Bromine Research Articles

Thermo-chemical recycling of plastics retrieved from waste electric and electronic equipment (WEEE) by pyrolysis: Identification of the polymer type, removal of bromine compounds from plastics based on an environmentally-friendly process and characterization of the pyrolysates

The increased amounts of plastics originating from waste electric and electronic equipment (WEEE) necessitates finding environmentally friendly solutions for their handling. Taking into account the importance of the aforementioned issue, in this work attention is paid to the recycling of various plastic materials coming from WEEE. Plastic samples including parts from televisions, computers, printers, remote controls and a calculator, were collected from a recycling plant and from end-of-life household appliances. After collection and size reduction, they were analysed by various techniques, including Fourier transform Infra-Red spectroscopy (FTIR) measurements, for the identification of the polymers present in each device, since they were unknown. Their degradation behaviour was investigated via Evolved Gas Analysis (EGA), by heating them from 100 to 700 °C. Thermal pyrolysis was applied with the aim of recovering the monomers or secondary useful products during the samples’ degradation. X-ray fluorescence (XRF) analysis was applied to all samples collected in order to identify the possible presence of bromine, in case those plastics were brominated flame retarded; and it was found that 41% (7/17) of the samples contained bromine. The brominated samples were subjected to Soxhlet extraction aiming to reduce the bromine incorporated into them. Results showed that bromine was reduced in all cases tested, reaching up to 35% reduction. According to EGA analysis, the thermal degradation in most cases followed a one-step mechanism. FTIR and thermal pyrolysis results revealed that most samples consisted of high-impact polystyrene (HIPS), while some of them were blends of polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) or ABS. The chemical recycling of the samples, via pyrolysis, led to monomers (e.g., styrene), or other valuable compounds, including hydrocarbons or phenols, depending on the type of the polymer present in each sample.

Chemical Characterization of Atmospheric Aerosols in Monte Fenton, Punta Arenas, Chilean Southern Patagonia

This work addresses the chemical characterization of atmospheric aerosols and precipitation in the period from May to November 2019 at Monte Fenton (53.16° S, 71.05° W, 612 m.a.s.l.), 9 km west of Punta Arenas, to study the contribution and distribution of emission sources and chemical enrichment. The main ions (Ca2+, Cl−, K+, Mg2+, Na+, NH4+, NO3− and SO42−) were studied using ion chromatography, and trace elements (Al, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Se, Si, Ti, V and Zn) using energy dispersive X-ray fluorescence. Ions concentration ranged from 5.0 × 10−1 to 2.9 × 104 mg/m3 for Ca2+ and Cl−, respectively; whilst the concentration of elements varied between 8.8 × 10−11 and 2.1 × 10−2 mg/m3, for crZn (crustal Zn) and Fe, respectively. The electrical conductivity (EC, mean = 32.5 µS/cm) and the pH (mean = 6.8), showed the atmosphere of the study site was relatively neutral compared to the standard pH for rain (or snow) without contamination (pH = 5.6), and presented relatively low levels of conductivity compared to the EC standards for distilled water (0.5 to 3 µS/cm) and seawater (30,000 to 60,000 µS/cm). The main contribution to aerosols in the atmosphere of Monte Fenton came from marine and lithospheric sources, followed by local anthropogenic sources such as burning firewood and/or urban waste for heating production, etc., that led to the enrichment of aerosols with high Fe, K, Mn and V content. The results of this study contribute to filling a gap in knowledge of the chemistry of atmospheric aerosols in Southern Patagonia.

Formation of Targeted and Novel Disinfection Byproducts during Chlorine Photolysis in the Presence of Bromide.

