Laboratory and on-road testing for brake wear particle emissions: a review.

Brake wear emission is a significant contributor to vehicle-related particulate matter, especially in areas with high traffic density and braking frequency. Only recently, non-exhaust emissions from car brake wear have been regulated under Euro 7 regulation, which introduces emission limits for both brake and tires. It also introduces a standard brake particle assessment procedure which includes sampling procedure and measurement techniques defined in the Global Technical Regulation on brakes from light-duty vehicles up to 3.5 t. Over the years, various experimental setups have been tried leading to non-comparable results. The brake wear particle emissions, expressed as emission factors, are mostly estimated as particle mass or particle number and described using different units (e.g., mg/stop brake, mg/km brake; particle number/cm3) making the comparison between studies very difficult. The aim of the present literature review is to present the state-of-the-art of different experimental methods tuned for assessing brake wear emissions, including electric vehicles. The experiments are carried in close, semi-closed, and open systems, and depending on the experimental design, different sampling methods are applied to reduce particle transport loss and guarantee the efficiency of the particle sampling. Driving condition (e.g., speed and applied pressure), formulation of brake materials, and friction temperature have been found to strongly affect the emission characteristics of brake particles, and this needs to be considered when designing study procedures. The findings reported in this review can be beneficial to policy makers and researchers.

Occurrence of per- and polyfluorinated alkyl substances in wastewater treatment plants in Northern Italy.

Wastewater treatment plants are known to be relevant input sources of per- and polyfluoroalkyl substances (PFAS) in the aquatic environment. This study aimed to investigate the occurrence, fate, and seasonal variability of twenty-five PFAS in four municipal wastewater treatment plants (WWTP A, B, C, and D) surrounding the city of Milan (Northern, Italy). Composite 24-h wastewater samples were collected in July and October 2021 and May and February 2022 from influents and effluents of the four WWTPs. PFAS were detected at concentrations ranging between 24.1 and 66.9 µg L-1 for influent and 13.4 and 107 µg L-1 for effluent wastewater samples. Perfluoropentanoic acid was the most abundant (1.91-30.0 µg L-1) in influent samples, whereas perfluorobutane sulfonic acid predominated (0.80-66.1 µg L-1) in effluent samples. In sludge, PFOA was detected in plant A at concentrations in the range of 96.6-165 ng kg-1 dw in primary sludge samples and 98.6-440 ng kg-1 dw in secondary treatment sludge samples. The removal efficiency of total PFAS varied between 6 % and 96 %. However, an increase of PFAS concentrations was observed from influents to effluents for plant D (during July and October), plant A (during October and May), and plant C (during May) indicating that biotransformation of PFAS precursors can occur during biological treatments. This was supported by the observed increase in concentrations of PFOA from primary to secondary treatment sludge samples in plant A. Moreover, the plant operating at shorter hydraulic retention times (plant D) showed lower removal efficiency (<45 %). Seasonal variation of PFAS in influent and effluent appears rather low and more likely due to pulse release instead of seasonal factors.

Particle and gas phase sampling of PCDD/Fs and dl-PCBs by activated carbon fiber and GC/MS analysis.

Polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and polychlorobiphenyls (PCBs) are semi-volatile compounds and can be partitioned in the atmosphere between the gas and particulate phase, due to their physicochemical properties. For this reason, the reference standard methods for air sampling include a quartz fiber filter (QFF) for the particulate and a polyurethane foam (PUF) cartridge for the vapor phase, and it is the classical and most popular sampling method in the air. Despite the presence of the two adsorbing media, this method cannot be used for the study of the gas-particulate distribution, but only for a total quantification. This study presents the results and the performance aim to validate an activated carbon fiber (ACF) filter for the sampling of PCDD/Fs and dioxin-like PCBs (dl-PCBs) using laboratory and field tests. The specificity, precision, and accuracy of the ACF in relation to the QFF + PUF were evaluated through the isotopic dilution technique, the recovery rates, and the standard deviations. Then the ACF performance was assessed on real samples, in a naturally contaminated area, through parallel sampling with the reference method (QFF + PUF). The QA/QC was defined according to the standard methods ISO 16000-13 and -14 and EPA TO4A and 9A. Data confirmed that ACF meets the requirements for the quantification of native POPs compounds in atmospheric and indoor samples. In addition, ACF provided accuracy and precision comparable to those offered by standard reference methods using QFF + PUF, but with significant savings in terms of time and costs.

