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Abstract Graphic vandalism causes detrimental effects on architectural stone surfaces. Among the cleaning methods developed in the last decades, laser cleaning showed considerable effectiveness but the available equipment still lacks full adaptability for the use on site, while the cleaning process is time-consuming for the site work requirements. In this paper, the feasibility of a fiber laser operating at 1064 nm (Yb:YAG) at high repetition rate (kHz) for the removal of vandal graffiti from marble is investigated, as it is potentially suitable for cleaning of large surfaces. Indeed, this device exploits a scan system covering a wider area than that of solid state lasers, while maintaining excellent portability. Evaluation of the cleaning procedure on a selection of spray paints and felt-tip permanent markers applied on marble mock-ups is carried out with a multimodal approach (optical microscopy combined with surface pattern reconstruction, colour monitoring, Fourier Transform Infrared spectroscopy in external reflection and ATR mode, Thin Layer Chromatography, Raman spectroscopy, thermal monitoring, scanning electron microscopy). Ablation and thermal effects are observed varying the laser setting and the type of paint layer, with repetition rate showing a strong impact on the type of interaction. Overall, best cleaning procedures are achieved for the thinning of the black marker and the removal of the black spray paint. Some residues on the best results were observed, suggesting that the laser needs to be integrated with a second step of chemical cleaning. This study, focused on graffiti removal, shows that fiber laser can be a useful tool for cleaning of large monumental surfaces. Graphical Abstract

We investigated the removal of spray paint from heritage granite surfaces using a nanosecond pulse laser and compared the results, in terms of the effectiveness of treatment and preservation of the stone surface from potential damage, with results obtained using a femtosecond pulse laser. We show that, with the nanosecond laser, the ablation threshold of the stone was measured at 0.5 J·cm-2, but it was only possible to remove certain types of spray paints, such as blue and green paints, at a higher fluence of 0.9 J·cm-2. To remove other types of paints, such as red and yellow, it was necessary to increase even further the laser fluence to 1.5 J·cm-2, well above the ablation threshold of the stone. In this case, damage was induced in the minerals, such as melting of biotite, and a general roughening of the other minerals' surfaces was observed. Despite nanosecond pulse lasers being more widespread for cleaning purposes, we demonstrate that femtosecond pulse lasers allowed better effectiveness in removing various colours of paint, without leaving residues, while keeping the laser energy below the damage threshold of the underlying stone, allowing complete preservation of the substrate, and avoiding the melting of the most sensitive mineral grains (particularly biotite). We determined the ablation efficiency of spray paint using the femtosecond pulse laser and found a maximum ablation regime centered around 6.2 J·cm-2, at 8.36 mm3·(min·W)-1. This study highlights the benefits of using a laser with femtosecond pulses instead of longer pulse durations (nanosecond range) for the preservation and maintenance of heritage stone. [ABSTRACT FROM AUTHOR]

Graphic vandalism causes detrimental effects on architectural stone surfaces. Among the cleaning methods developed in the last decades, laser cleaning showed considerable effectiveness but the available equipment still lacks full adaptability for the use on site, while the cleaning process is time-consuming for the site work requirements. In this paper, the feasibility of a fiber laser operating at 1064 nm (Yb:YAG) at high repetition rate (kHz) for the removal of vandal graffiti from marble is investigated, as it is potentially suitable for cleaning of large surfaces. Indeed, this device exploits a scan system covering a wider area than that of solid state lasers, while maintaining excellent portability. Evaluation of the cleaning procedure on a selection of spray paints and felt-tip permanent markers applied on marble mock-ups is carried out with a multimodal approach (optical microscopy combined with surface pattern reconstruction, colour monitoring, Fourier Transform Infrared spectroscopy in external reflection and ATR mode, Thin Layer Chromatography, Raman spectroscopy, thermal monitoring, scanning electron microscopy). Ablation and thermal effects are observed varying the laser setting and the type of paint layer, with repetition rate showing a strong impact on the type of interaction. Overall, best cleaning procedures are achieved for the thinning of the black marker and the removal of the black spray paint. Some residues on the best results were observed, suggesting that the laser needs to be integrated with a second step of chemical cleaning. This study, focused on graffiti removal, shows that fiber laser can be a useful tool for cleaning of large monumental surfaces. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of aqueous leaf extract of Ageratum conyzoides on spray-paint-induced injury in the lungs of adult Wistar rats. The 30 adult Wistar rats weighing between 250g and 280g that were used in this research were divided into 5 groups of six 6 rats per group. The haematological outcome showed that spray paint caused some derangements in haematolodical parameters especially lymphocytes, monocytes, granulocytes and platelets. Histologically, interstitial haemorrhage, pulmonary edema, and activation of lymphoid tissue were observed in the rat treated with spray paint only. Ageratum conyzoides shrunk the local activated immune system and the florid-activated broncho-alveolar aggregates of the immune system in the Ageratum conyzoides treated rats. In conclusion, Ageratum conyzoides has ameliorative effects against spray-paint-induced injury in the lungs of Wistar rats and its effect is inversely proportional to dosage. It is more potent at low doses. [ABSTRACT FROM AUTHOR]