Chlorine photolysis is an advanced oxidation process that relies on the combination of direct chlorination by free available chlorine, direct photolysis, and reactive oxidants to transform contaminants. In waters that contain bromide, free available bromine and reactive bromine species can also form. However, little is known about the underlying mechanisms or formation potential of disinfection byproducts (DBPs) under these conditions. We investigated reactive oxidant generation and DBP formation under dark conditions, chlorine photolysis, and radical-quenched chorine photolysis with variable chlorine (0-10 mg-Cl2/L) and bromide (0-2,000 μg/L) concentrations, as well as with free available bromine. Probe loss rates and ozone concentrations increase with chlorine concentration and are minimally impacted by bromide. Radical-mediated processes partially contribute to the formation targeted DBPs (i.e., trihalomethanes, haloacetic acids, haloacetonitriles, chlorate, and bromate), which increase with increasing chlorine concentration. Chlorinated novel DBPs detected by high-resolution mass spectrometry are attributable to a combination of dark chlorination, direct halogenation by reactive chlorine species, and transformation of precursors, whereas novel brominated DBPs are primarily attributable to dark bromination of electron-rich formulas. The formation of targeted and novel DBPs during chlorine photolysis in waters with elevated bromide may limit treatment applications.

Low concentration of bromide ions improves sulfadiazine phytoremoval and attenuates its phytotoxicity

Sulfonamide antibiotics (SAs) are ubiquitous in surface water and soil environments, raising considerable concerns about their risk and removal. However, the impacts of various bromide ion (Br−) concentrations on the phytotoxicity, uptake and fate of SAs in plant growth and physiological metabolism of plants have not been well understood. Our research demonstrated that low concentrations of Br− (0.1, 0.5 mM) promoted the uptake and degradation of sulfadiazine (SDZ) in wheat and attenuated the phytotoxicity of SDZ. Additionally, we proposed a degradation pathway and identified the brominated product of SDZ (SDZBr), which attenuated the dihydrofolate synthesis inhibition by SDZ. The primary mechanism was that Br− reduced the level of reactive oxygen radicals (ROS) and alleviated oxidative damage. The production of SDZBr and the high consumption of H2O2 suggest the potential generation of reactive bromine species, contributing to the degradation of the electron-rich SDZ and thus reducing its toxicity. Moreover, metabolome analysis of wheat roots indicated that low concentrations of Br− stimulated the production of indoleacetic acid under SDZ stress, promoting growth and enhancing the uptake and degradation of SDZ. Conversely, high Br− (1 mM) concentration produced a deleterious effect. These findings provide valuable insights into the mechanisms of antibiotic removal, suggesting a potentially novel approach to plant-based antibiotic remediation.

Analysis of rain-deposited dust on polysulfone membranes using proton-induced X-ray emission spectroscopy

Proton-induced X-ray emission spectroscopy (PIXE) is a long-established method of nondestructive elemental analysis for environmental samples. While a standard method of recovery of solids from rainwater involves filtration onto polysulfone media, PIXE analysis has not typically been used on such substrates. We describe methodologies of the University of North Texas Ion Beam Laboratory for PIXE analysis of dust in Texas rainwater on polysulfone membranes from the National Atmospheric Deposition Program (NADP). PIXE analyses utilized a 2 MeV proton beam of 1 × 1 mm2 spot size with beam currents of 1–5nA. A 100 µm Al absorber attenuated X-rays produced by S native to the polysulfone and minimized pileup, allowing use of higher beam currents at the expense of detecting elements of Z < 22. Uniformity of dust deposition on the membranes was evaluated by utilizing Fe concentration as a dust tracer. Areas of uniform particulate deposition with comparable results to averages across the entire membrane were located, allowing reduced acquisition time. GeoPIXE software was used for quantitative analysis, and 18 elements (Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Hg and Pb) were investigated for a collaborative project. Average minimum detection limits (MDL) were ≤ 10 ng/cm2 for 21 > Z greater than 36 and 10–30 ng/cm2 for 36 < Z < 83. Polysulfone is shown to be an appropriate substrate for PIXE analysis of environmental samples, especially when quantification of low-Z elements is not a priority.

Enhancing Ferrate Oxidation of Micropollutants via Inducing Fe(V)/Fe(IV) Formation Needs Caution: Increased Conversion of Bromide to Bromate.

