Verteilung von Phthalsäureestern im Innenraum: Anwendung und Beurteilung von Innenluftmodellen

This study reports results of a reaserch project that determined the distribution of phthalic acid esters ("phthalates") between different indoor matrices (air, dust, different surfaces) using the target compounds di-butylphthalate (DBP) and di-2(ethylhexyl)phthalate (DEHP). Various experiments in emission test chambers and a simulated indoor environment were performed. Afterwards, the results were evaluated using an emission model that allows the prediction of the air concentration in a system under known environmental conditons. The chosen model is able to predict the mass-transfer from the emission source into the well mixed air on the basis of the material properties. The experiments showed that the distribution of DEHP between the emitting polymer and possible sinks (e.g. dust) does not mainly happen via the gas phase. If direct contact between dust and polymer is given, the mass-transfer of DEHP is considerably higher. The mass-transfer was found to be depending on the initial concentration in the material. Furthermore, the results illustrated the changes of the emission rate of a material in presence of airborne particles in indoor air. In principle, the sum of a compound in gas phase and bound to the airborne particle phase may reach a concentration above the saturation concentration of the compound in air. Finally, the predicition of physically based indoor models was found to be associated with a high uncertainty due to the complicated characterization of a real indoor environment without extensive measurements.Das durchgeführte Forschungsprojekt untersuchte die Verteilung von Phthalsäuresstern („Phthalaten“) zwischen verschiedenen Innenraummatrices (Luft, Staub, sonstige Oberflächen) anhand der beiden Referenzsubstanzen Di-butyl-phthalat (DBP) und Di-2(ethylhexyl)-phthalat (DEHP). Zu diesem Zweck wurden verschiedene Experimente in Emissionsprüfkammern sowie einer simulierten Innenraumumgebung durchgeführt und anschließend mit einem geeigneten Emissionsmodell für die Vorhersage der Konzentrationsentwicklung unter den gewählten Bedingungen nachvollzogen. Das eingesetzte Modell erlaubt die Berechnung des Massentransfers von der Emissionquelle in die Raumluft aus Basis der Materialeigenschaften der Quelle. Es zeigte sich, dass die Verteilung von DEHP aus einem Polymer in mögliche Senken (z.B. Staub) nur in geringem Maße über einen Gasphasentransfer geschieht. Erst durch direkten Kontakt zwischen Staub und Polymer findet ein stärkerer Massentransfer von DEHP statt, der Abhängig von der Konzentration im Polymer ist. Des weiteren, erhöhen luftgetragene Partikel die Emissionsrate von SVOC in einem Material und erlauben prinzipiell die Einstellung einer Summenkonzentration Gas- und Partikelphase in der Luft, die größer als die Sättigungskonzentration der Substanz ist. Die Ergebnisse von physikalisch basierten Modellen für die Vorhersage von SVOC-Konzentrationen in der Innenraumluft sind mit erheblichen Unsicherheiten belastet, da eine vollständige Charakterisierung des modellierten Systems nicht ohne vorherige Messungen möglich ist

Investigating Particulate and Nitrogen Oxides Emissions of a Plug-In Hybrid Electric Vehicle for a Real-World Driving Scenario

Plug-in hybrid electric vehicles (PHEVs) show a high pollutant emission variability that strongly depends on the operating conditions of the internal combustion engine. Additionally, studies indicate that driving situations outside of the real driving emissions boundary conditions can lead to substantial pollutant emission increases. The objective of this study is to measure and analyze the particulate number (PN) and nitrogen oxides (NOx) emissions of a Euro 6 PHEV for a selected real-world driving test route in the Stuttgart metropolitan area. For this purpose, the vehicle is set out with multiple measurement devices to monitor vehicle internal and external parameters. Particle distribution results show an overall uniform pattern, which allows a comparative analysis of the different test scenarios on the basis of the PN concentration. While the trip-average PN emissions are in good agreement, transient effects during highway driving can substantially increase emissions, whereas the fuel consumption does not necessarily increase in such situations. PN measurements including ultrafine particles (UFP) show a significant increase in urban emissions due to higher cold start emission peaks. Additionally, low ambient temperatures raise the uncertainty of NOx and PN cold start emissions. With regard to future emission regulations, which claim that vehicles need to be as clean as possible in all driving situations, PHEV emission investigations for further situations outside of the current legislations are required

Role of clothing in both accelerating and impeding dermal absorption of airborne SVOCs

To assess the influence of clothing on dermal uptake of semi-volatile organic compounds (SVOCs), we measured uptake of selected airborne phthalates for an individual wearing clean clothes or air-exposed clothes and compared these results with dermal uptake for bare-skinned individuals under otherwise identical experimental conditions. Using a breathing hood to isolate dermal from inhalation uptake, we measured urinary metabolites of diethylphthalate (DEP) and di-n-butylphthalate (DnBP) from an individual exposed to known concentrations of these compounds for 6 h in an experimental chamber. The individual wore either clean (fresh) cotton clothes or cotton clothes that had been exposed to the same chamber air concentrations for 9 days. For a 6-h exposure, the net amounts of DEP and DnBP absorbed when wearing fresh clothes were, respectively, 0.017 and 0.007 μg/kg/(μg/m3); for exposed clothes the results were 0.178 and 0.261 μg/kg/(μg/m3), respectively (values normalized by air concentration and body mass). When compared against the average results for bare-skinned participants, clean clothes were protective, whereas exposed clothes increased dermal uptake for DEP and DnBP by factors of 3.3 and 6.5, respectively. Even for non-occupational environments, wearing clothing that has adsorbed/absorbed indoor air pollutants can increase dermal uptake of SVOCs by substantial amounts relative to bare skin