Extractable denuders for selective sampling of vapour phase organics in the atmosphere.

Extractable denuders were designed to collect trace atmospheric semivolatile organic compounds with high volume (38.30 and 200 L/ min) samplers. Denuders were made of multichannel ceramic support coated with sodium silicate and functionalised with phenyl moieties. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzodioxins and polychlorinated dibenzofurans and chlorobenzenes in ambient air of a sub-urban area of Monterotondo, Italy, were sampled. Samplings were of 24 h, 48 h and 1 week period. Precision was determined using field triplicates and compared to the conventional high volume sampler methods. The fraction of analytes in the particle phase measured with the filter/ PUF system ranged from 0.2 % for naphthalene to 98.5 % for benzo(ghi)perylene; this fraction measured with the denuder ranged from 0.5 % for naphthalene to 99.0 % for benzo(ghi)perylene. A paired t-test indicated that these values were significantly (t = 3.58, P < 0.01) higher for the denuder. Results showed good repeatability (0.4-4.6 %), sampling efficiency (>99 %) and good capacity as variations in experimental efficiency were not observed also for longer (1 week) period sampling. As significant changes in efficiency were observed (0.7-5.6 %), the developed denuder cannot be reused more than once. However, it is possible to regenerate the denuder with a new silanization step. A good linear correlation was found plotting the vapour/particle distribution ratio versus the vapour pressure (R2 ranged between 0.59 and 0.84) and versus the octanol/air partition coefficient (R2 ranged between 0.85 and 0.88) of each selected SVOCs, in good agreement with the theoretical models for partitioning of SVOCs.

Activated Porous Carbon Fiber: New Adsorbent for Sampling and Analysis by Thermal Desorption of Siloxanes in Biogas and Biomethane.

The growing global energy demand requires the continuous development and optimization of the production of alternative energy sources. According to the circular economy approach, waste conversion into biogas and biomethane represent an interesting energy source. The input into the distribution network and energy conversion systems of biomethane requires quality monitoring and the use of cleaning up systems. Therefore, there is a need to constantly invest in the development of sampling and analysis systems that save time, costs, and materials. The purpose of this study was to use activated porous carbon fiber (APCF), an extremely versatile material for sampling and analysis by thermal desorption, to show the advantages it has over the adsorbents traditionally used for siloxane monitoring. Siloxanes are among the contaminating compounds that are mainly present in biogas and biomethane, and if not removed sufficiently, they endanger the quality and use of the gas. These are highly harmful compounds since during combustion, they produce quartz particles that are abrasive to the surfaces of the materials involved in the energy production process. In addition, siloxanes directly hinder the energy properties of biomethane during combustion, due to their radical scavenger properties. In this work, the efficiency of APCF tube was evaluated by comparing it with common multilayer tube thought sampling and analyzing siloxanes in lab scale and in real scale (biogas plant). Thermal desorption analysis coupled with GC-MS for the determination of siloxanes showed that the use of APCF allows to obtain better performance. This allows to deduce that APCF is an innovative material for the establishment of a better sampling and analysis method than the current ones, enabling better results to be achieved in the process of monitoring fuel quality in biomethane production and storage facilities.

"For Asia Market Only": A Green Tattoo Ink between Safety and Regulations.

