Investigating the suitability of online flow cytometry for monitoring full-scale drinking water ozone system disinfection effectiveness

While online monitoring of physicochemical parameters has widely been incorporated into drinking water treatment systems, online microbial monitoring has lagged behind, resulting in the use of surrogate parameters (disinfectant residual, applied dose, concentration × time, CT) to assess disinfection system performance. Online flow cytometry (online FCM) allows for automated quantification of total and intact microbial cells. This study sought to investigate the feasibility of online FCM for full-scale drinking water ozone disinfection system performance monitoring. A water treatment plant with high lime solids turbidity in the ozone contactor influent was selected to evaluate the online FCM in challenging conditions. Total and intact cell counts were monitored for 40 days and compared to surrogate parameters (ozone residual, ozone dose, and CT) and grab sample assay results for cellular adenosine triphosphate (cATP), heterotrophic plate counts (HPC), impedance flow cytometry, and 16S rRNA gene sequencing. Online FCM provided insight into the dynamics of the full-scale ozone system, including offering early warning of increased contactor effluent cell concentrations, which was not observed using surrogate measures. Positive correlations were observed between online FCM intact cell counts and cATP levels (Kendall's tau=0.40), HPC (Kendall's tau=0.20), and impedance flow cytometry results (Kendall's tau=0.30). Though a strong correlation between log intact cell removal and CT was not observed, 16S rRNA gene sequencing results showed that passage through the ozone contactor significantly changed the microbial community (p < 0.05). Potential causes of the low overall cell inactivation in the contactor and the significant changes in the microbial community after ozonation include regrowth in the later chambers of the contactor and varied ozone resistance of drinking water microorganisms. This study demonstrates the suitability of direct, online microbial analysis for monitoring full-scale disinfection systems.

Reducing Soil-Emitted Nitrous Acid as a Feasible Strategy for Tackling Ozone Pollution

Severe ozone (O3) pollution has been a major air quality issue and affects environmental sustainability in China. Conventional mitigation strategies focusing on reducing volatile organic compounds and nitrogen oxides (NOx) remain complex and challenging. Here, through field flux measurements and laboratory simulations, we observe substantial nitrous acid (HONO) emissions (FHONO) enhanced by nitrogen fertilizer application at an agricultural site. The observed FHONO significantly improves model performance in predicting atmospheric HONO and leads to regional O3 increases by 37%. We also demonstrate the significant potential of nitrification inhibitors in reducing emissions of reactive nitrogen, including HONO and NOx, by as much as 90%, as well as greenhouse gases like nitrous oxide by up to 60%. Our findings introduce a feasible concept for mitigating O3 pollution: reducing soil HONO emissions. Hence, this study has important implications for policy decisions related to the control of O3 pollution and climate change.

Atmospheric Oxidation Capacity Elevated during 2020 Spring Lockdown in Chengdu, China: Lessons for Future Secondary Pollution Control

This study presents the measurement of photochemical precursors during the lockdown period from January 23, 2020, to March 14, 2020, in Chengdu in response to the coronavirus (COVID-19) pandemic. To derive the lockdown impact on air quality, the observations are compared to the equivalent periods in the last 2 years. An observation-based model is used to investigate the atmospheric oxidation capacity change during lockdown. OH, HO2, and RO2 concentrations are simulated, which are elevated by 42, 220, and 277%, respectively, during the lockdown period, mainly due to the reduction in nitrogen oxides (NOx). However, the radical turnover rates, i.e., OH oxidation rate L(OH) and local ozone production rate P(O3), which determine the secondary intermediates formation and O3 formation, only increase by 24 and 48%, respectively. Therefore, the oxidation capacity increases slightly during lockdown, which is partly attributed to unchanged alkene concentrations. During the lockdown, alkene ozonolysis seems to be a significant radical primary source due to the elevated O3 concentrations. This unique data set during the lockdown period highlights the importance of controlling alkene emission to mitigate secondary pollution formation in Chengdu and may also be applicable in other regions of China given an expected NOx reduction due to the rapid transformation to electrified fleets in the future.

Foliar mycobiome remains unaltered under urban air-pollution but differentially express stress-related genes

Air pollution caused by tropospheric ozone contributes to the decline of forest ecosystems; for instance, sacred fir, Abies religiosa (Kunth) Schltdl. & Cham. forests in the peri-urban region of Mexico City. Individual trees within these forests exhibit variation in their response to ozone exposure, including the severity of visible symptoms in needles. Using RNA-Seq metatranscriptomic data and ITS2 metabarcoding, we investigated whether symptom variation correlates with the taxonomic and functional composition of fungal mycobiomes from needles collected in this highly polluted area in the surroundings of Mexico City. Our findings indicate that ozone-related symptoms do not significantly correlate with changes in the taxonomic composition of fungal mycobiomes. However, genes coding for 30 putative proteins were differentially expressed in the mycobiome of asymptomatic needles, including eight genes previously associated with resistance to oxidative stress. These results suggest that fungal communities likely play a role in mitigating the oxidative burst caused by tropospheric ozone in sacred fir. Our study illustrates the feasibility of using RNA-Seq data, accessible from global sequence repositories, for the characterization of fungal communities associated with plant tissues, including their gene expression.

Application of catalytic ozonation using Y zeolite in the elimination of pharmaceuticals in effluents from municipal wastewater treatment plants

Catalytic ozonation using faujasite-type Y zeolite with two different SiO2/Al2O3 molar ratios (60 and 12) was evaluated for the first time in the removal of 25 pharmaceutical compounds (PhCs) present in real effluents from two municipal wastewater treatment plants both located in the Mediterranean coast of Spain. Additionally, control experiments including adsorption and direct ozonation, were conducted to better understand the fundamental aspects of the different individual systems in wastewater samples. Commercial zeolites were used in sodium form (NaY). The results showed that the simultaneous use of ozone and NaY zeolites significantly improved the micropollutants degradation rate, able to degrade 95 % of the total mixture of PhCs within the early 9 min using the zeolite NaY-12 (24.4 mg O3 L-1 consumed), while 12 min of reaction with the zeolite NaY-60 (31 mg O3 L-1 consumed). In the case of individual experiments, ozonation removed 95 % of the total mixture of PhCs after 25 min (46.2 mg O3 L-1 consumed), while the direct adsorption, after 60 min of contact time, eliminated 30 % and 44 % using the NaY-12 and NaY-60 zeolites, respectively. Results showed that the Brønsted acid sites seemed to play an important role in the effectiveness of the treatment with ozone. Finally, the environmental assessment showed that the total risk quotients of pharmaceuticals were reduced between 87 %-99 % after ozonation in the presence of NaY-60 and NaY-12 zeolites. The results of this study demonstrate that catalytic ozonation using NaY zeolites as catalysts is a promising alternative for micropollutant elimination in real-world wastewater matrices.

Temporal characteristics and health effects related to NO2, O3, and SO2 in an urban area of Iran

This study reports on temporal variations of NO2, O3, and SO2 pollutants and their related health effects in urban air of Khorramabad, Iran using AirQ 2.2.3 software. Based on data between 2015 and 2021, hourly NO2, O3, and SO2 concentrations increase starting at 6:00 a.m. local time until 9:00 p.m., 3:00 p.m., and 7:00 p.m. local time, respectively, before gradually decreasing. The highest monthly NO2, O3, and SO2 concentrations are observed in October, August, and September, respectively. Annual median NO2, O3, and SO2 concentrations range between 17 ppb and 38.8 ppb, 17.5 ppb-36.6 ppb, and ∼14 ppb-30.8 ppb, respectively. Two to 93 days and 17-156 days between 2015 and 2021 exhibit daily concentrations of NO2 and SO2 ≤ WHO AQGs, respectively, while 187-294 days have 8-h maximum O3 concentrations ≤ WHO AQGs. The mean excess mortality ascribed to respiratory mortality, cardiovascular mortality, hospital admissions for COPD, and acute myocardial infraction are 121, 603, 39, and 145 during 2015-2021, respectively. O3 is found to exert more significant health effects compared to SO2 and NO2, resulting in higher cardiovascular mortality. The gradual increase in NO2 and possibly O3 over the study period is suspected to be due to economic sanctions, while SO2 decreased due to regulatory activity. Sustainable control strategies such as improving fuel quality, promoting public transportation and vehicle retirement, applying subsidies for purchase of electric vehicles, and application of European emission standards on automobiles can help decrease target pollutant levels in ambient air of cities in developing countries.

Ozone as an environmental driver of influenza

Under long-standing threat of seasonal influenza outbreaks, it remains imperative to understand the drivers of influenza dynamics which can guide mitigation measures. While the role of absolute humidity and temperature is extensively studied, the possibility of ambient ozone (O3) as an environmental driver of influenza has received scant attention. Here, using state-level data in the USA during 2010-2015, we examined such research hypothesis. For rigorous causal inference by evidence triangulation, we applied 3 distinct methods for data analysis: Convergent Cross Mapping from state-space reconstruction theory, Peter-Clark-momentary-conditional-independence plus as graphical modeling algorithms, and regression-based Generalised Linear Model. The negative impact of ambient O3 on influenza activity at 1-week lag is consistently demonstrated by those 3 methods. With O3 commonly known as air pollutant, the novel findings here on the inhibition effect of O3 on influenza activity warrant further investigations to inform environmental management and public health protection.

