N-Nitrosodimethylamine formation from anthropogenic nitrogenous compounds during preozonation and post-chloramination with characteristic low treatment dose.

One effective option to minimize N-nitrosodimethylamine (NDMA) in finished drinking water is to identify and control its precursors. However, previous works to identify significant precursors use formation potential (FP) tests using high doses to assure the maximum NDMA formation rather than the NDMA formation in finished waters. In this study, we applied characteristic low treatment doses of ozone (O3)-to-dissolved organic carbon (DOC) of target compounds of 0.8 mg/mg and NH2Cl of 2.5 ± 0.2 mg Cl2/L to evaluate the NDMAFP yields of organic compounds bearing N,N-dimethylamine (DMA) and N,N-dimethylhydrazine (DMH) during preozonation and post-chloramination. The results in pH-buffered Milli-Q water showed a significant decrease from ≤ 52% to non-detectable levels in the O3-NDMAFP yields of O3-reactive precursors (i.e., DMH-like compounds) after preozonation and post-chloramination. Similarly, a significant decrease from 0.5 to 12% to nonquantifiable levels was observed for the NH2Cl-NDMAFP yields of NH2Cl-reactive precursors; however, the NH2Cl-NDMAFP yields of N,N-dimethylbenzylamine (DMBzA)-like compounds only decreased from ~ 110 to ≤ 43%, suggesting that these compounds could contribute to NH2Cl-NDMAFPs even after preozonation. The effect of the matrix in sewage-effluent and lake water samples varied and was specific for precursors; for example, the O3-NDMAFP yield of 1,1,1',1'-tetramethyl-4,4'-(methylene-di-p-phenylene) disemicarbazide (TMDS), an important O3-reactive NDMA precursor, did not significantly decrease when tested in sewage-effluent samples. Based on the previous occurrence concentration of TMDS in sewage samples, we estimated an NDMAFP of ~ 315 ng/L. This estimate exceeds the guidance concentrations of NDMA (3-100 ng/L), highlighting the importance of TMDS and its related compounds for NDMA formation.

Radical chemistry and VOCs-NOx-O3-nitrate sensitivity in the polluted atmosphere of a suburban site in the North China Plain.

In this study, the chemical mechanisms of O3 and nitrate formation as well as the control strategy were investigated based on extensive observations in Tai'an city in the NCP and an observation-constrained box model. The results showed that O3 pollution was severe with the maximum hourly O3 concentration reaching 150 ppb. Higher O3 concentration was typically accompanied by higher PM2.5 concentrations, which could be ascribed to the common precursors of VOCs and NOx. The modeled averaged peak concentrations of OH, HO2, and RO2 were relatively higher compared to previous observations, indicating strong atmospheric oxidation capacity in the study area. The ROx production rate increased from 2.8 ppb h-1 to 5 ppb h-1 from the clean case to the heavily polluted case and was dominated by HONO photolysis, followed by HCHO photolysis. The contribution of radical-self combination to radical termination gradually exceeded NO2 + OH from clean to polluted cases, indicating that O3 formation shifted to a more NOx-limited regime. The O3 production rate increased from 14 ppb h-1 to 22 ppb h-1 from clean to heavily polluted cases. The relative incremental reactivity (RIR) results showed that VOCs and NOx had comparable RIR values during most days, which suggested that decreasing VOCs or NOx was both effective in alleviating O3 pollution. In addition, HCHO, with the largest RIR value, made important contribution to O3 production. The Empirical Kinetic Modeling Approach (EKMA) revealed that synergistic control of O3 and nitrate can be achieved by decreasing both NOx and VOCs emissions (e.g., alkenes) with the ratio of 3:1. This study emphasized the importance of NOx abatement for the synergistic control of O3 and nitrate pollution in the Tai'an area as the sustained emissions control has shifted the O3 and nitrate formation to a more NOx-limited regime.

Effects of plasma surface treatment on the bond strength of zirconia with an adhesive resin luting agent.