The objectives of this study were to develop a novel analytical method for quantifying vinyl chloride (VC) emitted from aerosol products, to provide analytical data on VC in aerosol products, and to evaluate consumer VC exposure by aerosol products. Our quantitative method involves absorbing VC into dimethyl sulfoxide and analyzing it using headspace gas chromatography/mass spectrometry. The correlation coefficients of the VC calibration curves were ≥ 0.9994 in the range of 0.16–80 µg/mL VC standard gases, which were prepared under either nitrogen or emission gases containing dimethyl ether or liquid petroleum gas. VC concentrations in these emission gases were calculated using a VC calibration curve from standard gases prepared under nitrogen; they were within ± 10% of the actual concentrations. We analyzed 39 household aerosol products; VC concentrations of 0.095, 0.098, and 0.28 μg/L were detected in three polyvinyl chloride spray paints. Consumer VC inhalation exposure level was estimated through an exposure scenario, and the hazard quotient was confirmed to be very low when comparing the exposure level with a cancer risk level of 10−5 for inhaled VC. These results suggest that the human health risk from VC in spray paint was low. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of aqueous leaf extract of Ageratum conyzoides on spray-paint-induced injury in the lungs of adult Wistar rats. The 30 adult Wistar rats weighing between 250g and 280g that were used in this research were divided into 5 groups of six 6 rats per group. The haematological outcome showed that spray paint caused some derangements in haematolodical parameters especially lymphocytes, monocytes, granulocytes and platelets. Histologically, interstitial haemorrhage, pulmonary edema, and activation of lymphoid tissue were observed in the rat treated with spray paint only. Ageratum conyzoides shrunk the local activated immune system and the florid-activated broncho-alveolar aggregates of the immune system in the Ageratum conyzoides treated rats. In conclusion, Ageratum conyzoides has ameliorative effects against spray-paint-induced injury in the lungs of Wistar rats and its effect is inversely proportional to dosage. It is more potent at low doses.

Microplastics are recently discovered contaminants, yet knowledge on their sources and analysis is limited. For instance, paint microplastics are poorly known because soil separation protocols using flotation solutions cannot separate paint microplastics due to the higher density of paint microplastic versus common microplastics. Here, we designed a new two-step density separation protocol for paint microplastics, allowing paint microplastics to be separated from the soil without digestion. Paint particles were separated from soil samples collected around the graffiti wall at the Mauerpark, Berlin, then quantified according to their shape and color characteristic. The presence of polymers as binders in the paint particles was verified by Fourier transform infrared spectroscopy. Results show concentrations from 1.1 × 105 to 2.9 × 105 microplastics per Kg of dry soil, representing the highest microplastic concentration ever reported in the literature. Particle concentrations decreased and the median size increased with soil depth. Our results provide first evidence that spray painting, a technique with a wide range of applications from industry to art, leaves a legacy of environmental microplastic in soils that has so far gone unnoticed. [ABSTRACT FROM AUTHOR]

The diversity of techniques, methods and tools in creating Graffiti and Street Art allows artists to constantly evolve and discover new ways to express their ideas and implement their work. At the same time, a large number of researchers study and observe artists and their work, in an attempt to experiment with the emergence and spread of the phenomenon of urban art in combination with other scientific environments, such as engineering, robotics, programming and more. In this article, after the introduction to the power and importance of spray paint as a tool and symbol for the evolution of urban art, a first glimpse on the street artist - designer follows. This new type of creator can intervene radically in shaping the urban landscape by properly utilizing the designers' toolbox to help innovative ideas come to fruition. One of these ideas is to use polyurethane foam as a "three-dimensional spray". Using it, the artist can create embossed or three-dimensional works on a large scale, taking existing practices one step further. A case study illustrated by a variety of images is presented before the conclusion of this paper, describing the creation of a lion's head directly on the wall using polyurethane foam spray and then painting it with graffiti spray paint. [ABSTRACT FROM AUTHOR]

