Bryan Hellack

German Environment Agency

In the original publication [...]

As an important source of sub-micrometer particles, atmospheric new particle formation (NPF) has been observed in various environments. However, most studies provide little more than snapshots of the NPF process due to their underlying observations being limited in space and time. To obtain statistically relevant evidence on NPF across various envi...

Atmospheric volatile organic compounds (VOCs) constitute a wide range of species, acting as precursors to ozone and aerosol formation. Atmospheric chemistry and transport models (CTMs) are crucial to understanding the emissions, distribution, and impacts of VOCs. Given the uncertainties in VOC emissions, lack of evaluation studies, and recent chang...

Atmospheric volatile organic compounds (VOC) constitute a wide range of species, acting as precursors to ozone and aerosol formation. Atmospheric chemistry and transport models (CTMs) are crucial to understanding the emissions, distribution, and impacts of VOCs. Given the uncertainties in VOC emissions, lack of evaluation studies, and recent change...

As an important source of sub-micrometer particles, atmospheric new particle formation (NPF) has been observed in various environments. However, most studies provide little more than snapshots of the NPF process due to their underlying observations being limited in space and time. To obtain statistically relevant evidence on NPF across various envi...

The hazard posed to human health by inhaled amorphous silica nanomaterials (aSiO2 NM) remains uncertain. Herein, we assessed the cyto- and genotoxicity of aSiO2 NM variants covering different sizes (7, 15, and 40 nm) and surface modifications (unmodified, phosphonate-, amino- and trimethylsilyl-modified) on rat alveolar epithelial (RLE-6TN) cells....

The CO, CO2 and CH4 mole fractions have been measured since 2002 at the Environmental Research Station Schneefernerhaus, which is located approximately 300 m below the summit of Zugspitze in the German Alps. Although the station is located remotely at an altitude of 2650 m a.s.l., local pollution events by snow blowers and snow groomers can be dete...

The CO, CO2, and CH4 mole fractions have been measured since 2002 at the Environmental Research Station Schneefernerhaus (ZSF), which is located approximately 300 m below the summit of Mount Zugspitze. Although the station is located remotely at an altitude of 2666 m a.s.l., local pollution events by snow blowers and snow groomers can be detected i...

Ultrafine particles (UFP) are defined as airborne particles having diameters of less than 100 nm (0,1 μm). They are formed in almost any kind of natural and technical combustion processes, and are emitted either as particles directly, or are formed through nucleation and condensation in the plume of these processes. Furthermore, UFP are formed in t...

The immense diversity and constant development of nanomaterials (NMs) increase the need for facilitated risk assessment, which requires knowledge of the modes of action (MoAs) of NMs. This necessitates a comprehensive data basis, which can be obtained using omics. Furthermore, the establishment of suitable in vitro test systems is essential to foll...

Several reports on amorphous silica nanomaterial (aSiO2 NM) toxicity have been questioning their safety. Herein, we investigated the in vivo pulmonary toxicity of four variants of aSiO2 NM: SiO2_15_Unmod, SiO2_15_Amino, SiO2_7 and SiO2_40. We focused on alterations in lung DNA and protein integrity, and gene expression following single intratrachea...

With the rising interest in the effects of orally ingested engineered nanomaterials (ENMs), much effort is undertaken to develop and advance intestinal in vitro models. The cytotoxic, proinflammatory, and DNA damaging properties of polyvinylpyrrolidone‐capped silver (Ag‐PVP) and titanium dioxide (TiO2, P25) ENM in four in vitro models of increasing...

A total of 10 years of hourly aerosol and gas data at four rural German stations have been combined with hourly back trajectories to the stations and inventories of the European Emissions Database for Global Atmospheric Research (EDGAR), yielding pollution maps over Germany of PM10, particle number concentrations, and equivalent black carbon (eBC)....

TiO2 nanomaterials are among the most commonly produced and used engineered nanomaterials (NMs) in the world. There is controversy regarding their ability to induce inflammation-mediated lung injuries following inhalation exposure. Activation of the NACHT, LRR and PYD domains-containing protein 3 (NALP3) inflammasome and subsequent release of the c...

Background The immense variety and constant development of nanomaterials (NMs) raise the demand for a facilitated risk assessment, for which knowledge on NMs mode of actions (MoAs) is required. For this purpose, a comprehensive data basis is of paramountcy that can be obtained using omics. Furthermore, the establishment of suitable in vitro test sy...

Background: The immense variety and constant development of nanomaterials (NMs) raise the demand for a facilitated risk assessment, for which knowledge on NMs mode of actions (MoAs) is required. For this purpose, a comprehensive data basis is of paramountcy that can be obtained using omics. Furthermore, the establishment of suitable in vitro test s...

Nanomaterials (NMs) can be manufactured in plenty of variants differing in their physicochemical properties. Functional assays can be highly useful to cope with the enormous variability by supporting prioritization and categorization. Oxidative potential (OP) seems to be in particular important in this context and different assays are available. Ho...

