Ozone Air Research Articles

Simple and Low-Cost Ground Level Ozone Measurement System Based on Internet of Things

Air quality monitoring in Indonesia is still not optimal owing to the lack of ambient air quality monitoring stations. Air quality in Indonesia is expressed by the air pollution status index (ISPU). Ozone is one of the parameters with the highest intensity at ambient air quality monitoring stations which is one of the parameters of ISPU. This study aims to design an ambient air ozone concentration monitoring device connected to a wireless network using economical components. This system uses the MQ131 sensor, DHT22 sensor, STM32 Blue Pill microcontroller, and Lora module, which is equipped with a power supply and protector, and displays monitoring results that provide an overview and additional information related to the air quality of the monitoring location on the website. The designed monitoring device can record ambient air ozone levels at the monitoring location with an average value of 20.33 μg/m3 with an average percent error of 2.34%. The ISPU value obtained during the measurement was 8, and the ISPU status was categorized as good.

Exposure to tropospheric ozone and NO2 in the ambient air of Tehran metropolis: Spatiotemporal distribution and inhalation health risk assessment

BackgroundAir pollution has emerged as a critical challenge in the 21st century, necessitating alert monitoring of key pollutants such as ozone and nitrogen dioxide (NO2)F. These pollutants are exacerbated by urbanization and industrialization, posing significant health risks, particularly in densely populated metropolitan areas. ObjectiveThe aim of this study was inhalation health risk assessment of NO2 and ozone in various scenarios and spatiotemporal Distribution Interpolation. MethodsData were collected from the Tehran Air Quality Control Center, encompassing 18 monitoring stations from March 2019 to February 2022. Health risk assessments (HRA) were performed for adult age groups across three different exposure scenarios (3, 8, and 12 h) And a sensitivity analysis was also conducted to determine the relative importance of each parameter in assessing the risks of each scenario. ResultsThe hazard index (HI) values for NO2 and ozone in all three scenarios were found to range from 0.24 to 1.56 and 0.04 to 0.49, respectively and body weight is a risk-lowering factor in sensitivity analyses. The interpolation results of ozone, NOx, and NO2 using the IDW approach from March 2019 to February 2022 showed that overall, the north and northeast of Tehran had the highest concentrations of NO2 and NOx, and the north and west had the highest concentrations of ozone. SignificanceThis study underscores the HRA with exposure to NO2 and ozone, particularly for individuals spending more than 8 h outdoors. Given Tehran's high population density and persistent air pollution, it is imperative to implement effective control policies to safeguard public health. The findings advocate for limiting outdoor activity to less than 8 h per day, especially for vulnerable occupational groups. Additionally, the study highlights the importance of considering body weight in health risk assessments.

A-site doped LaFeO3 perovskite for highly active O3 catalytic decomposition

Nowadays, the treatment of ozone has become critically important due to the health risks caused by even minimal amount of ozone in the ambient air. In this work, LaFeO3 doped with Mg, Ca, Sr and Ce on A-site are synthesized by sol-gel method and adopted as a highly active ozone decomposition catalyst. The results show that the Ce doped LaFeO3 exhibits the highest catalytic activity with the optimal doping concentration marked as La0.5Ce0.5FeO3. It reaches high conversion efficiency of 97 % and 90 % to 1000 ppm ozone at high weight hourly space velocity of 720,000 and 1440,000 mL g−1 h−1, which is one of the highest in the literature. The distortion of [FeO6] octahedra reached the maximum when the doping amount of Ce was 0.5 as revealed by X-ray diffraction and Rietveld fitting. The high ozone catalytic activity could be assigned to the easy electron loss from eg orbit caused by high crystal field splitting energy, abundant oxygen vacancies resulting from the biggest distortion of [FeO6] octahedra and quick transfer between Fe2+ and Fe3+.