Identification of spray paint coats on various surfaces is often a subject of forensic examinations. The layer of paint, which creates inscription and drawing or painting such as graffiti, is thin and difficult to be separated from the base. Model examinations have been carried out aiming at the evaluation of the usefulness of infrared (ATR FTIR) and Raman spectrometry in the identification of paints. Seven red spray paints were placed on the surface of metal and glass slides as well as on paper and on different fabrics. It was found out that a spectrum suitable for identification of the type of paint depends on the thickness of the paint coat and on the type of the substrate. [ABSTRACT FROM AUTHOR]

Depending on the forensic disciplines and on the analytical techniques used, Bayesian methods of evaluation have been applied both as a two-step approach (first comparison, then evaluation) and as a continuous approach (comparison and evaluation in one step). However in order to use the continuous approach, the measurements have to be reliably summarized as a numerical value linked to the property of interest, which occurrence can be determined (e.g., refractive index measurement of glass samples). For paint traces analyzed by Fourier transform infrared spectroscopy (FTIR) however, the statistical comparison of the spectra is generally done by a similarity measure (e.g., Pearson correlation, Euclidean distance). Although useful, these measures cannot be directly associated to frequencies of occurrence of the chemical composition (binders, extenders, pigments). The continuous approach as described above is not possible, and a two-step evaluation, 1) comparison of the spectra and 2) evaluation of the results, is therefore the common practice reported in most of the laboratories. Derived from a practical question that arose during casework, a way of integrating the similarity measure between spectra into a continuous likelihood ratio formula was explored. This article proposes the use of a likelihood ratio approach with the similarity measure of infrared spectra of spray paints based on distributions of sub-populations given by the color and composition of spray paint cans. Taking into account not only the rarity of paint composition, but also the “quality” of the analytical match provides a more balanced evaluation given source or activity level propositions. We will demonstrate also that a joint statistical–expertal methodology allows for a more transparent evaluation of the results and makes a better use of current knowledge. [ABSTRACT FROM AUTHOR]

Manual recovery of spray paints from textiles using a microscope, the routine method in many laboratories, is often laborious. Beating the clothing with a plastic rod, the routine method used for recovery of glass traces within the authors' laboratory, is proposed as an alternative. The efficiency of the method was evaluated by spray tests with fluorescent paint. In these tests, paint particles in the acquired debris samples, as well as those remaining on the textiles, were investigated. The results show that beating is an efficient way to recover and concentrate paint particles. A good efficiency for jeans fabric and rough knitwear is reported. The results appeared to be less satisfactory for smooth woven fabric. Application of the method in casework was effective for graffiti paints as well as for flaked car paint. [ABSTRACT FROM AUTHOR]

Contemporary graffiti and murals became an artistic expression worthy of attention worldwide as well as their conservation. The application of spray paints with increasing technical performance mirrors the variety of the chemical composition of these increasingly common painting materials. An insight into the formulation and the ageing process is extremely important to predict and prevent the possible decay phenomena observed on outdoor urban artworks. This paper aims to investigate the relationship between the macroscopic outcomes and the chemical changes occurring on spray paints after the ageing by a multi-analytical approach. A systematic artificial ageing procedure was performed on multiple sets of concrete mock-ups painted with three different alkyd-based spray paints and in three different light-sensitive colours. The colour variation was assessed by colorimetric measurements, the changes in the paint cross section were observed by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) was applied both to characterize the spray paints and to detect the chemical changes of the organic compounds during the ageing. A significant and innovative contribution to this research is the application of the evolved gas analysis-mass spectrometry (EGA-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) with tetramethylammonium hydroxide in double-shot mode. These two analytical methodologies allowed an accurate classification of the different alkyd-based binders, the identification of plasticizers, organic pigments and other components often hard to spot in complex formulations, and an analysis of their fate following ageing. • Py-GC/MS analyses were carried out in the double shot mode with TMAH. • Photooxidative ageing causes thinning of the spray paint layers. • Colour change of spray paints depends on the stability of pigments rather than binders. • The loss of adhesion and cohesion of spray paints depends on the ageing of binders. [ABSTRACT FROM AUTHOR]

