Low Ozone Concentrations Research Articles

Ozone: complicated effects in central nervous system diseases.

Oxidative stress is closely related to various diseases. Ozone can produce redox reactions through its unique response. As a source of the oxidative stress response, the strong oxidizing nature of ozone can cause severe damage to the body. On the other hand, low ozone concentrations can activate various mechanisms to combat oxidative stress and achieve therapeutic effects. Some animal experiments and clinical studies have revealed the potential medical value of ozone, indicating that ozone is not just a toxic gas. By reviewing the mechanism of ozone and its therapeutic value in treating central nervous system diseases (especially ischemic stroke and Alzheimer's disease) and the toxic effects of ozone, we find that ozone inhalation and a lack of antioxidants or excessive exposure lead to harmful impacts. However, with adequate antioxidants, ozone can transmit oxidative stress signals, reduce inflammation, reduce amyloid β peptide levels, and improve tissue oxygenation. Similar mechanisms to those of possible new drugs for treating ischemic stroke and Alzheimer's disease indicate the potential of ozone. Nevertheless, limited research has restricted the application of ozone. More studies are needed to reveal the exact dose-effect relationship and healing effect of ozone.

Low ozone concentrations do not exert cytoprotective effects on tamoxifen-treated breast cancer cells in vitro.

Medical treatment with low ozone concentrations proved to exert therapeutic effects in various diseases by inducing a cytoprotective antioxidant response through the nuclear factor erythroid derived-like 2 (Nrf2) transcription factor pathway. Low ozone doses are increasingly administered to oncological patients as a complementary treatment to mitigate some adverse side-effects of antitumor treatments. However, a widespread concern exists about the possibility that the cytoprotective effect of Nrf2 activation may confer drug resistance to cancer cells or at least reduce the efficacy of antitumor agents. In this study, the effect of low ozone concentrations on tamoxifen-treated MCF7 human breast cancer cells has been investigated in vitro by histochemical and molecular techniques. Results demonstrated that cell viability, proliferation and migration were generally similar in tamoxifen-treated cells as in cells concomitantly treated with tamoxifen and ozone. Notably, low ozone concentrations were unable to overstimulate the antioxidant response through the Nfr2 pathway, thus excluding a possible ozone-driven cytoprotective effect that would lead to increased tumor cell survival during the antineoplastic treatment. These findings, though obtained in an in vitro model, support the hypothesis that low ozone concentrations do not interfere with the tamoxifen-induced effects on breast cancer cells.

Efficiency of ozone compared to commercial sanitizers for hatching eggs from older breeders

This study aimed to evaluate the potential of ozone as a sanitizer compared to commercial sanitizers for hatching eggs stored in hatching machines using different turning systems. The eggs (n = 120) were distributed in a completely randomized design using a factorial scheme (6x2) where the treatments were constituted by different sanitizers applied (non-treated eggs, Ozone 1.6 mg L-1, Ozone 3.2 mg L-1, Cyphenothrin, UVC, and paraformaldehyde) and two turning systems (vertical and horizontal) with 10 eggs each, with the egg considered as a replicate. Data collected were subjected to the Tukey test at 0.05. We observed a very similar performance in the incubation yield results of the hatching machines with different turning systems, where the hatching percentage of eggs stored in the hatching machine using vertical turning presented better (p < 0.05) results. Comparing ozone to other sanitizers, we observed that paraformaldehyde and UVC provided better (p < 0.05) hatching percentage. However, both ozone concentrations used also presented good hatching percentage results. Chicks from treated eggs, except those from eggs treated with the highest ozone concentration (3.2 mg L-1), were heavier (p < 0.05) at hatch. Chicks from eggs treated with the low concentration of ozone (1.6 mg L-1) presented, in several scenarios, higher (p < 0.05) weight at hatch than chicks from eggs treated with sanitizers commonly used, especially paraformaldehyde and UVC. Conclusively, ozone can be used as a sanitizer to treat eggs from older breeders, presenting potential to replace commonly used sanitizers stored in hatching machines using both vertical and horizontal turning systems.

