Management of ground tire rubber waste by incorporation into polyurethane-based composite foams.

Rapid economic growth implicated the developing multiple industry sectors, including the automotive branch, increasing waste generation since recycling and utilization methods have not been established simultaneously. A very severe threat is the generation of enormous amounts of post-consumer tires considered burdensome waste, e.g., due to the substantial emissions of volatile organic compounds (VOCs). Therefore, it is essential to develop novel, environmentally friendly methods for their utilization, which would hinder their environmental impacts. One of the most promising approaches is shredding, resulting in the generation of ground tire rubber (GTR), which can be introduced into polymeric materials as filler. The presented work is related to the thermomechanical treatment of GTR in a twin-screw extruder with zinc borate, whose incorporation is aimed to enhance shear forces within the extruder barrel. Modified GTR was introduced into flexible polyurethane (PU) foams, and the impact of modification parameters on the cellular structure, static and dynamic mechanical performance, thermal stability, as well as thermal insulation, and acoustic properties was investigated. Emissions of VOCs from applied fillers and prepared composites were monitored and evaluated. Depending on the treatment parameters, beneficial changes in foams' cellular structure were noted, which enhanced their thermal insulation performance, mechanical strength, and thermal stability. It was proven that the proposed method of GTR thermomechanical treatment assisted by zinc borate particles might benefit the performance of flexible PU foamed composites and hinder VOC emissions, which could broaden the application range of GTR and provide novel ways for its efficient utilization.

Chemical Composition of Atmospheric Air in Nemoral Scots Pine Forests and Submountainous Beech Forests: The Potential Region for the Introduction of Forest Therapy.

Studies show that forests are one of the main recreational destinations. This can be explained by their beneficial effects on the health of their visitors, which can be attributed to compounds from the terpene group. The aim of this research was to determine the chemical composition of air in the interiors of Nemoral Scots pine forests and submountainous beech forests, with the determination of compounds of the terpene group. Samples of organic compounds present in the air were collected with the use of Tenax TA sorbent tubes. The process of separation, identification, and determination of the extracted organic compounds was carried out with the use of the gas chromatography technique integrated with a flame ionization detector. Additional identification of the extracted compounds was carried out with the use of GC coupled with mass spectrometry. The most abundant group of compounds was the aliphatic hydrocarbons, both saturated (linear and branched) and unsaturated (terpenes). Carbonyl compounds were also found in the collected samples, but they constituted no more than 10% of all compounds present on the chromatograms. The concentrations of terpenes and terpenoids in the forest atmosphere varied from 10 to 74 µg·m-3, representing on average 33% of the total volatile organic compounds.

Understanding the early-stage release of volatile organic compounds from rapeseed oil during deep-frying of tubers by targeted and omics-inspired approaches using PTR-MS and gas chromatography.

During deep-frying, a plethora of volatile products is emitted with the fumes. These compounds could act as oil quality indicators and change the indoor air composition leading to health risks for occupants. The presented experiments focus on deep-frying of different tubers in rapeseed oil at different frying temperatures. Here, two scenarios for real-time monitoring of volatile organic compounds (VOCs) using proton transfer reaction mass spectrometry (PTR-MS) were proposed. The first, targeted, involved the application of gas chromatography with a flame ionization detector (GC-FID). The second, omics-inspired, involved the use of solid-phase microextraction (SPME) along with gas chromatography-mass spectrometry (GC-MS) and molecular networking algorithm as a complementary tool to the PTR-MS analysis. In a targeted approach, it was shown that the emission profile of pentanal and hexanal depends on the frying temperature and as the temperature increases, a sudden release of these compounds can be observed in the first minutes of frying. Meanwhile, using an omics-inspired protocol enables finding the relation between 1,4-heptadienal and 2-heptanone, octanal and limonene emissions. Using both approaches it was possible to record real-time changes in emission profiles of various oils' degradation products. It was also observed that the emission profiles of VOCs are strictly related to the frying temperature and the type of fried tuber.

Emission Profiles of Volatiles during 3D Printing with ABS, ASA, Nylon, and PETG Polymer Filaments.

