Non-carcinogenic occupational exposure risk related to foundry emissions: focus on the workers involved in olfactometric assessments.

The scope of this work is the evaluation of the non-carcinogenic occupational risk related to foundry emissions, focusing on the category of workers involved in olfactometric assessments. Odor pollution from industrial activities such as foundries is a serious environmental concern. Sensorial techniques (e.g. dynamic olfactometry, EN13725:2003) currently represent the preferred method for odor emission characterization. During olfactometric analyses, human assessors are directly exposed to the odor at increasing concentrations, thus requiring the assessment of the associated exposure risk to guarantee workers' safety. This paper presents an investigation aiming to produce an inventory of compounds emitted from foundries together with their odor thresholds and toxicological limits (TLVs), with the final objective to propose a procedure for ensuring workers' safety during olfactometric analyses. Looking at the database resulting from this study, among the >100 compounds emitted by foundries, 8 have a maximum concentration above their TLV. Among those, ammonia, H2S, phenol, toluene and trimethylamine, produce an odor stimulus before they reach a toxic concentration, thus not representing a risk for olfactometric workers. Benzene, formaldehyde and SO2 are identified as the most critical compounds because they may reach toxic concentrations in foundry emissions, and they start being perceived by humans above their TLV. The proposed procedure entails a minimum dilution factor of 27'000 to be applied to odor samples analyzed by olfactometry, which however might result inapplicable in practical cases, thus pointing out the necessity to adopt chemical measurements to investigate specifically the concentration of the most critical compounds identified in this study

Sulphur compounds: comparison of different sorbent tubes for their detection

Different techniques have been developed for the analysis of gaseous sulphur pollutants, to maximize the analytical signals. In a complex matrix, such as odorous emissions, the detection of sulphur compounds can be critical in GC analysis, due to the lower concentration of these pollutants and the disturbing effect of co-eluting hydrocarbons. However, their detection is fundamental because they have a non-negligible odour impact. In the field of gaseous emissions analytics, it is common to use sorbent tubes for the sampling step. This technology uses different adsorbent materials, with different selectivity depending on the nature of the gas to be analysed. This work aims to evaluate the ability of three different sorbent tubes to collect different sulphur compounds, belonging to the classes of mercaptans, thioethers and aromatic heterocyclic compounds. A standard solution of 10 sulphur compounds was prepared by diluting in methanol 50 µL of each liquid standard into a 10 mL flask. Subsequently, this solution was diluted in methanol to obtain sulphur standards at five different concentrations (approximately 5-500 ng/µL). The tubes were loaded with the standard solutions with an aliquot of each solution, using a gas chromatograph packed column injector and subsequently analysed by TD-GC-MS. By the results obtained - average Response Factor (RF) and its Relative Standard Deviation (% RSD), it is possible to conduct a comparison among these tubes and evaluate their performance. From the comparison of the tubes, discussing % RSD, it is possible to highlight a slightly better performance, in terms of the number of compounds with % RSD = 30%, for tubes specific for sulphur compounds. Focusing on RF values, multi-sorbent bed tubes show slightly higher RFs for very volatile sulphur compounds, but Sulphur tubes present higher RF values for 6 compounds out of 10 compounds considered. The performance of Tenax TA tubes, instead, appears strictly correlated with the compound’s volatility and therefore they don’t appear useful for sorption of very volatile compounds.Peer ReviewedPostprint (published version

Chemical characterization of odorous emissions: A comparative performance study of different sampling methods