Due to the increasing tattoo practicing in Eastern countries and general concern on tattoo ink composition and safety, the green tattoo inks Green Concentrate by Eternal, for European and "for Asia Market Only" were analyzed, under the premise that only the former falls under a composition regulation. A separation of the additives from the pigment was carried out by successive extraction in solvents of different polarities, i.e., water, acetone and dichloromethane. The solid residues were analyzed by IR and Raman spectroscopies, the liquid fractions by GC/mass spectrometry. The relative pigment load and element traces were also estimated. We found that the European and the Asian inks are based on the same pigment, PG7, restricted in Europe, though at different loads. They have a similar content of harmful impurities, such as Ni, As, Cd and Sb and both contain siloxanes, including harmful D4. Furthermore, they have different physical-chemical properties, the European ink being more hydrophilic, the Asian more hydrophobic. Additionally, the Asian ink contains harmful additives for the solubilization of hydrophobic matrices and by-products of the phthalocyanine synthesis. Teratogenic phthalates are present as well as chlorinated teratogenic and carcinogenic compounds usually associated to the laser treatment for removal purposes, to a larger extent in the European ink. The composition of the inks does not seem to reflect regulatory restrictions, where issued.

Saccharides as Particulate Matter Tracers of Biomass Burning: A Review.

The adverse effects of atmospheric particulate matter (PM) on health and ecosystems, as well as on meteorology and climate change, are well known to the scientific community. It is therefore undeniable that a good understanding of the sources of PM is crucial for effective control of emissions and to protect public health. One of the major contributions to atmospheric PM is biomass burning, a practice used both in agriculture and home heating, which can be traced and identified by analyzing sugars emitted from the combustion of cellulose and hemicellulose that make up biomass. In this review comparing almost 200 selected articles, we highlight the most recent studies that broaden such category of tracers, covering research publications on residential wood combustions, open-fire or combustion chamber burnings and ambient PM in different regions of Asia, America and Europe. The purpose of the present work is to collect data in the literature that indicate a direct correspondence between biomass burning and saccharides emitted into the atmosphere with regard to distinguishing common sugars attributed to biomass burning from those that have co-causes of issue. In this paper, we provide a list of 24 compounds, including those most commonly recognized as biomass burning tracers (i.e., levoglucosan, mannosan and galactosan), from which it emerges that monosaccharide anhydrides, sugar alcohols and primary sugars have been widely reported as organic tracers for biomass combustion, although it has also been shown that emissions of these compounds depend not only on combustion characteristics and equipment but also on fuel type, combustion quality and weather conditions. Although it appears that it is currently not possible to define a single compound as a universal indicator of biomass combustion, this review provides a valuable tool for the collection of information in the literature and identifies analytes that can lead to the determination of patterns for the distribution between PM generated by biomass combustion.

Dataset of PAHs determined in home-made honey samples collected in Central Italy by means of DLLME-GC-MS and cluster analysis for studying the source apportionment.

This paper would like to show all the data related to an intensive field campaign focused on the characterization of the Polyaromatic Hydrocarbons (PAHs) composition profile in almost 60 honey samples collected in Central Italy. The analytical data here reported are the base for a study aimed to identify the pollution sources in a region. 22 PAHs were analyzed by means of ultrasound-vortex-assisted dispersive liquid-liquid micro-extraction (DLLME) procedure followed by a triple quadrupole gas chromatograph/mass spectrometer (GC-MS). A chemometrics approach has been carried out for evaluating all the data: in particular, principal component analysis and cluster analysis has been used both for the identification of the main natural/anthropogenic pollutants affecting a site and for evaluating the air quality.

Comparative treatments of a green tattoo ink with Ruby, Nd:YAG nano- and picosecond lasers in normal and array mode.