Human-greenspace interactions with outdoor air: Landscape metric and PLS-SEM approach

Air pollution poses a significant global challenge, impeding the realization of sustainable development goals, especially in urban areas. Within built environment, the intricate interplay of human and greenspace primarily influences outdoor air quality. Therefore, to facilitate effective urban planning, the study investigates their complex interactions during the wet (May to October) and dry (November to April) seasons. This research employs landscape metrics to assess greenspace configurations within various buffers around 73 in-situ air quality moniroting stations accross Taiwan. These landscape metrics, anthorpogenic variables were utilized to construct the dimension of greenspace (GS) and anthoropogenic component (AC), respectively. Recorded air quality data were used to define the dimensions of outdoor air (OADs), encompassing air temperature (TEMP), wind speed (WS), relative humidity (RH), particle pollutant (PP), gaseous pollutant (GP), and OZONE. Subsequently, Partial Least Squares - Structural Equation Modeling was employed to explore the hypothesized relationships among these eight dimensions for each buffer and season. Results show that the AC exerts a more pronounced influence on the OADs compared to the GS. The GS shows greater effectiveness in mitigating the PP than the GP, while the AC substantially amplifies the GP during the two seasons. The GS and AC exhibit contrasting effects on the TEMP, RH, and GP. The GS exclusively affects the PP, while its effects on the OZONE and WS are insignificant during both seasons. Conversely, the AC has a negligible effect on the PP, but significantly impacts the OZONE, and WS. Through the GS, the AC indirectly influences the RH, PP, and GP during the two seasons, along with the TEMP during the wet season. Notably, the seven landscape metrics are identified for the GS, providing potential indicators for urban green planning to maximize its ecosystem services.

Impact of Molecular Chlorine Production from Aerosol Iron Photochemistry on Atmospheric Oxidative Capacity in North China.

Elevated levels of atmospheric molecular chlorine (Cl2) have been observed during the daytime in recent field studies in China but could not be explained by the current chlorine chemistry mechanisms in models. Here, we propose a Cl2 formation mechanism initiated by aerosol iron photochemistry to explain daytime Cl2 formation. We implement this mechanism into the GEOS-Chem chemical transport model and investigate its impacts on the atmospheric composition in wintertime North China where high levels of Cl2 as well as aerosol chloride and iron were observed. The new mechanism accounts for more than 90% of surface air Cl2 production in North China and consequently increases the surface air Cl2 abundances by an order of magnitude, improving the model's agreement with observed Cl2. The presence of high Cl2 significantly alters the oxidative capacity of the atmosphere, with a factor of 20-40 increase in the chlorine radical concentration and a 20-40% increase in the hydroxyl radical concentration in regions with high aerosol chloride and iron loadings. This results in an increase in surface air ozone by about 10%. This new Cl2 formation mechanism will improve the model simulation capability for reactive chlorine abundances in the regions with high emissions of chlorine and iron.

Interactive effect of ambient and elevated levels of tropospheric ozone, nutrition and PGPR on growth and yield of chickpea (Cicer arietinum)

An experiment was conducted during 2020 and 2021 at ICAR-Indian Agricultural Research Institute, New Delhi, to study the interactive effect of nutrient and PGPR (Plant growth promoting rhizobacteria) on growth and yield of chickpea (Cicer aeritinum L.) cv. Pusa 3043 under ambient and elevated levels of ozone in FAOE (Free air ozone enrichment). A loss of 15–16% in dry matter production was observed under elevated ozone (EO3) when compared to ambient ozone (AO3) conditions. Seed treatment with PGPR was found to compensate for this loss as an increase in seed yield 18–19% was observed over untreated seeds. In terms of seed yield, the PGPR treatments with 75% nitrogen showed significant improvement compared to the recommended dose of fertilizer (RDF) application. A yield increase of 12% and 14% was observed with PGPR like RPAN8 (Anabena laxa) and An-Rh (Anabena torulosa with Mesorhizobium ciceri) (chickpea rhizobium) respectively, suggesting an advantage of an–Rh over RPAN8 under EO3. A combination of both PGPRs outperformed the individual PGPR, showing a 19% yield increase over RDF. This proves the potential of seed treatment with PGPR (RPAN8 and An-Rh) in ameliorating tropospheric ozone-induced stress in chickpea plants.