Predictive modeling is an available tool to assess worker exposures to a variety of chemicals in different industries and product-use scenarios. The European Chemical Agency (ECHA)’s guidelines for manufacturers to fulfill the European Union’s legal requirements pursuant to the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) initiative include recommendations for the use of modeling to predict worker exposures. ECHA recommends different models for different target populations (i.e. workers, consumers, environment) and routes of exposure (i.e. skin absorption, ingestion, inhalation), and presents them hierarchically, with Tier 1 models presented as the most simplistic, conservative models and Tier 2 models recommended for further intensive evaluation of substances or preparations. In order to assess these models for one exposure (product-use) scenario, a simulation of the scenario was completed in a controlled environment and the measured results were compared with the modeling outputs. The authors predicted, based on the design of the modeling tools, that all models would overestimate worker exposures under the simulated product-use scenario, with the lower-tiered model producing the most conservative estimate of exposure. In this study, a Tier 1 model and a Tier 2 model were evaluated for comparison with the near-field, far-field (NF-FF) deterministic model and measured experimental results in a real-time worker inhalation exposure assessment. Modeling was conducted prior to actual air monitoring. The exposure scenario that was evaluated involved the application of a toluene-containing spray paint to a work surface. Air samples were collected to evaluate short-term (15-min) and long-term (240-min) exposures. Eight-hour time-weighted averages (8-h TWAs) were calculated and compared with the modeling outputs from the recommended REACH modeling tools and the NF-FF model. A comparison of each of the modeling tools with measured experimental results was generated. The Tier 1 Targeted Risk Assessment tool overestimated the 8-h TWA airborne concentration of toluene in the spray scenario by a factor of 3.61. The higher tiered Advanced REACH Tool and NF-FF models showed greater concordance with experimental results, overestimating the TWA exposure by a factor of 2.92 and 1.96, respectively. In conclusion, the Tier 1 and 2 exposure modeling tools performed as expected for the simulated exposure scenario, providing relatively accurate, though conservative, estimates according to the level of detail and precision accounted for in each model. [ABSTRACT FROM PUBLISHER]

Abstract: The thin layer of spray paint, which creates an inscription, smudge or a drawing on plaster has to be examined in situ. The application of reflectance IR spectroscopy enables one to identify in some cases the spray paint directly on plasters. However, very often the bands of plaster components overlay signals originating from paint, making its identification impossible. In pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) method the influence of inorganic substances on chromatographic results is very small. So, an attempt was made to use this method to spray paints examination. 15 spray paints, available on the Polish market were placed on surfaces of four types of plaster: mineral-based plaster, acrylic copolymer-based plaster, silicate-based plaster and silicone-based plaster. Then they were dried, collected and analysed. It was found that spray paints collected from the plasters can be effectively differentiated in many cases by means of Py-GC/MS based on a specific minor and major compounds content. [Copyright &y& Elsevier]

Two-component, polyurethane paints containing aliphatic isocyanates are widely used in autobody spray painting. Such isocyanates can cause asthma, and skin exposure may be an important route of sensitization and may contribute to the development of isocyanate asthma. Autobody workers are frequently in contact with recently painted, dried auto parts. It is not known how fast the newly painted car surfaces are fully cured, that is, for how long unbound, isocyanate species remain on painted surfaces after initial drying. To address this question, scrap sections of auto bodies were painted and dried by autobody shop painters following regular practice. Routinely used paints were sprayed 23 different times on the parts. Drying was accomplished by baking the part in a paint spray booth by heating it with a heat lamp or air drying in the shop. The 23 sprayed surfaces were sampled at regular time intervals after drying to determine the presence of free NCO groups using the semiquantitative SWYPE technique. Quantitative isocyanate analysis was also performed on two sprayed parts using NIOSH method 5525. Geometric mean curing time of 23 painted surfaces was 56.4 hr (range: 0.8 hrs to 32 days). Unbound isocyanate species of similar composition to the original bulk material remained present on the majority of sampled painted surfaces for up to 120 hours for typical paint formulations and for 1 month for others. The actual curing of polyurethane paints in autobody refinishing can be a slow process. Unbound isocyanates may remain on the surface of painted car parts for prolonged periods (days to weeks) after dried. Such surfaces are an under-recognized potential source of skin exposure to autobody workers. [ABSTRACT FROM AUTHOR]