Nanomaterials (NMs) can be produced in plenty of variants posing several challenges for NM hazard and risk assessment. Metabolomic profiling of NM-treated cells and tissues allows for insights into underlying Mode-of-Action (MoA) and offers several advantages in this context. It supports the description of Adverse Outcome Pathways (AOPs) and, there...

Ten years of hourly aerosol and gas data at four rural German stations have been combined with hourly back trajectories to the stations and inventories of the European EDGAR emission database yielding immission maps over Germany of PM10, particle number concentrations, and equivalent black carbon (eBC). The maps reflect aerosol emissions modified w...

In respect to the high number of released nanomaterials and their highly variable properties, novel grouping approaches are required based on the effects of nanomaterials. Proper grouping calls for a combination of an experimental setup with a higher number of structurally similar nanomaterials and for employing integrated omics approaches to ident...

Background: Nanomaterials (NMs) can be fine-tuned in their properties resulting in a high number of variants, each requiring a thorough safety assessment. Grouping and categorization approaches that would reduce the amount of testing are in principle existing for NMs but are still mostly conceptual. One drawback is the limited mechanistic understa...

Grouping can replace animal testing to demonstrate the safe use of nanomaterials, but previously case studies were missing.

Objectives: Particulate air pollution is linked to adverse cardiovascular effects, including arterial stiffness. The aim of the study was to investigate the effect of short-term exposure to indoor fine and ultrafine particles on augmentation index (AIx), augmentation pressure (AP), and pulse wave velocity (PWV), early signs of vascular damage. Me...

Nanomaterials (NMs) can be produced in numerous different variants of the same chemical substance. An in-depth safety assessment for each variant by generating test data will simply not be feasible. Thus, NM grouping approaches that would significantly reduce the time and amount of testing for novel NMs are urgently needed. However, identifying str...

Engineered nanomaterials (ENM) have a widespread presence in human life and are components of many products and applications. This warrants an easy and fast evaluation of potential environmental risks. However, so far this is hampered by the multitude of different nanomaterials on the markets in addition to the many variations in form, size and sur...

Biopersistent pro-inflammatory fibers are suspected human carcinogens. Cytotoxicity and transcription of pro- and anti-inflammatory mediators of different fibers were investigated in functional relationship to chemotaxis in vitro as a model for fiber-induced inflammation of the lung. We challenged NR8383 rat macrophages with multi-walled carbon nan...

Zusammenfassung In den vergangenen Jahren sind zunehmend kos-tengünstige Feinstaubsensoren auf den Markt gekommen, die typi-scherweise deutlich weniger als 50 € kosten. All diese Sensoren basieren auf der optischen Detektion von Partikeln durch Streulichtmessung. Aufgrund der erheblich geringeren Kosten ist zu erwarten, dass diese Sensoren nicht di...

Background: Although epidemiologic studies have shown associations between particle mass and daily mortality, evidence on other particle metrics is weak. Objectives: We investigated associations of size-specific particle number concentration (PNC) and lung-deposited particle surface area concentration (PSC) with cause-specific daily mortality in...

The oxidative potential (OP) of engineered nanomaterials (NM) is considered as promising metric for nanosafety research and risk assessment. Here, we present findings on the analysis of the oxidative potential of three different silver NM by means of a complementary electron paramagnetic resonance (EPR) spectroscopy-based approach, i.e., using the...

While land use regression models (LUR) are commonly used, e.g. for the prediction of spatially variable air pollutant mass concentrations, they are scarcely used for predicting the oxidative potential (OP), a suggested unifying predictor of health effects. Therefore a LUR model was developed to examine if long-term OP of fine particulate exposure c...

Manufactured nanomaterials (NMs) are being developed in many different variations such as size, shape, crystalline structure and surface modifications. To avoid the testing of each single nanomaterial variation, grouping and read-across strategies for nanomaterials similar to classical chemicals are discussed. Grouping and read-across aim to identi...

Materials that contain fine or nanoscale particles are already produced in large quantities and are currently re-assessed. At the same time, there is ongoing development of new and innovative nanoparticles (NPs). Risk assessment strategies for NPs are of key importance, as their impact on ecosystems and humans is still not fully understood. However...

Objectives: Particulate air pollution is linked to adverse cardiovascular effects. The aim of the study was to investigate the effect of short-term exposure to indoor particles on blood pressure (BP). Methods: We analyzed the association of particle emissions from indoor sources (candle burning, toasting bread, frying sausages) with BP changes i...

Despite the gaps in our knowledge on the toxicity of silver nanoparticles (AgNPs), the application of these materials is fast expanding, from medicine, to food as well as the use in consumer products. It has been reported that prolonged exposure might make cells more resistant to AgNPs. This prompted us to investigate if AgNPs may give rise to a ho...

While EU air quality policy has generally been quite successful and has resulted in significant reductions in concentrations of various harmful air pollutants, exceedances of limit values for airborne particulate matter (PM) are still encountered in many areas across the entire EU territory. Moreover, it has been suggested, that not only the partic...

