Search

Diesel-powered passenger cars currently outnumber gasoline-powered cars in many countries, particularly in Europe. In France, diesel cars represented 61% of Light Duty Vehicles in 2011 and this percentage is still increasing (French Environment and Energy Management Agency, ADEME). As part of the September 2011 joint PM-DRIVE (Particulate Matter- DiRect and Indirect on-road Vehicular Emissions) and MOCOPO (Measuring and mOdeling traffic COngestion and POllution) field campaign, the concentration and high-resolution chemical composition of aerosols and volatile organic carbon (VOC) species were measured adjacent to a major urban highway south of Grenoble, France. Alongside these atmospheric measurements, detailed traffic data were collected from nearby traffic cameras and loop detectors, which allowed the identification of vehicle type and characteristics, traffic concentration, and traffic speed to be quantified and compared to measured aerosol and VOCs. Six aerosol age and source profiles were resolved using the positive matrix factorization (PMF) model on real-time high-resolution aerosol mass spectra. These six aerosol source/age categories included a hydrocarbon-like organic aerosol (HOA) commonly associated with primary vehicular emissions, a nitrogen containing aerosol (NOA) with a diurnal pattern similar to that of HOA, oxidized organic aerosol (OOA), and biomass burning aerosol (BBOA). While quantitatively separating the influence of diesel vs. gasoline proved impossible, a low HOA : black carbon ratio, similar to that measured in other highdiesel environments, and high levels of NOx, also indicative of diesel emissions, were observed. A comparison between these high-diesel environment measurements and measurements taken in low-diesel (North American) environments was examined and the potential feedback between vehicular emissions and SOA formation was probed. Although the measurement site was located next to a large source of primary emissions, which are typically found to have low oxygen incorporation, OOA was found to comprise the majority of the measured organic aerosol, and the measured OOA contained mainly modern carbon, not fossil-derived carbon. Thus, even in this heavily vehicular-emission impacted environment, photochemical processes, biogenic emissions, and aerosol oxidation dominated the overall organic aerosol mass measured during most of the campaign. [ABSTRACT FROM AUTHOR]

We developed a chemical mechanism based on laboratory experiments that have shown efficient oligomerization from methyl vinyl ketone (MVK) in the bulk aqueous phase. Kinetic data are applied (if known) or fitted to the observed MVK decay and oligomer mass increase. The mechanism is then implemented into a multiphase box model that simulates (i) oligomer formation upon uptake of MVK from the gas phase, and (ii) SOA formation from isoprene, as a precursor of MVK and methacrolein (MACR) n the aqueous and gas phases. Model results show that under atmospheric conditions, the oligomer formation rate strongly depends on the availability of dissolved oxygen. If oxygen is consumed too quickly or its solubility is kinetically or thermodynamically limited, oligomerization is accelerated, in agreement with the laboratory studies. The comparison of predicted oligomer formation shows that for most model assumptions (e.g. depending on the assumed partitioning of MVK and MACR), SOA formation from isoprene in the gas phase exceeds aqueous SOA formation by a factor 3-4. However, at high aerosol liquid water content and potentially high partitioning of oligomer precursors into the aqueous phase, SOA formation in both phases might be equally efficient. [ABSTRACT FROM AUTHOR]