The tattoos removal has become an issue upon spread of the tattooing practice worldwide and hindsight regrets. Lasers are typically used for the purpose, though some colours such as green are considered "recalcitrant" to the treatment. In the current investigation, we aim at determining the efficacy of removal of a green ink water dispersion, using 5 laser treatments: Nd:YAG nano- and picosecond lasers in normal and array mode and Ruby nanosecond laser, keeping the total irradiated energy constant. The UV-Vis spectroscopy of the treated samples indicate that Nd:YAG picosecond laser is most effective, and the Ruby nanosecond laser is the least efficient. Fragment compounds generated from the pigment and siloxanes are common to all treatments, whereas hydrocarbon emerge by a larger amount upon Nd:YAG nanosecond treatment. Fibres are formed upon picosecond treatments and when operating in array mode, and lamellae are achieved by Ruby nanosecond laser treatment. Residual particles suspensions are very heterogeneous upon nanosecond treatments.

PAHs presence and source apportionment in honey samples: Fingerprint identification of rural and urban contamination by means of chemometric approach.

The quality of honey is assessed through the determination of some commodity parameters: a certain importance is to be attributed to the absence of contaminating residues, in particular of Polycyclic Aromatic Hydrocarbons (PAHs). This paper deeply investigates the presence of 22 PAHs in 57 honey samples collected in Central Italy and identifies the possible source apportionment and fingerprint identification by DLLME-GC-MS analysis and a chemometric approach. Cluster Analysis and Principal Component Analysis have allowed to identify the main PAHs responsible of the contamination, benzo[a]anthracene and phenanthrene, characteristics pollutants of areas constantly exposed. The entire database has been compared to similar ones present in literature, particularly data from Serbia and Belgrado samples. The PCA applied to overall the data confirms the combustion to be the main contamination source in Italian samples whereas highlights the importance of the role of naphthalene, added during beekeeping practices in the other data-set.

Evaluation of VOCs Emitted from Biomass Combustion in a Small CHP Plant: Difference between Dry and Wet Poplar Woodchips.

The combustion of biomass is a process that is increasingly used for the generation of heat and energy through different types of wood and agricultural waste. The emissions generated by the combustion of biomass include different kinds of macro- and micropollutants whose formation and concentration varies according to the physical and chemical characteristics of the biomass, the combustion conditions, the plants, and the operational parameters of the process. The aim of this work is to evaluate the effect of biomass moisture content on the formation of volatile organic compounds (VOCs) during the combustion process. Wet and dry poplar chips, with a moisture content of 43.30% and 15.00%, respectively, were used in a cogeneration plant based on a mobile grate furnace. Stack's emissions were sampled through adsorbent tubes and subsequently analyzed by thermal desorption coupled with the GC/MS. The data obtained showed that, depending on the moisture content of the starting matrix, which inevitably influences the quality of combustion, there is significant variation in the production of VOCs.

The vehicle braking systems as main source of inhalable airborne magnetite particles in trafficked areas.

Magnetite (Fe3O4) nano-particles (MNPs) have been found in human tissues and causally linked to serious illnesses. The possible negative role of MNPs has been not still fully ascertained even though MNPs might cause health effects due to their magnetic property, redox activity and surface charge. The origin of MNPs in human tissues still remains to be unambiguously identified since biological processes, natural phenomena and anthropogenic production have been proposed. According to this latter increasingly convincing hypothesis, anthropogenic MNPs might enter mainly in the human body via inhalation, penetrate deeply into the lungs and in the alveoli and also migrate into the blood circulation and gather in the extrapulmonary organs and central nervous system. In order to identify the releasing source of the potentially inhalable MNPs, we pioneered an innovative approach to rapidly investigate elemental profile and morphology of a large number of airborne micron and sub-micron-sized Fe-bearing particles (FePs). The study was performed by collecting a large amount of micron and sub-micron sized inhalable airborne FePs in trafficked and densely frequented areas of Rome (Italy). Then, we have investigated individually the elemental profile and morphology of the collected particles by means of high-spatial resolution scanning electron microscopy, energy dispersive spectroscopy and an automated software purposely developed for the metal-bearing particles analysis. On the basis of specific elemental tracing features, the investigation reveals that almost the total amount of the airborne FePs is released by the vehicle braking systems mainly in the form of magnetite. Furthermore, we point out that our approach might be more generally used to identify the releasing sources of different inorganic airborne particles and to contribute to establish more accurately the impact of specific natural or anthropogenic particles on the environment and human health.