The purpose of this study was to evaluate the effect of the atmospheric pressure plasma treatment as a surface treatment method on the contact angle and shear bond strength (SBS) of zirconia ceramics and the failure mode between the self-adhesive resin luting agent and zirconia. The zirconia specimens were divided into eight groups based on the surface treatment method: alumina blasting, air plasma, argon plasma (AP), Katana cleaner, ozonated water, ozonated water+AP, Katana cleaner+AP, and tap water+AP. The contact angles, SBS, and fracture modes were tested. AP treatment significantly reduced the contact angle (p<0.0001). The combination of AP and other cleaning methods showed a higher bond strength and more mixed fractures. Our findings indicate that using atmospheric pressure plasma with argon gas, combined with other cleaning methods, results in a stronger bond than when using alumina blasting alone.

The adjunctive use of antimicrobial photodynamic therapy, light-emitting-diode photobiomodulation and ozone therapy in regenerative treatment of stage III/IV grade C periodontitis: a randomized controlled clinical trial.

OBJECTIVES: To assess the short-term efficacy of multiple sessions of antimicrobial photodynamic therapy (aPDT), light-emitting-diode (LED) photobiomodulation, and topical ozone therapy applications following surgical regenerative treatments on clinical parameters, patient-centered outcomes, and mRNA expression levels of VEGF, IL-6, RunX2, Nell-1, and osterix in gingival crevicular fluid samples in patients with stage III/IV, grade C periodontitis. MATERIALS AND METHODS: Forty-eight systemically healthy patients were assigned into four groups to receive adjunctive modalities with regenerative periodontal surgical treatment. A 970 ± 15 nm diode laser plus indocyanine-green for aPDT group, a 626 nm LED for photobiomodulation group, and topical gaseous ozone were applied at 0, 1, 3, and 7 postoperative days and compared to control group. The clinical periodontal parameters, early wound healing index (EHI), and postoperative patients' morbidity were evaluated. The mRNA levels of biomarkers were assessed by real-time polymerase chain reaction. RESULTS: No significant difference in the clinical parameters except gingival recession (GR) was identified among the groups. For group-by-time interactions, plaque index (PI) and probing pocket depths (PD) showed significant differences (p = 0.034; p = 0.022). In sites with initial PD > 7 mm, significant differences were observed between control and photobiomodulation groups in PD (p = 0.011), between control and aPDT, and control and photobiomodulation groups in CAL at 6-month follow-up (p = 0.007; p = 0.022). The relative osterix mRNA levels showed a statistically significant difference among the treatment groups (p = 0.014). CONCLUSIONS: The additional applications of aPDT and LED after regenerative treatment of stage III/IV grade C periodontitis exhibited a more pronounced beneficial effect on clinical outcomes in deep periodontal pockets.

Local ozone injection compared to local glucocorticoid injection in carpal tunnel syndrome: A randomized controlled trial.

Objectives: This study aimed to compare the effectiveness of local ozone (O3) injection versus corticosteroid injection in the treatment of mild to moderate carpal tunnel syndrome (CTS). Patients and methods: This double-blind randomized controlled trial was performed on 42 patients (9 males, 33 females; mean age: 46.7±2.1 years; range, 18 to 70 years) with mild to moderate CTS between May 2021 and June 2021. The corticosteroid group (n=21) was injected with 40 mg triamcinolone, and in the O3 group B (n=21), 4 mL of a 10 mcg/mL oxygen (O2)-O3 mixture was injected. Symptom severity and functional impairments were assessed using a Visual Analog Scale and Boston Carpal Tunnel Questionnaire. Electrodiagnostic and ultrasonographic parameters were obtained at baseline and eight weeks after the procedure. Results: The O2-O3 solution improved pain and Boston Carpal Tunnel Questionnaire score after eight weeks (p<0.001); however, the change was nonsignificant compared to the corticosteroid group (p>0.05). Sensory nerve and compound muscle action potential latencies were not significantly changed eight weeks after O2-O3 injection (p>0.05), while both were significantly decreased in the steroid injection group (p<0.001). Volar bulging and median nerve cross-section surface area were not improved after O2-O3 injection, while the improvement was significant in the corticosteroid arm (p=0.02). Conclusion: Symptoms in patients with mild to moderate CTS may be alleviated by local O2-O3 injection; however, electrodiagnostic and ultrasonographic indices may be unchanged. Corticosteroid local injection may alleviate patient symptoms along with electrodiagnostic and ultrasonographic parameters.