This study explores the formation of bromate (BrO3-) in the copresence of Fe(VI) and bromide (Br-). It challenges previous beliefs about the role of Fe(VI) as a green oxidant and highlights the crucial role of intermediates Fe(V) and Fe(IV) in the conversion of Br- to BrO3-. The results show that the maximum concentration of BrO3- of 48.3 μg/L was obtained at 16 mg/L Br- and that the contribution of Fe(V)/Fe(IV) to the conversion was positively related to pH. The study suggests that a single-electron transfer from Br- to Fe(V)/Fe(IV) along with the generation of reactive bromine radicals is the first step of Br- conversion, followed by the formation of OBr- which was then oxidized to BrO3- by Fe(VI) and Fe(V)/Fe(IV). Some common background water constituents (e.g., DOM, HCO3-, and Cl-) significantly inhibited BrO3- formation by consuming Fe(V)/Fe(IV) and/or scavenging the reactive bromine species. While investigations proposing to promote Fe(V)/Fe(IV) formation in Fe(VI)-based oxidation to enhance its oxidation capacity have been rapidly accumulated recently, this work called attention to the considerable formation of BrO3- in this process.

Activation of peroxymonosulfate by base for degradation of methylene blue: role of bromide ions.

Bromide ions are inevitable in aquatic environment and influence the degradation of contaminants in non-radical based advanced oxidation processes, but the role of reactive bromine species (RBS) remain obscure. This study investigated the role of bromide ions in the degradation of methylene blue (MB) during the base/peroxymonosulfate (PMS) process. The formation of RBS as a function of bromide ions were evaluated using a kinetic modelling. Bromide ions were shown to play crucial roles in MB degradation. Increasing the dosage of NaOH and Br- increased the transformation kinetics of MB. However, brominated intermediates which are more toxic than precursor MB were generated in the presence of Br-. The formation of adsorbable organic halides (AOX) was enhanced by elevating the dosage of Br-. The formation of AOX was even more significant in the absence of NaOH, and the AOX values decreased with the increasing alkalinity. The kinetic model indicated that the dominant reactive species formed in the base/PMS/Br- process are 1O2 and HOBr, and Br2 in the Br-/PMS process. Therefore, the influence of bromide ions should be taken into consideration in the application of the base/PMS process for organic matters in bromide-containing natural water. Strategies should be developed to make full use of RBS for the abatement of organic pollutants and to reduce the formation of AOX. This study reveals that in the treatment of saline wastewater by PMS-based processes, increasing the amount of NaOH may be an effective strategy to inhibit the accumulation of AOX.

Insight into the formation of polyhalogenated carbazoles during seawater chlorination

Although polyhalogenated carbazoles (PHCZs) have been widely detected in the marine environment, their origin is far from clear. In this study, the formation of PHCZs in the chlorination of seawater containing carbazole and its derivatives was investigated. A total of 14 PHCZs including six commonly found and eight unknown congeners were identified in the chlorination of seawater with carbazole. In addition, this study for the first time demonstrated the production of common PHCZs from the chlorination of seawater with 3-methyl carbazole and 3-formyl carbazole, especially 1,8-dibromo-3,6-dichlorocarbazole from 3-methyl carbazole. The formation of PHCZs in the reaction resulted from the halogenation of carbazole by reactive chlorine species (RCS) and mainly reactive bromine species (RBS), forming from the oxidation of bromide by RCS. Results also indicated that the reaction followed a successive halogenation pattern. A higher content of free chlorine and bromide facilitated the generation of RBS, while a higher concentration of DOC exhibited an inhibitory effect. The effects of free chlorine, bromide, DOC, and temperature on the formation of PHCZs were congener-specific. Given the widespread use of chlorination in seawater disinfection, seawater chlorination might be a potential source of PHCZs in the marine environment.