In this short communication we characterize the emission of volatile organic compounds (VOCs) from fused filament fabrication (FFF) 3D printing using four polymer materials, namely polyethylene terephthalate glycol-modified (PETG), acrylonitrile styrene acrylate (ASA), Nylon, and acrylonitrile butadiene styrene (ABS). Detailed emission profiles are obtained during thermal degradation of the polymers as a function of temperature and also in real-time during 3D printing. Direct quantitative measurement was performed using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Qualitative determination of the volatiles emitted from the printed elements at various temperatures was accomplished using gas chromatography-mass spectrometry (GC-MS). The emission rates of VOCs differ significantly between the different polymer filaments, with the emission from Nylon and PETG more than an order of magnitude lower than that of ABS.

Ground Tire Rubber Modified by Elastomers via Low-Temperature Extrusion Process: Physico-Mechanical Properties and Volatile Organic Emission Assessment.

In this paper, low-temperature extrusion of ground tire rubber was performed as a pro-ecological waste tires recycling method. During this process, ground tire rubber was modified with constant content of dicumyl peroxide and a variable amount of elastomer (in the range: 2.5-15 phr). During the studies, three types of elastomers were used: styrene-butadiene rubber, styrene-ethylene/butylene-styrene grafted with maleic anhydride and ethylene-octene copolymer. Energy consumption measurements, curing characteristics, physico-mechanical properties and volatile organic compounds emitted from modified reclaimed GTR were determined. The VOCs emission profile was investigated using a passive sampling technique, miniature emission chambers system and static headspace analysis and subsequently quantitative or qualitative analysis by gas chromatography. The VOCs analysis showed that in the studied conditions the most emitted volatile compounds are dicumyl peroxide decomposition by-products, such as: α-methylstyrene, acetophenone, α-cumyl alcohol, methyl cumyl ether, while the detection level of benzothiazole (devulcanization "marker") was very low. Moreover, it was found that the mechanical properties of the obtained materials significantly improved with a higher content of styrene-butadiene rubber and styrene-ethylene/butylene-styrene grafted with maleic anhydride while the opposite trend was observed for ethylene-octene copolymer content.

Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples.

In the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application of molecularly imprinted polymers (MIPs) is gaining greater popularity. It is mainly related to their physicochemical properties, sorption capacity and selectivity, thermo-mechanical resistance, as well as a wide range of polymerization techniques allowing to obtain the desired type of sorption materials, adequate to a specific type of pesticide. This paper targets to summarize the most popular and innovative strategies since 2010, associated with the MIPs synthesis and analytical procedures for pesticides determination in environmental and food samples. Application of multi-criteria decision analysis (MCDA) allows for visualization of the most beneficial analytical procedures in case of changing the priority of each step of analysis (MIPs synthesis, sample preparation process-pesticides extraction, chromatographic analysis) bearing in mind metrological and environmental issues.

Insights into the Thermo-Mechanical Treatment of Brewers' Spent Grain as a Potential Filler for Polymer Composites.

This paper investigated the impact of twin-screw extrusion parameters on the properties of brewers' spent grain. The chemical structure, antioxidant activity, particle size, and color properties, as well as the emission of volatile organic compounds during extrusion, were investigated. The main compounds detected in the air during modifications were terpenes and terpenoids, such as α-pinene, camphene, 3-carene, limonene, or terpinene. They could be considered as a potential threat to human health and the environment. Changes in the chemical structure, antioxidant activity, and color of materials after modification indicated the Maillard reactions during extrusion, which resulted in the generation of melanoidins, especially at higher temperatures. This should be considered an exciting feature of this treatment method because modified brewers' spent grain may improve the thermooxidative stability of polymer materials. Moreover, the impact of the brewers' spent grain particle size on color and browning index used to determine the melanoidins content was investigated. The presented results show that proper adjustment of extrusion parameters enables the preparation of brewers' spent grain with the desired appearance and chemical properties, which could maximize the efficiency of the modification process.

Emissions and toxic units of solvent, monomer and additive residues released to gaseous phase from latex balloons.