Global impacts of an extreme solar particle event under different geomagnetic field strengths.

Solar particle events (SPEs) are short-lived bursts of high-energy particles from the solar atmosphere and are widely recognized as posing significant economic risks to modern society. Most SPEs are relatively weak and have minor impacts on the Earth's environment, but historic records contain much stronger SPEs which have the potential to alter atmospheric chemistry, impacting climate and biological life. The impacts of such strong SPEs would be far more severe when the Earth's protective geomagnetic field is weak, such as during past geomagnetic excursions or reversals. Here, we model the impacts of an extreme SPE under different geomagnetic field strengths, focusing on changes in atmospheric chemistry and surface radiation using the atmosphere-ocean-chemistry-climate model SOCOL3-MPIOM and the radiation transfer model LibRadtran. Under current geomagnetic conditions, an extreme SPE would increase NOx concentrations in the polar stratosphere and mesosphere, causing reductions in extratropical stratospheric ozone lasting for about a year. In contrast, with no geomagnetic field, there would be a substantial increase in NOx throughout the entire atmosphere, resulting in severe stratospheric ozone depletion for several years. The resulting ground-level ultraviolet (UV) radiation would remain elevated for up to 6 y, leading to increases in UV index up to 20 to 25% and solar-induced DNA damage rates by 40 to 50%. The potential evolutionary impacts of past extreme SPEs remain an important question, while the risks they pose to human health in modern conditions continue to be underestimated.

Multi-source observations on the effect of atmospheric blocking on air quality in Istanbul: a study case.

Air pollution is affected by the atmospheric dynamics. This study aims to determine that air pollution concentration values in Istanbul increased significantly and reached peak values due to atmospheric blocking between the 30th of December 2022 and the 5th of January 2023. In this study, hourly pollutant data was obtained from 16 air quality monitoring stations (AQMS), the exact reanalysis data was extracted from ERA5 database, and inversion levels and meteorological and synoptic analyses were used to determine the effects of atmospheric blocking on air pollution. Also, cloud base heights and vertical visibility measurements were taken with a ceilometer. Statistical calculations and data visualizations were performed using the R and Grads program. Omega-type blocking, which started in Istanbul on December 30, 2022, had a significant impact on the 1st and 2nd of January 2023, and PM10 and PM2.5 concentration values reached their peak values at 572.8 and 254.20 µg/m3, respectively. In addition, it was found that the average concentration values in the examined period in almost all stations were higher than the averages for January and February. As a result, air quality in Istanbul was determined as "poor" between these calendar dates. It was found that the blocking did not affect the ozone (µg/m3) concentration. It was also found that the concentrations of particulate matter (PM) 10 µm or less in diameter (PM10) and PM 2.5 µm or less in diameter (PM2.5) were increased by the blocking effect in the Istanbul area. Finally, according to the data obtained using the ceilometer, cloud base heights decreased to 30 m and vertical visibility to 10 m.

Effect of Ozone Therapy on Diabetes-related Foot Ulcer Outcomes: A Systematic Review and Meta-analysis.