Compact colorimetric method for determining formaldehyde in indoor air: Applying to an environment contaminated with hand sanitizer vapor

Hand sanitizer, widely used during the COVID-19 pandemic, must contain at least 60 % ethyl alcohol (ethanol) as an active ingredient. Due to its high vapor pressure, ethanol is rapidly transformed into vapor after the application over any surface. However, depending on the indoor air conditions, ethanol can rapidly oxidize to formaldehyde near harmful concentration levels. This study describes a simple and sensitive method to determine parts-per-billion (ppb) of gaseous formaldehyde using a cuvette (1.5 mL polystyrene, path length: 10 mm) as a microimpinger. Indoor and outdoor air was collected by the microimpinger containing 500 μL of 3-Methyl-2-benzothiazolinone hydrazone (MBTH) (2.32 × 10−3 mol L−1) at 50 mL min−1, resulting in a blue product after 30 min of sampling. Absorbance was measured at 680 nm and is proportional to the sampling period, analyte concentration, and sampling flow rate. Under the established conditions, a limit of detection of 7.0 ppb was achieved, which can be improved using longer sampling times. The analytical method was used to evaluate the oxidation of ethanol vapor by ozone in the indoor air. 10 min after the application of hand sanitizer, the air sample taken over the next 30 min revealed a notable rise in the concentration of low molecular weight aldehydes, measured as formaldehyde equivalent, within the room's air, and can reach around 100 ppb, which may be responsible for effects such as watery eyes, burning sensations in the mucous membrane, and difficulty breathing. The present technique affords a simple, inexpensive measurement with very little reagent consumption. Besides, the method is selective and highly sensitive. This method could be used either in outdoor or indoor environments.

Determination of Ozone Concentration Levels in Urban Environments Using a Laser Spectroscopy System

In urban areas, there has been a recent rise in ground-level ozone. Given its toxicity to both humans and the environment, the investigation of ozone pollution demands attention and should not be overlooked. Therefore, we conducted a study on ozone concentration in three distinct locations within the city of Magurele, Romania. This investigation considered variations in both structure and location during the spring and summer seasons, specifically at a breathing level of 1.5 m above the ground. Our analysis aimed to explore the impact of different locations and meteorological variables on ozone levels. The three measurement points were strategically positioned in diverse settings: within the city, in a forest, and within an industrial area. For these measurements, we used a laser spectroscopy system to determine the system’s sensitivity and selectivity and the influence of humidity in the detection of ozone in ambient air, which is a mixture of trace gases and water vapor. During the March–August campaign, the mean values in the three measuring points were 24.45 ± 16.44 ppb, 11.96 ± 3.80 ppb, and 95.01 ± 37.11 ppb. The peak concentrations of ozone were observed during the summer season. A diurnal analysis revealed that the atmospheric ozone levels were higher in the latter part of the day compared to the earlier part. These measurements suggest that the atmospheric temperature plays a significant role in tropospheric ozone production. Additionally, meteorological variables such as wind speed and direction were found to influence the ozone concentration. Remarkably, despite substantial traffic, the ozone levels remained consistently low throughout the entire period within the forested area. This observation may suggest the remarkable ability of trees to mitigate pollution levels.

Spatialtemporal evolution characteristics of ozone in China and its response to urbanization.