Chemical processes in clouds have been suggested to contribute significantly to the mass of organic aerosol particles in the atmosphere. Experimental and theoretical evidence suggest that organic mass production in clouds can be substantial and depends on the concentration of organic precursor compounds available in the gas phase. The present study aims at studying the aqueous phase reactivity of one of these overlooked precursors, i.e. 2,4-hexadienedial, an important and toxic intermediate in the atmospheric oxidation of aromatic species. Cautious synthesis and purification of 2,4-hexadienedial was performed. Its effective Henry's law constant was measured using a new simple and fast method based on online flow-injection analysis. The reactivity of 2,4-hexadienedial in the aqueous phase relevant to atmospheric conditions was studied, including hydrate formation, photolysis, ∙OH- and SO 4 ∙ - -oxidation as well as reaction with NH 3 . The results revealed a low hydration constant compared to other dicarbonyls (K hyd1  = 7 × 10 -2 ) and no dihydrate formation, indicating in an intermediate solubility (K H  = 1.0 × 10 4  M atm -1 ) and high absorption cross sections (σ 278nm  > 10 -16  cm 2 molecule -1 ). Compared to its gas phase photolysis, its aqueous phase photolysis showed low quantum yields (Φ 290-380nm  = 0.9 %), and a significant red shift of the absorbance maximum, leading to a fast aqueous photolysis kinetics (J aq,atm  = 8.7 × 10 -5 s -1 ) under atmospheric solar radiation, but no triplet state formation was detected. Radical oxidation experiments revealed extremely rapid oxidation kinetics (k ∙OH  = 1.10 × 10 10  M -1  s -1 and k SO4 ∙ -  = 1.4 × 10 9  M -1  s -1 ) driven by fast addition of the radicals to the unsaturated bonds. In contrast, the reaction with aqueous NH 3 (k NH3  = 2.6 × 10 -3  M -1  s -1 ) was found slower than glyoxal and 2-butenedial, likely due to the hyperconjugation of 2,4-hexadienedial. Using these new data complemented with assumed aqueous phase kinetics (for NO 3 , 3 C* and 1 O 2 reactions) and previous gas-phase kinetic ones, the multiphase atmospheric fate of 2,4-hexadienedial was established under atmospheric conditions reported from previous field measurements and models. The results revealed a short day lifetime (∼1 h) and a long night lifetime (>12 h). It was shown that daytime atmospheric chemistry of 2,4-hexadienedial can be influenced by aqueous-phase reactivity during cloud events, up to ∼50 % under thick cloud conditions (Liquid Water Content >2000 g/m 3 ), indicating that even a compound of intermediate solubility can be strongly affected by condensed-phase reactivity. Besides its fast aqueous phase reactivity towards ∙OH and photolysis, its daytime condensed-phase reactivity may be driven by reactions with dissolved triplet states ( 3 C*), up to 35 %, highlighting the need to study further the kinetics, the nature and concentrations of dissolved 3 C* under various atmospheric conditions. In addition, the molecular properties and atmospheric behavior of 2,4-hexadienedial were found different from those of glyoxal and 2-butenedial, highlighting the need for detailed atmospheric reactivity studies of polyfunctional compounds, in particular unsaturated compounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Organic UV filters are emerging contaminants in personal care products such as sunscreens. The toxicity of numerous of these UV filter compounds has been demonstrated in several marine taxa. However, whilst the biological impact has already been largely demonstrated, the anthropogenic drivers leading to UV filter contamination still need to be identified. In this work, a survey was conducted on a site of the French Atlantic Coast (i) to describe beachgoers' behaviours (sunscreen use and beach frequentation), (ii) provide an estimation of the UV filters released at sea and (iii) highlight the effect of air temperature on these behaviours and on the release of UV filters. In parallel with these estimations of the UV filters released at sea, in situ chemical measurements were performed. By comparing the results of both approaches, this interdisciplinary work provides an insight of how the observations of beachgoers' behaviour modulations and attendance level fluctuations could be used to prevent UV filter contaminations and ultimately manage the ecotoxicological risk., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pesticides in the atmosphere can exist in both gaseous and particulate phases due to their semi-volatile properties. They can undergo degradation when exposed to atmospheric oxidants like ozone and hydroxyl radicals. The majority of studies on the atmospheric reactivity of pesticides study them in combination, without considering potential mixture effects that could induce uncertainties in the results. Therefore, this study aims to address this gap, through laboratory studies using a flow reactor, and by evaluating the degradation kinetics of pendimethalin mixed with folpet, tebuconazole, and S-metolachlor, which were simultaneously adsorbed on hydrophobic silica particles that mimic atmospheric aerosols. The comparison with other mixtures, including pendimethalin, from the literature has shown similar reactivity with ozone and hydroxyl radicals, indicating that the degradation kinetics of pesticides is independent of the mixture. Moreover, the degradation rates of the four pesticides under study indicate that they are not or slightly degraded by ozone, with half-lives ranging from 29 days to over 800 days. In contrast, when exposed to hydroxyl radicals, tebuconazole exhibited the fastest reactivity, with a half-life of 4 days, while pendimethalin had a half-life of 17 days., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Etienne QUIVET reports financial support was provided by French National Research Agency., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved.