Association between long-term ozone exposure and readmission for chronic obstructive pulmonary disease exacerbation

The relationship between long-term ozone (O₃) exposure and readmission for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains elusive. In this study, we collected individual-level information on AECOPD hospitalizations from a standardized electronic database in Guangzhou from January 1, 2014, to December 31, 2015. We calculated the annual mean O₃ concentration prior to the dates of the index hospitalization for AECOPD using patients' residential addresses. Employing Cox proportional hazards models, we assessed the association between long-term O₃ concentration and the risk of AECOPD readmission across several time frames (30 days, 90 days, 180 days, and 365 days). We estimated the disease and economic burden of AECOPD readmissions attributable to O₃ using a counterfactual approach. Of the 4574 patients included in the study, 1398 (30.6%) were readmitted during the study period, with 262 (5.7%) readmitted within 30 days. The annual mean O₃ concentration was 90.3 μg/m3 (standard deviation [SD] = 8.2 μg/m3). A 10-μg/m3 increase in long-term O₃ concentration resulted in a hazard ratio (HR) for AECOPD readmission within 30 days of 1.28 (95% confidence interval [CI], 1.09 to 1.49), with similar results for readmission within 90, 180, and 365 days. Older patients (aged 75 years or above) and males were more susceptible (HR, 1.33; 95% CI, 1.10-1.61 and HR, 1.29; 95% CI, 1.09-1.53, respectively). The population attributable fraction for 30-day readmission due to O₃ exposure was 29.0% (95% CI, 28.4%-30.0%), and the attributable mean cost per participant was 362.3 USD (354.5-370.2). Long-term exposure to elevated O₃ concentrations is associated with an increased risk of AECOPD readmission, contributing to a significant disease and economic burden.

Peripheral HMGB1 is linked to O3 pathology of disease-associated astrocytes and amyloid

INTRODUCTION

Ozone (O3) is an air pollutant associated with Alzheimer's disease (AD) risk. The lung-brain axis is implicated in O3-associated glial and amyloid pathobiology; however, the role of disease-associated astrocytes (DAAs) in this process remains unknown.

METHODS

The O3-induced astrocyte phenotype was characterized in 5xFAD mice by spatial transcriptomics and proteomics. Hmgb1fl/fl LysM-Cre+ mice were used to assess the role of peripheral myeloid cell high mobility group box 1 (HMGB1).

RESULTS

O3 increased astrocyte and plaque numbers, impeded the astrocyte proteomic response to plaque deposition, augmented the DAA transcriptional fingerprint, increased astrocyte-microglia contact, and reduced bronchoalveolar lavage immune cell HMGB1 expression in 5xFAD mice. O3-exposed Hmgb1fl/fl LysM-Cre+ mice exhibited dysregulated DAA mRNA markers.

DISCUSSION

Astrocytes and peripheral myeloid cells are critical lung-brain axis interactors. HMGB1 loss in peripheral myeloid cells regulates the O3-induced DAA phenotype. These findings demonstrate a mechanism and potential intervention target for air pollution-induced AD pathobiology.

HIGHLIGHTS

Astrocytes are part of the lung-brain axis, regulating how air pollution affects plaque pathology. Ozone (O3) astrocyte effects are associated with increased plaques and modified by plaque localization. O3 uniquely disrupts the astrocyte transcriptomic and proteomic disease-associated astrocyte (DAA) phenotype in plaque associated astrocytes (PAA). O3 changes the PAA cell contact with microglia and cell-cell communication gene expression. Peripheral myeloid cell high mobility group box 1 regulates O3-induced transcriptomic changes in the DAA phenotype.

Performance evaluation and optimization of a suspension-type reactor for use in heterogeneous catalytic ozonation

Packed fixed-bed reactors are traditionally used for heterogeneous catalytic ozonation. However, a high solid-to-liquid requirement, poor ozone dissolution, ineffective utilization of catalyst surface area, and production of large amounts of catalyst waste impede application of such reactors. In this study, we designed a suspension catalytic ozonation reactor and compared the performance of this reactor with that of a traditional fixed-bed catalytic ozonation reactor employing oxalic acid (OA) as the target contaminant. Our results showed that total O3 dissolved into the suspension reactor (117-134 mg.L-1) was much higher compared to that measured in the fixed-bed reactor (53 mg.L-1) due to a higher O3(g) interphase mass transfer rate in the suspension reactor. In accordance with the higher O3(g) interphase mass transfer, we observed a much higher proportional OA removal (32 %) compared to that achieved in the fixed-bed reactor (10%) employing an Fe-oxide catalyst supported on Al2O3 (Fe-oxide@Al2O3) in both reactors. Use of a double-layered Cu-Al hydroxide (Cu-Al LDHs) catalyst in the suspension reactor further enhanced the performance with nearly 90 % OA removal observed. Given the superior performance of the suspension reactor, we investigated the impact of operating conditions (catalyst dosage, hydraulic retention time and ozone dosage) employing Cu-Al LDHs as the catalyst. We also developed a mathematical kinetic model to describe the performance of the suspension reactor and, through use of the kinetic model, showed that O3(g) interphase transfer rate was the rate-limiting step in OA removal. Thus, improvement in ozone gas diffuser design is required to improve the performance of the suspension reactor. Overall, the present study demonstrated that suspension reactors were more effective than fixed-bed reactors for oxidation of surface-active organic compounds such as OA due to the higher ozone interphase mass transfer rate and effective utilization of the catalyst surface area that can be achieved. As such, further research on suspension reactor design and development of catalysts suitable for use in suspension reactors should facilitate large-scale application of catalytic ozonation processes by the wastewater treatment industry.

Dielectric barrier discharge plasma promotes disinfection-residual-bacteria inactivation via electric field and reactive species

Traditional disinfection processes face significant challenges such as health and ecological risks associated with disinfection-residual-bacteria due to their single mechanism of action. Development of new disinfection processes with composite mechanisms is therefore urgently needed. In this study, we employed liquid ground-electrode dielectric barrier discharge (lgDBD) to achieve synergistic sterilization through electric field electroporation and reactive species oxidation. At a voltage of 12 kV, Pseudomonas fluorescens (ultraviolet and ozone-resistant) and Bacillus subtilis (chlorine-resistant) were completely inactivated within 8 and 6 min, respectively, surpassing a 7.0-log reduction. The lgDBD process showed good disinfection performance across a wide range of pH values and different practical water samples. Staining experiments suggest that cellular membrane damage contributes to this inactivation. In addition, we used a two-dimensional parallel streamer solver with kinetics code to fashion a representative model of the basic discharge unit, and discovered the presence of a persistent electric field during the discharge process with a peak value of 2.86 × 106 V/m. Plasma discharge generates excited state species such as O(1D) and N2(C3Πu), and further forms reactive oxygen and nitrogen species at the gas-liquid interface. The physical process, which is driven by electric field-induced cell membrane electroporation, synergizes with the bactericidal effects of reactive oxygen and nitrogen species to provide effective disinfection. Adopting the lgDBD process enhances sterilization efficiency and adaptability, underscoring its potential to revolutionize physicochemical synergistic disinfection practices.

Stacking Machine Learning Models Empowered High Time-Height-Resolved Ozone Profiling from the Ground to the Stratopause Based on MAX-DOAS Observation

Ozone (O3) profiles are crucial for comprehending the intricate interplay among O3 sources, sinks, and transport. However, conventional O3 monitoring approaches often suffer from limitations such as low spatiotemporal resolution, high cost, and cumbersome procedures. Here, we propose a novel approach that combines multiaxis differential optical absorption spectroscopy (MAX-DOAS) and machine learning (ML) technology. This approach allows the retrieval of O3 profiles with exceptionally high temporal resolution at the minute level and vertical resolution reaching the hundred-meter scale. The ML models are trained using parameters obtained from radiative transfer modeling, MAX-DOAS observations, and a reanalysis data set. To enhance the accuracy of retrieving the aqueous phosphorus from O3, we employ a stacking approach in constructing ML models. The retrieved MAX-DOAS O3 profiles are compared to data from an in situ instrument, lidar, and satellite observation, demonstrating a high level of consistency. The total error of this approach is estimated to be within 25%. On balance, this study is the first ground-based passive remote sensing of high time-height-resolved O3 distribution from ground to the stratopause (0-60 km). It opens up new avenues for enhancing our understanding of the dynamics of O3 in atmospheric environments. Moreover, the cost-effective and portable MAX-DOAS combined with this versatile profiling approach enables the potential for stereoscopic observations of various trace gases across multiple platforms.