Improving the Method for Measuring Bromine Compounds in Flue Gas

The method detection limit (MDL) using UV-VIS spectrometry (UV/VIS) is the primary method to detect bromine compounds in the flue gas. However, the level of bromine compounds in the flue gas is 0.6 ppm, reaching 20% of the emission limit of 3.0 ppm, which limits the analysis of low-concentration samples. As per the United States Environmental Protection Agency and official test standards for water pollution, bromine compound analysis was performed using ion chromatography (IC). Hydrogen chloride was analyzed using IC, referencing official test standards for air pollution. Therefore, 0.1 M NaOH and distilled water (D.W.) were applied to the absorption solution of the IC analysis sample. Validation was conducted for IC (D.W.), IC (0.1 M NaOH), and UV/VIS (0.1 M NaOH) to improve the analysis method for bromine compounds in the flue gas. The linearity (R&lt;sup&gt;2&lt;/sup&gt;) of the calibration curve for IC (D.W.) satisfied the R&lt;sup&gt;2&lt;/sup&gt; (0.98 or more) value calculated in the UV/VIS of the official test standards for air pollution. However, the R&lt;sup&gt;2&lt;/sup&gt; of UV/VIS (0.1 M NaOH) and IC (0.1 M NaOH) was not satisfied. In IC (D.W.) analysis results, the average values of MDL, MLQ (minimum level of quantification), accuracy and precision were 0.127 ppm, 0.403 ppm, 3.7%, and 102.9%, respectively. MDL and MLQ showed the lowest concentration compared to the other two methods, and had high accuracy and precision. Regarding the recovery rate by the absorbing liquid, IC (D.W.) was the highest at 93.55%, followed by UV/VIS (0.1 M NaOH) and IC (0.1 M NaOH). This study analyzed bromine compounds in flue gas with higher accuracy and precision using the IC (D.W.) method compared to IC (0.1 M NaOH) and UV/VIS (0.1 M NaOH).

Photo-transformation of acetaminophen sensitized by fluoroquinolones in the presence of bromide

Fluoroquinolones (FQs) are a class of antibiotics with emerging concern. This study investigated the photochemical properties of two representative FQs, i.e., norfloxacin (NORF) and ofloxacin (OFLO). Results showed that both FQs could sensitize the photo-transformation of acetaminophen under UV-A irradiation, during which excited triplet state (3FQ*) was the main active species. In the presence of 3 mM Br‾, the photolysis rate of acetaminophen increased by 56.3% and 113.5% in the solutions with 10 μM NORF and OFLO, respectively. Such an effect was ascribed to the generation of reactive bromine species (RBS), which was verified by 3,5-dimethyl-1H-pyrazole (DMPZ) probing approach. 3FQ* reacts with acetaminophen through one-electron transfer, producing radical intermediates which then couple to each other. Presence of Br‾ did not lead to the formation of brominated products but the same coupling products, which suggests that radical bromine species, rather than free bromine, were responsible for the accelerated acetaminophen transformation. According to the identified reaction products and assisted with the theoretical computation, the transformation pathways of acetaminophen under UV-A irradiation were proposed. The results reported herein suggest that sunlight-driven reactions of FQs and Br‾ may influence the transformation of coexisting pollutants in surface water environments.

Electrochemical Synthesis of Dimeric λ3-Bromane: Platform for Hypervalent Bromine(III) Compounds.

A straightforward and scalable approach to a previously unreported class of cyclic hypervalent Br(III) species capitalizes on the anodic oxidation of aryl bromide to dimeric benzbromoxole that serves as a versatile platform to access a range of structurally diverse Br(III) congeners such as acetoxy-, alkoxy-, and ethynyl-λ3-bromanes as well as diaryl-λ3-bromanes. The synthetic utility of dimeric λ3-bromane is exemplified by photoinduced Minisci-type heteroarylation reactions and benzylic oxidation.

Source mechanisms and transport patterns of tropospheric bromine monoxide: findings from long-term multi-axis differential optical absorption spectroscopy measurements at two Antarctic stations