Evaluation of Extraction Procedure of PCDD/Fs, PCBs and Chlorobenzenes from Activated Carbon Fibers (ACFs).

Active carbon-based sorbents are well known and are used in analytical chemistry. Activated carbon fibers (ACFs) are mainly used as abatement systems in industrial emission pollution control. The objective of this study was to extend the use of ACFs in analytical chemistry for the analysis of polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), dioxin-like polychlorobiphenyls (PCBs), and chlorobenzenes (CBs). For this purpose, the extraction efficiency was evaluated based on the QA/QC criteria defined by EPA/ISO reference methods on 13C-standards recovery rates. The procedures tested were ultrasonic assisted extraction (UAE), Soxhlet extraction (SE), accelerated solvent extraction (ASE), and microwave-assisted extraction (MAE). Each experiment was performed in triplicate to ensure the repeatability of the results, and a second extraction assessed the complete extraction. The comparison of the results of each set of experiments with the minimum requirements of the reference methods for each class of compounds led to SE being chosen as the best technique. SE with toluene resulted in a reduction of time and costs and with respect to the other investigated techniques. The present work demonstrated that ACFs can be used in environmental fields means of both prevention and control (exploiting the adsorbent characteristics) and for analytical purposes (exploiting the desorption) for the described chlorinated classes of pollutants.

Laser vs. thermal treatments of green pigment PG36: coincidence and toxicity of processes.

Comparative laser and thermal treatments were carried out on PG36, a green phthalocyanine-based pigment, permitted in European countries where legislation on tattoo composition was issued. Prior to the treatments, PG36 was characterized by SEM imaging, EDX, IR and UV-Vis spectroscopies, revealing an excess of Si and C and O as compared to the pure halogenated Cu-phthalocyanine. Laser treatments were carried out with a Nd:YAG device applied to H2O and propan-2-ol dispersions. Pyrolysis and calcinations were carried out in air or under N2 flow. The outcome of the different procedures was analyzed by UV-Vis spectroscopy, GC-mass spectrometry, X-ray diffraction of the solid residues, SEM microscopy and dynamic light scattering. The comparative analysis indicated the production of different fragment compounds depending on the treatment, (pyrolysis or laser), and, to some extent, to the solvent of the dispersion, with pyrolysis generating a larger number of hazardous compounds. Hydrocarbons and cyclic siloxanes present as additives in PG36 were stable or degraded depending on the treatment. The morphology of the products is also treatment-dependent with nanoparticles < 20 nm and fibers being produced upon laser treatments only. Based on the experimental findings, the equivalence of laser and thermal treatments is evaluated.

Evaluation of the concentration of the toxic 2,3,6,7-tetrachlorobiphenylene in air after an electrical material fire.

It is known that when fires or explosions involve electrical systems, along with PCDDs and PCDFs, polychlorinated biphenylenes (PCBPs) are also produced. These chlorinated tricyclic aromatic pollutants were noticed in fire rubbles and after the World Trade Center destruction. However, the analytical difficulties in developing an efficient method have limited the knowledge of their environmental distribution. In light of the equipotency of 2,3,6,7-TeCBP and 2,3,7,8-TeCDD, PCBPs call for more accurate investigations. In this paper, for the first time, the level and persistence of 2,3,6,7-TeCBP have been investigated in air samples (both indoor and outdoor) after a fire broke out in an industrial building. GC-MS/MS analysis revealed that 2,3,6,7-TeCBP concentrations after the fire (3046 fg/m3 at the "epicentre") were remarkably higher than that of the 2,3,7,8-TeCDD. Moreover, the monitoring for over two years has demonstrated the persistent nature of this compound. 2,3,6,7-TeCBP was also analyzed in two different ambient air scenario: industrial and periurban areas and in both cases its concentrations were no matter of concern, confirming the correlation of 2,3,6,7-TeCBP with fire episodes. Collectively, 2,3,6,7-TeCBP, because of its toxicity, concentration and persistence, is a crucial compound in the evaluation of the health effects correlated with fires of electrical systems.