Transdermal uptake of diethyl phthalate and di(n-butyl) phthalate directly from air: Experimental verification

Background: Fundamental considerations indicate that, for certain phthalate esters, dermal absorption from air is an uptake pathway that is comparable to or larger than inhalation. Yet this pathway has not been experimentally evaluated and has been largely overlooked when assessing uptake of phthalate esters. Objectives: This study investigated transdermal uptake, directly from air, of diethyl phthalate (DEP) and di(n-butyl) phthalate (DnBP) in humans. Methods: In a series of experiments, six human participants were exposed for six hours in a chamber containing deliberately elevated air concentrations of DEP and DnBP. The participants either wore a hood and breathed air with phthalate concentrations substantially below those in the chamber or did not wear a hood and breathed chamber air. All urinations were collected from initiation of exposure until 54 hours later. Metabolites of DEP and DnBP were measured in these samples and extrapolated to parent phthalate intakes, corrected for background and hood air exposures. Results: For DEP the median dermal uptake directly from air was 4.0 µg/(µg/m3 in air) compared with an inhalation intake of 3.8 µg/(µg/m3 in air). For DnBP the median dermal uptake from air was 3.1 µg/(µg/m3 in air) compared with an inhalation intake of 3.9 µg/(µg/m3 in air). Conclusions: This study shows that dermal uptake directly from air can be a meaningful exposure pathway for DEP and DnBP. For other semivolatile organic compounds (SVOCs) whose molecular weight and Kow are in the appropriate range, direct absorption from air is also anticipated to be significant

Multiblend JET A-1 in practice: results of an R&D project on synthetic paraffinic kerosenes

The research and demonstration project, DEMO-SPK, a model project under the German Mobility and Fuel Strategy (MFS), investigated the use of renewable kerosene at the Leipzig/Halle airport. Its primary goal was to examine and verify the behavior of blends consisting of several types of renewable kerosene and fossil JET A-1, under the realistic supply conditions of a major airport. The project demonstrated that the supply chain for multiblend JET A-1 was technically feasible and that the fuel could be used without requiring any changes in the normal operating procedures. The project also confirmed that the use of multiblend JET A-1 resulted in a 30–60% reduction in particulate emissions for ground operations and a reduction in CO2 equivalents, compared with pure fossil JET A-1.The R&D project on the use of renewable kerosene at Leipzig/Halle airport (DEMO-SPK) involved the collaboration of more than 20 international partners from industry and science. It was initiated as a model project of the Mobility and Fuel Strategy (MFS) and financed by the Federal Ministry of Transport and Digital Infrastructure (BMVI)

Aircraft Engine Particulate Matter Emissions from Sustainable Aviation Fuels: Results from Ground-Based Measurements during the NASA/DLR Campaign ECLIF2/ND-MAX

The use of alternative jet fuels by commercial aviation has increased substantially in recent years. Beside the reduction of carbon dioxide emission, the use of sustainable aviation fuels (SAF) may have a positive impact on the reduction of particulate emissions. This study summarizes the results from a ground-based measurement activity conducted in January 2018 as part of the ECLIF2/ND-MAX campaign in Ramstein, Germany. Two fossil reference kerosenes and three different blends with the renewable fuel component HEFA-SPK (Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene) were burned in an A320 with V2527-A5 engines to investigate the effect of fuel naphthalene/aromatic content and the corresponding fuel hydrogen content on non-volatile particle number and mass emissions. Reductions up to 70% in non-volatile particle mass emission compared to the fossil reference fuel were observed at low power settings. The reduction trends to decrease with increasing power settings. The fuels showed a decrease in particle emission with increasing fuel hydrogen content. Consequently, a second fossil fuel with similar hydrogen content as one of the HEFA blends featured similar reduction factors in particle mass and number. Changes in the fuel naphthalene content had significant impact on the particle number emission. A comparison to in-flight emission data shows similar trends at cruise altitudes. The measurements highlight the importance of individual fuel components in regulating engine emissions, particularly at the low thrust settings typically employed during ground operations (e.g. during idle and taxi). Therefore, when selecting and mixing SAF blends to meet present fuel-certification standards, attention should be paid to minimizing complex aromatic content to achieve the greatest possible air quality and climate benefits

Targeted Use of Sustainable Aviation Fuel to Maximize Climate Benefits

Sustainable aviation fuel (SAF) can reduce aviation’s CO2 and non-CO2 impacts. We quantify the change in contrail properties and climate forcing in the North Atlantic resulting from different blending ratios of SAF and demonstrate that intelligently allocating the limited SAF supply could multiply its overall climate benefit by factors of 9-15. A fleetwide adoption of 100% SAF increases contrail occurrence (+5%), but lower nonvolatile particle emissions (-52%) reduce the annual mean contrail net radiative forcing (-44%), adding to climate gains from reduced life cycle CO2 emissions. However, in the short term, SAF supply will be constrained. SAF blended at a 1% ratio and uniformly distributed to all transatlantic flights would reduce both the annual contrail energy forcing (EFcontrail) and the total energy forcing (EFtotal, contrails + change in CO2 life cycle emissions) by ~0.6%. Instead, targeting the same quantity of SAF at a 50% blend ratio to ~2% of flights responsible for the most highly warming contrails reduces EFcontrail and EFtotal by ~10 and ~6%, respectively. Acknowledging forecasting uncertainties, SAF blended at lower ratios (10%) and distributed to more flights (~9%) still reduces EFcontrail (~5%) and EFtotal (~3%). Both strategies deploy SAF on flights with engine particle emissions exceeding 1012 m-1, at nighttime, and in winter