Emerging application of a structural and chemical analyzer for the complete characterization of metal-rich particulate matter.

Clean air is considered to be a basic requirement of human health and well-being. An increasing range of adverse health effects has been linked to air pollution, at ever-lower concentrations. This research shows the newly developed Structural and Chemical Analyzer (SCA) to be a successful combination of Raman spectroscopy and scanning electron microscope-energy dispersive X-rays that opens up new insight into the composition of particulate matter (PM). The results obtained with soil and lichen samples demonstrate the capability of the technique to obtain elemental and molecular information of every single atmospheric PM focused at the micrometer and submicrometer levels. The SCA approach permitted the individual PM analysis, allowing the identification of the molecular (most commonly as sulphides, sulphates, carbonates, or oxides) form in which several hazardous metals (Zn, Pb, Cu, etc.) are evolved into potentially inhalable PM. During the present research, the synchronization of both techniques at a time revealed the morphological, elemental, and molecular forms of metal-rich PM, avoiding some analysis precautions and making the sample preparation and measurement steps more dynamic. In addition, the thermodynamic simulations carried out with the information obtained were helpful to differentiate whether the PM may be retained in the alveoli (i.e., galena) or if it may be dissolved and pass into the bloodstream (i.e., plattnerite).

Diagnosing the traffic impact on roadside soils through a multianalytical data analysis of the concentration profiles of traffic-related elements.

The road traffic has become one of the most serious environmental problems in many cities and the main source of pollution of urban soils. To diagnose properly the magnitude of such impacts on roadside soils, eight urban and metropolitan soils were selected as a function of traffic density, distance to the road and years of operation, for which the concentration of 60 elements (major, minor and trace elements) were measured by semi-quantitative ICP-MS after acid digestion, as a first step in assessing the traffic impact. With this information, a comprehensive study was carried out focusing on the quantitative analysis of the concentration of 46 elements from the 8 sampling areas, analyzing the vertical and horizontal distributions of the metals in the roadside soils. The chemometric analysis showed that only the traffic-related elements accumulate in topsoil and present a high decreasing profile with depth and the distance to the road; however, this clear behavior takes places only in old roads that have undergone the traffic impact for a long time, but not in new roads or roads with low traffic density. Finally, the geoaccumulation indexes are suggested to be used instead of the local guidelines to assess the pollution state of the roadside soils, especially for the emerging trace elements like Antimony.