Validation studies on activated carbon fiber passive sampler for PCDD/Fs and PCBs in water.

The toxicity of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) is well known, and for this reason studying and monitoring these chemicals is fundamental. Activated carbon fibers (ACFs) are made of an adsorbent material widely used in the industrial field for the removal of micropollutants. The first step in this work was to perform a physico-chemical characterization of the adsorbent, focused on the analytical use of it. In particular, its specific surface area was defined around 2500 m2/g consisting in a homogeneous microporosity distribution and the characterization of ACF surface functional groups pointed out a balance between basic and acidic group. The validity of using the ACF as solid phase extraction and as passive sampler for PCDD/Fs and PCBs in water, has been evaluated by the percentage recovery (R %) of 13C12-labeled standards of PCDD/Fs and PCBs added in a known volume of water. The results were compared to the R% of Liquid-Liquid Extraction which showed a better reproducibility of the results and the proposed method satisfy completely the requirements of US EPA reference methods.

Environmental impact of co-combustion of polyethylene wastes in a rice husks fueled plant: Evaluation of organic micropollutants and PM emissions.

Co-combustion of biomass and plastic waste has emerged as one of the most promising approach at the plastic waste management challenge. This strategy is particularly attractive since it can simultaneously solve the increasing energy demand and reduce the plastic wastes volume. However, since the combustion of both plastic wastes and natural materials is a potential source of organic micropollutants, such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and of polycyclic aromatic hydrocarbons (PAHs), beside particulate matter, the environmental sustainability of the waste to energy (WtE) co-combustion strategy has to be assessed. To this end, the emissions of dioxin like (dl)-PCBs, PCDD/Fs and PAHs from a 4-MW thermal power plant fueled with rice husk, partially replaced by end-of-life polyethylene (PE) industrial waste (up to 15% of the thermal power of the plant), were investigated. GC-MS/MS analyses have demonstrated that the co-combustion of PE waste and rice husk presents a profile of environmental sustainability. The concentrations of dl-PCBs, PCDD/Fs and PAHs were extremely low and they have remained almost unaffected by introducing PE in feed. In particular, emissions of PCCD/Fs and dl-PCBs in flue gas were in the range 0.6-1.0 and 0.2-0.6 pg TEQ/Nm3, respectively, while PAHs concentrations ranged from 410 to 825 ng/Nm3. Furthermore, the emission factors of these organic pollutants were found to be lower with PE increasing rate while particulate matter emissions were not affected by co-combustions. Collectively, the investigation has demonstrated that the noils of the industrial PE, due to the low content in halides and metals, can be used as auxiliary fuel and energetically recycled through co-combustion with rice husk. This case of study represents an effective application of the WtE strategy and a concrete approach to mitigate the threat of plastic pollution.

Volatilization and oxidative artifacts of PM bound PAHs collected at low volume sampling (1): Laboratory and field evaluation.