Ozonated Sunflower Oil (OSO) Alleviates Inflammatory Responses in Oxazolone-Induced Atopic Dermatitis (AD)-Like Mice and LPS-Treated RAW 264.7 Cells

Ozone, a highly reactive oxidant molecule, is widely used as a complementary therapy for various skin diseases, including wound healing, pressure ulcers, diabetic foot, and infections. However, there is limited research on the effectiveness of ozone for atopic dermatitis (AD). Ozonated sunflower oil (OSO) is an active ingredient obtained from partially ozonated sunflower oil (SO). OSO markedly reduced the LPS-induced increase in IL-1β and nitric oxide (NO) levels in RAW 264.7 mouse macrophage cells. Oxazolone (OXZ) was applied to hairless mice to induce AD-like skin symptoms and immune response. OSO significantly alleviated the OXZ-induced increases in the number of infiltrating mast cells, epidermal thickness, AD symptoms, thymic stromal lymphopoietin (TSLP), and filaggrin, as well as the serum levels of NO, IgE, IL-1β, and TNF-α. Furthermore, OSO inhibited the IL-4/STAT3/MAPK pathway and the expression of NF-κB. Our results suggest that OSO treatment could relieve AD-mediated skin damage through its anti-inflammatory and antioxidant activities. Therefore, it can be used as a therapeutic agent against AD-related skin diseases.

Disinfection by-products control in wastewater effluents treated with ozone and biological activated carbon followed by UV/Chlor(am)ine processes

Sequential utilization of ozone (O3) and biological activated carbon (BAC) followed by UV/chlor(am)ine advanced oxidation process (AOP) has drawn attention in water reuse. However, the formation of disinfection by-products (DBPs) in this process is less evaluated. This study investigated the DBP formation and the relevant toxicity during the O3-BAC-UV/chlor(am)ine treatment of sand-filtered municipal secondary effluent. DBP formation in UV/chlorine and UV/dichloramine (NHCl2) processes were compared, where the impact of key operational parameters (e.g., UV wavelength, pH) on DBP formation were comprehensively evaluated. O3-BAC significantly reduced DBP formation potential (DBPFP) (58.2 %). Compared to UV/chlorine AOP, UV/NHCl2 AOP reduced DBP formation by 29.7 % in short-time treatment, while insignificantly impacting on DBPFP (p > 0.05). UV/NHCl2 AOP also led to lower calculated cytotoxicity (67.7 %) and genotoxicity (55.9 %) of DBPs compared to UV/chlorine AOP. Compared to 254 nm UV light, the utilization of 285 nm UV light decreased the formation of DBPs in wastewater treated with the UV/chlorine AOP and UV/NHCl2 AOP by 31.3 % and 19.2 %, respectively. However, the cytotoxicity and genotoxicity in UV/NHCl2 AOP using 285 nm UV light increased by 83.4 % and 58.5 %, respectively, compared to 254 nm. The concentration of DBPs formed in the UV/NHCl2 AOP at pH 8 was 54.3 % lower than that at pH 7, suggesting a better control of DBPs at alkaline condition. In the presence of bromide, UV/NHCl2 AOP tended to generate more brominated DBPs than UV/chlorine AOP. Overall, UV/NHCl2 AOP resulted in lower concentration and toxicity of DBPs compared to UV/chlorine AOP.

Enhancement Effect Induced by the Second Metal to Promote Ozone Catalytic Oxidation of VOCs

It is a promising research direction to develop catalysts with high stability and ozone utilization for low-temperature ozone catalytic oxidation of VOCs. While bimetallic catalysts exhibit excellent catalytic activity compared with conventional single noble metal catalysts, limited success has been achieved in the influence of the bimetallic effect on the stability and ozone utilization of metal catalysts. Herein, it is necessary to systematically study the enhancement effect in the ozone catalytic reaction induced by the second metal. With a simple continuous impregnation method, a platinum-cerium bimetallic catalyst is prepared. Also highlighted are studies from several aspects of the contribution of the second metal (Ce) to the stability and ozone utilization of the catalysts, including the "electronic effect" and "geometric effect". The synergistic removal rate of toluene and ozone is nearly 100% at 30 °C, and it still shows positive stability after high humidity and a long reaction time. More importantly, the instructive significance, which is the in-depth knowledge of enhanced catalytic mechanism of bimetallic catalysts resulting from a second metal, is provided by this work.

Switching reactive oxygen species reactions derived from Mn-Pt anchored zeolite for selective catalytic ozonation

Rationally switching reactive oxygen species (ROS) reactions in advanced oxidation processes (AOPs) is urgently needed to improve the adaptability and efficiency for the engineering application. Herein we synthesized bimetallic Mn-Pt catalysts based on zeolite to realize the switching of ROS reactions in catalytic ozonation for sustainable degradation of organic pollutants from water. The ROS reactions switched from singlet oxygen (1O2, 71.01%) to radical-dominated (93.79%) pathway by simply introducing defects and changing Pt/Mn ratios. The oxygen vacancy induced by anchoring Mn-Pt species from zeolite external surface (MnPt/H-Beta) to internal framework (MnPt@Si-Beta) exposes more electron-rich Pt2+/Pt4+ redox sites, accelerating the decomposition of O3 to generate •OH via electron transfer and switching ROS reactions. The Mn site acted as a bridge plays a critical role in conducting electrons from organic pollutants to Pt sites, which solidly solves the electron loss of catalysts, facilitating the efficient degradation of pollutants. A 34.7-fold increase in phenol degradation compared with the non-catalytic ozonation and an excellent catalytic stability are achieved by MnPt@Si-Beta/O3. The 1O2-dominated ROS reaction originated from MnPt/H-Beta/O3 exhibits superior performances in anti-interference for Cl-, HCO3-, NO3-, and SO4-. This work establishes a novel strategy for switching ROS reactions to expand the targeted applications of O3 based AOPs for environmental remediation.

Effect of pH on the ozonolysis degradation of p-nitrophenol in aquatic environment and the synergistic effect of hydroxy radical

Density functional theory (DFT) was employed to elucidate the mechanisms for ozonolysis reaction of p-nitrophenol (PNP) and its anion form aPNP. Thermodynamic data, coupled with Average Local Ionization Energies (ALIE) analysis, reveal that the ortho-positions of the OH/O- groups are the most favorable reaction sites. Moreover, rate constant calculations demonstrate that the O3 attack on the C2-C3 bond is the predominant process in the reaction between neutral PNP and O3. For the aPNP + O3 reaction, the most favorable pathways involve O3 attacking the C1-C2 and C6-C1 bonds. The rate constant for PNP ozonolysis positively correlates with pH, ranging from 5.47 × 108 to 2.86 × 109 M-1 s-1 in the natural aquatic environment. In addition, the formation of hydroxyl radicals in the ozonation process of PNP and the mechanisms of its synergistic reaction of PNP with ozone were investigated. Furthermore, the ozonation and hydroxylation processes involving the intermediate OH-derivatives were both thermodynamically and kinetic analyzed, which illustrate that OH radicals could promote the elimination of PNP. Finally, the toxic of PNP and the main products for fish, daphnia, green algae and rat were assessed. The findings reveal that certain intermediates possess greater toxicity than the original reactant. Consequently, the potential health risks these compounds pose to organisms warrant serious consideration.

Excessive Ozonation Stress Triggers Severe Membrane Biofilm Accumulation and Fouling

The established benefits of ozone on microbial pathogen inactivation, natural organic matter degradation, and inorganic/organic contaminant oxidation have favored its application in drinking water treatment. However, viable bacteria are still present after the ozonation of raw water, bringing a potential risk to membrane filtration systems in terms of biofilm accumulation and fouling. In this study, we shed light on the role of the specific ozone dose (0.5 mg-O3/mg-C) in biofilm accumulation during long-term membrane ultrafiltration. Results demonstrated that ozonation transformed the molecular structure of influent dissolved organic matter (DOM), producing fractions that were highly bioavailable at a specific ozone dose of 0.5, which was inferred to be a turning point. With the increase of the specific ozone dose, the biofilm microbial consortium was substantially shifted, demonstrating a decrease in richness and diversity. Unexpectedly, the opportunistic pathogen Legionella was stimulated and occurred in approximately 40% relative abundance at the higher specific ozone dose of 1. Accordingly, the membrane filtration system with a specific ozone dose of 0.5 presented a lower biofilm thickness, a weaker fluorescence intensity, smaller concentrations of polysaccharides and proteins, and a lower Raman activity, leading to a lower hydraulic resistance, compared to that with a specific ozone dose of 1. Our findings highlight the interaction mechanism between molecular-level DOM composition, biofilm microbial consortium, and membrane filtration performance, which provides an in-depth understanding of the impact of ozonation on biofilm accumulation.

Ozone alters the chemical signal required for plant - insect pollination: The case of the Mediterranean fig tree and its specific pollinator

Tropospheric ozone (O3) is likely to affect the chemical signal emitted by flowers to attract their pollinators through its effects on the emission of volatile organic compounds (VOCs) and its high reactivity with these compounds in the atmosphere. We investigated these possible effects using a plant-pollinator interaction where the VOCs responsible for pollinator attraction are known and which is commonly exposed to high O3 concentration episodes: the Mediterranean fig tree (Ficus carica) and its unique pollinator, the fig wasp (Blastophaga psenes). In controlled conditions, we exposed fig trees bearing receptive figs to a high-O3 episode (5 h) of 200 ppb and analyzed VOC emission. In addition, we investigated the chemical reactions occurring in the atmosphere between O3 and pollinator-attractive VOCs using real-time monitoring. Finally, we tested the response of fig wasps to the chemical signal when exposed to increasing O3 mixing ratios (0, 40, 80, 120 and 200 ppb). The exposure of the fig tree to high O3 levels induced a significant decrease in leaf stomatal conductance, a limited change in the emission by receptive figs of VOCs not involved in pollinator attraction, but a major change in the relative abundances of the compounds among pollinator-attractive VOCs in O3-enriched atmosphere. Fig VOCs reacted with O3 in the atmosphere even at the lowest level tested (40 ppb) and the resulting changes in VOC composition significantly disrupted the attraction of the specific pollinator. These results strongly suggest that current O3 episodes are probably already affecting the interaction between the fig tree and its specific pollinator.