A comparison among different sampling methods (3 types of sorbent tubes and polymeric bags) commonly adopted in chemical analyses of odorous emissions was performed. To investigate the different performances, a lignocellulosic biomass storage plant was selected to obtain preliminary information about the chemical nature of odorous emissions. Samples of odorous emissions were collected at different biomass piles and analysed by dynamic olfactometry and TD-GC-MS. By comparing the two adopted sampling methods (tubes and bags), different performances are shown, depending on their specificity. By the comparison among the three types of sorbent tubes (Multi-sorbent bed (Carbotrap, Carbopack X and Carboxen 569), Tenax and Sulphur), Sulphur and Multi-sorbent bed present similar performance, while Tenax TA tubes show a different trend in terms of type and numerosity of detected compounds. In addition, from the comparison between tubes and polymeric bags, the number and types of compounds detected in bags are more comparable to those observed in the Multi-sorbent bed and Sulphur tubes. However, a difference between the two methods appears, especially in the detection of low-molecular weight organic compounds. In this study, it is possible to highlight that, due to the complexity of odorous emissions, the selection of the sampling material may affect the obtained chemical results. The detection of different classes of compounds, is a crucial point, to obtaining the most complete characterization of mixtures and comparing the chemical profile with olfactometric results: care must be taken in the choice of sampling material and procedure.Peer ReviewedPostprint (author's final draft

Analisi chimica di composti odorigeni mediante TD-GC-MS/FID/PFPD

In questo studio si vuole presentare l’applicazione di un gascromatografo dotato di tre rivelatori in parallelo per l’analisi di miscele odorigene. Nello studio, è stato utilizzato un gascromatografo Agilent (mod. 8890), dotato di uno spettrometro di massa (Agilent 5977B MSD), un rivelatore a ionizzazione di fiamma (FID, Agilent) e un rivelatore fotometrico a fiamma pulsata (PFPD, OI Analytical mod. 5833). Questo sistema consente la contemporanea acquisizione dei segnali generati dai 3 diversi rivelatori. La ripartizione del campione nei tre rivelatori viene effettuata alla fine della colonna cromatografica, mediante uno splitter a tecnologia di flusso capillare (Agilent Splitter CFT). Utilizzando questo strumento è stato possibile ottenere la rilevazione e la quantificazione specifica di composti organici mediante analisi FID, di composti solforati mediante PFPD e l’identificazione dei composti non noti mediante analisi MS, attraverso il confronto con gli spettri di massa. Sulla base dei risultati preliminari ottenuti e qui presentati, la sua applicazione all’analisi di campioni odorigeni permette la determinazione di classi specifiche di composti, anche qualora presenti in tracce. Questa combinazione consente un significativo risparmio di tempo e di costi nella calibrazione e nell’analisi dei dati cromatografici.This work aims to present the applicability of a gas chromatograph equipped with three detectors for the analysis of odorous mixtures. An Agilent gas chromatograph (mod. 8890), equipped with a mass spectrometer (Agilent 5977B MSD), a Flame Ionization Detector (FID, Agilent) and a Pulsed Flame Photometric Detector (PFPD, OI Analytical mod. 5833) was adopted, obtaining simultaneous acquisition with MS, FID and PFPD detectors. The splitting of the sample into the three detectors was carried out at the end of the chromatographic column, by a capillary flow technology splitter (Agilent Splitter CFT). By using this system, it is, therefore, possible to achieve the specific detection and quantification of organic compounds by FID analysis, sulphur compounds by PFPD and the identification of the compounds by MS analysis, via comparison with mass spectra. Based on the preliminary outcomes obtained, the application of this system in the analysis of odour samples enabled the determination of specific classes, even in traces: by this, the subsequent identification of these compounds during a single chromatographic run is possible. This combination provides significant time and costs savings in the calibration and analysis of chromatographic data

Evaluation of Occupational Exposure Risk for Employees Working in Dynamic Olfactometry: Focus On Non-Carcinogenic Effects Correlated with Exposure to Landfill Emissions