PURPOSE: This study aimed to assess the effectiveness of ozone therapy in treating Diabetes-related Foot Ulcer (DFU) and its outcomes. METHODS: A systematic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, and ProQuest databases for published studies evaluating the use of ozone as an adjunct treatment for DFU, from inception to December 21, 2022. The primary outcome measure was the change in wound size after the intervention compared to pretreatment. Secondary outcomes included time to complete ulcer healing, number of healed patients, adverse events, amputation rates, and hospital length of stay. Quantitative data synthesis for the meta-analysis was performed using a random-effects model and generic inverse variance method, while overall heterogeneity analysis was conducted using a fixed-effects model. Interstudy heterogeneity was assessed using the I2 index (<50%) and the Cochrane Q statistic test. Sensitivity analysis was performed using the leave-one-out method. RESULTS: The meta-analysis included 11 studies comprising 960 patients with DFU. The results demonstrated a significant positive effect of ozone therapy on reducing foot ulcer size (Standardized Mean Difference (SMD): -25.84, 95% CI: -51.65 to -0.04, p = 0.05), shortening mean healing time (SMD: -38.59, 95% CI: -51.81 to -25.37, p < 0.001), decreasing hospital length of stay (SMD: -8.75, 95% CI: -14.81 to -2.69, p < 0.001), and reducing amputation rates (Relative Risk (RR): 0.46, 95% CI: 0.30-0.71, p < 0.001), compared to standard treatment. CONCLUSION: This meta-analysis indicates that ozone therapy has additional benefits in expediting complete DFU healing, reducing the amputation rates, and decreasing hospital length of stay, though its effects do not differ from standard treatments for complete ulcer resolution. Further research is needed to address the heterogeneity among studies and to better understand the potential beneficial effects of ozone therapy.

Short-term ozone exposure and cancer mortality in Brazil: A nationwide case-crossover study.

Exposure to ambient ozone (O3) is linked to increased mortality risks from various diseases, but epidemiological investigations delving into its potential implications for cancer mortality are limited. We aimed to examine the association between short-term O3 exposure and site-specific cancer mortality and investigate vulnerable subgroups in Brazil. In total 3,459,826 cancer death records from 5570 Brazilian municipalities between 2000 and 2019, were included. Municipal average daily O3 concentration was calculated from a global estimation at 0.25°×0.25° spatial resolution. The time-stratified case-crossover design was applied to assess the O3-cancer mortality association. Subgroup analyses by age, sex, season, time-period, region, urban hierarchy, climate classification, quantiles of GDP per capita and illiteracy rates were performed. A linear and non-threshold exposure-response relationship was observed for short-term exposure to O3 with cancer mortality, with a 1.00% (95% CI: 0.79%-1.20%) increase in all-cancer mortality risks for each 10-µg/m3 increment of three-day average O3. Kidney cancer was most strongly with O3 exposure, followed by cancers of the prostate, stomach, breast, lymphoma, brain and lung. The associated cancer risks were relatively higher in the warm season and in southern Brazil, with a decreasing trend over time. When restricting O3 concentration to the national minimum value during 2000-2019, a total of 147,074 (116,690-177,451) cancer deaths could be avoided in Brazil, which included 17,836 (7014-28,653) lung cancer deaths. Notably, these associations persisted despite observed adaptation within the Brazilian population, highlighting the need for a focus on incorporating specific measures to mitigate O3 exposure into cancer care recommendations.

Evaluation of postoperative pain in endodontic retreatment with apical periodontitis using ozonated 2% chlorhexidine and 0.1% octenidine application: A randomized clinical trial.

