Micro-analytical methodologies for the characterization of airborne inorganic pollutants collected on unconventional substrates

Bertolotti, Giulia (2014) Micro-analytical methodologies for the characterization of airborne inorganic pollutants collected on unconventional substrates. PhD thesis, University of Trento.

PDF - Doctoral Thesis
Available under License Creative Commons Attribution Non-commercial.



The present work regards the development of a methodology for the study of atmospheric particulate matter (PM) which is alternative to instrumental measurements. The methodology developed exploits the surfaces already present in the field as samplers of PM. In particular, conifer needles and building facades are employed to investigate different temporal ranges: conifer needles potentially retain particles circulating in the atmosphere from the recent past up to now, while building facades could retain particles from an older period up to know. The field of application of the approach developed are the situations in which a wide territory must be monitored, eventually including remote locations, or information on past pollution scenario must be reconstructed in the absence of monitoring stations. For instance, the evaluation of the improved efficiency of off-gas abatement systems of industrial plants is a typical case of application. These pollution sources affect large areas and might have been active before regulation on air quality required constant monitoring of their emissions. Typically in such a case the methodology could assist in evaluating how large was in the past and it is nowadays the area of impact of the plant. In general, such an approach could be valuable whenever relying on instrumental measurements is cost and time consuming in terms of installing a large network of monitoring stations to study the dispersion of pollutants from a single or few sources. To have a detailed description of the spatial distribution of pollutant particles, they are studied individually with subsequent higher magnification. Where no traces of a source are detected by scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDXS), the samples are analyzed with the higher resolution of transmission electron microscopy coupled with energy dispersive x-ray spectroscopy (TEM-EDXS) and selected area electron diffraction (SAED) in order to make sure that no smaller particles, able to travel farther from their source, are present at a certain site. All data provided by electron microscopy analysis of particles collected by conifer needles are placed in the context of elemental concentrations measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), which is a bulk analytical technique. The same is not possible for the data on single particles present on building facades given the inorganic matrix of the substrate, especially in the case of metal oxide paints, which does not allow the bulk measurement. Both the preparation of the samples for bulk analytical techniques and single particle analysis by electron microscopy were optimized. For method development and evaluation, the analytical protocol was applied to estimate spatial and temporal trends of accumulation of inorganic pollutants that can be related with changes in the emissions of atmospheric pollutants by an electric arc furnace (EAF) steelmaking plant located in a test site. The benefits of combining the single particle and bulk analytical techniques emerged especially for the discrimination of the emissions from different sources.

Item Type:Doctoral Thesis (PhD)
Doctoral School:Materials Science and Engineering
PhD Cycle:XXVI
Subjects:Area 08 - Ingegneria civile e Architettura > ICAR/03 INGEGNERIA SANITARIA-AMBIENTALE
Area 05 - Scienze biologiche > BIO/03 BOTANICA AMBIENTALE E APPLICATA
Area 03 - Scienze chimiche > CHIM/01 CHIMICA ANALITICA
Area 09 - Ingegneria industriale e dell'informazione > ING-IND/22 SCIENZA E TECNOLOGIA DEI MATERIALI
Uncontrolled Keywords:Particulate matter, air quality, conifer needles, passive sampling, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma atomic emission spectroscopy, EAF emissions, electric arc furnace dust, fugitive emissions, biomonitoring.
Funders:Agenzia Provinciale per la Protezione dell'Ambiente, Mediterranean Scientific Association of Environmental Protection
Repository Staff approval on:15 May 2014 15:04

Repository Staff Only: item control page