7 μg m-3, representing about 40% of the average PM10. The analyzed data show a considerable seasonal and daily variation. The PM2.5 levels measured at the city center exceed by far the USA EPA PM2.5 annual air quality standard (15 μg m-3). Daily PM2.5 concentrations exceeded the European Union (CAFE) proposed 24-hours average air quality guideline (35 μg m-3) on approx. 48% of the sampling days. In addition, significant contribution from traffic emissions and meteorological conditions is evidenced at the above particulate concentrations. [ABSTRACT FROM AUTHOR]