Introduction: This study aimed to evaluate and compare postoperative pain (PP) in single-visit nonsurgical endodontic retreatment (SV NSER) with 2% chlorhexidine (CHX), 0.1% octenidine (OCT) with or without ozone, and 5.25% sodium hypochlorite (NaOCl). Materials and Methods: In this randomized, parallel, prospective, double-blind, clinical trial, 132 single-rooted, root-filled teeth with symptomatic apical periodontitis (AP) requiring NSER were allocated into six groups randomly (n = 22/group): 2% CHX with NaOCl (CHXH), 2% Ozonated CHX without NaOCl (OCHX), 2% Ozonated CHX with NaOCl (OCHXH), 0.1% OCT with NaOCl (OCTH), 0.1% Ozonated OCT without NaOCl (OOCT), and 0.1% Ozonated OCT with NaOCl (OOCTH). Standard NSER protocol was followed groups were irrigated with 15 ml of ozonated or nonozonated irrigant (CHX/OCT) for 3-5 min with ultrasonic agitation. PP at baseline, after 6, 12, 24, 48 h, and 7 days was recorded using the Visual Analog Scale (VAS). Logistic regression of predictor variables was compared using the Chi-square test. For group-wise and time-wise comparisons, a two-way analysis of variance followed by the post hoc Bonferroni test was carried out. Results: None of the patient-related variables in logistic regression obtained a statistically significant (P > 0.05) role in PP. The VAS score after 6 h was OCHX (4.72) > OOCT (4.42) > CHXH (4.23) > OCTH (3.95) > OCHXH (3.42) > OOCTH (3.21). OOCTH and OCHXH groups demonstrated statistically significant reductions in VAS scores at various time intervals (P < 0.05). Conclusion: SV NSER with ozonated OCT, CHX irrigation, and NaOCl resulted in lesser PP at all time intervals, i.e., 6, 12, 24, 48 h, and 7 days in patients with symptomatic AP.

Increasing Cyetpyrafen Spray Volume and Ozone Spray Improves the Control Effects against Two-Spotted Spider Mite (Tetranychus urticae) in Strawberries.

The two-spotted spider mite (Tetranychus urticae) is a constant threat to greenhouse strawberry production. The application of synthetic acaricides is the main method of controlling T. urticae. However, resistance development to traditional acaricides reduces their efficacy and eventually leads to control failure. It is important for strawberry growers to look for new acaricides and application technologies that can limit the harmfulness of T. urticae in environmentally friendly ways. In the current study, laboratory toxicity tests and field trials were performed to screen high-efficiency acaricides, and then application technologies were improved to enhance the management of T. urticae. In the laboratory toxicity tests, the results showed that the LC50 (median lethal concentration) value of cyetpyrafen, cyenopyrafen, cyflumetofen, bifenazate, abamectin, azocyclotin, pyridaben, spirodiclofen, and etoxazole against adult T. urticae was 0.226, 0.240, 0.415, 3.583, 5.531, 25.58, 39.69, 140.3, and 267.7 mg/L, respectively. In addition, the LC50 value of the nine acaricides against eggs of T. urticae was 0.082, 0.097, 0.931, 18.56, 25.52, 45.61, 36.32, 1.954, and 0.040 mg/L, respectively. The field trial results showed that the best control effect was obtained in cyetpyrafen at 300 mL/ha treatment. Cyetpyrafen was chosen for further application technology tests. In the spray volume tests, the results showed that increasing the spray volume from 900 to 1050 L/ha significantly improved the control of T. urticae. In addition, the results from the spray instrument tests demonstrated that the control effects on T. urticae in the ozone spray treatments were significantly higher than those of the conventional and electrostatic sprays 1 and 3 days after treatment (DAT). Therefore, this study suggested that cyetpyrafen effectively controlled T. urticae both in the laboratory tests and in the field trials. Increasing the spray volume and application of ozone spray significantly improved T. urticae management.

Performance Evaluation of Sinusoidal Power Supplies for Ozone Generation in Water Purification Applications.

Ozone generation is a water disinfection method, superior to chlorine in terms of fewer byproducts and no residual taste. However, its high production cost limits its widespread adoption. This paper designs an ozone generation sinusoidal power supply for water treatment. Ozone generation requires a high-frequency and high-voltage power supply to produce ozone from oxygen molecules. The study evaluates two power supply topologies, one with a parallel LC filter and the other with an LCL filter, assessing their feasibility, effectiveness, and reliability. Theoretically, the LCL filter achieves higher gains than the parallel LC filter. The larger inductance in the parallel LC filter reduces gain, while the larger inductance in the LCL filter increases gain. Simulation and practical results validate these findings, achieving gains of 40 for the parallel LC filter and 150 for the LCL filter.

Prediction of hydroxyl radical exposure during ozonation using different machine learning methods with ozone decay kinetic parameters.