Based on the background of urbanization in China, we used the dynamic spatial panel Durbin model to study the driving mechanism of ozone pollution empirically. We also analyzed the spatial distribution of ozone driving factors using the GTWR. The results show that: i) The average annual increase of ozone concentration in ambient air in China from 2015 to 2019 was 1.68μg/m3, and 8.39μg/m3 elevated the year 2019 compared with 2015. ii) The Moran's I value of ozone in ambient air was 0.027 in 2015 and 0.209 in 2019, showing the spatial distribution characteristics of "east heavy and west light" and "south low and north high". iii) Per capita GDP industrial structure, population density, land expansion, and urbanization rate have significant spillover effects on ozone concentration, and the regional spillover effect is greater than the local effect. R&D intensity and education level have a significant negative impact on ozone concentration. iv) There is a decreasing trend in the inhibitory effect of educational attainment and R&D intensity on ozone concentration, and an increasing trend in the promotional effect of population urbanization rate, land expansion, and economic development on ozone concentration. Empirical results suggest a twofold policy meaning: i) to explore the causes behind the distribution of ozone from the new perspective of urbanization, and to further the atmospheric environmental protection system and ii) to eliminate the adverse impacts of ozone pollution on nature and harmonious social development.

Antimicrobial activity of safe concentrations of ozone, hydrogen peroxide, and triethylene glycol in air and surfaces

The application of low and non-toxic concentrations of antimicrobial compounds in indoor air is an interesting strategy to reduce airborne bacteria and fungi thereby reducing infection risk.

A comparative analysis of linear regression, neural networks and random forest regression for predicting air ozone employing soft sensor models

The proposed methodology presents a comprehensive analysis of soft sensor modeling techniques for air ozone prediction. We compare the performance of three different modeling techniques: LR (linear regression), NN (neural networks), and RFR (random forest regression). Additionally, we evaluate the impact of different variable sets on prediction performance. Our findings indicate that neural network models, particularly the RNN (recurrent neural networks), outperform the other modeling techniques in terms of prediction accuracy. The proposed methodology evaluates the impact of different variable sets on prediction performance, finding that variable set E demonstrates exceptional performance and achieves the highest average prediction accuracy among various software sensor models. In comparing variable set E and A, B, C, D, it is observed that the inclusion of an additional input feature, PM10, in the latter sets does not improve overall performance, potentially due to multicollinearity between PM10 and PM2.5 variables. The proposed methodology provides valuable insights into soft sensor modeling for air ozone prediction.Among the 72 sensors, sensor NNR[Y]C outperforms all other evaluated sensors, demonstrating exceptional predictive performance with an impressive R2 of 0.8902, low RMSE of 24.91, and remarkable MAE of 19.16. With a prediction accuracy of 81.44%, sensor NNR[Y]C is reliable and suitable for various technological applications.

A Numerical Investigation on Laminar Flame Speed of Syngas in Air with Ozone Addition

In the context of energy and propulsion systems, in recent years engineering research has increased its efforts to develop more efficient technologies with a lower environmental impact. Specifically, new combustion systems have been investigated, such as ultra-lean combustion and Homogeneous Charge Compression Ignition (HCCI) combustion, and sustainable fuels have been employed. With respect to the latter option, syngas and hydrogen have emerged as attractive choices. However, the low specific energy of syngas and the presence of diluents can cause flame failure and instability. On the other hand, it is well known that ozone-assisted combustion enhances the Laminar Flame Speed (LFS), reduces the ignition delay time, and improves the flame stabilization of fuels such as methane, n-heptane and iso-octane, since it affects the chemistry in the Low Temperature Combustion (LTC) regime. In this context, the aim of the present work is to evaluate the effect of ozone on the LFS of syngas/ozone/air mixtures. Specifically, 1-D simulations have been carried out to compute the LFS of CO/H2 and CO/H2/N2 syngas mixtures. The model has been validated against experimental data available in the scientific literature by considering four different reaction mechanisms. Then, the model has been used to perform a parametric analysis by considering different conditions in terms of syngas composition (three different CO/H2 ratios) and equivalence ratio (from 0.5 to 5). The results show that the addition of 2500 ppm of ozone in air results in an increase in LFS for all equivalence ratios examined. The four different mechanisms give comparable results in terms of LFS and LFS increase for CO/H2 syngas, and are also able to predict ozone effect on LFS enhancement for CO/H2/N2 mixtures. Finally, the results show that the influence of ozone, in terms of LFS percentage increase, is greater for CO/H2 ultra lean mixtures with a lower CO/H2 ratio.