This work aims to evaluate the non-carcinogenic health effects related to landfill odor emissions, therefore focusing on workers involved in dynamic olfactometry. Currently, the most common technique to quantify odor emissions is dynamic olfactometry, a sensorial analysis involving human assessors. During the analysis, assessors are directly exposed, at increasing concentrations, to odor samples, and thus to the hazardous pollutants contained therein. This entails the need to estimate the associated exposure risk to guarantee examiners’ safety. Therefore, this paper evaluates the exposure risk for olfactometric examiners to establish the minimum dilution level to be adopted during the analysis of landfills’ odorous samples to guarantee panelists’ safety. For this purpose, an extensive literature review regarding the pollutants emitted by landfill odor sources was conducted, comparing compounds’ chemical concentrations and threshold limit values (TLVs) to calculate the Hazard Index (HI) and thus establish a minimum dilution value. The data collected indicate that a non-negligible non-carcinogenic risk exists for all landfill emissions considered. However, from the data considered, the minimum dilution factor to be adopted is lower than the typical odor concentration observed for these sources. Therefore, the olfactometric analysis of landfill samples can be generally conducted in safe conditions

Definition of an Emission Factor for VOC Emitted from Italian and European Refineries

Refineries are a major source of atmospheric emissions, which typically include CO, SO2, NOX, particulates, and volatile organic compounds (VOCs). There has been an increasing level of attention toward the emissions of VOCs related to their environmental impact as well as their potential to cause adverse effects on human health and the discomfort associated with their unpleasant odor. In general, an emission factor (EF) represents a model for a first order estimate of emissions, which correlates the quantity of pollutant released into the atmosphere with a so-called “activity index” related to the release of that pollutant. Based on the study of the scientific and technical literature regarding the Italian and European refining scenarios, an attempt was made to verify the existence of a correlation between the size of a refinery and the related total VOC emissions. Once this correlation was evaluated, it was possible to develop an emission factor for VOC emissions considering the plant capacity as the related activity index. After collecting and analyzing data concerning operative capacity and total VOCs emitted from 15 refineries in 2018, the resulting emission factor turned out to be equal to 188 ± 166 g per ton of crude oil processed. This value is in agreement with the range of 50–1000 g/ton reported in the European Best Available Techniques Reference Document for the Refining of Mineral Oil and Gas

Biofiltrazione di effluenti gassosi da un processo di compostaggio: confronto tra differenti mezzi di riempimento

During the last decades, the sector of air pollution control has encountered important technological advances. The biological filtration of the exhaust air coming from various civil and industrial processes has followed the same path. Nevertheless, the selection of the most appropriate filtering media is still challenging in biofltration systems and this choice is a key factor to ensure satisfying removal efficiencies in biofilters. Although organic filtering media are characterized by low costs, broad availability, microbial diversity and a relatively high nutrient content, they suffer from a shorter lifetime than inorganic materials. The present study has the purpose of evaluating the application of different filtering media for their adoption in biofiltration systems, with the aim of reducing the concentration of volatile organic compounds (VOCs), hydrogen sulphide (H2S) and odors. To this purpose, a pilot-scale plant was created to simulate the gaseous effluent generated from a composting process. The pilot-scale plant consists in a biocell with an inner volume of 1 m3, a scrubber for the abatement of ammonia, and three biofiltration columns filled with 1) wood chips, 2) lava rock (50%) and peat (50%) combination and 3) peat only. The biocell was filled with mixed organic waste, composed of the organic fraction of municipal solid waste and green waste. The biocell was fed with an airflow rate of 6 Nm3 h-1 by alternating aeration/no aeration phases. The duration of each phase was set to 30 min. Air samples were taken during four days distributed along the first phase of the composting process, during which the waste undergoes strong oxiditation by the microorganisms. The air samples were analyzed through dynamic olfactometry, photoionization and an electronic nose analyzer, to evaluate the removal efficiency of the biofilters in terms of abatement of the concentrations of odors, VOCs and H2S, respectively. To control the process, key parameters were continuously monitored, such as the temperature within the waste in the biocell, the temperature of the air at the inlet of the biofilters, the pH of the leachate extracted from the biocell and the pressure drop between the entrance and the exit of the three biofilters. The waste temperature was characterized by a constant increase during the first week of the experiment, and achieved a peak temperature of about 63\ub0C. The temperature was permanently > 55\ub0C for ten consecutive days, allowing for proper sterilization of the waste. A decreasing temperature trend was observed starting from the 13th day. The trend of air temperature at the inlet of the biofilters resembles the trend of the waste temperature, although the thermal excursion is lower as well as the temperature values, due to the cooling effect generated by the scrubber and by the transit along the pipelines. For this reason, the inlet temperature varied in the range 27\uf736\ub0C during the experiment. After an acidic phase at the beginning of the experiment, with values comprised between 5 and 6, the pH of the leachate showed an increase until reaching a peak value of 8,81. After the achievement of the peak value, the pH started decreasing and reached values slightly higher than neutrality. The pressure drop, moreover, was < 300 Pa during the entire process for all the media used, with initial higher values for lava rock-peat and peat only columns, probably related to higher water content after the inoculation phase. The analyses on the air samples collected during the experiment showed that lava rock-peat combination seems to be the most interesting solution for the abatement of odors, VOCs and H2S generated from composting processes in biocells, especially at the beginning of the process, when the pollutant load is higher. The biofilter filled with lava rock and peat allowed obtaining average removal efficiencies of 96%, 95% e 77%, respectively for the abatement of odors, VOCs and H2S. Wood chips and peat only showed a weaker performance, respectively with average removal efficiencies of 90%, 88% e 62% and 95%, 89% e 69%. The results obtained in this paper show that lava rock and peat combination can be considered as a promising option for the biofiltration sector