Preserving the Aromatic Profile of Aged Toma Piemontese PDO Cheese with Gaseous Ozone Technology: A Quality Assessment via SPME-GC–MS/E-Nose

The efficacy of low gaseous ozone concentrations (300 ppb and 400 ppb) in controlling spoilage microflora and preserving the quality of the aged Toma Piemontese PDO cheese was explored. The research integrates consumer tests, Gas Chromatography-Mass Spectrometry (GC-MS) with Solid phase Microextraction (SPME) fiber and Electronic Nose (e-nose) analysis to conduct a detailed assessment of the cheese's aromatic composition. Results indicate that low ozone concentrations significantly affected spoilage microflora, preserving the overall quality. Through GC-FID (Flame Ionization Detection) analysis, 22 of all identified compounds by GC-MS were quantified, including ethyl acetate (sweety), diacetyl and acetoin (buttery). Compared with the untreated sample, ozone treatments maintained the distinctive characteristics of Toma Piemontese PDO cheese, reducing the formation of off-flavors-related compounds (i.e., ethanol). Moreover, ozone-treated samples correlated with positive aroma scores given by consumers. However, sensory perception involves complex interactions among aroma compounds, highlighting the importance of advanced approaches. The utilization of a 12-sensor Quartz Microbalance (QMB) e-nose played a crucial role in identifying subtle differences in aroma, contributing to a more nuanced understanding of ozone treatments on the cheese's sensory profile. In conclusion, this research demonstrates the potential of ozone technology as a viable and effective method for improving the quality of aged Toma Piemontese PDO cheese.

Retrieval of upper stratospheric ozone profiles from SCIAMACHY Hartley-Huggins limb scatter spectra using WMART

ABSTRACT The hyperspectral SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument, launched by Envisat in March 2002, measures atmospheric scattered radiance within the ultraviolet (UV) to near infrared range and has three geometric observation modes: nadir, occultation, and limb. This study describes a retrieval scheme to obtain middle and upper stratospheric ozone profiles from SCIAMACHY limb-scattered solar radiance. Owing to the low ozone concentration at high altitudes and rapid changes in ozone absorption cross-sections in the Hartley – Huggins band, a fundamental objective of this study was to establish a simple and effective retrieval scheme to derive reliable ozone profiles at high altitudes from UV spectral bands. In this study, short UV wavelengths of 302, 312, and 322 nm and a long wavelength of 331 nm were used for wavelength pairing to simplify the retrieval algorithm. Moreover, we employed the weighted multiplicative algebraic reconstruction technique (WMART), which is straightforward to understand, and easy to implement, combined with a radiative transfer model (i.e. SCIATRAN), and produced stable results. The retrieval error estimates for the upper stratosphere were provided, and the total retrieval error of the ozone profile was usually < 18% in the altitude range of 30–53 km. The results were compared with the SCIAMACHY v3.5 product and validated against profiles derived from Optical Spectrometer and InfraRed Imaging System (OSIRIS) v7.1, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) v4.0 for 30–53 km altitude. The retrieved ozone profiles agreed with data from SCIAMACHY v3.5 within − 10%–5%, except at an altitude of 45 km, where the bias became larger (approximately −15%). The comparison of retrieved profiles with OSIRIS v7.1 showed differences within ± 10% for 30–53 km altitude. The errors were mostly less than − 5% below 43 km compared with ACE-FTS v4.0, but there was a large negative deviation in the upper stratosphere.

Optical study on the effect of ozone addition on a diesel/ammonia dual fuel engine with pilot injection

Influenced by the concept of carbon neutrality, ammonia is gaining widespread attention in the transport sector as a zero-carbon fuel. Diesel/ammonia dual fuel engines can achieve stable combustion of ammonia and reduce carbon emissions. To further enhance the low load combustion performance of a diesel/ammonia dual fuel engine, the effect of ozone addition on in-cylinder combustion and flame development was investigated based on an optical engine. Beyond that, ozone addition on pure diesel was also tested to understand the effect of ozone addition on diesel combustion enhancement in diesel/ammonia reactivity controlled compression ignition (RCCI) mode. The results show that the addition of ozone significantly advances the ignition phase, increases the flame area and brightness, and results in a growth in flame luminescence intensity along the radial length and closer to the center of the view field for diesel/ammonia RCCI combustion. In addition, chemical kinetic analysis shows that diesel/ammonia combustion requires higher ozone concentrations to overcome the inhibitory effect of ammonia to reach the upper limit of the promotional effect on the ignition phase and indicated mean effective pressure (IMEP), due to the large amount of OH consumed by ammonia compared to pure diesel. The promotional effect of added ozone on IMEP is similar for different pilot injection ratios (PIRs). At a low PIR and high ozone concentration, the diesel/ammonia RCCI engine achieves the highest IMEP, indicating that ozone addition combined with optimization of diesel injection parameters contributes to improve the performance of the diesel/ammonia RCCI engine at low loads.