Organochlorinated pesticides are highly persistent organic pollutants having important adverse effects in the environment. To study their fate, compound-specific isotope analysis (CSIA) may be used to investigate their degradation pathways and mechanisms but is currently limited to 13 C isotope ratios. The assessment of 37 Cl isotope ratios from mass spectra is complicated by the large number of isotopologues of polychlorinated compounds. For method development, chlordecone (C 10 Cl 10 O 2 H 2 ; hydrate form), an organochlorine insecticide that led to severe contamination of soils and aquatic ecosystems of the French West Indies, was taken as a model analyte. Chlorine isotope analysis of chlordecone hydrate was evaluated using high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), enabling smooth ionization to detect the molecular ion. First, a new evaluation scheme is presented to correct for multiple isotope presence in polychlorinated compounds. The scheme is based on probability calculations of the most frequent isotopologues, distributions by binomial probability functions, and corrections for the presence of nonchlorine heavy isotopes. Second, mobile-phase modifiers, ionization energy (sampling cone tension) and scan time were optimized for accurate chlorine isotope ratios. Chlordecone standard samples were measured up to 10-fold and bracketed with a second chlordecone external standard. δ 37 Cl values were obtained after conversion to the SMOC scale by a two-point calibration. The robustness of the analysis method and evaluation scheme were tested and gave satisfactory results with standard errors (σ m ) of ±0.34‰ for precision and ±0.89‰ for long-term accuracy of chlorine isotope ratios of chlordecone hydrate. This work opens perspectives for applications of the C-Cl CSIA approach to investigate the fate of highly toxic and low reactive polychlorinated compounds in the environment.

Isothiazolinones, a family of biocides, are used as preservatives for their fungicidal, bactericidal, and algacidal properties. These compounds can be found in a wide range of consumer and building products, such as paints, varnishes, shampoos, and liquid detergents. A robust analytical UPLC-MS/MS method to identify and quantify seven isothiazolinones (MIT, CMI, BIT, MBIT, BBIT, OIT, and DCOIT) in consumer products and their emissions was developed and validated according to ISO/IEC 17025. The limits of detection (LODs) ranged from 0.14 μg L -1 (BIT) to 0.54 μg L -1 (CMI). The method was applied for the quantification of the seven isothiazolinones in four types of consumer products (i.e., cosmetics, air fresheners, cleaning products, and building products) and the indoor emissions from a paint. Matrix effects were observed for the shampoo (63-74%), the shower gel (67-84%), and the ceramic glass cleaner (53-57%). All isothiazolinones indicated by the manufacturer (i.e., MIT, CMI, BIT, OIT, and DCOIT) were detected in the products and successfully quantified by the UPLC-MS/MS method., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

The mutagenicity of four organic UV filters namely oxybenzone (benzophenone-3), dioxybenzone (benzophenone-8), avobenzone, and octyl methoxycinnamate, in chlorinated bromide-rich water (artificial seawater) was investigated. Mutagenicity was evaluated using Ames test in Salmonella typhimurium TA98 without S9 mix. Chemical analysis using high-resolution mass spectrometry was carried out to elucidate the mutagenic transformation products. Among the studied UV filters, only dioxybenzone exhibited a clear mutagenic activity following chlorination in seawater at ratio 1:10 (UV filter:chlorine). In contrast, no mutagenic activity was detected when chlorine was added at higher doses (ratio 1:1000). High-resolution mass spectrometry analysis showed that mutagenic extracts contained several brominated transformation products of dioxybenzone. Time course analysis of the transformation products at increasing chlorine doses showed that they were unstable and disappeared more quickly at higher chlorine doses. This instability explained the absence of mutagenic activity of dioxybenzone when 1000-fold excess chlorine was added, as no transformation products were detected. Relevance of these findings to the context of swimming pool is discussed. Further investigations taking into consideration the mutagenicity of not only the intermediate transformation products but also the final disinfection byproducts are needed to determine the overall impact of high levels of chlorine on the overall mutagenicity. This study highlights the importance of considering the reactivity of organic UV filters and their transformation products in disinfected recreational waters when sunscreen formulations are prepared., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Organic ultraviolet (UV) filters are used in sunscreens and other personal-care products to protect against harmful effects of exposure to UV solar radiation. Little is known about the fate of UV filters in seawater swimming pools disinfected with chlorine. The present study investigated the occurrence and fate of five commonly used organic UV filters, namely dioxybenzone, oxybenzone, avobenzone, 2-ethylhexyl-4-methoxycinnamate, and octocrylene, in chlorinated seawater swimming pools. Pool samples were collected to monitor the variation of UV filter concentrations during pool opening hours. Furthermore, laboratory-controlled chlorination experiments were conducted in seawater spiked with UV filters to investigate the reactivity of UV filters. Extracts of chlorination reaction samples were analyzed using high-resolution mass spectrometry and electron-capture detection to identify the potentially formed byproducts. In the collected pool samples, all the UV filters except dioxybenzone were detected. Chlorination reactions showed that only octocrylene was stable in chlorinated seawater. The four reactive UV filters generated brominated transformation products and disinfection byproducts. This formation of brominated products resulted from reactions between the reactive UV filters and bromine, which is formed rapidly when chlorine is added to seawater. Based on the identified byproducts, the transformation pathways of the reactive UV filters were proposed for the first time. Bromoform was generated by all the reactive UV filters at different yields. Bromal hydrate was also detected as one of the byproducts generated by oxybenzone and dioxybenzone.