PFAS removal from landfill leachate by ozone foam fractionation: System optimization and adsorption quantification

Landfills are the primary endpoint for the disposal of PFAS-laden waste, which subsequently releases PFAS to the surrounding environments through landfill leachate. Ozone foam fractionation emerges as a promising technology for PFAS removal to address the issue. This study aims to (i) assess the effectiveness of the ozone foam fractionation system to remove PFAS from landfill leachate, and (ii) quantify equilibrium PFAS adsorption onto the gas-water interface of ozone bubbles, followed by a comparison with air foam fractionation. The results show that ozone foam fractionation is effective for PFAS removal from landfill leachate, with more than 90 % long-chain PFAS removed. The identified operating conditions provide valuable insights for industrial applications, guiding the optimization of ozone flow rates (1 L/min), dosing (43 mg/L) and minimizing foamate production (4 % wettability). The equilibrium modelling reveals that the surface excess of air bubbles exceeds that of ozone bubbles by 20-40 % at a corresponding PFAS concentration. However, the overall removal of PFAS from landfill leachate by ozone foam fractionation remains substantial. Notably, ozone foam fractionation generates foamate volumes 2 - 4 times less, resulting in significant cost savings for the final disposal of waste products and reduced site storage requirements.

Gamma irradiation and ozone application as preservation methods for longer-term storage of bee pollen

Bee pollen is a healthy product with a good nutritional profile and therapeutic properties. Its high moisture content, however, promotes the growth of bacteria, molds, and yeast during storage commonly result in product degradation. Therefore, the aim of this study is to assess the effectiveness of gamma irradiation (GI) and ozone (OZ) as bee pollen preservation methods for longer storage time, as well as whether they are influenced by pollen species. To do that, GI at a dosage of 2.5, 5.0, and 7.5 kGy was applied at a rate of 0.68 kGy/h and OZ application at a concentration of 0.01, 0.02, and 0.03 g/m3 was applied for one time for 6 h, to Egyptian clover and maize bee pollen, then stored at ambient temperature for 6 months. We then determined the total phenolic content (TPC) and antioxidant activity of treated and non-treated pollen samples at 0, 3, and 6 months of storage. Total bacteria, mold, and yeast count were also evaluated at 0, 2, 4, and 6 months. Statistical analyses revealed that, TPC, antioxidant, and microbial load of both clover and maize pollen samples were significantly (p < 0.05) affected by both treatment and storage time and their interaction. Both methods were extremely effective at preserving the antioxidant properties of pollen samples after 6 months of storage at room temperature. Furthermore, the highest concentrations of both GI and OZ applications completely protected pollen samples from mold and yeast while decreasing bacterial contamination. GI at the highest dose (7.5 KGy) was found to be more effective than other GI doses and OZ application in preserving biologically active compounds and lowering the microbial count of pollen samples for 6 months. As a result, we advise beekeepers to use GI at this dose for longer-term storage.

Characterization of VOC emissions and health risk assessment in the plastic manufacturing industry

Volatile organic compounds (VOCs) significantly contribute to ozone pollution formation, and many VOCs are known to be harmful to human health. Plastic has become an indispensable material in various industries and daily use scenarios, yet the VOC emissions and associated health risks in the plastic manufacturing industry have received limited attention. In this study, we conducted sampling in three typical plastic manufacturing factories to analyze the emission characteristics of VOCs, ozone formation potential (OFP), and health risks for workers. Isopropanol was detected at relatively high concentrations in all three factories, with concentrations in organized emissions reaching 322.3 μg/m3, 344.8 μg/m3, and 22.6 μg/m3, respectively. Alkanes are the most emitted category of VOCs in plastic factories. However, alkenes and oxygenated volatile organic compounds (OVOCs) exhibit higher OFP. In organized emissions of different types of VOCs in the three factories, alkenes and OVOCs contributed 22.8%, 67%, and 37.8% to the OFP, respectively, highlighting the necessity of controlling them. The hazard index (HI) for all three factories was less than 1, indicating a low non-carcinogenic toxic risk; however, there is still a possibility of non-cancerous health risks in two of the factories, and a potential lifetime cancer risk in all of the three factories. For workers with job tenures exceeding 5 years, there may be potential health risks, hence wearing masks with protective capabilities is necessary. This study provides evidence for reducing VOC emissions and improving management measures to ensure the health protection of workers in the plastic manufacturing industry.

Influence of ozonation and UV/H2O2 on the genotoxicity of secondary wastewater effluents

The implementation of novel wastewater treatment technologies, including Advanced Oxidation Processes (AOPs) such as ozonation and ultraviolet radiation (UV) combined with hydrogen peroxide (H2O2), can be a promising strategy for enhancing the quality of these effluents. However, during effluent oxidation AOPs may produce toxic compounds that can compromise the water reuse and the receiving water body. Given this possibility, the aim of this study was to evaluate the genotoxic potential of secondary effluents from two different Wastewater Treatment Plants (WWTP) that were subjected to ozonation or UV/H2O2 for periods of 20 (T1) and 40 (T2) minutes. The genotoxic potential was carried out with the Comet assay (for clastogenic damage) and the Micronucleus assay (for clastogenic and aneugenic damage) in HepG2/C3A cell culture (metabolizing cell line). The results of the comet assay revealed a significant increase in tail intensity in the Municipal WWTP (dry period) effluents treated with UV/H2O2 (T1 and T2). MN occurrence was noted across all treatments in both Pilot and Municipal WWTP (dry period) effluents, whereas nuclear buds (NBs) were noted for all Pilot WWTP treatments and UV/H2O2 treatments of Municipal WWTP (dry period). Moreover, the UV/H2O2 (T1) treatment of Municipal WWTP (dry period) exhibited a noteworthy incidence of multiple alterations per cell (MN + NBs). These findings imply that UV/H2O2 treatment demonstrates higher genotoxic potential compared to ozonation. Furthermore, seasonal variations can have an impact on the genotoxicity of the samples. Results of the study emphasize the importance of conducting genotoxicological tests using human cell cultures, such as HepG2/C3A, to assess the final effluent quality from WWTP before its discharge or reuse. This precaution is essential to safeguard the integrity of the receiving water body and, by extension, the biotic components it contains.

Ultrasonic treatment of dye chemicals in wastewater: A review

The existence of pollutants, such as toxic organic dye chemicals, in water and wastewater raises concerns as they are inadequately eliminated through conventional water and wastewater treatment methods, including physicochemical and biological processes. Ultrasonic treatment has emerged as an advanced treatment process that has been widely applied to the decomposition of recalcitrant organic contaminants. Ultrasonic treatment has several advantages, including easy operation, sustainability, non-secondary pollutant production, and saving energy. This review examines the elimination of dye chemicals and categorizes them into cationic and anionic dyes based on the existing literature. The objectives include (i) analyzing the primary factors (water quality and ultrasonic conditions) that influence the sonodegradation of dye chemicals and their byproducts during ultrasonication, (ii) assessing the impact of the different sonocatalysts and combined systems (with ozone and ultraviolet) on sonodegradation, and (iii) exploring the characteristics-based removal mechanisms of dyes. In addition, this review proposes areas for future research on ultrasonic treatment of dye chemicals in water and wastewater.

Ultrasound-Guided Pes Anserine Bursitis Injection Choices: Prolotherapy or Oxygen-Ozone or Corticosteroid: A Randomized Multicenter Clinical Trial

OBJECTIVE

Pes anserine bursitis is the most common cause of periarticular knee pain. The aim of the study was to evaluate the efficacy of local injection-based therapies with different materials.

DESIGN

The enrolled patients were randomly allocated to three groups to receive different interventions. Outcome measures included pain severity using the visual analog scale and the Western Ontario and McMaster Universities osteoarthritis index that was evaluated before the intervention, 1 and 8 wks after that.

RESULTS

This trial was performed on 72 participants, with male-to-female ratio of 0.14 and with a mean age of 61.49 ± 9.35 yrs. Corticosteroids in the first group, oxygen-ozone in the second group, and dextrose 20% in the third group, were injected into the pes anserine bursa under ultrasound guidance. Interaction between time and group showed a statistically significant improvement in visual analog scale and Western Ontario and McMaster Universities Arthritis Index ( P ≤ 0.05) in favor of corticosteroids and oxygen-ozone groups after 1 wk and in favor of oxygen-ozone and prolotherapy groups after 8 wks.

CONCLUSIONS

All three treatment options are effective for patients with pes anserine bursitis. This study showed that the effects of oxygen-ozone injection and prolotherapy last longer than those of corticosteroid injection.