Abstract. The presence of reactive bromine in polar regions is a widespread phenomenon that plays an important role in the photochemistry of the Arctic and Antarctic lower troposphere, including the destruction of ozone, the disturbance of radical cycles, and the oxidation of gaseous elemental mercury. The chemical mechanisms leading to the heterogeneous release of gaseous bromine compounds from saline surfaces are in principle well understood. There are, however, substantial uncertainties about the contribution of different potential sources to the release of reactive bromine, such as sea ice, brine, aerosols, and the snow surface, as well as about the seasonal and diurnal variation and the vertical distribution of reactive bromine. Here we use continuous long-term measurements of the vertical distribution of bromine monoxide (BrO) and aerosols at the two Antarctic sites Neumayer (NM) and Arrival Heights (AH), covering the periods of 2003–2021 and 2012–2021, respectively, to investigate how chemical and physical parameters affect the abundance of BrO. We find the strongest correlation between BrO and aerosol extinction (R=0.56 for NM and R=0.28 for AH during spring), suggesting that the heterogeneous release of Br2 from saline airborne particles (blowing snow and aerosols) is a dominant source for reactive bromine. Positive correlations between BrO and contact time of air masses, both with sea ice and the Antarctic ice sheet, suggest that reactive bromine is not only emitted by the sea ice surface but by the snowpack on the ice shelf and in the coastal regions of Antarctica. In addition, the open ocean appears to represent a source for reactive bromine during late summer and autumn when the sea ice extent is at its minimum. A source–receptor analysis based on back trajectories and sea ice maps shows that main source regions for BrO at NM are the Weddell Sea and the Filchner–Ronne Ice Shelf, as well as coastal polynyas where sea ice is newly formed. A strong morning peak in BrO frequently occurring during summer and that is particularly strong during autumn suggests a night-time build-up of Br2 by heterogeneous reaction of ozone on the saline snowpack in the vicinity of the measurement sites. We furthermore show that BrO can be sustained for at least 3 d while travelling across the Antarctic continent in the absence of any saline surfaces that could serve as a source for reactive bromine.

UV-induced degradation of contaminants of emerging concern in the presence of monobromoamine: Role of N-Br bond and degradation mechanisms

The N-Br bond in monobromoamine (NH2Br) can be cleaved by UV irradiation to generate Br• and subsequently HO•, resulting in an advanced oxidation condition (i.e., UV/NH2Br). This study investigated the degradation of six contaminants of emerging concern (CECs) in the UV/NH2Br process, including the phenolic hydrocarbons phenol and bisphenol A (BPA), the amines aniline and sulfadiazine (SDZ), and the persistent organic pollutants ibuprofen (IBP) and carbamazepine (CBZ). The results showed that UV/NH2Br process significantly improved the degradation of CECs following pseudo-first order kinetics, and the degradation of CECs was enhanced with the increase of NH2Br dosage. UV/NH2Br was more efficient in degrading CECs containing phenolic hydroxyl groups (100 %), followed by those containing amine groups (> 95 %). The degradation efficiency was influenced by the pH value and was highest at pH 7. It was found that low concentrations of Cl− (< 0.5 mM) and HCO3− (< 0.5 mM) promoted the degradation of SDZ and IBP, but further increases in Cl− and HCO3− (0.5 ∼ 5.0 mM) resulted in inhibition. SDZ and IBP degradation was inhibited by photo absorption competition and free radical depletion in natural organic matter and actual water. Probe experiments showed that reactive bromine species (RBS), reactive nitrogen species (RNS), and hydroxyl radical (HO•) played a dominant role in CEC degradation. During the degradation of IBP by UV/NH2Br, hydroxylation, bromination, and quinylation were proposed as the primary reaction mechanisms. As compared to HOCl disinfection, NH2Cl disinfection after the UV/NH2Br process produced lower concentrations of disinfection by-products (DBPs).

Elemental Composition and Sources of Fine Particulate Matter (PM2.5) in Delhi, India.

In this study we have analysed the elemental composition of fine particulate matter (PM2.5) to examine the seasonal changes and sources of the elements in Delhi, India from January, 2017 to December, 2021. During the entire sampling period, 19 elements (Al, Fe, Ti, Cu, Zn, Cr, Ni, As, Mo, Cl, P, S, K, Pb, Na, Mg, Ca, Mn, and Br) of PM2.5 were identified by Wavelength Dispersive X-ray Fluorescence Spectrometer. The higher annual mean concentrations of S (2.29µg m-3), Cl (2.26µg m-3), K (2.05µg m-3), Ca (0.96µg m-3) and Fe (0.93µg m-3) were recorded during post-monsoon season followed by Zn > Pb > Al > Na > Cu > Ti > As > Cr > Mo > Br > Mg > Ni > Mn > and P. The annual mean concentrations of elemental composition of PM2.5 accounted for 10% of PM2.5 (pooled estimate of 5 year). Principal Component Analysis (PCA) identified the five main sources [crustal/soil/road dust, combustion (BB + FFC), vehicular emissions (VE), industrial emissions (IE) and mixed source (Ti, Cr and Mo rich-source)] of PM2.5 in Delhi, India.

