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Advisor(s)
Abstract(s)
Atmospheric pollution by motor vehicles is considered a relevant source of damage to
architectural heritage. Thus the aim of this work was to assess the atmospheric depositions
and patterns of polycyclic aromatic hydrocarbons (PAHs) in façades of historical monuments.
Eighteen PAHs (16 PAHs considered by US EPA as priority pollutants, dibenzo[a,l]pyrene
and benzo[j]fluoranthene) were determined in thin black layers collected from façades of two
historical monuments: Hospital Santo António and Lapa Church (Oporto, Portugal). Scanning
electron microscopy (SEM) was used for morphological and elemental characterisation of
thin black layers; PAHs were quantified by microwave-assisted extraction combined with
liquid chromatography (MAE-LC). The thickness of thin black layers were 80–110 μm and
they contained significant levels of iron, sulfur, calcium and phosphorus. Total concentrations
of 18 PAHs ranged from 7.74 to 147.92 ng/g (mean of 45.52 ng/g) in thin black layers of
Hospital Santo António, giving a range three times lower than at Lapa Church (5.44–
429.26 ng/g; mean of 110.25 ng/g); four to six rings compounds accounted at both monuments
approximately for 80–85% of ΣPAHs. The diagnostic ratios showed that traffic emissions
were significant source of PAHs in thin black layers. Composition profiles of PAHs in
thin black layers of both monuments were similar to those of ambient air, thus showing that
air pollution has a significant impact on the conditions and stone decay of historical building
façades. The obtained results confirm that historical monuments in urban areas act as passive
repositories for air pollutants present in the surrounding atmosphere.
Description
Keywords
Air pollution Polycyclic aromatic hydrocarbons (PAHs) Traffic emissions historical monuments Thin black layers MAE-LC
Citation
Publisher
Taylor & Francis