Ozone-induced oxidative stress alleviation by biogenic silver nanoparticles and ethylenediurea in mung bean (Vigna radiata L.) under high ambient ozone

Ground-level ozone (O3) is the most phytotoxic secondary air pollutant in the atmosphere, severely affecting crop yields worldwide. The role of nanoparticles (NP) in the alleviation of ozone-induced yield losses in crops is not known. Therefore, in the present study, we investigated the effects of biogenicB-AgNPs on the mitigation of ozone-induced phytotoxicity in mung bean and compared its results with ethylenediurea (EDU) for the first time. Two mung bean cultivars (Vigna radiata L., Cv. SML-668 and PDM-139) were foliar sprayed with weekly applications of B-AgNPs (0 = control, 10 and 25 ppm) and EDU (0 = control, 200 and 300 ppm) until maturation phase. Morphological, physiological, enzymatic, and non-enzymatic antioxidant data were collected 30 and 60 days after germination (DAG). The mean O3 and AOT40 values (8 h day-1) during the cultivation period were approximately 52 ppb and 4.4 ppm.h, respectively. More biomass was accumulated at the vegetative phase due to the impact of B-AgNPs and EDU, and more photosynthates were transported to the reproductive phase, increasing yield. We observed that the 10 ppm B-AgNPs treatment had a more noticeable impact on yield parameters and lower Ag accumulation in seeds for both cultivars. Specifically, SML-668 cultivar treated with 10 ppm B-AgNPs (SN1) showed greater increases in seed weight plant-1 (124.97%), hundred seed weight (33.45%), and harvest index (37.53%) in comparison to control. Our findings suggest that B-AgNPs can enhance growth, biomass, yield, and seed quality, and can improve mung bean ozone tolerance. Therefore, B-AgNPs may be a promising protectant for mung bean.

Sustainable crop production: Highlights on economic, environmental and social life cycle thinking

Seeking multi-dimensional inclusion is one of the most global concerns of the crop production sector worldwide. Socio-eco-effectiveness or socio-eco-efficiency optimization plays a crucial role in future strategy establishment. Life cycle is a widely used approach examining economic, environmental, and social impacts. Recently, life cycle thinking approaches have been increasingly utilized to bring to light useful perceptions of the crop production processes. This study aims to apply a systematic review and prescriptive analytics to critically investigate the life cycle thinking approaches application according to sustainability pyramid aspects, life cycle thinking unicity, goal and scope variability, functional units' causality, system boundary' diversity, involved aspect' concentration, indicators, impacts categories and influencing variables distribution, as well as to define a first datasheet model and directive axis to apply per aspect and family for socio-eco-effectiveness or socio-eco-efficiency evaluation. Over 295 peer-reviewed studies from 2019 to the middle of 2023, 52 reviews and articles gathered from Web of Science and Scopus meet the criteria to be analyzed. Our inspection revealed that related reviews are few, approximately 2 %. Moving from the traditional life cycle perspective to the sustainability pyramid approach, the indicators applied by researchers were classified per aspect and family belonging. A deductive analysis was carried out to narrow the impact categories, and the influencing factors to the population's main interests: four economic (input status, resources consumption, waste, and Costs of Life Cycle), eight environmental (Climate Change, Global Warming, Ozone, Acidification, Eutrophication, Photochemical Oxidation, Abiotic Depletion, and Toxicity), and three social families (Human Toxicity, employment, and Ionizing Radiation). The results combination highlights the construction need for a directive datasheet model to address the optimizing problem under the identified families and aspects constraints, as well as to envisage the units and methods worldwide standardization's necessity for spatial-temporal studies comparison in the present, the past, and the future.

Tire additives: Evaluation of joint toxicity, design of new derivatives and mechanism analysis of free radical oxidation

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) is one of the most widely used antioxidant agents in tire additives. Its ozonation by-product 6PPD-quinone has recently been recognized as inducing acute mortality in aquatic organisms such as coho salmon. In this study, we aimed to develop an in-silico method to design environmentally friendly 6PPD derivatives and evaluate the joint toxicity of 6PPD with other commonly used tire additives on coho salmon through full factorial design-molecular docking and molecular dynamic simulation. The toxicity mentioned in this study is represented by the binding energy of chemical(s) binding to the coho salmon growth hormone. The recommended formula for tire additives with relatively low toxicity was then proposed. To further reduce the toxicity of 6PPD, 129 6PPD derivatives were designed based on the N-H bond dissociation reaction, and three of these derivatives showed improved antioxidant activity and 6PPD-106 was finally screened as the optimum alternative with lower toxicity to coho salmon. Besides, the mechanism of free radical oxidation (i.e., antioxidation and ozonation metabolic pathway) for 6PPD-106 was also analyzed and found that after ozonation, the toxicity of 6PPD-106's by-products is much lower than that of 6PPD's by-products. This study provided a molecular modelling-based examination of 6PPD, which comprehensively advanced the understanding of 6PPD's environmental behaviors and provided more environmentally friendly 6PPD alternatives with desired functional property and lower ecological risks.

Comparison on removal performance of virus, antibiotic-resistant bacteria, cell-associated and cell-free antibiotic resistance genes, and indicator chemicals by ozone in the filtrated secondary effluent of a sewage treatment plant

Due to the widespread appearance of viruses, antibiotic-resistant bacteria (ARBs), and antibiotic resistance genes (ARGs) in the aquatic environment, more powerful oxidation processes such as ozonation are needed to enhance the efficiency of their inactivation and removal during wastewater treatment. However, information is lacking on the elimination rates of viruses, ARBs, cell-associated ARGs (ca-ARGs), and cell-free ARGs (cf-ARGs) during ozonation. This study examined the kinetics and dose-dependent inactivation of a virus (MS2 coliphage) and an ARB (Ampicillin-resistant [AmpR] E. coli) and the removal of ca- and cf-ARGs (plasmid-encoded blaTEM) by ozonation in a filtered secondary effluent (SE) of a municipal sewage treatment plant (STP). In addition, the ozonation kinetics of carbamazepine (CBZ) and metoprolol (MTP)-ubiquitous organic micropollutants with different removal rate constants-were also investigated in order to monitor their effectiveness as indicators for the abovementioned biological risk factors. Our results showed that ozonation was an efficient way to remove MS2, AmpRE. coli, ARGs, CBZ, and MTP. We investigated the kinetics of their inactivation/removal with respect to exposure in terms of CT (dissolved ozone concentration C and contact time T) value, and found their inactivation/removal constants were in the following order: MS2 (8.66 ×103 M-1s-1) ≈ AmpRE. coli (8.19 ×103 M-1s-1) > cf-ARG (3.95 ×103 M-1s-1) > CBZ (3.21 ×103 M-1s-1) > ca-ARG (2.48×103 M-1s-1) > MTP (8.35 ×102 M-1s-1). In terms of specific ozone dose, > 5-log inactivation of MS2 was observed at > 0.30 mg O3/mg DOC, while > 5-log inactivation of AmpRE. coli was confirmed at 1.61-2.35 mg O3/mg DOC. Moreover, there was almost no removal of ca-ARG when the specific ozone dose was < 0.68 mg O3/mg DOC. However, 2.86-3.42-log removal of ca-ARG was observed at 1.27-1.31 mg O3/mg DOC, while 1.14-1.36-log removal of cf-ARG was confirmed at 3.60-4.30 mg O3/mg DOC. As alternative indicators, > 4-log removal of CBZ was observed at > 1.00 mg O3/mg DOC, while > 2-log removal of MTP was confirmed at > 2.00 mg O3/mg DOC. Thus, it was observed that inactivation of E. coli needs a greater ozone dose to achieve the same level of inactivation of AmpRE. coli; for ARGs, cf-ARG can persist longer than ca-ARG if low dosages of ozone are applied in the filtrated SE, CBZ might act as an indicator with which to monitor the inactivation of viruses and ARBs, while MTP might act as an indicator with which to monitor removal of ARGs. Moreover, cf-ARG cannot be neglected even after ozonation due to the possibility that ca-ARGs can become cf-ARGs during ozonation and be discharged with the final effluent, posing a potential risk to the receiving environment.

Oxidant-mediated radical reactions of the azole fungicide TEB in aquatic media: Degradation mechanism and toxicity evolution

The degradation of tebuconazole (TEB) by UV/H2O2, UV/NaClO, and ozonation was investigated in this research. The experimental findings unveiled that under the specified conditions, the degradation percentages of TEB were raised to 99% within 40 s, 5 min, and 3 min for UV/H2O2, UV/NaClO and ozonation, respectively. The mineralization percentages within 1 h were 59%, 31% and 8% for the three AOPs. UV/H2O2 and UV/NaClO technologies mainly acted through OH·, while O3 treatment primarily relied on the free radicals such as 1O2 and O2·-. UV-based AOPs achieved almost complete dechlorination within 1 h, whereas O3 treatment had a less effective dechlorination, reaching only 27.61%. Notably, UV alone achieved a dechlorination percentage of 43.07%. By identifying the TPs, we found that the three AOPs shared three similar degradation pathways. The degradation mechanism of TEB mainly entailed the removal of the benzene ring, tert-butyl group and triazolyl group. Toxicity assessment revealed an initial increase followed by a gradual decrease in toxicity for UV/NaClO and O3 treatments, whereas UV/H2O2 treatment exhibited a sustained decrease. This was due to the presence of TP278 and TP303 by UV/NaClO and TP168 and TP153 by ozonation. After estimating the costs of the three AOPs, UV/H2O2 standed out as the best choice for achieving a 90% degradation percentage and exhibiting lower toxicity performance, while O3 treatment was favored for low TOC demands. These research findings provided valuable reference for understanding the degradation mechanism and developing a new technology of the removal of TEB.