Ozone Pollution Characteristics and Formation Mechanism in a Typical Tropical Seaside City

To investigate the pollution characteristics and formation mechanism of ambient air ozone(O3) in a typical tropical seaside city, we conducted an observational experiment on O3 and its precursors at an urban site in Haikou, Hainan Province, from June to October 2019. The O3 pollution characteristics were analyzed comprehensively; the O3-NOx-VOCs sensitivities and key precursors were determined, and the control strategies for O3 pollution were carried out. The results were as follows:1 O3 pollution in Haikou mainly occurred in September and October, with daily maximum 8-h O3 concentrations in the range of 39-190 μg·m-3, and the daily variation in O3 was unimodal, peaking at approximately 14:00. 2 The concentrations of NO2 and VOCs were higher during O3 pollution episodes than their respective mean values in Haikou City. The increased O3 precursor concentrations were an important factor leading to O3 pollution, whereas O3 pollution was also influenced by regional transport, with pollutants mainly transported from the northeastern part of Haikou City. 3 O3-NOx-VOCs sensitivity in Haikou City was in the VOCs and NOx transitional regime, and the most sensitive precursors in various months were different. O3 formation in September was sensitive to anthropogenic VOCs the most; however, in October it was sensitive to NOx. 4 In the future, the reduction ratio of VOCs to NOx should be 1:1-4:1 to control O3 pollution effectively in Haikou.

A cobalt-vacant Co3O4 as a stable catalyst for room-temperature decomposition of ozone in humid air

Conventionally ozone-decomposition catalysts such as MnO2 face the gradual deactivation due to occupation of reactive site, i.e., oxygen vacancy by intermediates like O22- or ubiquitous water vapor in air. Herein, we synthesized a Co2+-vacant Co3O4 (Co3−xO4) with dominant exposure of (110) facets, it maintained superior efficiency of 98% in decomposing 100 ppm ozone over 180 h under the space velocity of 1200 L/g·h at 25 ℃ and relative humidity (RH) of 50%, well beyond the performance of any reported metal oxides catalysts. Especially, it kept stable efficiency even under RH 90% and ultrahigh space velocity of 6000 L/g·h. A new ozone decomposition mechanism under humid conditions is revealed, i.e., the Co2+ vacancy significantly promotes O3 adsorption and the hydroxylation of coordination-unsaturated oxygen (CUO), and Co3+ work together with surface OH group to decompose ozone avoiding the deactivation. This study demonstrates a new way, i.e., creating metal vacancy rather than oxygen vacancy to design stable and efficient catalysts for ozone decomposition under humid conditions.

Response of PM2.5 and O3 to Emission Reductions in Nanjing Based on Random Forest Algorithm