The abatement of micropollutants by ozonation can be accurately calculated by measuring the exposures of molecular ozone (O3) and hydroxyl radical (•OH) (i.e., ∫[O3]dt and ∫[•OH]dt). In the actual ozonation process, ∫[O3]dt values can be calculated by monitoring the O3 decay during the process. However, calculating ∫[•OH]dt is challenging in the field, which necessitates developing models to predict ∫[•OH]dt from measurable parameters. This study demonstrates the development of machine learning models to predict ∫[•OH]dt (the output variable) from five basic input variables (pH, dissolved organic carbon concentration, alkalinity, temperature, and O3 dose) and two optional ones (∫[O3]dt and instantaneous ozone demand, IOD). To develop the models, four different machine learning methods (random forest, support vector regression, artificial neural network, and Gaussian process regression) were employed using the input and output variables measured (or determined) in 130 different natural water samples. The results indicated that incorporating ∫[O3]dt as an input variable significantly improved the accuracy of prediction models, increasing overall R2 by 0.01-0.09, depending on the machine learning method. This suggests that ∫[O3]dt plays a crucial role as a key variable reflecting the •OH-yielding characteristics of dissolved organic matter. Conversely, IOD had a minimal impact on the accuracy of the prediction models. Generally, machine-learning-based prediction models outperformed those based on the response surface methodology developed as a control. Notably, models utilizing the Gaussian process regression algorithm demonstrated the highest coefficients of determination (overall R2 = 0.91-0.95) among the prediction models.

Tropospheric ozone effect on olfactory perception and olfactory bulb dopaminergic interneuron excitability.

Ozone (O3) forms in the Earth's atmosphere, both naturally and by reactions of man-made air pollutants. Deleterious effects of O3 have been found in the respiratory system. Here, we examine whether O3 alters olfactory behavior and cellular properties in the olfactory system. For this purpose, mice were exposed to O3 at a concentration found in highly polluted city air [0.8 ppm], and the behavior elicited by social and non-social odors in habituation/dishabituation tests was assessed. In addition, the electrical responses of dopaminergic olfactory bulb (OB) neurons were also evaluated. O3 differentially compromises olfactory perception to odors: it reduces responses to social and non-social odors in Swiss Webster mice, while this effect was observed in C57BL/6J mice only for some non-social odors. Additionally, O3 reduced the rate of spontaneous spike firing in periglomerular dopaminergic cells (PG-DA) of the OB. Because this effect could reflect changes in excitability and/or synaptic inputs, the ability of O3 to alter PG-DA spontaneous activity was also tested together with cell membrane resistance, membrane potential, rheobase and chronaxia. Taken together, our data suggest the ability of O3 to affect olfactory perception.

Characterization of Mild Delayed Gestational Hypertension in Rats Following Ozone Exposure.

The contribution of air pollution-induced cardiopulmonary damage on the development of hypertensive disorders of pregnancy and other adverse outcomes of pregnancy has gained increased attention as epidemiological data continue to highlight spatiotemporal pregnancy trends related to air pollution exposure. However clinical mechanistic data surrounding gestational complications remain sparse, necessitating the need for the use of animal models to study these types of complications of pregnancy. The current study seeks to examine the real-time effects of mid-gestational ozone exposure on maternal blood pressure and body temperature through the use of radiotelemetry in a rat model. The exposure resulted in acute depression of heart rate and core body temperature as compared to control animals. Ozone-exposed animals also presented with a slight but significant increase in arterial blood pressure which was perpetuated until term. The data presented here illustrates the feasibility of murine models to assess cardiovascular complications caused by inhaled toxicants during the window of pregnancy.

Joint Effect of Short-Term Exposure to Fine Particulate Matter and Ozone on Mortality: A Time Series Study in 272 Chinese Cities.