Targeted regulation of digestate dewaterability by the ozone/persulfate oxidation process

Dewatering is the first step in the subsequent treatment and disposal of food waste digestate (FWD). However, FWD is difficult to dewatering. In this study, persulfate was synergistic oxidized by ozone to improve digestate dewaterability. The optimal conditions was at pH = 3, O3＝40 mg/g TS and PDS＝0.1 g/g TS, under which the reductions in the normalized capillary suction time (NCST) and bound moisture (BM) of the FWD were 89.97% and 65.79%, respectively. Hydrophilic functional groups (oxygen- and nitrogen-containing groups) and hydrophilic protein molecular structures were decomposed by the reactive species of sulfate radical (SO4·-) and hydroxyl radicals (·OH) generated in the ozone-persulfate oxidation process, disrupting the binding between EPS and water molecules. The contributions of SO4·- and ·OH to digestate dewaterability were 42.51% and 28.55%. In addition, the introduction of H+ reduced electrostatic repulsion and contributed to the condensation of digestate flocs. The environmental implication assessment and economic analysis suggested that the O3/PDS oxidation process was cost-effective and has a low environmental implication when applied to the FWD dewaterability improvement process. These results can serve as a reference for the management of FWD and further improvement of FWD treatment and disposal efficiency.

Efficacy of an experimental gaseous ozone-based sterilization method for clear aligners

OBJECTIVES

To assess effectiveness of an experimental sterilization method based on the exposure of an O3/O2 gas mixture directly inside the packaging for clear aligners.

MATERIALS AND METHODS

Fifty samples consisting of pieces of polyethylene terephthalate glycol (PET-G) aligners were contaminated by manual handling and subsequently divided into different groups (n = 30 for exposure to O3/O2 gas at different times, n = 10 for positive control with 2% chlorhexidine digluconate, n = 10 for negative control). The measurement of optical densities (OD) of the initial and final microbial cultures was recorded for all groups. Kruskal-Wallis test was used for differences between groups while Wilcoxon test was used to compare initial and final OD values within groups. Statistical significance was set at P < .05.

RESULTS

Comparison within the groups showed statistically significant differences for exposure to the gaseous mixture (72 hours), for positive and negative controls. Other significant differences were found in the multiple comparisons between the application of gaseous ozone (48 hours and 72 hours) and the negative control.

CONCLUSIONS

The direct exposure of gaseous ozone on the aligners inside their packaging showed microbicidal capacity at 72 hours, which was equivalent to the positive control with immersion in chlorhexidine digluconate. This innovative sterilization procedure could be considered in the final manufacturing processes of clear aligners to eliminate the potentially pathogenic microorganisms that are deposited on surfaces of these orthodontic devices.

A bibliometric analysis of research on the health impacts of ozone air pollution

Ground-level ozone (O3) is one of the major air pollutants. A large body of literature has linked O3 air pollution to various adverse human health effects. The objective of this study is to attain a comprehensive and in-depth understanding of the progress and frontiers of research on O3 and human health. We used bibliometric methods to summarize publications on O3 air pollution and public health between 1990 and 2022 obtained from the Web of Science Core Collection database. VOSviewer and R software were used for bibliometric analysis and visualization. A total of 4501 relevant papers were included in the analysis. There has been a significant increase in the number of publications since 2013, with the USA being the major contributor, followed by China and England. Harvard University was the most prolific research institution, followed by the US Environmental Protection Agency and the University of North Carolina System. Professor Joel Schwartz was the most published author and has established a complex network of national and international collaborations. Co-occurrence analysis of keywords suggested evolving research hotspots, from toxicological studies to population-based epidemiological studies and from the respiratory system to the extra-pulmonary system. Research on O3 and its human health effects has progressed rapidly over the past few decades, but academic disparities still persist between developed and developing countries. There is an urgent need to strengthen international cooperation to address the public health challenges posed by rising O3 air pollution in the future.

Investigation of HO2 uptake mechanisms onto multiple-component ambient aerosols collected in summer and winter time in Yokohama, Japan

The heterogeneous loss of HO2 radicals onto ambient aerosols plays an important role in tropospheric chemistry. However, sparse investigation of the dominating parameters controlling the HO2 uptake coefficients onto ambient aerosols (γHO2) has largely hindered the application of the measured γHO2 to the global spatial prediction. Here we induced an offline method using LFP-LIF technique to measure the kinetics of HO2 uptake onto ambient aerosols collected in summertime and wintertime in Yokohama city, a regional urban site near Tokyo, Japan. By controlling the dominating parameters which influence γHO2, we were able to investigate the detailed HO2 uptake mechanism. We characterized the chemical composition of the collected ambient aerosols, including organics, inorganics, transition metals ions, etc. and modeled γHO2 using different mechanisms. Results show that γHO2 increased with the increase in RH, and the aerosol states ("dry" or wet/aqueous) have large effects on γHO2. With fixed RH and aerosol chemical composition, γHO2was highly dependent on pH and inversely correlated with [HO2]0. By combing the measured γHO2 values with the modeled ones, we found that both the HO2 self-reaction and transition metal-catalyzed reactions should be accounted for to yield a single parameterization to predict γHO2, and different chemical compositions may have collective effects on γHO2. Results may serve for extending the γHO2 values measured at one observation site to different environmental conditions, which will help us to achieve more accurate modeling results concerning secondary pollutant formation (i.e., ozone).

Efficient treatment of veterinary pharmaceutical industrial wastewater by catalytic ozonation process: degradation of enrofloxacin via molecular ozone reactions

The study focused on the efficacious performance of bimetallic Fe-Zn loaded 3A zeolite in catalytic ozonation for the degradation of highly toxic veterinary antibiotic enrofloxacin in wastewater of the pharmaceutical industry. Batch experiments were conducted in a glass reactor containing a submerged pump holding catalyst pellets at suction. The submerged pump provided the agitation and recirculation across the solution for effective contact with the catalyst. The effect of ozone flow (0.8-1.55 mg/min) and catalyst dose (5-15 g/L) on the enrofloxacin degradation and removal of other conventional pollutants COD, BOD5, turbidity was studied. In batch experiments, 10 g of Fe-Zn 3A zeolite efficiently removed 92% of enrofloxacin, 77% of COD, 69% BOD5, and 61% turbidity in 1 L sample of pharmaceutical wastewater in 30 min at 1.1 mg/min of O3 flow. The catalytic performance of Fe-Zn 3A zeolite notably exceeded the removal efficiencies of 52%, 51%, 52%, and 59% for enrofloxacin, COD, BOD5, and turbidity, respectively, achieved with single ozonation process. Furthermore, an increase in the biodegradability of treated pharmaceutical industrial wastewater was observed and made biodegradable easily for subsequent treatment.

Heterogeneous (gas-solid) chemistry of atmospheric Cr: A case study of Astana, Kazakhstan

Hexavalent chromium (Cr(VI)) is a known carcinogen derived from both anthropogenic and natural sources. This work reports the size-segregated concentrations of total Cr(VI) in particulate matter (PM) in Astana, the capital of Kazakhstan, and provides new insights into the gas-solid reactions of atmospheric Cr. A study of total Cr(VI) in the particulate matter, via a microwave-assisted digestion technique, was conducted using a 5-stage Sioutas Cascade impactor that captures airborne particles in size ranges: >2.5 μm, 1.0-2.5 μm, 0.50-1.0 μm, 0.25-0.50 μm, and <0.25 μm. The total Cr(VI) concentration in the size fraction <0.25 μm was the highest with a maximum value of 9.7 ng/m3. This high concentration may pose a greater risk because smaller airborne particles can penetrate deeper into the lower respiratory tract of the lungs. Total suspended particles Cr(VI) exceeded the 8.0 ng/m3 Reference Concentration (RfC) by 22 times. The overall total Cr(VI) concentration in summer was significantly higher than in fall (p < 0.05), which could be due to factors, including higher temperatures, ozone, and NO2 concentrations in summer and a higher VOC concentration in fall. The results indicate that the interaction between Cr(III) and Cr(VI) through gas-solid reaction can control the speciation of atmospheric Cr.