Laboratory and field studies were carried out to assess the effects of oxidative degradation and volatilization on PM10 bound polycyclic aromatic hydrocarbons (PAHs), collected at low volume condition according to the EU sampling reference method EN12341:2014 (flow rate 2.3 m3 h-1), on 47 mm quartz filters. For the laboratory experiments, pairs of twin samples were collected in field and, after treatments favoring decomposition or/and volatilization of PAHs on one sample, the PAH amount was compared with that of the corresponding untreated sample. Ozone exposure caused a general PAHs decay with more marked effects on benzo [a]pyrene, perylene and benz [a]anthracene; these compounds showed, similarly to benzo [ghi]perylene, correlations between ozone dose and losses. Treatments with zero air exhibited losses due to volatilization even for 5-ring PAHs up to benzo [a]pyrene, whereas a linear dependence was observed between filter PAH load and losses for benzo [a]anthracene, chrysene and benzofluoranthenes. Concentrations on samples collected simultaneously over 48, 24, 12 and 6 h were compared. Results confirmed a lack of temporal auto-consistency in the PAHs sampling methodology here adopted. In particular higher atmospheric PAH concentrations were ascertained on samples constituted by cumulative filters exposed over shorter sampling times. When 24-h and 2 × 12-h samples were compared, comparable losses were evaluated in the hot and cold seasons. This finding shows that, although in summer meteorology conditions favor sampling artifacts, the effectiveness of these phenomena continue in the winter, probably due to the larger amount of PAH available on the sampling filter (total PAHs ∼ 10 vs 0.5 ng m-3).

Volatilization and oxidative artifacts of PM bound PAHs at low volume sampling (2): Evaluation and comparison of mitigation strategies effects.

The artifacts induced by oxidative degradation and volatilization were assessed with regards to determination of particulate atmospheric PAHs collected at low volume conditions (2.3 m3 h-1) according to the EU Reference Method EN 12341:2014. In order to evaluate the oxidative degradation, PAH measures carried out through collecting airborne particulate with and without ozone denuders were examined. Simultaneously, the influence of volatilization was investigated by comparing concentrations of PAHs in particulate samples collected over 24-h and 12-h using conventional instruments. Summer and winter/spring campaigns were carried out in order to assess the influence of environmental contour on the artifact processes. Oxidative degradation led to a general decrease of PAH concentrations in both periods; in particular, the highest losses were observed for benzo[a]pyrene and perylene reaching, in average, ca. 20%. In the summer, the effect of volatilization exceeded that of oxidative degradation for light PAHs up to benzo[e]pyrene. In the winter/spring time, the influence of both artifact typologies could be mitigated by splitting the normal 24-h collection interval starting at midnight into two 12-h intervals. A mitigation of the losses could even be obtained by fixing the start time sampling fixed at noon or in the first hours of the day. Finally, the feasibility of collecting PAHs through prolonged sampling (>1 month) at the flow rate of 1.1 L min-1 was preliminarily investigated. Results indicated that this approach is unsuitable for minimizing the oxidative artifacts.

Analysis of polychlorodibenzo-p-dioxins and polychlorodibenzofurans in stationary source emissions in GC-MS/MS using hydrogen as the carrier gas.

The European and American methods for the determination of polychlorodibenzo-p-dioxins and polychlorodibenzofurans in stationary source emissions require a high-resolution mass spectrometer detector. At the same time, all of the 17 toxic 2,3,7,8-chlorine-substituted isomers have to be separated by an appropriate chromatographic method. The resulting analysis has long runtimes and sometimes a double-column run is needed, which results in a huge waste of time, money and manual labor. To obtain a fast and cost-effective but still reliable analytical system, a single-column gas chromatography with hydrogen as carrier gas and tandem mass spectrometry detection is proposed. The use of hydrogen as the carrier gas is a good choice to shorten runtimes and improve the chromatographic resolution, while tandem mass spectrometry is a well-known alternative for this analysis. All the chromatographic and mass spectrometric parameters fill the requirements of the reference methods with a 35% reduction of runtimes. The accuracy is tested with three fly ash samples of a proficiency interlaboratory test. A good correlation between the results is obtained (R2  = 0.992, slope = 0.9675), and no coelutions are noted. The system robustness is tested during 5 years of constant use and the maximal relative standard deviation of the relative response factor is 18.8%.