Mn-TiO2 catalyst collaborates with trace O3 to enhance the removal of mercury in ESP environment

Ozone, known for its strong oxidizing properties, is commonly utilized in water pollution control. However, the catalytic ozonation of gaseous pollutants also shows potential as an emission reduction technology. The challenge lies in the high concentrations of ozone required in the catalytic process, which increases costs and complexity, hindering widespread adoption. Industrial electrostatic precipitators (ESPs) powered by high-voltage sources can produce ozone during operation, potentially causing environmental pollution if not managed. This study suggests utilizing a catalyst in the low-concentration ozone environment generated by an ESP for the catalytic oxidation of Hg0 in flue gas. The removal efficiency of Hg0 by either the catalyst alone or ozone alone (O3: 10 ppm) is modest at 43 % and 8 % respectively. However, when combined, the catalyst and ozone demonstrate a remarkable removal efficiency of over 98 %, significantly outperforming their individual capabilities. Furthermore, this process exhibits consistent high efficiency in a wide temperature range of 50–150 ℃. The study reveals that in the absence of O3, adsorbed oxygen acts as the primary oxidant, limiting the oxidation of Hg0. The introduction of O3 enhances electron transfer within the Mn-Ti catalyst, optimizing the electronic structure of oxygen and enhancing the oxidizing capacity of lattice oxygen, resulting in superior Hg0 removal efficiency. These findings offer valuable insights for the catalytic ozonation of Hg0.

Enhanced ozone gas detection with Sb doped ZnO nanorods synthesized on MEMS microheater

Metal oxide semiconductors infused with noble metals or metalloids are studied and employed in semiconductor sensors applications to a greater extent. In this study, antimony (Sb) is doped with ZnO in 4 different concentrations to compare the optimal parameters in gas sensing properties. Sb/ZnO nanostructure is synthesized by hydrothermal process and deposited on MEMS (Micro electro mechanical system) microheater device. The morphology of the nanostructure is analyzed for planar structure, oxidation states and the presence of Sb/ZnO is successfully verified. Ozone is a powerful oxidizing gas which is a health hazard in public places, so low concentrations of ozone is tested with Sb/ZnO sensor at various parameters. Since Sb acts as catalyst to promote the gas sensing properties, the sensor responses have been enhanced compared to pure ZnO sensor. Sensor performed its best at 200 °C and has the lowest detection gas concentration of 10 ppb. Sb/ZnO showed good selectivity over ozone gas.

Interactions between aerosols and surface ozone in arid and semi-arid regions of China.

Atmospheric aerosols affect surface ozone concentrations by influencing radiation, but the mechanism and dominant factors are unclear. Therefore, this paper analyses the changes in aerosol-radiative-surface ozone in China's arid and semi-arid regions with the help of the Atmospheric Radiative Transfer (SBDART) model. The results suggest that Aerosol Optical Depth (AOD) and coarse Particulate Matter (PM10) have the same trend, with high values in spring and winter and low values in summer and autumn. Surface ozone is high in spring and summer and low in autumn and winter. Surface ozone is higher in spring and summer and lower in autumn and winter. In winter, mainly secondary pollutants are dominated by high pollution levels. In the rest of the seasons, a mixture of dust, motor vehicle exhaust, and soot is dominated by low pollution levels. Surface ozone is positively correlated with fine particles and negatively correlated with coarse particles. Temperature is positively correlated with surface ozone in all seasons and negatively correlated with PM10 in summer, autumn, and winter. Precipitation negatively correlates with PM10 each season and surface ozone in winter and spring. Analysis of surface ozone and PM10 sources in the more polluted city of Hohhot based on the back-line trajectory model showed that airflow trajectories mainly transported surface ozone and PM10 pollution from northwestern Inner Mongolia and western Mongolia. During dusty solid weather, the decrease in radiation reaching the Earth's surface and the cooling effect of aerosols lead to lower temperatures, which slows down the rate of chemical reactions of precursors of surface ozone, resulting in lower ozone concentrations at the surface. This study can provide a theoretical reference for aerosol and surface ozone control in arid and semi-arid areas of China.