This study describes the VOCs emissions from commercially available latex balloons. Nine compounds are determined to be emitted from 13 types of balloons of different colors and imprints in 30 and 60 °C. The average values of total volatile organic compounds (TVOCs) emitted from studied samples ranged from 0.054 up to 7.18 µg g-1 and from 0.27 up to 36.11 µg g-1 for 30 °C and 60 °C, respectively. The dataset is treated with principal component analysis (PCA) and multiple curve resolution (MCR) to characterize its internal patterns. Here two groups on compounds are recognized - the first one related to balloon material, the second one being emissions of compounds previously adsorbed on balloon material. The toxicity assessment of MCR modeled balloons' emissions was performed by toxic unit (TU) approach. The obtained TUs were summed to give toxicity emission assessment. The incorporation of TUs allows to identify the balloons with the most toxic emissions- imprinted ones in 60 °C. The compounds of the highest TUs are hexanal and benzene. FTIR analysis shows that all balloons are made of the same polymeric material - isoprene, so all differences in emissions are related to different additives like pigments, imprints or these responsible for opaqueness. Analyzing the obtained research results it was noticed that latex balloons might be considered as an important source of emission of aliphatic and monoaromatic hydrocarbons to the gaseous phase.

POM/EVA Blends with Future Utility in Fused Deposition Modeling.

Polyoxymethylene (POM) is one of the most popular thermoplastic polymers used in the industry. Therefore, the interest in its potential applications in rapid prototyping is understandable. Nevertheless, its low dimensional stability causes the warping of 3D prints, limiting its applications. This research aimed to evaluate the effects of POM modification with ethylene-vinyl acetate (EVA) (2.5, 5.0, and 7.5 wt.%) on its processing (by melt flow index), structure (by X-ray microcomputed tomography), and properties (by static tensile tests, surface resistance, contact angle measurements, differential scanning calorimetry, and thermogravimetric analysis), as well as very rarely analyzed emissions of volatile organic compounds (VOCs) (by headspace analysis). Performed modifications decreased stiffness and strength of the material, simultaneously enhancing its ductility, which simultaneously increased the toughness even by more than 50% for 7.5 wt.% EVA loading. Such an effect was related to an improved linear flow rate resulting in a lack of defects inside the samples. The decrease of the melting temperature and the slight increase of thermal stability after the addition of EVA broadened the processing window for 3D printing. The 3D printing trials on two different printers showed that the addition of EVA copolymer increased the possibility of a successful print without defects, giving space for further development.

The preparation and evaluation of core-shell magnetic dummy-template molecularly imprinted polymers for preliminary recognition of the low-mass polybrominated diphenyl ethers from aqueous solutions.

The design, preparation process, binding abilities, morphological characteristic and prospective field of application of dummy-template magnetic molecularly imprinted polymer (DMMIP) for preliminary recognition of the selected low-mass polybrominated diphenyl ethers (PBDE-47 and PBDE-99) from aquatic environment were investigated. The surface of iron oxide (Fe3O4) nanopowder (50-100 nm particles size) was modified with tetraethoxysilane and next prepared Fe3O4@SiO2 particles were dispersed in anhydrous toluene functionalized by (3-aminopropyl)triethoxysilane. Finally, MIPs' thin film layer on the surface of Fe3O4@SiO2@NH2 was formed in acetonitrile as a solvent solution, using ethylene glycol dimethacrylate as the cross-linker, building monomer, 1,1'-Azobis(cyclohexanecarbonitrile) as the radical initiator, methacrylic acid as a functional monomer and 4,4'-Dihydroxydiphenyl ether as the dummy template molecule as a structural analogue of low-mass PBDEs. To characterize the chemical structure of prepared DMMIPs, the Fourier transform infrared spectroscopy analysis was performed. The specific surface area of the developed sorbent was estimated using Brauner-Emmet-Teller nitrogen adsorption/desorption analysis. To assess the average pore sizes, pore diameters and pore volumes of the prepared sorbent, the Barret-Joyner-Halenda technique was applied. The average values of imprinting factor for PBDE-47 and PBDE-99 were 11.3 ±â€¯1.6 and 13.7 ±â€¯1.2, respectively. The average value of recovery of PBDE-47 and PBDE-99 for developed DMMIPs from modelling water: methanol solution were 85.4 ±â€¯6.7% and 86.4 ±â€¯9.4%, respectively. In a case of spiked distilled water, tap water as well as local river water the calculated recovery values ranged from 65%% up to 82% and from 33% up to 76% for PBDE-47 and PBDE-99, respectively. Following the preliminary research on selected water samples, the proposed combination of imprinting technology and core-shell materials with magnetic properties might be considered as a promising sorption tool used for targeted recognition of low-mass PBDEs in aquatic solutions.

Emissions of selected monoaromatic hydrocarbons as a factor affecting the removal of single-use polymer barbecue and kitchen utensils from everyday use.

