Particulate matter measurements (PM₁₀, PM₂.₅) using a beta radiation attenuation monitor were performed at the Akrotiri research station (May 2003-March 2006) on the island of Crete (Greece). The mean PM₁₀ concentration during the measuring period (05/02/03-03/09/04) was equal to 35.0 ± 17.7 μg/m³ whereas the mean PM₂.₅ concentration (03/10/04-04/02/06) was equal to 25.4 ± 16.5 μg/m³. The aerosol concentration at the Akrotiri station shows a large variability during the year. Mean concentrations of particulate matter undergo a seasonal change characterised by higher concentrations during summer [PM₁₀, 38.7 ± 10.8 μg/m³ (2003); PM₂.₅, 27.9 ± 8.7 μg/m³ (2004) and 27.8 ± 9.7 μg/m³ (2005)] and lower concentrations during winter [PM₁₀, 28.7 ± 22.5 μg/m³ (2003/2004); PM₂.₅, 21.0 ± 13.0 μg/m³ (2004/2005) and 21.4 ± 21.9 μg/m³ (2005/2006)]. Comparative measurements of the PM₁₀ concentration between the beta radiation attenuation monitor, a standardized low volume gravimetric reference sampler and a low volume sequential particulate sampler showed that PM₁₀ concentrations measured by the beta radiation attenuation monitor were higher than values given by the gravimetric samplers (mean ratio 1.17 ± 0.11 and 1.21 ± 0.08, respectively). Statistical and back trajectory analysis showed that elevated PM concentrations (PM₁₀, 93.8 ± 49.1 μg/m³; PM₂.₅: 102.9 ± 59.9 μg/m³) are associated to desert dust events. In addition regional transport contributes significantly to the aerosol concentration levels whereas low aerosol concentrations were observed during storm episodes.

Source apportionment analysis was used to identify the factors contributing to atmospheric pollution at a monitoring location in the Southeast of Spain, a well documented area with an arid climate and high insolation favouring two sources of particulate matter: secondary transformation in the atmosphere and resuspension of crustal dry soils to the air. These conditions are further complicated by numerous industrial facilities in the area of the historical city of Cartagena. This paper describes the air quality of an area which includes a zinc metallurgical industry, a petrochemical factory, an oil power station, a shipyard and natural phenomena including African dust transport and resuspension of regional and/or local crustal materials. Major and trace element concentrations in PM10 and PM2.5 were determined at two monitoring stations in Cartagena (one PM10 sampler located at a traffic hotspot and the PM2.5 sampler at a suburban station), during 2004 and 2005. Results showed that in the PM10 fraction, the zinc metallurgical activity was linked to high levels of Cd, Zn and Pb; shipyard emission was associated with high levels of Cr and Ni; and high Ni and V levels were associated with the secondary aerosol indicating the contribution from oil combustion (oil-fired power station or petrochemical facilities). In the PM2.5 size fraction, the zinc source is defined by Zn and Pb; V, Ni and As appear with the oil combustion emissions. In contrast to PM10, shipyard activity is not consistently defined. Consistent sources found in both size fractions include crustal materials and traffic emissions.

The distribution of nonylphenol ethoxylates (NPEOn) and their derivatives of nonylphenol (NP) and nonylphenoxy ethoxy acetic acids (NPEnC) in the sediments of a relatively closed freshwater reservoir was investigated using sediment layers sliced from undisturbed sediment cores collected with a gravity core sampler at three sampling sites (St. 1, St. 2 and St. 3) along the water flow direction. The relationships between the bound content of these compounds and the sediment organic matter as well as the likely transformation pathways were evaluated. The total content of NPEOn (n = 1-15) fell in 84.6-336.5, 59.9-135.5 and 77.0-623.4 μg/kg-dry for all sliced layers at St.1, St.2 and St.3, respectively, with the content of individual NPEOn species showing a general decreasing trend with the attached molar number of the ethoxy (EO) chain. Compared to each detected NPEOn species, the bound content of NP was much higher, falling in 73.2-248.4, 79.9-358.2 and 25.5-1,988.4 μg/kg-dry at St. 1, St. 2 and St. 3, respectively. A general increasing trend of the NP content along the water flow direction of the reservoir was revealed. NPEnC (n = 1-10) varied in 1.93-4.12, 2.85-9.84 and 1.05-19.1 μg/kg-dry for sediment at the respective site of St. 1, St. 2 and St. 3, with the averaged values at these sites (2.91, 4.71 and 6.72 μg/kg-dry) showing an increasing trend from the upstream to the downstream. For NPEnC, a parametric trend of increases in the content of NPE₁C, NPE₂C and NPE₃C with the bound sediment organic matter (9.06-11.8%) seemed to be existent. Furthermore, the computed magnitudes of NPEO₁-₂/NPEO₁-₁₅, NP/NPEO₁-₁₅ and NPEC₁-₁₀/NPEO₁-₁₅ suggested that non-oxidative hydrolytic transformation was probably prevailing within the sedimented mud phase of the reservoir, with the oxidative hydrolytic transformation pathway being less involved.

Understanding and controlling air pollution in highly populated areas is very important, although interpreting the levels of gaseous pollutants and airborne particulate matter is complicated by dominant natural and anthropogenic emissions, micro-meteorological processes, and chemical reactions which take place directly in the atmosphere. For this reason, it is very difficult to relate the characteristics of air pollution to one or more specific emission sources. The aim of this paper is to detect associations among elements and organic compounds emitted from specific sources by means of chemical analyses, statistical processing of data, seasonal evolution study, and geochemical considerations to trace their origin. A detailed characterization of air quality during the period September 2000-September 2001 was carried out in three locations of the Venice region: A heavy traffic urban site, a public park, and the island centre of the city of Venice. Twenty-eight inorganic elements, four polycyclic aromatic hydrocarbons, CO and benzene were quantified and processed by a statistical procedure based on factor analysis considering variations on a seasonal basis. Results show the presence of associations between elements and compounds with the same behaviour in all sampling points. This indicates that several pollutants originate from a common source, and are then “diluted” throughout the study area, maintaining the imprint of their origin. Pt, polycyclic aromatic hydrocarbons, CO and benzene originating from the exhaust gas of vehicles are all linked in the traffic factor, whereas Cd is associated with Se, having a common source in industrial processes.

This study investigated particulate matter (PM) granulometry delivered in source area runoff as a function of hydrologic transport and settling. At a Baton Rouge, LA paved urban watershed, event runoff volume and PM load were “fully captured” and recovered in settling tanks. Events were differentiated as mass-limited (ML) or flow-limited (FL) and PM differentiated into suspended (1 to ~25 μm), settleable (~25 to 75 μm), sediment (75 to 4,750 μm) fractions; and also particle size distributions (PSDs). Suspended sediment concentration (SSC)-turbidity relationships were unique for FL events compared to ML events; while 60 min of quiescent settling produced a single distinct relationship across all events. ML events transported higher proportions of settleable and sediment mass compared to higher suspended mass for FL events. Event-based ratios of settled and unsettled turbidity as well as SSC mass were statistically different for ML and FL events. For the same settling conditions, treatment of ML and FL events were statistically different. Results demonstrated that PM separation by a unit operation was a deterministic function of granulometry, hydrodynamics, unit operation mechanisms and loads, but significantly influenced by the indeterminate nature of local climate; and hydrology which drives PM delivery and is not known a priori. Combining the influences of scour and lack of maintenance, unit operation performance is non-stationary and cannot be described by a single value. Treatment should be tied to an effluent concentration; granulometry and load.