Aerosol-cloud interaction contributes to the largest uncertainties in the estimation and interpretation of the Earth's changing energy budget. The present study explores experimentally the impacts of water condensation-evaporation events, mimicking processes occurring in atmospheric clouds, on the molecular composition of secondary organic aerosol (SOA) from the photooxidation of methacrolein. A range of on- and off-line mass spectrometry techniques were used to obtain a detailed chemical characterization of SOA formed in control experiments in dry conditions, in triphasic experiments simulating gas-particle-cloud droplet interactions (starting from dry conditions and from 60% relative humidity (RH)), and in bulk aqueous-phase experiments. We observed that cloud events trigger fast SOA formation accompanied by evaporative losses. These evaporative losses decreased SOA concentration in the simulation chamber by 25-32% upon RH increase, while aqueous SOA was found to be metastable and slowly evaporated after cloud dissipation. In the simulation chamber, SOA composition measured with a high-resolution time-of-flight aerosol mass spectrometer, did not change during cloud events compared with high RH conditions (RH > 80%). In all experiments, off-line mass spectrometry techniques emphasize the critical role of 2-methylglyceric acid as a major product of isoprene chemistry, as an important contributor to the total SOA mass (15-20%) and as a key building block of oligomers found in the particulate phase. Interestingly, the comparison between the series of oligomers obtained from experiments performed under different conditions show a markedly different reactivity. In particular, long reaction times at high RH seem to create the conditions for aqueous-phase processing to occur in a more efficient manner than during two relatively short cloud events.

The heterogeneous reactions of gas-phase ozone and two pyrethroid pesticides, deltamethrin and permethrin, which are the most frequently applied insecticides today, has been investigated. Tentative identifications of heterogeneous ozonolysis products of both pesticides reveal that the reaction mechanisms differ and are mainly influenced by the presence of the cyano moiety at the α-position of deltamethrin (pyrethroid type II). The mechanism study also suggests the important role of water. Finally, several of the degradation products emerged from the ozonolysis of deltamethrin and permethrin may pose further health and environmental hazard due to their higher toxicity, such as phosgene for permethrin, and bromophosgene, 3-phenoxybenzaldehyde (3-PBA) and fulminic acid for deltamethrin. The results obtained in this study can contribute to better describe the atmospheric fate of pesticides in the particle phase., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Microelectronic wafers are exposed to airborne molecular contamination (AMC) during the fabrication process of microelectronic components. The organophosphate compounds belonging to the dopant group are one of the most harmful groups. Once adsorbed on the wafer surface these compounds hardly desorb and could diffuse in the bulk of the wafer and invert the wafer from p-type to n-type. The presence of these compounds on wafer surface could have electrical effect on the microelectronic components. For these reasons, it is of importance to control the amount of these compounds on the surface of the wafer. As a result, a fast quantitative and qualitative analytical method, nondestructive for the wafers, is needed to be able to adjust the process and avoid the loss of an important quantity of processed wafers due to the contamination by organophosphate compounds. Here we developed and validated an analytical method for the determination of organic compounds adsorbed on the surface of microelectronic wafers using the Direct Analysis in Real Time-Time of Flight-Mass Spectrometry (DART-ToF-MS) system. Specifically, the developed methodology concerns the organophosphate group., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Oxybenzone (2-hydroxy-4-methoxyphenone, benzophenone-3) is one of the UV filters commonly found in sunscreens. Its presence in swimming pools and its reactivity with chlorine has already been demonstrated but never in seawater swimming pools. In these pools, chlorine added for disinfection results in the formation of bromine, due to the high levels of bromide in seawater, and leads to the formation of brominated disinfection byproducts, known to be more toxic than chlorinated ones. Therefore, it seems important to determine the transformation products of oxybenzone in chlorinated seawater swimming pools; especially that users of seawater swimming pools may apply sunscreens and other personal-care products containing oxybenzone before going to pools. This leads to the introduction of oxybenzone to pools, where it reacts with bromine. For this purpose, the reactivity of oxybenzone has been examined as a function of chlorine dose and temperature in artificial seawater to assess its potential to produce trihalomethanes and to determine the byproducts generated following chlorination. Increasing doses of chlorine and increasing temperatures enhanced the formation of bromoform. Experiments carried out with excess doses of chlorine resulted in the degradation of oxybenzone and allowed the determination of the degradation mechanisms leading to the formation of bromoform. In total, ten transformation products were identified, based on which the transformation pathway was proposed.