Hydrogeochemical processes in rural coastal aquifer (Haha region, Morocco).

In arid and semi-arid regions, groundwater is the principal source of urban and rural water supply. Given that groundwater is the only source of water supply in the Haha region (Moroccan Atlantic coast), the evaluation of this vital resource, using the hydrogeochemical approach, is the main objective of this study. The interpretation of these analytical data showed that the chemical composition of the groundwater is of Ca-Mg-Cl, Na-HCO3, and Na-Cl, with the dominance of the first type. Hydrochemical characteristics using the bivariate diagrams of major (Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, NO3-, and SO42-) and some trace elements (Br- and F-), mineral saturation indices, and statistical analysis show that the water-rock interaction, cation exchange processes, and marine effect are the main processes that control groundwater mineralization. Also, the majority of analyzed samples have concentrations above the thresholds for human consumption fixed by WHO, especially F-, NO3-, K+, Cl-, and HCO3- concentrations. This requires treatment of this groundwater before any consumption and domestic uses. For agricultural uses, the groundwater of the Haha region remains adequate, especially for plants, which can withstand water with electrical conductivity greater than 1000 µS/cm. However, the results obtained can be used as a basis for decision-makers for better water management in the Haha region.

Levels and distribution of chemical elements in house dust from the area of an abandoned Pb-Zn smelter in North Macedonia

The content of 41 chemical elements (Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hf, In, K, La, Li, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Rb, Sb, Sc, Se, Sm, Sr, Tb, Th, Ti, Tm, U, V, W, and Zn) was determined in attic dust, household dust and soil samples collected from 33 houses in the area of the town of Veles, North Macedonia. Silver, Cd, Cu, Li, P, and, Pb were analyzed by inductively coupled plasma - atomic emission spectrometry while the other elements were analyzed by neutron activation analysis. The study area has been continuously exposed to high amounts of potentially toxic elements due to the emission from an abandoned Pb-Zn smelter plant. In this study, attic and household dust together with soil samples collected from the yards of the houses were used to assess the level of historical and present air contamination by potentially toxic elements. It was found that the contents of Ag, As, Cd, Cu, In, Pb, Sb, Se, and, Zn in dust samples represented an anthropogenic association of elements, with very high contents in samples collected from the town of Veles, which is close to the Pb-Zn smelter, compared with those collected from the mountainous area.

Reactive X (where X = O, N, S, C, Cl, Br, and I) species nanomedicine.

Reactive oxygen, nitrogen, sulfur, carbonyl, chlorine, bromine, and iodine species (RXS, where X = O, N, S, C, Cl, Br, and I) have important roles in various normal physiological processes and act as essential regulators of cell metabolism; their inherent biological activities govern cell signaling, immune balance, and tissue homeostasis. However, an imbalance between RXS production and consumption will induce the occurrence and development of various diseases. Due to the considerable progress of nanomedicine, a variety of nanosystems that can regulate RXS has been rationally designed and engineered for restoring RXS balance to halt the pathological processes of different diseases. The invention of radical-regulating nanomaterials creates the possibility of intriguing projects for disease treatment and promotes advances in nanomedicine. In this comprehensive review, we summarize, discuss, and highlight very-recent advances in RXS-based nanomedicine for versatile disease treatments. This review particularly focuses on the types and pathological effects of these reactive species and explores the biological effects of RXS-based nanomaterials, accompanied by a discussion and the outlook of the challenges faced and future clinical translations of RXS nanomedicines.