The main focus of this study is the emission of monoaromatic hydrocarbons because these are the preliminary factors of potential solvent and monomer residues present in single-use plastic barbecue and kitchen utensils comprising polystyrene, polypropylene, natural cellulose, and biodegradable polymers intended for use with hot meal or beverages. Herein, the emissions of monoaromatic hydrocarbons (styrene, benzene, toluene, ethylbenzene, and xylene compounds and the total volatile organic compounds (TVOC)) from nine types of disposable plastic utensils are reported. Seventy two samples of single-use plastic utensils were conditioned at 40 and 80 °C using a stationary emission microchamber system. The average TVOC released from the studied polystyrene, polypropylene, and natural or biodegradable utensils were (2.3 ±â€¯1.3), (1.01 ±â€¯0.15), and (0.48 ±â€¯0.37) µg g-1, respectively, at 40 °C and (11.1 ±â€¯1.2), (46.1 ±â€¯9.5), and (5.5 ±â€¯1.1) µg g-1, respectively, at 80 °C. Significant emissions of styrene (ranged from 3.5 up to 15.3 × 103 ng∙g-1), toluene (from 2.8 up to 0.53 × 103 ng∙g-1), and ethylbenzene (from 3.7 up to 5.7 × 103 ng∙g-1) from the studied samples were observed, especially at 80 °C. Thus, elevated temperatures increase the potential emission of solvent and monomer residues from plastics and could affect the quality of consumed meals or beverages, such as taste. Additionally, to determine the possible interactions between the measured chemical compounds in the plastic utensils, the Pearson's correlation coefficients were calculated.

Exploratory analysis and ranking of analytical procedures for short-chain chlorinated paraffins determination in environmental solid samples.

Short-chain chlorinated paraffins are ones of the most recent chemical compounds that have been classified as persistent organic pollutants. They have various applications and are emitted to the environment. Despite the fact, that the content levels of these compounds in the environmental compartments should be monitored, there is still a lack of well-defined and validated analytical procedures, proposed or suggested by the national or international environmental protection agencies. Finding an appropriate analytical procedure (sensitive and green at the same time) from many available ones is very often a difficult task. Therefore it can be supported with multicriteria decision analysis. The dataset consisting of 22 procedures was described by 7 criteria, mainly referring to procedures greenness. The data treatment with cluster analysis and principal component analysis revealed the internal structure of the dataset. Moreover, both statistical tools allowed for reduction of dataset criteria to three. This was used for applying ternary plot to show the multicriteria decision analysis results within all possible weights. With the aid of chemometric and multicriteria decision analysis tools it was easy to assess the set of analytical procedure. Depending on the applied weights to assessment criteria different analytical procedures are the most appropriate (winners).

Analytical procedures for short chain chlorinated paraffins determination - How to make them greener?

The aim of the following paper was to gather current scientific information about the analytical protocols dedicated to measuring the content level of short-chain chlorinated paraffins (SCCPs) in various types of environmental samples. Moreover, the data about the basic validation parameters of applied procedures for SCCPs determination are listed. The main issue which is highlighted in the paper is the possibility of the application of green analytical chemistry (GAC) principals in the SCCPs measuring process to reduce the environmental impact of the applied methodology. Analytical methods dedicated to SCCPs determination contain a significant number of steps and require advanced analytical equipment during the quantitative and qualitative analysis. In addition, there is a substantial issue associated with the reliability of the obtained results, especially in the case of the quantification of individual SCCPs in the studied samples. Due to this fact, the paper attempts to discuss the various stages of the analytical procedure, in which appropriate changes in the formula or equipment solutions might be introduced to ensure a better quality of the analytical results, as well as to meet the requirements of the philosophy of green analytical chemistry. The most important case which concerns this subject is finding an optimal consensus between the economic and logistic aspects and the quality and "greenness" of the analytical procedure employed in SCCPs determination process.

Structure and performance properties of environmentally-friendly biocomposites based on poly(ɛ-caprolactone) modified with copper slag and shale drill cuttings wastes.