Background Oxidative stress, a commonly used paradigm to explain nanoparticle (NP)-induced toxicity, results from an imbalance between reactive oxygen species (ROS) generation and detoxification. As one consequence, protein carbonyl levels may become enhanced. Thus, the qualitative and quantitative description of protein carbonylation may be used t...

Background: Oxidative stress, a commonly used paradigm to explain nanoparticle (NP)-induced toxicity, results from an imbalance between reactive oxygen species (ROS) generation and detoxification. As one consequence, protein carbonyl levels may become enhanced. Thus, the qualitative and quantitative description of protein carbonylation may be used...

Oxidative potential (OP) of ambient particulate matter (PM) has been suggested as a health-relevant exposure metric. In order to use OP for exposure assessment, information is needed about how well central site OP measurements and modeled average OP at the home address reflect temporal and spatial variation of personal OP. We collected 96-hour pers...

Nanomaterials are commonly used in everyday life products and during their life cycle they can be released into the environment. Soils and sediments are estimated as significant sinks for those nanomaterials. To investigate and assess the behaviour of nanomaterials in soils and sediments standardized test methods are needed. In this study the appli...

At an urban background station in Mülheim-Styrum, North Rhine Westphalia, Germany, a set of 75 PM10 samples was collected over a one year period, followed by analyses for mass, chemical composition and hydroxyl radical (OH) formation potency. Additionally, the origin of air masses for the sampling days was calculated by 48-h backward trajectories,...

Ambient particulate matter (PM10) was sampled alongside a motorway in North-Rhine Westphalia, Germany, during a one-year period. In sum, 120 PM10 samples on quartz fibre filters, 60 samples at each side of the motorway, were taken during clear cross-wind direction situations, i.e. upwind (local background situation) and downwind (traffic influenced...

Oxidative potential (OP) of particulate matter (PM) has been proposed as a more health relevant metric than PM mass. However, little is known about the temporal and spatial variation of OP, which is crucial if OP were to be used as an exposure metric in epidemiological studies. We studied OP on routinely collected PM2.5 samples (every 6th day) from...

The authors wish to make the following amendments to their paper published in International Journal of Environmental Research and Public Health [1][...]

Introduction We evaluated associations between three a-cellular measures of the oxidative potential (OP) of particulate matter (PM) and acute health effects. Methods We exposed 31 volunteers for 5 h to ambient air pollution at five locations: an underground train station, two traffic sites, a farm and an urban background site. Each volunteer visite...

Particulate air pollution is linked to impaired respiratory health. We analyzed particle emissions from common indoor sources (candles burning (CB), toasting bread (TB), frying sausages (FS)) and lung function in 55 healthy volunteers (mean age 33.0 years) in a randomized cross-over controlled exposure study. Lung-deposited particle surface area co...

Increased use of nanomaterials in everyday products leads to their environmental release and therefore, the information need on their fate and behaviour. Nanomaterials have to be suspended with high repeatability and comparability for studies on environmental effects. They also have to be well characterised with a focus on the state of agglomeratio...

The reactive oxygen species (ROS) generation capacity of ambient particulate matter (PM) represents a promising predictor for particle induced adverse health effects. An intrinsic method to determine ROS generation, adaptable for environmental monitoring is introduced here. The approach is based on the aligned electron paramagnetic resonance spectr...

The capacity of Particulate Matter (PM) to oxidise target molecules, defined as its oxidative potential (OP), has been proposed as a biologically more relevant metric than PM mass. Different assays exist for measuring OP and their methodologies vary in the choice of extraction solvent and filter type. Little is known about the impact of extraction...

The oxidative potential (OP) of particulate matter (PM) has been proposed as a more health relevant metric than PM mass. Different assays exist for measuring OP and little is known about how the different assays compare. To assess the OP of PM collected at different site types and to evaluate differences between locations, size fractions and correl...

Dental composites typically contain high amounts (up to 60 vol%) of nano-sized filler particles. There is a current concern that dental personnel (and patients) may inhale nano-sized dust particles (<100 nm) during abrasive procedures to shape, finish or remove restorations, but so far it has never been investigated whether airborne nanoparticles a...

In this study two different topics were analysed. The first part dealt with the development of a methodological approach testing the stability of ENM coatings. The methodological approach was tested with two functionalised TiO2 nanomaterials. The nanomaterials were NM103 (trade name: UV Titan M262) coated with aluminium oxide and dimethicone and NM...

It is well accepted that airborne particles can induce adverse health effects dependent on the source, composition, morphology and size. Studies indicate that ultrafine particles (diameter < 100 nm) are of specific importance. Therefore, upwind and downwind field measurements of particle number size distributions (14–750 nm), nitrogen oxides, PM10...

Particulate air pollution is a major problem to public health. Lately, the carbonaceous compounds of aerosols have attracted interest not only for their implications in the adverse health effects, but also for the contribution to global climate change. The carbonaceous aerosol is a dominant component of fine particle matter (PM2.5), and consists of...