Large presence of bromine and toxic metals in ambient fine particles from urban fires

Urban fires in densely populated areas can burn large amounts of manmade structures and synthetic materials. Realworld chemical composition data of urban fire plumes are vital for evaluating health impacts; however, they are rarely available. Online monitoring of trace elements in ambient PM2.5 at five sites throughout Hong Kong in 2021 provided unprecedented opportunities to observe the highly transient fire plumes. Sharp spikes were captured for bromine (up to 0.65 μg m−3), chlorine (7.0 μg m−3), and certain metals such as lead (0.97 μg m−3), zinc (8.3 μg m−3), and copper (0.32 μg m−3) during four urban fires, showing ∼10–6000 times higher concentrations than pre-fire periods. These elements showed decreased concentrations with increased distance from the fire location, but their concentration ratios remained relatively constant. During fire-influenced hours, these elements exhibited 3–101 times enrichment relative to iron, an element that had no discernible increase in concentration. Our results represent the first observation of the co-emissions of Br and certain metals from urban fires. Reactive bromine released from burning of the wide-spread brominated synthetic chemicals was suggested to facilitate the mobilization of toxic metals into the atmosphere. This mechanistic knowledge will help us understand the emissions and impacts of fires occurring in wildland urban interface zones. The work also calls attention to previously overlooked influence of urban fires-mobilized metals on human health and of bromine on atmospheric oxidizing capacity in megacities.

Elemental Variability of PM2.5 Aerosols in Historical and Modern Areas of Jeddah, Saudi Arabia

Air particulate matter with a diameter of 2.5 µm (PM2.5) were assembled for a whole year from the historical Jeddah district. Additional PM2.5 aerosols were collected during the autumn and winter seasons from another newly constructed district in Jeddah city (Alnaeem). The annual concentration of the total mass of the PM2.5 aerosols from the historical Jeddah site was found to be 43 ± 6 µg/m3. In addition, the average of the total mass concentration at the Alnaeem site was 61 ± 14 µg/m3. These values were greater than the annual mass concentration of the air quality standards of the European Commission (25 µg/m3) and the World Health Organization (10 µg/m3). The elemental analysis of the collected fine atmospheric aerosols was achieved by energy dispersive X-ray fluorescence (EDXRF) with three secondary targets (CaF2, Ge, and Mo). Quantitative elemental analyses of twenty-two (22) elements were achieved starting from the low atomic number element (Na) up to the high atomic number element (Pb). Although the historical Jeddah site is not well organized, the elemental concentrations and total mass concentrations were lower than those of the other site. The statistical analyses including enrichment factors, correlation analysis, and the principal component analysis revealed more information about the source identification of the PM2.5 aerosols collected from both locations. It was recognized that the elements Al, Si, K, Ca, Ti, Mn, Fe, Rb, and Sr originated from a natural source. On the other hand, the elements Ta, Br, Pb, Sc, Ni, Cu, Zn, and S originated from anthropogenic sources. Finally, the elements Na, Cl, and Br came mainly from the sea spray source.

Apparent Reactivity of Bromine in Bromochloramine Depends on Synthesis Method: Implicating Bromine Chloride and Molecular Bromine as Important Bromine Species.

The chloramination of bromide containing waters results in the formation of bromine containing haloamines: monobromamine (NH2Br), dibromamine (NHBr2), and bromochloramine (NHBrCl). Many studies have directly shown that bromamines are more reactive than chloramines in oxidation and substitution reactions with organic water constituents because the bromine atom in oxidants is more labile than the chlorine atom. However, similar studies have not been performed with NHBrCl. It has been assumed that NHBrCl has similar reactivity as bromamines with organic constituents in both oxidation and substitution reactions because NHBrCl, like bromamines, rapidly oxidizes N,N-diethyl-p-phenylenediamine. In this study, we examined the reactivity of NHBrCl with phenol red to determine if NHBrCl reacts as readily as bromamines in an isolated substitution reaction. NHBrCl was synthesized two ways to assess whether NHBrCl or the highly reactive intermediates, bromine chloride (BrCl) and molecular bromine (Br2), were responsible for bromine substitution of phenol red. NHBrCl was found to be much less reactive than bromamines with phenol red and that BrCl and Br2 appeared to be the true brominating agents in solutions where NHBrCl is formed. This work highlights the need to reexamine what the true brominating agents are in chloraminated waters containing bromide.