Remediation of oil-drilling cuttings by ozonation in a bubble flow reactor

Oil-drilling cuttings (ODCs) are the major wastes generated during oil/gas exploration and extraction. In the present work, a new method based on ozonation is suggested for the remediation of ODCs at ambient conditions, without pre-drying. During the ozonation process, the pressure drop across the gas phase along with the pH, redox potential, and temperature of liquid phase are monitored with the aid of built-in sensors. Occasionally, solid and liquid samples are collected to measure the total organic carbon (TOC) of each phase as a function of time, while the concentration of the total petroleum hydrocarbons (TPH) is measured before and after the completion of treatment. The maximum TOC removal efficiency for the solid phase reached ∼60% and that of TPH ∼ 40% whereas the energy efficiency was ∼ 0.1 kWh/g-TOC. The main mechanisms of ODC remediation are the mass-transfer of organic species from the solid to aqueous phase, and the direct oxidation by dissolved ozone, whereas their synergistic action is reflected in fluctuations of TOC concentration in liquid phase. The TOC removal efficiency of the solid phase increases with the flow rate decreasing, the ozone concentration increasing, and the mass ratio of ODC to seawater (SW) increasing. Ozonation in the liquid phase after its separation from treated ODC proceeds very fast through the direct oxidation by ozone. The process energy efficiency is favoured for low ozone concentration, low gas flow rate, high ODC to SW mass ratio, oxygen as feed gas, and without the addition of sodium dodecyl sulphate (SDS) as surfactant.

Convective modes reveal the incoherence of the Southern Polar Vortex

The Southern Polar Vortex (SPV) is prominent over Antarctica in the Austral winter, and typically associated with a region of low temperature, low ozone concentration, negative potential vorticity, and polar stratospheric clouds. Seasonal and unexpected changes in the SPV have a profound influence on global weather. A methodology which identifies the SPV’s coherence and breakup using only wind and pressure data is developed and validated against temperature, ozone and potential vorticity data. The process identifies “convective modes”, each with an assigned “coherence” value, which form building blocks for the observed spatial variation of the SPV. Analysis and interpretation are presented for 4 years with quite different known behavior of the SPV: 1999 (a relatively standard year), 2002 (when the SPV split into two), 2019 (an atmospheric warming year which led to an early dissipation in the SPV), and the most recent year 2022 (which was influenced by submarine volcano eruptions and a prolonged La Niña event). In decomposing convective effects into modes with quantifiable coherence, this study solidifies connections between wind velocities and atmospheric variables while providing new tools to study the evolution of coherent structures and signal the occurrence of atypical geophysical events.

