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Measurements of aerosol particles are vital for enforcing EU air quality regulations to protect human health, and for research on climate change effects. Although metrics such as PM10 and PM2.5 are currently in use, the level of uncertainty of aerosol metrics is too high and the traceability is insufficient. The project AEROMET, which has been started in June 2017 aims at implementing improvements in a) the uncertainty of particle mass, size and number concentration measurements and b) in the characterization of regulated components in airborne particles. Both are demanded by existing networks within the EU as well as by global atmospheric research.
On-site measurement campaigns
One of the objects is the application of mobile x-ray spectroscopy techniques combined with aerosol sampling techniques for quantifying particle compositions in the field for real time analysis. During two in-field measurement campaigns in Budapest, Hungary in May 2018 and Cassino, Italy in September 2018 the size dependent mass concentrations of specific elements in ambient aerosols were monitored under dynamic conditions.
Typically, airborne particles are sampled on filter substrates. During this project new sampling methods with specially designed substrate holders for an in-situ TXRF analysis were developed and applied for the first time. This approach allows a direct time and size resolved analysis without laborious digestion steps and a reduced risk of contamination.
Aerosol particles were sampled in a 13-stage DLPI impactor - size range from 0,03 µm to 10 µm - which was equipped with special adapters for acrylic discs of 30 mm diameter, serving as substrates. TXRF analysis was performed on site with the transportable spectrometer S2 PICOFOX (Bruker Nano GmbH) equipped with a Mo X-ray tube and a 30 mm² Silicon Drift Detector (SDD). Excitation conditions were 50 kV, 600 µA, measurement time 1000 s. Quantification was based on internal standardization using 50 ng of Y in solution, which was pipetted into the centre of the discs prior to sampling.
At moderate air pollution levels, i.e. PM10 ~ 20 µg/m³, sampling times of less than 2 hours were enough for the detection of elements in different particle size bins. The in-situ approach and the high sensitivity of TXRF enables the observation of rather quick changes in the quantity and distribution of elements in an ambient aerosol on the day of sampling, as the below example from the Cassino field campaign on 11 Sept. 2018 shows: The analysis of the morning and afternoon sampling shifts reveals the occurrence of the elements Fe, Ca and Si in different size bins as well as their significant temporal change in respective mass concentrations over the day while the distributions of several other elements in the aerosol remain unchanged.
The validation of these results by backup measurements is planned.
Previous studies have shown that desktop 3D printers (Fused Filament Fabrication) emit high numbers of particulate matter, mainly as ultrafine particles (UFP, particle diameter less than 100 nm). However, the chemical composition of emitted particles has been less extensively investigated. In this study, we therefore focused on the chemical composition of particles emitted from 3D printing. The measurements were conducted in a 1 m³ emission test chamber. Emitted particles were sampled by a 13-stage low-pressure cascade impactor onto aluminum foils and then analyzed by TD-GC/MS to identify their organic compounds. Nine commercial filaments made from basic polymers such as Acrylonitrile Butadiene Styrene (ABS), Acrylonitrile Styrene Acrylate (ASA), Polycarbonate (PC), Poly(methyl methacrylate) (PMMA), Nylon, High Performance Polystyrene (HIPS) and a copper-filled Polylactide (PLA) were investigated. The results show that the organic components of the particles are primarily plastic additives such as plasticizer, antioxidant agents, lubricants, UV-absorbers and UV-stabilizers from the filaments.
In industrialised countries more than 80% of the time is spent indoors. Products, such as building materials and furniture, emit volatile organic compounds (VOCs), which are therefore ubiquitous in indoor air. VOC in combination may, under certain environmental and occupational conditions, result in reported sensory irritation and health complaints. Emission concentrations can become further elevated in new or refurbished buildings where the rate of air exchange with fresh ambient air may be limited due to improved energy saving aspects. A healthy indoor environment can be achieved by controlling the sources and by eliminating or limiting the release of harmful substances into the air. One way is to use (building) materials proved to be low emitting. Meanwhile, a worldwide network of professional commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability of test results must be ensured. A laboratory’s proficiency can be proven by internal and external validation measures that both include the application of suitable emission reference materials (ERM). For the emission test chamber procedure according to EN 16516, no artificial ERM is commercially available. The EU-funded EMPIR project MetrIAQ aims to fill this gap by developing new and improved ERMs. The goal is to obtain a material with a reproducible and temporally constant compound release (less than 10% variability over 14 days). Different approaches, such as the impregnation of porous materials, are being tested. The generation as well as results of the most promising materials will be presented.