An analytical chemical method has been developed for determination of β-hydroxymyristic acid (β-HMA), a component of lipopolysaccharides (LPSs/endotoxins) in dialysis water. In our investigation, the β-HMA component was used as a chemical marker for endotoxin presence in dialysis water because it is available in the molecular subunit (lipid A) and responsible for toxicity. It is the most abundant saturated fatty acid in that subunit. The developed method is based on fluorescence derivatization with 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ). A high-performance liquid chromatographic separation of the β-HMA derivative was achieved using an octadecyl silica column in gradient elution. A wide dynamic range of β-HMA was tested and a calibration curve was constructed with accuracy of 90% and variability of less than 10%. The limits of detection and quantification obtained were 2 and 5μM, respectively. The developed method was applied to detect endotoxins in dialysis water by alkaline hydrolysis of LPS using NaOH (0.25M) at 60°C for 2h. After hydrolysis, free acid was detected as its NBD-PZ derivative using high-performance liquid chromatography/mass spectrometry (HPLC/MS). Good recovery rates ranging from 98 to 105% were obtained for β-HMA in dialysis water., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Purpose: The excellent tissue differenciation provided by MRI in the three directions and the lack of ionizing radiations make it ideal for interventional procedures. Many problems must still be solved: the access to the patient, the size of the artefact produced by interventional instruments and the acquisition time. In this study, we evaluated the influence of field strength for standard imaging sequences on the MRI artefact of a non ferro-magnetic biopsy needle. Then, we developed very fast sequences on a opened 0.1 T dedicated magnet to test in vitro and ex vivo the potential ability of this system in the guidance of the needle., Material and Methods: The biopsy needle was a new stainless steel needle made of 49% Nickel. The needle artefact's size measurements were made at 0.1 T, 0.5 T and 1 T on a bicompartmental phantom (one compartment with a long T1 and another with a long T2), with standard gradient echo (400/12/90 degrees) and spin echo (500/25) sequences. At 0.1 T, we optimized very fast steady state 3D FAST (T1 weighted) and 3D CE-FAST (T2 weighted) sequences to reduce the acquisition time, preserving good image contrasts for a field of view reaching 38 mm and 48 x 64 or 24 x 32 matrix., Results: The larger needle artefact observed on gradient echo images varied from 3.6 mm at 0.1 T to 8.6 mm at 1 T. The shortest acquisition time for 4 contiguous slices of 2mm with a 1.2 mm/pixel resolution and a 24 x 32 matrix was 1.5 s for the 3D FAST (16/9/65 degrees) sequence and 3 s for the 3D CE-FAST (29/22/65 degrees) sequence. We realized a complete MRI guided abdominal puncture on a cat cadaver with 4 series of 15 s 3D FAST images (16/9/65 degrees, 4 slices, 5 excitations, 1.2 mm/pixel, FOV = 77 mm). Besides the cat positioning and the image reconstruction time, the whole puncture lasted 1 min (4 x 15 s)., Conclusion: Low field MRI (0.1 T) combined with very fast 3D steady state sequences is adapted for the real time guidance of biopsy needles.