The effects of gravity waves on ozone over the Tibetan Plateau

The ozone valley over the Tibetan Plateau (TP) has an important effect on global weather and climate. As a significant source of atmospheric gravity waves (GWs), TP is also a key area of global stratosphere-troposphere exchange (STE), yet the exploration of the causes of low ozone values over the TP has been scarce from the perspective of GW. In this paper, we used the hyperspectral Atmospheric Infrared Sounder (AIRS) data to extract GWs and deep convection over the TP and analyzed the statistical characteristics of ozone for corresponding events. The results show that: (1) The GWs observed by AIRS mainly occur in the mid-latitude region, with a maximum frequency of >10%, and their intensity varies with longitude. Three large-value regions have been identified on the coast of Southeast Asia, Central America, and Central Africa. (2) Most deep convection occurs in the Intertropical Convergence Zone (ITCZ), with three large value centers in the East Asian monsoon region, Central America and Central Africa. Among them, the Indian monsoon region, the Northwest Pacific region to the east of the Philippines, and the western side of the South China Sea (SCS) are the large-value areas within the East Asian monsoon region, with the maximum occurrence frequency exceeding 15%. (3) TP is a region with a large frequency of convective gravity waves. In most areas of the southern foothills of the TP, the frequency of GWs related to convection is 30%–50%. Almost all deep convection over the TP and its adjacent areas are accompanied by GWs, with a frequency of 60–90%. (4) The composite analysis results show that the occurrence of GWs or deep convection is accompanied by negative anomalies of ozone in most areas of the southern foothills of the TP, indicating a decrease in the integrated column amount of ozone. (5) By analyzing the anomaly distribution of meteorological elements such as cloud fraction, cloud top height, tropopause height, and outgoing longwave radiation (OLR), the results show a dual effect in the presence of GWs or deep convection. The effect involves not only an increased generation of clouds, conducive to convection but also elevated cloud top height, promoting the formation of high clouds, some even beyond the tropopause. In addition, the occurrence of GW or deep convection can also affect the tropopause height, strengthen convective activity, and facilitate the upward transfer of low-concentration ozone from the lower layer to the upper layer, thereby causing a decrease in the integrated column amount of ozone.

Decisive role of atmospheric circulation in the troposphere on ozone pollution in the Beijing-Tianjin-Hebei region

Using ozone observations and the ERA5 reanalysis, general circulation conditions between high and low ozone periods in the Beijing-Tianjin-Hebei (BTH) region in June are compared. The atmospheric circulation pattern is contrastingly different in midlatitudes between high and low ozone concentration periods. During high ozone periods in the BTH region, the East Asia–Pacific jet center shifts further eastward in the upper troposphere. Additionally, positive geopotential height anomalies develop at 500 hPa over the BTH region, accompanied by anomalously warm near surface conditions. In contrast, during low ozone periods in BTH, a similar circulation pattern is observed but with the sign reversed. During high (low) ozone periods, the temperature in the lower troposphere usually rises (reduces), solar ultraviolet radiation increases (decreases), and cloud cover, precipitation, and humidity decreases (increases). Moreover, during high (low) ozone periods in BTH, warm (cold) anomalies develop in the low troposphere, extending from the surface upward. This meteorological condition is (not) conducive to photochemical reactions in the near surface layer. The tropopause over the BTH region is anomalously higher (lower) during high (low) ozone periods, and the upper tropospheric ozone is ∼20% less (∼17.5% higher) than the average. Ozone from the upper levels might not consistently contribute to an increase (decrease) in the near surface ozone concentration in BTH, while negative (positive) ozone concentration anomalies prevail in upper levels. Existing evidence suggests that the frontal zone in the troposphere offsets the dynamic contribution of stratospheric transport to changes in ozone content in BTH.

Modifications of Blood Molecular Components after Treatment with Low Ozone Concentrations.

The ex vivo treatment of a limited volume of blood with gaseous oxygen-ozone (O2-O3) mixtures and its rapid reinfusion into the patient is a widespread medical procedure. O3 instantly reacts with the blood's antioxidant systems, disappearing before reinfusion, although the molecules formed act as messengers in the organism, inducing multiple antioxidant and anti-inflammatory responses. An appropriate dose of O3 is obviously essential to ensure both safety and therapeutic efficacy, and in recent years, the low-dose O3 concept has led to a significant reduction in the administered O3 concentrations. However, the molecular events triggered by such low concentrations in the blood still need to be fully elucidated. In this basic study, we analysed the molecular modifications induced ex vivo in sheep blood by 5 and 10 µg O3/mL O2 by means of a powerful metabolomics analysis in association with haemogas, light microscopy and bioanalytical assays. This combined approach revealed increased oxygenation and an increased antioxidant capacity in the O3-treated blood, which accorded with the literature. Moreover, original information was obtained on the impact of these low O3 concentrations on the metabolic pathways of amino acids, carbohydrates, lipids and nucleotides, with the modified metabolites being mostly involved in the preservation of the oxidant-antioxidant balance and in energy production.

The public-health significance of far-UVC-induced indoor ozone and its associated secondary chemistry.