High levels of fine particulate matter (PM2.5) and ozone (O3) in ambient air affect climate change and also endanger human health and ecosystems. Air pollution in Nanjing has been improving since the implementation of the "Air Pollution Prevention and Control Action Plan" in 2013. However, Nanjing still faces PM2.5 and O3 pollution. Evaluating the response of pollutant concentrations to the reductions in precursor emissions is helpful to obtain effective strategies of emission reduction to improve pollution levels. The sensitive simulations of emission perturbation in atmospheric chemistry models directly demonstrate the response of pollution to the reductions in emissions. Nevertheless, these sensitive simulations are limited in computing time and resources. The random forest algorithm was trained by using the simulation results of the atmospheric chemical transport model (GEOS-Chem) in 2015. The changes in daily PM2.5 and daily maximum eight-hour O3 (MDA8 O3) concentrations in Nanjing in 2019 were efficiently predicted under different reduction scenarios of anthropogenic emissions. The simulations showed that the seasonal average of ρ(PM2.5) in Nanjing would decrease by 2-4 μg·m-3 with the reduction in anthropogenic emissions of 10% in 2019 in China. In the case of controlling only local emissions in Nanjing, the concentrations of PM2.5 in Nanjing decreased significantly without local anthropogenic emissions. Additionally, the simulations showed that the annual average of ρ(PM2.5) in Nanjing could be lower than the national secondary limit (35 μg·m-3) when the anthropogenic emission reduction in China was higher than 20% in 2019. For ozone, the equal proportional emission reductions in nitrogen oxides (NOx) and volatile organic pollutants (VOCs) of O3 precursors in China likely led to the increase in seasonal average concentrations of O3 in Nanjing. For the proportional reduction of anthropogenic emissions by 10%-50% in China, the seasonal average of ρ(MDA8 O3) in Nanjing in 2019 would increase by 1-3 μg·m-3 in spring, 1-4 μg·m-3 in autumn, and 3-11 μg·m-3 in winter, respectively, compared with that in the base simulation. With the reduction in anthropogenic NOx emission by 10% and VOCs by 20%, the seasonal average of ρ(MDA8 O3) in Nanjing would decrease by 3-6 μg·m-3. On this basis, further increasing the proportion (30%) of VOCs emission reduction could reduce the annual average of ρ(MDA8 O3) in Nanjing by 7 μg·m-3. However, the annual average of ρ(MDA8 O3) of Nanjing in 2019 increased by 1 μg·m-3, with the local emission reduction of NOx by 10% and VOCs by 30%. Therefore, this showed that the key to alleviate ozone pollution in Nanjing is a reasonable control ratio of ozone precursor emissions and the implementation of regional joint prevention and control. In order to effectively reduce the O3 pollution in Nanjing, the emission reduction ratio of NOx and VOCs in China should be less than 1:2. The response of pollutant concentrations to reductions in precursor emissions were efficiently obtained by the random forest algorithm and GEOS-Chem model. The simulations would provide the scientific basis for the emission control strategy to alleviate air pollution.

Ozone Generation from a Germicidal Ultraviolet Lamp with Peak Emission at 222 nm.

Recent interest in commercial devices containing germicidal ultraviolet lamps with a peak emission wavelength at 222 nm (GUV222) has focused on mitigating virus transmission indoors while posing minimum risk to human tissue. However, 222 nm light can produce ozone (O3) in air. O3 is an undesirable component of indoor air because of health impacts from acute to chronic exposure and its ability to degrade indoor air quality through oxidation chemistry. In seven four-hour experiments we measured O3 produced from a single filtered GUV222 lamp in a 31.5 m3 stainless steel chamber. Using an emission model, we determined an O3 generation rate of 19.4 ppbv h-1 ± 0.3 ppbv h-1 (equivalent to 1.22 mg h-1 ± 0.02 mg h-1). We estimated the fluence rate from the lamp using two methods: (1) chemical actinometry using tetrachloroethylene (actinometry) and (2) geometric projection of the irradiance field from radial and angular distribution measurements of the GUV222 lamp fluence (irradiance). Using the estimated lamp fluence rates of 2.2 μW cm-2 (actinometry) and 3.2 μW cm-2 (irradiance) we predicted O3 production in our chamber within 20 % of the average measured mixing ratio. Future studies should evaluate the indoor air quality impacts of GUV222 technologies.

Chemical Characteristics and Source Apportionment for VOCs During the Ozone Pollution Episodes and Non-ozone Pollution Periods in Qingdao