Test chamber measurements are an important tool to improve indoor air quality and occupational safety. Test chamber measurements are possible for a wide range of materials, products and technologies. Determination of concerning contaminants is important to ensure good indoor air quality. The detection of concerning contaminants depends on the approriate sampling and analysis.
EN 16516 sets the test method and requirements for the determination of emissions of Volatile Organic Compounds (VOCs) from building materials into indoor air. To address the quality control requirements for the class of semi-VOCs (SVOCs), VSL developed gaseous reference materials. A novel home-made dynamic gas mixture preparation system, operating according to ISO 6145-4 (continuous injection method), has recently been developed and validated. Thanks to the stable temperature control up to 100 oC, the system can prevent condensation of the SVOCs in air at indoor air concentration levels. The in-situ obtained SVOC gas standards can be sampled in sorbent tubes to obtain SVOC transfer standards. A study was performed to determine the optimal sorbent material and storage conditions. This study will be presented together with the results of the 2018 Round Robin test for emission test chamber measurements organised by BAM. Using the novel system, VSL prepared transfer standards with known amounts of VOCs and SVOCs for participants to evaluate their analytical performance.
Axial passive sampling of VOCs with Tenax® TA and thermal desorption GC-MS analysis is an accepted alternative to active sampling in occupational hygiene. In theory, the uptake into the passive sampler is only dependent on the diffusion coefficient of the analyte in air and the geometry of the sampler (ideal adsorption). For characterization, the uptake rate (UR) is used defined as the ratio of the mass adsorbed and the product of ambient concentration and exposure time. Various reported effective uptake rates (UR,eff) differ to an increasing degree from ideal values (UR,id) with increasing exposure doses (denominator of the given definition of UR), (Tolnai, 2001). In national and international standards, uptake rates are essentially sorted by the applicable exposure time, while detailed information about the corresponding concentration range is lacking. Moreover, especially for long exposure periods as applied in indoor air monitoring, the number of itemized substances is limited. Therefore it is the aim of this contribution to review and expand uptake rate data by comparison of literature and own laboratory values of assured quality. Passive samplers were exposed to nine single compound atmospheres of known concentrations for seven days. Concentrations were checked twice a day via active sampling.The determined uptake rates are considered accurate in terms of RSD and comparability to literature values and can be recommended for exposure times of seven days at 50 – 100 μg m-3 (approximately 100 – 300 ppm min). Seven-day uptake rates in ISO16017-2 and ASTM D6196 are not generally suited for this purpose, as has been exemplarily shown for benzene. Thus, it is crucial for optimization of the method to produce more reliable uptake rate data, including specific information about applicable exposure times and concentrations, which will be promoted in the course of this ongoing study.
Since 1997, the Committee for Health-related Evaluation of Building Products (AgBB) has been developing the basis for building regulations for protection against indoor health risks that may arise when building products are used. In 2009, the AgBB decided to include relevant VVOCs in the assessment procedure. The ISO 16000-6 (2021) states that the use of the thermal desorption gas chromatography technique is appropriate for VVOCs, if adaptations are considered. However, a suitable method for the trustworthy quantification of VVOC emissions from building products and in the indoor air is still missing.
This webinar will present the results of a research project on the development of a procedure for VVOC analysis:
• identification of the gaps towards standardization
• investigations on gas standards and the suitability of chromatography columns
• investigations on sorbent combinations and water management
• validation of the method and screening of VVOC emissions from building products.
The ISO 16000-6 standard describes a method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air by sorbent-based active sampling, thermal desorption and gas chromatography coupled with mass spectrometry (GC/MS). It also gives directions to adapt this methodology to very volatile organic compounds (VVOCs). Indeed, toxicologically based guideline values are being implemented for these compounds and it becomes necessary to measure them. But a comprehensive and robust measurement method is lacking. Investigations on the use of gaseous standards, the suitability of chromatography columns, the suitable sorbent combinations and the water removal are required. The talk will highlight the points that need to be explored towards the standardisation of a suitable procedure and provide appropriate preliminary results.
Today glass is broadly used in modern architecture. For applications indoor it is possible to produce decor glass by using enamel colors and glass painting techniques without any problems. However, this is more limited for applications outdoor. Humidity and environmental pollution attack the surface of the coating and damage it strongly. There are only few colors on the market which are resistant towards acids and bases until now. Additionally, most of those colors are opaque. In order to extend the color palette, chemically resistant colored glasses are being developed which are transparent, relatively low melting and intensively toned even in thin coat thickness. To achieve such ambitious aim, many parameters have to match which act in complex manner. Metal oxides were used to color the glasses. A lead-free glass composition was developed to avoid an exposition of heavy metals to the environment. The glasses were characterized, in particular in terms of their thermal properties, their crystallization and corrosion behavior as well as their chemical and environmental durability. Different practical applications will be shown.