Removal characteristics of 53 micropollutants during ozonation, chlorination, and UV/H2O2 processes used in drinking water treatment plant

The removal of 53 emerging micropollutants (MPs), including 10 per- and polyfluorinated substances (PFASs), 25 pharmaceuticals and personal care products (PPCPs), 7 pesticides, 5 endocrine disrupters (EDCs), 3 nitrosamines, and 3 taste and odor compounds (T&Os), by chlorination, ozonation, and UV/H2O2 treatment was examined in deionized water and surface waters used as the raw waters in drinking water treatment plants (DWTPs) in South Korea. The UV/H2O2 treatment was effective in the removal of most MPs, whereas chlorination was selectively effective for 19 MPs, including EDCs (>70 %). MPs containing aromatic ring with electron-donating functional group, or primary and secondary amines were effectively removed by chlorination immediately upon reaction initiation. The removal of MPs by ozonation was generally lower than that of the other two processes at a low ozone dose (1 mg L-1), but higher than chlorination at a high ozone dose (3 mg L-1), particularly for 16 MPs, including T&Os. Compared in deionized water, the removals of MPs in the raw water samples were lower in all three processes. The regression models predicting the rate constants (kobs) of 53 MPs showed good agreement between modeled and measured value for UV/H2O2 treatment (R2 = 0.948) and chlorination (R2 = 0.973), despite using only dissolved organic carbon (DOC) and oxidant concentration as variables, whereas the ozonation model showed a variation (R2 = 0.943). Our results can provide the resources for determining which oxidative process is suitable for treating specific MPs present in the raw waters of DWTPs.

Formation and toxicity contribution of chlorinated and dechlorinated halobenzoquinones from dichlorophenols after ozonation

Halobenzoquinones (HBQs) are a class of disinfection byproducts with high cytotoxicity and potential carcinogenicity, which have been widely detected in chlorination of drinking water and swimming pool water. However, to date, the formation of HBQs upon ozonation and the HBQ precursors have been overlooked. This study investigated the formation of chlorinated and dechlorinated HBQs from six dichlorophenol (DCP) isomers. The monomeric and dimeric HBQs were identified in all the ozonation effluents, exhibiting 1-100 times higher toxicity levels than their precursors. The sum of detected HBQs intensity had a satisfactory linear relation with the maximum toxic unit (R2 = 0.9657), indicating the primary toxicity contribution to the increased overall toxicity of effluents. Based on density functional theory calculations, when ozone attacks the para carbon to the hydroxyl group of 2,3-DCP, the probability of producing chlorinated HBQs is 80.41 %, indicating that the para carbon attack mainly resulted in the formation of monomeric HBQs. 2,3-dichlorophenoxy radicals were successfully detected in ozonated 2,3-DCP effluent through electron paramagnetic resonance and further validated using theoretical calculation, revealing the formation pathway of dimeric HBQs. The results indicate that chlorinated phenols, regardless of the positions of chlorine substitution, can potentially serve as precursors for both chlorinated and dechlorinated HBQs formation during ozonation.

Mortality Risk After a Major Cancer Surgery Is Associated With Preoperative Exposure to Air Pollution: A Nationwide Cohort Study in South Korea

OBJECTIVE

The aim of the study is to examine whether preoprerative exposure to air pollution is associated with mortality after a major cancer surgery.

METHODS

All patients who underwent major cancer surgeries after hospitalization between January 1, 2016, to December 31, 2020, were included.

RESULTS

In total, 244,766 patients who underwent major cancer surgeries were included. Both 0.001-ppm increase in sulfur dioxide and 0.1-ppm increase in carbon monoxide were associated with a 7% increase in 90-day mortality rate after a major cancer surgery. Furthermore, a 0.001-ppm increase in sulfur dioxide, 0.1 ppm increase in carbon monoxide, and 1 μg/m 3 increase in particulate matter 2.5 were associated with a 4%, 3%, and 1% increase in 1-year all-cause mortality rate after a major cancer surgery.

CONCLUSIONS

Preoperative exposure to air pollution was associated with an increased risk of mortality in patients after major cancer surgery.

Heatwave 1987: the Piraeus versus Athens case

Background

Heatwaves represent the main indices of climate change, while mortality is one of the established markers of their human effects. For unknown reasons populations adapt to temperature variations/challenges differently. Thus, to allow better precision and prediction, heatwave evaluations should be enriched by historical context and local data.

Methods

The mortality data for 1987 were collected from the Piraeus municipality registry, whereas data for Athens were obtained from literature retrieved from PUBMED. Ambient characteristics were extracted from the Geronikolou's 1991 BSc thesis and the reports of national organizations. From the death events, the odds ratio and relative risk in Piraeus compared to the Athens were calculated. Finally, a simple neural network proposed the dominant ambient parameter of the heatwave effects in the city residents of each location.

Results

The 1987 heatwave was more lethal (seven-fold) in Athens than in Piraeus and dependent on atmospheric nitric oxide (NO) concentration (with probability 0.999). In the case of Piraeus in 1987, ozone characterized the phenomenon (with probability 0.993).

Conclusions

The odds of dying due to a heatwave are highly dependent on lifestyle, population sensitivity to preventive measures and public health policy, while the phenomenon was mainly moderated by ozone in Piraeus in 1987, and NO in Athens irrespective of year.

Machine learning analysis of socioeconomic drivers in urban ozone pollution in Chinese cities

The escalation of ground-level ozone (O3) pollution presents a significant challenge to the sustainable growth of Chinese cities. This study utilizes advanced machine learning algorithms to investigate the intricate interplay between urban socioeconomic growth and O3 levels. Surpassing traditional environmental chemistry, it assesses the effectiveness of these algorithms in interpreting socioeconomic and environmental data, while elucidating urban development's environmental impacts from a novel socioeconomic perspective. Key findings indicate that factors such as urban infrastructure, industrial activities, and demographic dynamics significantly influence O3 pollution. The study highlights the particular sensitivity of urban public transportation and population density, each exerting a unique and substantial effect on O3 levels. Additionally, the research identifies nuanced interactions among these factors, indicating a complex web of influences on urban O3 pollution. These interactions suggest that the impact of individual socioeconomic elements on O3 pollution is interdependent, being either amplified or mitigated by other factors. The study emphasizes the crucial need to integrate socioeconomic variables into urban O3 pollution strategies, advocating for policies tailored to each city's distinct characteristics, informed by the detailed analysis provided by machine learning. This approach is essential for developing effective and nuanced urban pollution management strategies.

Localized biogenic volatile organic compound emission inventory in China: A comprehensive review

Volatile organic compounds (VOCs) are the precursors of forming ozone (O3) and fine particulate matter (PM2.5). Accurate estimates of biogenic VOC (BVOC) emissions is essential for understanding the formation mechanism of O3 and PM2.5 pollution and precise reduction on anthropogenic emissions and thereby mitigating O3 and PM2.5 pollution. To gain comprehensive knowledge of BVOC emissions and improve the accuracy of their estimation, this study reviewed localized national, regional, and municipal emission estimations in China. From their comparisons, BVOC emission characteristics and deficiencies in the inventory compilation methodology were also investigated. The estimated BVOC emissions in China ranged between 10 and 58.9 Tg yr-1 and 10.9-18.9 Tg C yr-1, with diverse contributions for different BVOC categories. The simulated historical and future BVOC emissions exhibited an increasing trend. The uncertainty of the BVOC estimates was mainly from the applications of incomplete emission models, less localized accurate emission factors, deficient vegetation cover information, and low-resolution meteorological data in the inventory compilation. The regional and municipal BVOC emission inventories mainly focused on the Beijing-Tianjin-Hebei, Pearl River Delta, Sichuan Basin, and Yangtze River Delta regions, as well as the cities therein. For the same area, different studies reported diverse BVOC emissions by a maximum of two orders of magnitude. There is usually a lack of basic data with more detailed investigations and higher precision for estimation of BVOC emissions. By summarizing the measurements on terrestrial and marine BVOC emission fluxes, they are mainly focused on the Guangdong, Zhejiang and Jiangxi provinces, and Yellow Sea, East China Sea, and South China Sea, respectively. Expanding the temporal and spatial scales of observations is encouraged to enhance our understanding on the emissions and improve the emission estimates.

Deep Characterisation of the sn-Isomer Lipidome Using High-Throughput Data-Independent Acquisition and Ozone-Induced Dissociation

In recent years there has been a significant interest in the development of innovative lipidomics techniques capable of resolving lipid isomers. To date, methods applied to resolving sn-isomers have resolved only a limited number of species. We report a workflow based on ozone-induced dissociation for untargeted characterisation of hundreds of sn-resolved glycerophospholipid isomers from biological extracts in under 20 min, coupled with an automated data analysis pipeline. It provides an order of magnitude increase in the number of sn-isomer pairs identified as compared to previous reports and reveals that sn-isomer populations are tightly regulated and significantly different between cell lines. The sensitivity of this method and potential for de novo molecular discovery is further demonstrated by the identification of unexpected lipids containing ultra-long monounsaturated acyl chains at the sn-1 position.

Combining fungal bioremediation and ozonation for rinse wastewater treatment

In this work, agricultural rinse wastewater, which is produced during the cleaning of agricultural equipment and constitutes a major source of pesticides, was treated by fungal bioremediation and ozonation, both individually and combined in a two-stage treatment train. Three major pesticides (thiacloprid, chlortoluron, and pyrimethanil) were detected in rinse wastewater, with a total concentration of 38.47 mg C L-1. Comparing both technologies, ozonation in a stirred reactor achieved complete removal of these pesticides (720 min) while proving to be a more effective approach for reducing colour, organic matter, and bacteria. However, this technique produced transformation products and increased toxicity. In contrast, fungal bioremediation in a rotating drum bioreactor attenuated toxicity levels and did not produce such metabolites, but only removed approximately 50 % of target pesticide - hydraulic retention time (HRT) of 5 days - and obtained worse results for most of the general quality parameters studied. This work also includes a preliminary economic assessment of both technologies, revealing that fungal bioremediation was 2 times more cost-effective than ozonation. The treatment train, consisting of a first stage of fungal bioremediation followed by ozonation, was found to be a promising approach as it synergistically combines the advantages of both treatments, achieving high removals of pesticides (up to 100 %) and transformation products, while reducing operating costs and producing a biodegradable effluent. This is the first time that fungal bioremediation and ozonation technologies have been compared and combined in a treatment train to deal with pesticides in agricultural rinse wastewater.