There has been much recent interest in whole-room far-UVC (wavelength around 222 nm) to markedly and safely reduce overall levels of airborne pathogens in occupied indoor locations. Far-UVC light produces very low levels of ozone-in real-world scenarios induced ozone levels of less than 10 ppb, and much less in moderately or well-ventilated rooms compliant with US far-UVC dose recommendations, and very much less in rooms compliant with international far-UVC dose standards. At these very low ozone levels, there is no epidemiological evidence of increased health risks from any of the very large outdoor ozone studies, whether from ozone alone or from ozone plus associated pollutants. Indoors, at the low ozone concentrations of relevance here, ozone does not react rapidly enough with preexisting airborne volatile organic compounds to compete with even extremely low levels of room ventilation, so significant ozone-induced ultrafine particle production is very unlikely. Direct measurements in real-life room scenarios are consistent with these conclusions. A potential exception is the cleaning material limonene, which has an unusually high ozone interaction cross-section; in the far-UVC context, turning off far-UVC lights during cleaning with limonene products would be reasonable.

Reduced graphene oxide-cuprous oxide composites for low concentration ozone detection

In this research, cuprous oxide (pristine Cu2O) and rGO (reduced graphene oxide)-doped Cu2O were prepared using a simple synthetic route and adopted as sensitive materials for ozone detection. The microstructural, morphological and compositional properties of as-prepared samples have been analyzed by several characterization techniques including X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Energy dispersive spectrometer (EDS), UV-Visible spectrophotometer (UV–vis), Multi-functional field emission scanning electron microscope (FESEM), X-ray Photoelectron Spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). Meanwhile, the sensing features of as-prepared samples have been investigated carefully and the as-prepared 0.5 wt% rGO-Cu2O exhibited best ozone sensing properties, such as high stability, sensitivity and selectivity. It can be found that the response value of 0.5 wt% rGO-Cu2O-based sensor towards 20 ppb ozone and 1 ppm ozone were 9.2/1734, respectively, and the corresponding response and recovery times were 11/64 s and 11/411 s, respectively. More importantly, the detection limit of the 0.5 wt% rGO-Cu2O sensor was as low as 0.1 ppb. Furthermore, the possible mechanism for the enhanced sensing performance of the as-prepared rGO-Cu2O has been discussed.

Towards a generic solution to onsite wastewater treatment

Decentralized wastewater treatment, specifically onsite treatment, is fundamental to recent wastewater management paradigms. However, onsite solutions often produce inadequate effluent quality for reuse and are ineffective in removing organic micropollutants (OMPs). This study suggests a multistep onsite system for treating wastewater in varying conditions. The system comprises biological treatment in a recirculating vertical-flow bioreactor (RVFB) followed by ozonation and ultrafiltration. The system was constructed on a farm in the Israeli Negev desert and tested year-round for its effluent quality and removal of two model OMPs. Additionally, laboratory-scale experiments were conducted to understand the field data. The system has demonstrated stable performance over varying climate conditions and wastewater qualities during one year of operation. The RVFB reduced the total suspended solid (TSS) concentration by up to 96 %, the dissolved organic carbon by up to 88 %, and the biodegradable OMP, Ibuprofen, by approximately 82 %. Ozonation had limited impact on effluent quality, most likely due to low ozone concentrations, but interestingly efficiently reduced Carbamazepine, a recalcitrant OMP, by around 87 %. Additionally, the laboratory experiments using the farm's wastewater demonstrated the ozone's potential efficiency in improving effluent quality. The final membrane filtration treatment step fully removed the residual TSS and E. coli, achieving effluent quality that meets the standards for wastewater reuse. The membrane exhibited stable performance over one month without chemical cleaning, probably due to the pre-ozonation step. Overall, this study highlights the potential of the suggested system to effectively treat diverse wastewater types and produce high-quality effluent suitable for reuse.