Fluorometric sensing is a versatile approach for trace analysis outside of the laboratory, requiring suitable sensor materials and their integration into sensing devices. The versatility of fluorophores as probes, especially in terms of the possibility to tailor their optical as well as their recognition properties by synthetic modifications in a wide range, renders them as superior active component for the preparation of optical sensing devices. Recent works at BAM in this field include, for example, the detection of nerve gas agents, illustrating impressively the aforementioned benefits of fluorophores in optical sensing applications.
In the interdisciplinary project presented here, we target hazardous gases such as ammonia, benzene, and hydrogen sulfide, next to others, which pose a major threat to human health and environmental safety and for which the availability of a sensitive and reliable detection method is highly desirable. The dyes presented follow a “turn-on” fluorescence schematic, which allows for the selective and sensitive detection of the respective gaseous analyte. The immobilization of the probe in polymeric matrices is then the next step toward the fabrication of a prototype device for molecular sensing. Further steps in the project include the assembly of instruments for test-atmosphere generation, the referencing of the sensor system, development and implementation of an optical setup, and the testing of the prototype device under laboratory conditions and in the field.
In this presentation, we give an overview over the recent developments on this topic in our groups. Highlights are hydrogen sulfide sensitive, BODIPY based transition metal complexes, which allow for a sensitive as well as selective detection of the toxic gas. In addition, we present a novel class of highly substituted BODIPY derivatives – pocket-BODIPYs – which are of a synthetically high versatility and can readily be modified to create pockets in the periphery of the molecule of defined geometries. This is illustrated on the successful encapsulation of benzene by a pocket-BODIPY derivative, confirmed by X-ray crystallographic analysis as well as by further spectroscopic and analytical methods.
Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments and required by EU air quality regulations. Typically, airborne particles are sampled on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). Within the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling was combined with on-site total reflection X-ray fluorescence (TXRF) spectroscopy. The study aimed at a proof of principles for this new mobile and on-size tool for the quantification of aerosol element compositions and element mass concentrations within short time intervals of less than 12 h. In a field campaign the method’s technical feasibility could be demonstrated. The TXRF results were traced back to a stationary, reference-free XRS setup in the laboratory of the German national metrology institute PTB at the BESSY II electron storage ring in Berlin, Germany. Simultaneous PM10-filter sampling, followed by standardized lab-based analysis, allowed for a comparison of the field campaign data of both methods. As Fig. 1 shows, the correspondence between PM10 filter sampling and ICP-MS, and on the other hand, cascade impactor sampling and TXRF is quite encouraging. However, for some of the analysed elements, e.g. V and Pb, the observed deviations are higher than expected and this highlights the fact, that spectral deconvolution strategies for TXRF on cascade impactor samples still need some improvement.
This work was supported by the EMPIR programme, co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme, through grant agreements 16ENV07 AEROMET and 19ENV08 AEROMET II
The chemical emissions from products are tested by means of emission test chambers under defined conditions (climate, loading, air change rate). The standard method for the determination of volatile organic compounds (VOC) is the sampling onto Tenax-tubes followed by thermal desorption (TDS) and gas chromatography-mass spectrometry (GC-MS) analysis. The EU-LCI list includes some very volatile organic compounds (VVOC) and some VOC for which there are limitations when using the standard method. For VVOC additional sampling is required using stronger absorbers like Carbotrap or multi-bed adsorption tubes. The analysis of VVOC also requires a different GC oven program and a different column for the separation. For the determination of formaldehyde and other low boiling aldehydes (e.g. acetaldehyde, acetone, propanal, propenal) DNPH-cartridges are used which are extracted with acetonitrile followed by liquid chromatography (HPLC-UV) analysis. The derivatisation of propenal and other unsaturated aldehydes (e.g. 2-butenal) with DNPH might lead to lower findings due to incomplete derivatization and forming of by-products. For a better quantification of acetic acid the use of ion chromatography (IC) is recommended because the analysis of acetic acid with the standard method (TDS) leads to lower findings due to break through during sampling. The use of ion chromatography for the analysis of organic acids requires a third sampling technique. The acids are adsorbed onto silica-gel and extracted with water.
Environmental sustainability and –stability of Materials concerning the Migration of pollutants
(2018)
MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long-term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics.
Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance.
As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known.
The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer-based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS.