Synthesis and Characterization of Organic Peroxides from Monoterpene-Derived Criegee Intermediates in Secondary Organic Aerosol

Ozonolysis of alkenes is known to produce reactive intermediates─stabilized Criegee intermediates (SCIs), and their subsequent bimolecular reactions with various carboxylic acids can form α-acyloxyalkyl hydroperoxides (AAHPs), which is considered a major class of organic peroxides in secondary organic aerosol (SOA). Despite their atmospheric and health importance, the molecular-level identification of organic peroxides in atmospheric aerosols is highly challenging, preventing further assessment of their environmental fate. Here, we synthesize 20 atmospherically relevant AAHPs through liquid-phase ozonolysis, in which two types of monoterpene-derived SCIs from either α-pinene or 3-carene are scavenged by 10 different carboxylic acids to form AAHPs with diverse structures. These AAHPs are identified individually by liquid chromatography coupled with high-resolution mass spectrometry. AAHPs were previously thought to decompose quickly in an aqueous environment such as cloud droplets, but we demonstrate here that AAHPs hydrolysis rates are highly compound-dependent with rate constants differing by 2 orders of magnitude. In contrast, the aqueous-phase formation rate constants between SCI and various carboxylic acids vary only within a factor of 2-3. Finally, we identified two of the 20 synthesized AAHPs in α-pinene SOA and two in 3-carene SOA, contributing ∼0.3% to the total SOA mass. Our results improve the current molecular-level understanding of organic peroxides and are useful for a more accurate assessment of their environmental fate and health impact.

Preparation of ceramsite using solid residue from anaerobic digestion of waste activated sludge and its enhancing effect on catalytic ozonation

Anaerobic digestion is an environmentally friendly method for reclaiming waste activated sludge. However, it cannot be overlooked that the solid residue generated from this process can still pose environmental risks and impose economic pressure on society. To mitigate and recycle the solid residue, this study utilized it as a primary raw material for manufacturing ceramsite with potential applications in wastewater treatment. The optimal ratio of solid residue to fly ash was demonstrated to be 6:4 with an additional 15% of clay supplementing the raw ceramsite materials. Furthermore, the optimal sintering process was established as preheating at 300 °C for 25 min followed by sintering at 1085 °C for 10 min, as determined through an L16 (44) Orthogonal test. The prepared ceramsite demonstrated advantageous performance parameters that exceeded the standards outlined in the Chinese industry standard CJ/T 299-2008 for water treatment artificial ceramsite. When utilized in an ozonation system, the ceramsite exhibited remarkable catalytic activity for phenol degradation by promoting the decomposition of molecular O3 into hydroxyl radicals. Additionally, it displayed minimal leaching of heavy metals and lower application costs. These findings emphasize its attractiveness in water and wastewater treatment processes and present a practical strategy for reclaiming this solid residue.

Efficient wastewater disinfection using a novel microwave discharge electrodeless ultraviolet system with ozone at an ultra-low dose

Microwave discharge electrodeless lamp (MDEL) is a novel ultraviolet (UV) light source. Synergistic disinfection using UV light emitted by MDEL (MWUV) coupled with ozone (O3) at an ultra-low dose was investigated. Escherichia coli and Bacillus subtilis were deactivated more effectively by MWUV/O3 than by either MWUV or O3 alone. MWUV/O3 treatment using an O3 concentration of 0.4 mg/L gave an E. coli inactivation rate of 5.52 log. The photoreactivation degree and rate of E. coli were lower after inactivation by MWUV/O3 treatment than after MWUV treatment alone. The maximum photoreactivation rates after the MWUV/O3 and MWUV treatments were 2.90% and 16.08%, respectively. MWUV/O3 disinfection also inhibited dark resurrection of E. coli and gave a maximum dark resurrection rate of 0.0036%. Electron paramagnetic resonance spectroscopy indicated that more hydroxyl radicals were generated during MWUV/O3 treatment. Scanning electron microscopy and laser confocal scanning microscopy observations indicated that O3 played a key role in breaking down the cell structure. MWUV/O3 treatment gave a good disinfection effect on fecal coliform bacteria in actual domestic wastewater. The results indicated that inactivation of bacteria can be more effectively achieved by MWUV treatment with O3.

Effects of ozone dose on brominated DBPs in subsequent chlor(am)ination: A comprehensive study of aliphatic, alicyclic and aromatic DBPs

Ozone‒chlor(am)ine is a commonly used combination of disinfectants in drinking water treatment. Although there are quite a few studies on the formation of some individual DBPs in the ozone‒chlor(am)ine disinfection, an overall picture of the DBP formation in the combined disinfection is largely unavailable. In this study, the effects of ozone dose on the formation and speciation of organic brominated disinfection byproducts (DBPs) in subsequent chlorination, chloramination, or chlorination‒chloramination of simulated drinking water were investigated. High-molecular-weight, aliphatic, alicyclic and aromatic brominated DBPs were selectively detected and studied using a powerful precursor ion scan method with ultra performance liquid chromatography/electrospray ionization triple quadrupole mass spectrometry (UPLC/ESI-tqMS). Two groups of unregulated yet relatively toxic DBPs, dihalonitromethanes and dihaloacetaldehydes, were detected by the UPLC/ESI-tqMS for the first time. With increasing ozone dose, the levels of high-molecular-weight (m/z 300-500) and alicyclic and aromatic brominated DBPs generally decreased, the levels of brominated aliphatic acids were slightly affected, and the levels of dihalonitromethanes and dihaloacetaldehydes generally increased in the subsequent disinfection processes. Despite different molecular compositions of the detected DBPs, increasing ozone dose generally shifted the formation of DBPs from chlorinated ones to brominated analogues in the subsequent disinfection processes. This study provided a comprehensive analysis of the impact of ozone dose on the DBP formation and speciation in subsequent chlor(am)ine disinfection.

2D-Like Catalyst with a Micro-nanolinked Functional Surface for Water Purification

In water purification, the performance of heterogeneous advanced oxidation processes significantly relies upon the utilization of the catalyst's specific surface area (SSA). However, the presence of the structural "dead volume" and pore-size-induced diffusion-reaction trade-off limitation restricts the functioning of the SSA. Here, we reported an effective approach to make the best SSA by changing the traditional 3D spherule catalyst into a 2D-like form and creating an in situ micro-nanolinked structure. Thus, a 2D-like catalyst was obtained which was characterized by a mini "paddy field" surface, and it exhibited a sharply decreased dead volume, a highly available SSA and oriented flexibility. Given its paddy-field-like mass-transfer routine, the organic capture capability was 7.5-fold higher than that of the catalyst with mesopores only. Moreover, such a catalyst exhibited a record-high O3-to-·OH transition rate of 2.86 × 10-8 compared with reported millimetric catalysts (metal base), which contributed to a 6.12-fold higher total organic removal per catalyst mass than traditional 3D catalysts. The facile scale preparation, performance stability, and significant material savings with the 2D-like catalyst were also beneficial for practical applications. Our findings provide a unique and general approach for designing potential catalysts with excellent performance in water purification.

Novel vacuum UV/ozone/peroxymonosulfate process for efficient degradation of levofloxacin: Performance evaluation and mechanism insight

Vacuum UV (VUV) irradiation has advantage in coupling oxidants for organics removal because VUV can dissociate water to produce reactive oxygen species (ROS) in situ and decompose oxidants rapidly. In this study, the synergistic activation of peroxymonosulfate (PMS) by VUV and ozone (O3) was explored via developing a novel integrated VUV/O3/PMS process, and the performance and mechanisms of VUV/O3/PMS for levofloxacin (LEV) degradation were investigated systematically. Results indicated that VUV/O3/PMS could effectively degrade LEV, and the degradation rate was 1.67-18.79 times of its sub-processes. Effects of PMS dosage, O3 dosage, solution pH, anions, and natural organic matter on LEV removal by VUV/O3/PMS were also studied. Besides, hydroxyl radical and sulfate radical were main ROS with contributions of 49.7% and 17.4%, respectively. Moreover, the degradation pathways of LEV in VUV/O3/PMS process were speculated based on density functional theory calculation and by-products detection. Furthermore, synergistic reaction mechanisms in VUV/O3/PMS process were proposed. The energy consumption of VUV/O3/PMS decreased by 22.6%- 88.1% compared to its sub-processes. Finally, the integrated VUV/O3/PMS process showed satisfactory results in removing LEV in actual waters, manifesting VUV/O3/PMS had great application potential and feasibility in removing organics in wastewater reuse.