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The possible use of an FT-IR imaging system for surface studies of atmospheric corrosion products on zinc and nickel samples has been explored. Samples have been exposed in an urban site located at Rouen in France. Corrosion products, detected by means of energy-dispersive spectrometry/X-ray diffraction (EDS/XRD) and FT-IR spectroscopy, are mainly Zn4CO3(OH)6·H2O, ZnSO3·nH2O, Zn4SO4(OH)6·nH2O, and NiSO4·xH2O. IR microspectroscopy and mapping techniques allow the observation of the heterogeneous distribution of chemical species on sample surfaces. While the zinc corroded surface seems uniform, inhomogeneity in the development of carbonate and hydroxysulfate compounds in layers is observed. The imaging chemical analysis enables the assignment of the 1550 cm−1 absorption band of the corrosion product to zinc hydroxycarbonate. The corrosion mechanism observed on nickel is pitting corrosion. Pit size, chemical mapping, and 3-D visualization determined from SEM/EDS and FT-IR maps are very similar.

A tunnel-type semi-enclosed atmosphere is characterized by a higher particulate pollution than urban zones and highlights the particulate species having an impact on material degradation. Therefore, a transverse approach between air composition and its consequences upon longevity of materials is necessary, requiring a better knowledge of tunnel atmosphere and a better understanding of material degradation inside a tunnel for operating administration. The characterization of particulate matter collected inside a road tunnel in Rouen (France) allows us to set up the features of the particle characteristics of the real conditions of field exposure. Two sampling campaigns include analyses of organic and water-soluble ionic fractions. The current work shows that organic species, grouped into two sets derived primarily from engine exhaust and debris with wear particles resuspended by the traffic, are divided into two groups: a majority comprising n-alkanes, alkanoic acids, phthalates, ketones, and benzothiazole and a minority one composed of BTEX (benzene, toluene, ethylbenzene, and xylenes), polycyclic aromatic hydrocarbons (PAHs), fatty acid methyl esters (FAMEs), furans, phenols, and alkenes. As regards the water-soluble ionic fraction, the ionic species such as Cl, and Na þ are involved in the degradation process. The inorganic particles (insoluble and slightly soluble), debris and wear particles, organic acids, and relative humidity play a key role and are important factors to consider in the degradation process.Implications: Particles, together with relative humidity, can play an important role in the degradation of materials inside a road tunnel. Depth knowledge of the environment prevailing inside a tunnel improves the criteria for selection of materials of equipments contained therein. In the present study, it appears that the particulate mass can be divided into two groups with distinct effects: a water-soluble particle group is the source of ionic species involved in the degradation process, and a slightly water-soluble or insoluble particle group that acts as reservoir of condensed water when covering the surface of the material.

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