Potential benefits of short-term indoor exposure to sweet orange essential oil for relaxation during mental work breaks

With people's pursuit of a high-quality life, the use of essential oils to improve perceived indoor air quality has increased in recent years because of their pleasant odor. The smell-scape is increasingly being considered with respect to healthy building practices. To close the gap between the health benefits of essential oils and the incidental pollution problems, a cross-over study was conducted in an environment with lower concentrations of ozone and particulate matter based on a realistic method for their use. We compared the physiological parameters blood pressure, heart rate (HR), and heart rate variability (HRV), as well as various cognitive performance indicators, perceived indoor air quality, odor, and mood states between indoor environments with and without sweet orange essential oil. We alleviated the secondary pollution problem of essential oil by maintaining low-ozone spaces. During mental work breaks, the participants' HRV in the environment with sweet orange essential oil emission increased during four rest periods by 36.4%, 47.5%, 33.4%, and 25.0%, respectively, although there was no significant effect on cognitive performance between the control phase and the exposure phase. A significant increase in diastolic blood pressure following mental work indicated emotional stress and was confirmed by mood state evaluation. This stress was alleviated by exposure to sweet orange essential oil. The present study indicates that following a mental work period, the release of sweet orange essential oil has the potential benefits of promoting relaxation during a rest period, provided that the dose follows scientific dosage guidance, and that ozone and particulate matter concentrations are controlled.

Assessment of the air disinfection effect of low-concentration ozone in a closed environment

Ozone, a prevalent pollutant in enclosed spaces, can pose health risks even at low levels. Despite its widespread use for disinfection, the efficacy in neutralizing airborne pathogens in confined settings remains uncertain. A study was conducted to investigate the disinfection capabilities of low-concentration ozone (several dozen parts per billion, ppb), within an isolation ward. Serratia marcescens and phi-X174 were used as tracer bioaerosols. The study examined two scenarios of applying low-concentration ozone in closed environments: direct introduction of low-concentration ozone into the ward and comparison of air disinfection effects of ozone-producing and non-ozone-producing UVC lamps. The UVC lamps chosen for this study were of 185 nm and 254 nm, which cannot coexist with humans when turned on. The results revealed that ozone concentrations below 60 ppb did not significantly impact air disinfection regarding Serratia marcescens and there was no noteworthy difference in effectiveness between the two types of UVC lamps for both Serratia marcescens and phi-X174. However, using UVC lamp resulted in a significantly higher air disinfection effect compared to the absence of a UVC lamp. For Serratia marcescens, the inclusion of ozone-producing and non-ozone producing UVC lamps (k = 49.8 ± 9.2 h−1, 52.9 ± 8.6 h−1, mean ± SD) significantly enhanced the decay rate by 29.6 h−1 and 32.7 h−1 respectively, compared with the absence of UVC lamps (k = 20.2 ± 2.3 h−1, mean ± SD). These findings highlight the limited potential of low-concentration ozone for air disinfection and emphasize the need for cautious utilization in enclosed environments.

Ozone pretreatment alleviates ischemia[sbnd]reperfusion injury-induced myocardial ferroptosis by activating the Nrf2/Slc7a11/Gpx4 axis

Myocardial ischemiareperfusion injury (MIRI) is defined as the additional damage that occurs during the process of restoring blood flow to the heart tissue after ischemia-induced damage. Ozone is a powerful oxidizer, but low concentrations of ozone can protect various organs from oxidative stress. Some studies have demonstrated a link between ozone and myocardioprotection, but the mechanism remains unclear. To establish an in vivo animal model of ischemiareperfusion injury (I/R), this study utilized C57 mice, while an in vitro model of hypoxia-reoxygenation (H/R) injury was developed using H9c2 cardiomyocytes to simulate ischemiareperfusion injury. Ozone pretreatment was used in in vitro and in vivo experiments. Through this research, we found that ozone therapy can reduce myocardial injury, and further studies found that ozone regulates the expression levels of these ferroptosis-related proteins and transcription factors in the H/R model, which were screened by bioinformatics. In particular, nuclear translocation of Nrf2 was enhanced by pretreatment with ozone, inhibited ferroptosis and ameliorated oxidative stress by initiating the expression of Slc7a11 and Gpx4. Significantly, Nrf2 gene silencing reverses the protective effects of ozone in the H/R model. In summary, our results suggest that ozone protects the myocardium from I/R damage through the Nrf2/Slc7a11/Gpx4 signaling pathway, highlighting the potential of ozone as a new coronary artery disease therapy.