Dynamic Olfactometry and Oil Refinery Odour Samples: Application of a New Method for Occupational Risk Assessment

Refineries are characterized by relevant odour impacts, and the control and monitoring of this pollutant have become increasingly important. Dynamic olfactometry, a sensorial analysis that involves human examiners, is currently the most common technique to obtain odour quantification. However, due to the potential presence of hazardous pollutants, the conduction of occupational risk assessment is necessary to guarantee examiners\u2019 safety. Nevertheless, the occupational risk for olfactometric examiners, specifically correlated with oil refineries emissions, has not been investigated yet. Therefore, this paper applies a new methodology of risk assessment for workers involved in dynamic olfactometry, focusing on odorous refineries emissions. The chemical characterization of refinery emissions was obtained by TD-GC-MS, analysing odorous samples collected at different refinery odour sources. A database of chemical pollutants emitted from a refinery plant was built up, and the minimum dilution values to be adopted during the analysis of refinery odorous samples was calculated. In particular, this evaluation highlighted that, in this scenario, a non-negligible carcinogenic risk may exist for panellists exposed to refineries\u2019 samples, and the carcinogenic risk is sometimes higher than what is acceptable. Therefore, a minimum dilution value between 1.01 and 5, according to the specific sample, must be set to guarantee the examiners\u2019 safety

Polymer Nanoparticles for the Release of Fragrances: How the Physicochemical Properties Influence the Adsorption on Textile and the Delivery of Limonene

The market of cosmetic and personal care products is continuously growing its impact. In particular, the products that are currently driving this growth have a strict connection with fragrances (e.g., perfumes, detergents, body creams, and softeners). Since the fragrances are volatile molecules, very often, they are encapsulated in polymeric nanoparticles (NPs) that mediate their release and hence prolong the fragrance perception. Toward this aim, it is highly desirable to maximize the interaction between the carrier and the substrate, which would avoid the NP desorption following scrubbing and repeated washing. In the case of laundry products, limited NP desorption is also crucial to prevent the accumulation of nanoplastics in the environment, which is nowadays strictly regulated. Therefore, a thorough study highlighting the influence of the different physicochemical properties of the NPs on their adsorption behavior is urgently required. In this work, we synthesized polymer NPs with different sizes, surface charges, glass transition temperatures, and degrees of cross-linking through emulsion free-radical polymerization to investigate how these parameters affect the NP adsorption onto a textile substrate (composition: 90% cotton/10% elastane). This study can provide interesting guidelines in the design of new fragrance delivery systems as well as in the optimization of those already adopted in the market. Finally, we investigated the possibility of loading and mediating the release in air of limonene, one of the most common odorous molecules in the cosmetic field, overcoming its well-known volatility