The potential application of two types of industrial wastes, drill cuttings (DC) and copper slag (CS), as silica-rich modifiers of poly(ɛ-caprolactone) (PCL) was investigated. Chemical structure and physical properties of DC and CS fillers were characterized using X-ray diffractometer, X-ray fluorescence spectroscopy, particle size and density measurements. PCL/DC and PCL/CS composites with a variable content of filler (5 to 50 parts by weight) were prepared by melt compounding in an internal mixer. It was observed that lower particle size of DC filler enhanced processing of biocomposites comparing to CS filler. Smaller particles of DC filler and thus the higher specific surface area, enabled better encapsulation of filler by polymer chains, hence lower porosity and consequently higher tensile properties comparing to PCL/CS biocomposites. It was noticed, that the impact of waste filler characteristics on tensile properties became negligible at higher loadings. This indicates weak interactions between waste filler and PCL matrix, due to aggregation of filler particles and formulation of voids in phase boundary. This phenomenon was confirmed by scanning electron microscopy, headspace analysis and thermogravimetric analysis. Microbial tests revealed that prepared biocomposites show no toxic effect towards analyzed bacterial strains, therefore could be considered as environmentally-friendly.

Preparation and characterization of dummy-template molecularly imprinted polymers as potential sorbents for the recognition of selected polybrominated diphenyl ethers.

The main aim of this work was to conduct the preliminary/basic research concerning the preparation process of a new dummy molecularly imprinted polymer (DMIP) materials. Developed DMIPs were proposed as a sorption material in solid-phase extraction (SPE) technique for recognition of selected low mass polybrominated diphenyl ethers (PBDEs) - PBDE-47 and PBDE-99. Four new DMIPs were synthesized employing bulky polymerization technique by application of structural analogue of low mass PBDEs - 4,4'-Dihydroxydiphenyl ether, as a dummy template. The DMIPs and corresponding non-imprinted polymers were prepared using different functional monomers: methacrylic acid; methyl methacrylate and different porogen agents: acetonitrile and tetrahydrofuran. The polymerization reaction was thermally initiated with 1,1'-azobis (cyclohexanecarbonitryle). Ethylene glycol dimethacrylate was applied as a cross-linker. To optimize geometries and to calculate energies of the respective template-monomer complexes, the computational molecular modeling method was employed. The particles morphology and physicochemical characteristics of developed DMIPs and their equivalent NIPs were performed using nitrogen sorption porosimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy. The sorption capacities of prepared DMIPs and corresponding NIPs were studied using standard binding test. The adsorption capability studies give a possibility to assess the imprinting factor (IF) values, which were in the range from 1.1 to 4.0, depending on the DMIP type. The recovery values of PBDE-47 and PBDE-99 from prepared organic solutions were in the range from 43 to 92%, depending on the studied DMIP. Performed basic laboratory studies give a possibility to select the optimal DMIP material which might be applied in the environmental samples preparation process as a potential sorbent for the recognition of low mass PBDEs.

Assessment of ecotoxicity and total volatile organic compound (TVOC) emissions from food and children's toy products.

The development of new methods for identifying a broad spectrum of analytes, as well as highly selective tools to provide the most accurate information regarding the processes and relationships in the world, has been an area of interest for researchers for many years. The information obtained with these tools provides valuable data to complement existing knowledge but, above all, to identify and determine previously unknown hazards. Recently, attention has been paid to the migration of xenobiotics from the surfaces of various everyday objects and the resulting impacts on human health. Since children are among those most vulnerable to health consequences, one of the main subjects of interest is the migration of low-molecular-weight compounds from toys and products intended for children. This migration has become a stimulus for research aimed at determining the degree of release of compounds from popular commercially available chocolate/toy sets. One of main objectives of this research was to determine the impact of time on the ecotoxicity (with Vibrio fischeri bioluminescent bacteria) of extracts of products intended for children and to assess the correlation with total volatile organic compound emissions using basic chemometric methods. The studies on endocrine potential (with XenoScreen YES/YAS) of the extracts and showed that compounds released from the studied objects (including packaging foils, plastic capsules storing toys, most of toys studied and all chocolate samples) exhibit mostly androgenic antagonistic behavior while using artificial saliva as extraction medium increased the impact observed. The impact of time in most cases was positive one and increased with prolonging extraction time. The small-scale stationary environmental test chambers - µ-CTE™ 250 system was employed to perform the studies aimed at determining the profile of total volatile organic compounds (TVOCs) emissions. Due to this it was possible to state that objects from which the greatest amounts of contaminants are released are plastic containers (with emission rate falling down from 3273 to 2280 ng/g of material at 6 h of conditioning in elevated temperature).

Indoor air quality of everyday use spaces dedicated to specific purposes-a review.