Short-term exposure to PM2.5 or O3 can increase mortality risk; however, limited studies have evaluated their interaction. A multicity time series study was conducted to investigate the synergistic effect of PM2.5 and O3 on mortality in China, using mortality data and high-resolution pollutant predictions from 272 cities in 2013-2015. Generalized additive models were applied to estimate associations of PM2.5 and O3 with mortality. Modification and interaction effects were explored by stratified analyses and synergistic indexes. Deaths attributable to PM2.5 and O3 were evaluated with or without modification of the other pollutant. The risk of total nonaccidental mortality increased by 0.70% for each 10 µg/m3 increase in PM2.5 when O3 levels were high, compared to 0.12% at low O3 levels. The effect of O3 on total nonaccidental mortality at high PM2.5 levels (1.26%) was also significantly higher than that at low PM2.5 levels (0.59%). Similar patterns were observed for cardiovascular or respiratory diseases. The relative excess risk of interaction and synergy index of PM2.5 and O3 on nonaccidental mortality were 0.69% and 1.31 with statistical significance, respectively. Nonaccidental deaths attributable to short-term exposure of PM2.5 or O3 when considering modification of the other pollutant were 28% and 31% higher than those without considering modification, respectively. Our results found synergistic effects of short-term coexposure to PM2.5 and O3 on mortality and suggested underestimations of attributable risks without considering their synergistic effects.

Particle-ozone complex pollution under diverse synoptic weather patterns in the Yangtze River Delta region: Synergistic relationships and the effects of meteorology and chemical compositions.

There is considerable academic interest in the particle-ozone synergistic relationship (PO) between fine particulate matter (PM2.5) and ozone (O3). Using various synoptic weather patterns (SWPs), we quantitatively assessed the variations in the PO, which is relevant to formulating policies aimed at controlling complex pollution in the air. First, based on one-year sampling data from March 2018 to February 2019, the SWPs classification of the Yangtze River Delta (YRD) was conducted using the sum-of-squares technique (SS). Five dominant SWPs can be found in the YRD region, including the Aleutian low under SWP1 (occurring 45 % of the year), a tropical cyclone under SWP2 (21 %), the tropical cyclone and western Pacific Subtropical High (WPSH) under SWP3 (15.4 %), the WPSH under SWP4 (6.9 %), and a continental high pressure under SWP5 (3.1 %). The phenomenon of a "seesaw" between PM2.5 and O3 concentrations exhibited significant spatial heterogeneity, which was influenced by meteorological mechanisms. Second, the multi-linear regression (MLR) model and the partial correlation (PCOR) analysis were employed to quantify the effects of dominant components and meteorological factors on the PO. Meteorological variables could collectively explain only 33.0 % of the PM2.5 variations, but 58.0 % for O3. O3 promoted each other with low concentrations of PM2.5 but was inhibited by high concentrations of PM2.5. High relative humidity (RH) was conducive to the generation of PM2.5 secondary components and enhanced the radiative effects of aerosols and the negative correlation of PO. In addition, attention should be paid to assessing the combined effects of precursor levels, weather, and chemical reactions on the particle-ozone complex pollution. The control of O3 pollutants should be intensified in summer, while the focus should be on reducing PM2.5 pollutants in winter. Prevention and control measures need to reflect the differences in weather conditions and pollution characteristics, with a focus on RH and secondary components of PM2.5.

Efficient degradation of p-nitrophenol from water by enhancing dielectric barrier discharge (DBD) plasma through ozone circulation: Optimization, kinetics and mechanism.

Non-thermal dielectric barrier discharge (DBD) plasma has received great attention for degradation of persistent organic pollutants such as p-nitrophenol (PNP). However, the feasibility of the DBD implementation is not clear due to its high energy consumption and relatively low degradation efficiency. In this research, a novel strategy was suggested based on re-circulation of the generated O3 in the DBD system to enhance the PNP degradation efficiency and energy yield. The potential mechanism and possible pathway of PNP degradation were studied by EPR, ESR, DFT and GS-MS analytical tests. According to the results, the PNP degradation efficiency and energy yield increased from 57.4% to 94.4% and from 0.52 to 1.18 g kW-1h-1, respectively through ozone circulation into the DBD reactor. This was due to the more release of long-lived and short-lived reactive species (ROS) in the DBD-O3 system by the O3 circulation. The variations in pH (4-10), initial concentration (50-90 mg L-1), and the presence of co-existing substances in the water matrix had minimal impact on the DBD-O3 system, in comparison to the conventional system. The biological toxicity evaluation revealed that the hybrid DBD-O3 system transform PNP to less toxic intermediates. This study proposes a promising strategy to improve the utilization of DBD for the degradation of PNP.