Environmental sustainability and –stability of materials concerning the migration of pollutants
(2019)
In addition to previously reported results on the accelerated weathering of polystyrene samples (PS) containing 1 wt. % hexabromocyclododecane (HBCD), we present the first results of our investigations of polypropylene samples (PP) containing 0.1 wt. % BDE-209. All studied polymer samples were exposed to a defined weathering schedule in a climate chamber in accordance to regulation EN ISO 4892-3:2006. For the determination of BDE-209 in the collected raining water the samples were prepared in accordance to a validated protocol. Before the analyses each sample was spiked with isotopically labeled BDE-209. Subsequently the samples were extracted with isooctane. The obtained extracts were concentrated, and the resulting solutions were analyzed by GC/MS. Additionally, the total bromine content was monitored for the weathered and untreated samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and X-ray fluorescence analysis (XRF) as a non-destructive and rapid method. In general, the resulting data from the accelerated weathering will be compared to those from the natural weathering experiments. Here, the surfaces of the test pieces were analyzed by LA-ICP-MS and XRF as well. Moreover, soil bed tests were conducted in a well characterized model soil. This soil (boulder-clay, sand with 12 % loam, particle size in total 0.2-4 mm) is filled in a free-draining basin inside of an air-conditioned cellar. In this manner, TOC, water capacity and humidity are recorded parameters. To induce a leaching process from the samples by the raining water, the target water content is calculated to 8%. The actual humidity is measured by a tensiometer, assuring the duration of the raining period. A defined humidity is a fundamental parameter for a biological activity in the soil. The test polymers were placed up to the half in the soil. Microbial activity of the soil is monitored by a reference polymer (polyurethane) and should induce the release of HBCD and BDE-209 out of the test materials. These released analytes will be captured by passive samplers (silicone tubes) placed in a distinct distance to the polymer samples in the soil. The soil bed experiments are complementary to the weathering experiments due to the biological activity in the soil.
Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m3 emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r2 of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r2: 0.145), thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 μg/m3), especially when more conservative exposure scenarios were considered.
This study shows that formaldehyde Emission results in micro-scale emission chambers are comparable with results in bigger chambers both for particle boards and wooden toys. On the contrary, the WKI flask method was leading to more variable results depending on sample geometry. Thus, microchambers could be used for reliable routine market surveillance. An exposure assessment led to noticeable formaldehyde indoor air concentration values, pointing out the need for an effective Surveillance of such samples.
The presentation gives general information about the European Standard EN 16516 “Construction products – Assessment of release of dangerous substances – Determination of emissions into indoor air”. This test standard was developed based on the mandate M/366 of the European commission and is a horizontal reference method for the determination of volatile organic compounds (VOC) from different classes of construction (building) products. Specific test conditions are to be selected by the product TCs (technical committees) in a way that a product is tested under its intended condition of use.
The test is based on the use of emission test chambers which are operated at constant air change rate and climate (23°C, 50 % r.h.) over 28 days. The standard defines the conditions and requirements for the measurement including loading factor, air change rate, sampling, analysis and calculation of emission rates of the substances. A 30 m³ reference room is described which is used to calculate air concentrations from the determined emission rates.
The standard EN 16516 enables the evaluation of construction products regarding their emissions into indoor air under defined and comparable conditions. The evaluation includes the determination of identified target compounds, non-identified target compounds, volatile carcinogenic compounds and the sum values TVOC, TSVOC and R.
Each year, an immense amount of plastic debris enters marine ecosystems, much of which ends up in the Great Pacific Garbage Patch (GPGP). The plastic fragments are home to a diverse community of microorganisms, and while researchers have gained a better understanding of these marine plastic biofilms, we lack insights into the physiology and genomic potential of the bacteria that colonize them. Examining the lifestyle of plastic colonizers from the GPGP is particularly intriguing, as the high concentration of plastics in this accumulation zone might allow for a microbial adaptation to this unique man-made habitat. A range of pigmentation was observed in 67 isolated strains obtained directly from plastic pieces sampled from the GPGP surface water. Sequence comparison between the cultivated bacterial strains and the 16S rRNA gene amplicon dataset confirmed that most of the cultivates could also be captured through DNA-only methods. Whole genome analysis of four taxonomically diverse representatives revealed multiple carotenoid pathways, including those to produce less common glycosylated carotenoids, like sarcinaxanthin glucoside. Further, we identified a potentially new Rhodobacteraceae species containing a photosynthetic gene cluster (PGC). Absorption analysis confirmed the actual production of the carotenoids and bacteriochlorophyll a. Floating plastics represent a habitat with strong UV-light exposure, making the protection with antioxidant carotenoids as well as the ability to use light as an energy source highly beneficial traits for plastic colonizers. Our findings indicate, that the production of pigments is a common adaption mechanism for plastic-associated bacteria, and that plastic biofilms present a so far overlooked source of rare carotenoids and light-harvesting mechanisms.