|
Abstract:
|
Abstract Santiago de Chile is a big city with huge air
quality problems, being one of the most polluted cities in
the world. This is aggravated during winter by the topography
and meteorological conditions of the city. Although
public policies have been developed to minimise the
atmospheric aerosol pollution, there is a lack of adequate
knowledge and poor characterisation of these aerosols
(in its PM2.5 and PM10 fractions). In this study we sampled
atmospheric particles during winter in two distinct areas of
Santiago: downtown (Teatinos Street) and in a more residential
area (Macul). Major (Si, Al, Fe, Ca and K)
and some trace element (S, Cl, Ti, P, Cr, Cu and Zn)
compositions were obtained by proton-induced X-ray
emission (PIXE). Morphological, type and chemical characterisation
was also performed using scanning electron
microscopy (SEM) coupled with an energy dispersive
X-ray microanalysis system (SEM–EDX). Besides the
carbon particles, the contribution of which can be quite
important in the atmospheric aerosol, especially in downtown,
unambiguously lithogenic (i.e. of geological origin)
particles and elements are the second highest contributors.
Enrichment factor calculation, together with particle identification
and element correlation allow the origin of some
elements and particles to be traced, revealing anthropogenic
origins for some of them that are specific to the
Santiago area. |