Abstract: Identification of spray paint coats on various surfaces (usually plaster) is often a subject matter of forensic examination. The layer of paint, which creates an inscription, smudge or a drawing, is thin and difficult to be separated from the base. Model examinations have been carried out aiming at the evaluation of the usefulness of the reflection technique of microinfrared spectrometry in the identification of paints. About 20 spray paints, available on the Polish market,—white and black—were placed on the surface in the form of metal, glass, foil, fabric and a wall made of brick, plaster board and mineral plaster. It was found out that, obtaining a reflectance spectrum suitable for identification of the type of paint depends on the thickness of the paint coat and on the type of the base. It was observed that, the smoother and less absorptive the base is the less is its influence deforming the reflection spectrum of paint. [Copyright &y& Elsevier]

Red spray paints from different European suppliers were characterised to determine the discriminating power of a sequence of analysing techniques. A total of 51 red spray paints were analysed with the help of three techniques: (1) optical microscopy, (2) Fourier transform infrared spectrometry and (3) X-ray fluorescence. Infrared spectra were classified according to binder type, filler and pigment composition and a searchable spectral library was created. Due to the difference in the elemental composition of spray paints, a further discrimination was possible. The microscopic analysis was not taken into consideration for classification purposes. The structure of the substrate under a paint coating strongly affects the surface characteristics of this spray paint. Together with the spectral library, a database of information of spray paints was build. [Copyright &y& Elsevier]

Diisocyanates, highly reactive monomers which cross-link polyurethane, are the most widely recognized causes of occupational asthma. Many exposed workers are end-users, including autobody spray painters who form a large population at risk. Neither the factors which determine incidence rate nor strategies for control have been adequately studied in this setting. We have conducted a cross-sectional survey of 23 (about one in five) autobody shops in the New Haven area to determine the feasibility of clinical epidemiological studies in this population. Among 102 workers, there was a high rate of airway symptoms consistent with occupational asthma (19.6%). Symptoms were most prevalent among those with the greatest opportunity for exposure (dedicated spray painters) and least among office workers; part-time painters had intermediate rates. Atopy was not associated with risk while smoking seemed to correlate with symptoms. Regular use of air-supplied respirators appeared to be associated with lower risk among workers who painted part- or full-time. We were unable to validate the questionnaire responses with peak expiratory flow record data attempted on a 1/3 sample of the workers. Despite intensive training and effort, subject compliance was limited. Among those who provided adequate data (24 of 38), only two demonstrated unequivocal evidence of labile airways; two others demonstrated lesser changes consistent with an occupational effect on flow rates. There was no clear association between these findings and either questionnaire responses or exposure classification. Overall, the survey suggests that there is a high prevalence of airway symptoms among workers in autobody shops, at least in part due to work-related asthma. However, there is need for both methodological and substantive research in this setting to document rates of occupational asthma and to develop a scientific basis for its effective control. [ABSTRACT FROM PUBLISHER]

Previous studies have provided evidence that bioremediation deals a novel approach to graffiti removal, thereby overcoming well-known limitations of current cleaning methods. In the present study eight bacteria aerobic, mesophilic and culturable from the American ATCC and the German DSMZ collections of microorganisms, some isolated from car paint waste, colored deposits in a pulp dryer and wastewater from dye works, were tested in the removal of silver and black graffiti spray paints using immersion strategies with glass slides. Absorbance at 600 nm and live/dead assays were performed to estimate bacterial density and activity in all samples. Also, pH and dissolved organic carbon (DOC) and inorganic carbon (DIC) measurements in the liquid media were made, as well as, thickness, colorimetric and infrared (FTIR) spectroscopy measurements in graffiti paint layers were used to evaluate the presence of the selected bacteria in the samples and the graffiti bioremoval capacity of bacteria. Data demonstrated that of the eight bacteria studied, Enterobacter aerogenes , Comamonas sp. and a mixture of Bacillus sp., Delftia lacustris , Sphingobacterium caeni , and Ochrobactrum anthropi were the most promising for bioremoval of graffiti. According to significant changes in FTIR spectra, indicating an alteration of the paint polymeric structure, coupled with the presence of a consistent quantity of live bacteria in the medium as well as a significant increase of DIC (a measure of metabolic activity) and a change in paint color. Unlabelled Image • A methodology to assess the bioremoval capacity by bacteria is proposed. • Combined physical-chemical-biological analysis are needed to evaluate the biocleaning. • FTIR, color, DIC and bacterial growth analysis are the most indicative parameters. • ATCC 13048, ATCC 53922 (mixed culture) and ATCC 700440 are the most promising strains. [ABSTRACT FROM AUTHOR]