Deciphering the seasonal dynamics of multifaceted aerosol-ozone interplay: Implications for air quality management in Eastern China.

We employed an enhanced WRF-Chem to investigate the discrete mechanisms of aerosol-radiation-feedback (ARF), extinction-photochemistry (AEP), and heterogeneous-reactions (AHR) across different seasons in eastern China, aiming to assess the synergistic effects arising from the simultaneous operation of multiple processes on O3 and PM2.5. Our findings demonstrated that ARF fostered the accumulation of pollutants and moisture, initiating two distinct feedback mechanisms concerning O3. The elevation in the NO/NO2 ratio amplified O3 consumption. Increased near-surface moisture diminished upper-level cloud formation, thereby enhancing photolysis rates and O3 photochemical production. The pronounced impact of heightened NO/NO2 on O3 led to a decrease of 0.1-2.7 ppb. When decoupled from ARF, AEP led to a more significant reduction in photolysis rates, resulting in declines in both O3 and PM2.5, except for an anomalous increase observed in summer, with O3 increasing by 1.6 ppb and PM2.5 by 2.5 µg m-3. The heterogeneous absorption of hydroxides in spring, autumn, and winter predominantly governed the AHR-induced variation of O3, leading to a decrease in O3 by 0.7-1 ppb. Conversely, O3 variations in summer were primarily dictated by O3-sensitive chemistry, with heterogeneous absorption of NOy catalyzing a decrease of 2.4 ppb in O3. Furthermore, AHR accentuated PM2.5 by facilitating the formation of fine sulfates and ammonium while impeding nitrate formation. In summer, the collective impact of ARF, AEP, and AHR (ALL) led to a substantial reduction of 6.2 ppb in O3, alleviating the secondary oxidation of PM2.5 and leading to a decrease of 0.3 µg m-3 in PM2.5. Conversely, albeit aerosol substantially depleted O3 by 0.4-4 ppb through their interactions except for summer, aerosol feedback on PM2.5 was more pronounced, resulting in a significant increase of 1.7-6.1 µg m-3 in PM2.5. Our study underscored the seasonal disparities in the ramifications of multifaceted aerosol-ozone interplay on air quality.

Large potential of strengthening the land carbon sink in China through anthropogenic interventions.

The terrestrial ecosystem in China mitigates 21%-45% of the national contemporary fossil fuel CO2 emissions every year. Maintaining and strengthening the land carbon sink is essential for reaching China's target of carbon neutrality. However, this sink is subject to large uncertainties due to the joint impacts of climate change, air pollution, and human activities. Here, we explore the potential of strengthening land carbon sink in China through anthropogenic interventions, including forestation, ozone reduction, and litter removal, taking advantage of a well-validated dynamic vegetation model and meteorological forcings from 16 climate models. Without anthropogenic interventions, considering Shared Socioeconomic Pathways (SSP) scenarios, the land sink is projected to be 0.26-0.56 Pg C a-1 at 2060, to which climate change contributes 0.06-0.13 Pg C a-1 and CO2 fertilization contributes 0.08-0.44 Pg C a-1 with the stronger effects for higher emission scenarios. With anthropogenic interventions, under a close-to-neutral emission scenario (SSP1-2.6), the land sink becomes 0.47-0.57 Pg C a-1 at 2060, including the contributions of 0.12 Pg C a-1 by conservative forestation, 0.07 Pg C a-1 by ozone pollution control, and 0.06-0.16 Pg C a-1 by 20% litter removal over planted forest. This sink can mitigate 90%-110% of the residue anthropogenic carbon emissions in 2060, providing a solid foundation for the carbon neutrality in China.