According to literature data, some of the main factors which significantly affect the quality of the indoor environment in residential households or apartments are human activities such as cooking, smoking, cleaning, and indoor exercising. The paper presents a literature overview related to air quality in everyday use spaces dedicated to specific purposes which are integral parts of residential buildings, such as kitchens, basements, and individual garages. Some aspects of air quality in large-scale car parks, as a specific type of indoor environment, are also discussed. All those areas are characterized by relatively short time use. On the other hand, high and very high concentration levels of xenobiotics can be observed, resulting in higher exposure risk. The main compounds or group of chemical compounds are presented and discussed. The main factors influencing the type and amount of chemical pollutants present in the air of such areas are indicated.

New Polymeric Materials for Solid Phase Extraction.

Solid phase extraction (SPE) is a popular sample preparation technique, which can be applied directly in gas-solid phase and liquid-solid phase, or indirectly to solid samples by using, e.g., thermodesorption with subsequent chromatographic analysis. Although SPE can be described as a physical extraction process involving a liquid phase and a solid phase, the increased use of packed sorbent formats seems to have led to a bias toward packed sorbent SPE devices. Without any doubt, the heart of the SPE technique is the sorbent material as it has a direct influence on the selectivity, sorptive capacity, and the format or the configuration of the resultant SPE device. There will always be a need for new sorbent materials, and therefore, it is imperative to focus research efforts on versatile sorbent fabrication techniques that could address current and anticipated challenges. Various polymeric materials have been developed and implemented in everyday life. They are also extensively used in analytical chemistry. This review provides an updated summary of the most important features of polymeric sorptive materials used at the stage of preparing samples for analysis. The application of each new polymeric sorbent material is discussed in detail. Moreover, the comparison between these materials is done.

Indoor air quality in public utility environments-a review.

Indoor air quality has been the object of interest for scientists and specialists from the fields of science such as chemistry, medicine and ventilation system design. This results from a considerable number of potential factors, which may influence the quality of the broadly understood indoor air in a negative way. Poor quality of indoor air in various types of public utility buildings may significantly affect an increase in the incidence of various types of civilisation diseases. This paper presents information about a broad spectrum of chemical compounds that were identified and determined in the indoor environment of various types of public utility rooms such as churches, museums, libraries, temples and hospitals. An analysis of literature data allowed for identification of the most important transport paths of chemical compounds that significantly influence the quality of the indoor environment and thus the comfort of living and the health of persons staying in it.

Concentrations of monoaromatic hydrocarbons in the air of the underground car park and individual garages attached to residential buildings.

The paper describes the characteristics of a two-level underground car park and three individual garages attached to residential buildings, differing by the resident utilization habits, located in North Poland (Tri-City agglomeration area). The strategy of collecting the analyte samples from air in mentioned enclosed areas, concerning the determination of benzene, toluene, ethylbenzene, o-xylene and p,m-xylenes (BTEX) concentrations was performed using passive sampling technique - Radiello® diffusive passive samplers with graphitised charcoal cartridge as a sorption medium. The stage of liberation and final determination of collected analytes was conducted with the use of thermal desorption-gas chromatography-flame ionisation detector (TD-GC-FID) system. As a result of the performed measurements in two-level underground car park, it was observed that the time-weighted average concentrations of BTEX in air were as follows: Level-1 - benzene - 5.2±1.1µg/m3, toluene - 12.3±2.4µg/m3, ethylbenzene 2.85±0.80µg/m3, o-xylene - 4.6±1.4µg/m3, p, m-xylenes - 8.8±2,4µg/m3; Level-2 - benzene - 5.2±1.1µg/m3, toluene - 12.9±3.6µg/m3, ethylbenzene - 2.73±0.79µg/m3, o-xylene - 4.2±1.1µg/m3, p, m-xylenes - 8.5±2.3µg/m3. As for residential garages, the time-weighted average concentrations of BTEX in air were in the following ranges: from 5.9 to 53µg/m3 (benzene), from 7.1 to 195µg/m3 (toluene), from 3.0 to 39µg/m3 (ethylbenzene), from 5.6 to 44µg/m3 (o-xylene) and from 6.3 to 99µg/m3 (p,m-xylenes). Also, BTEX concentration ratios such as: tol/benz ratio and (m, p)-xyl/et.benz coefficient, were calculated based on the obtained results to assess the "freshness" of air mass and the influence exerted by vehicle movement on the concentration of BTEX in air in studied enclosed areas.