The ambient concentration of ozone is high in Qingdao, and ozone pollution episodes occur frequently in summer. The refined source apportionment of ambient volatile organic compounds (VOCs) and their ozone formation potential (OFP) during ozone pollution episodes and non-ozone pollution periods can play an important role in effectively reducing air ozone pollution in coastal cities and continuously improving ambient air quality. Therefore, this study applied the online VOCs monitoring data with hourly resolution in summer (from June to August) in 2020 in Qingdao to analyze the chemical characteristics of ambient VOCs during the ozone pollution episodes and non-ozone pollution periods and conducted the refined source apportionment of ambient VOCs and their OFP using a positive matrix factorization (PMF) model. The results showed that the average mass concentration of ambient VOCs in Qingdao in summer was 93.8 μg·m-3, and compared with that during the non-ozone pollution period, the mass concentration of ambient VOCs during the ozone pollution episodes increased by 49.3%, and the mass concentration of aromatic hydrocarbons increased by 59.7%. The total OFP of ambient VOCs in summer was 246.3 μg·m-3. Compared with that in the non-ozone pollution period, the total OFP of ambient VOCs in the ozone pollution episodes increased by 43.1%; that of alkanes increased the most, reaching 58.8%. M-ethyltoluene and 2,3-dimethylpentane were the species with the largest increase in OFP and its proportion during the ozone pollution episodes. The main contributors of ambient VOCs in Qingdao in summer were diesel vehicles (11.2%), solvent use (4.7%), liquefied petroleum gas and natural gas (LPG/NG) (27.5%), gasoline vehicles (8.9%), gasoline volatilization (26.6%), emissions of combustion- and petrochemical-related enterprises (16.4%), and plant emissions (4.8%). Compared with that in the non-ozone pollution period, the contribution concentration of LPG/NG in the ozone pollution episodes increased by 16.4 μg·m-3, which was the source category with the largest increase. The contribution concentration of plant emissions increased by 88.6% in the ozone pollution episodes, which was the source category with the highest increase rate. In addition, emissions from combustion- and petrochemical-related enterprises were the largest contributor to the OFP of ambient VOCs in summer in Qingdao, with its OFP and contribution proportion being 38.0 μg·m-3and 24.5%, respectively, followed by that of LPG/NG and gasoline volatilization. Compared with the non-ozone pollution period, the total contributions of LPG/NG, gasoline volatilization, and solvent use to the increase in OFP for ambient VOCs in the ozone pollution episodes were 74.1%, which were the main contribution source categories.

Optically levitated, single-particle reactor for the study of surface and heterogeneous chemistry-reactions of particulate-bound mercury with ozone in air

We created a micron-sized, single-particle reactor (SPR) freely levitated in air using optical trapping of a single particulate-bound mercury particle formed by mixing HgCl2, HgBr2, or HgBrCl (HgX2, X = Cl, Br) with single-walled carbon nanotubes. Position- and time-resolved, single-particle Raman spectra show clear evidence of reactions of solid-state HgX2 in the presence of excessive O3 under the illumination of 532-nm light. We propose a reaction mechanism: Hg(II)X2 (solid) + O → Hg(I)X + XO, XO + O → O2 + X on the surface of the SPR. This exploratory study demonstrates that the SPR is a new tool for the study the surface and heterogeneous chemistry of mercury at atmospherically relevant surfaces, e.g., aerosols.

Short-Term Ambient Air Ozone Exposure and Components of Metabolic Syndrome in a Cohort of Mexican Obese Adolescents.

Ambient air pollution is a major global public health concern; little evidence exists about the effects of short-term exposure to ozone on components of metabolic syndrome in young obese adolescents. The inhalation of air pollutants, such as ozone, can participate in the development of oxidative stress, systemic inflammation, insulin resistance, endothelium dysfunction, and epigenetic modification. Metabolic alterations in blood in components of metabolic syndrome (MS) and short-term ambient air ozone exposure were determined and evaluated longitudinally in a cohort of 372 adolescents aged between 9 to 19 years old. We used longitudinal mixed-effects models to evaluate the association between ozone exposure and the risk of components of metabolic syndrome and its parameters separately, adjusted using important variables. We observed statistically significant associations between exposure to ozone in tertiles in different lag days and the parameters associated with MS, especially for triglycerides (20.20 mg/dL, 95% CI: 9.5, 30.9), HDL cholesterol (-2.56 mg/dL (95% CI: -5.06, -0.05), and systolic blood pressure (1.10 mmHg, 95% CI: 0.08, 2.2). This study supports the hypothesis that short-term ambient air exposure to ozone may increase the risk of some components of MS such as triglycerides, cholesterol, and blood pressure in the obese adolescent population.

Growth acceleration of Nile tilapia at 21 to 31 weeks of age with plasma-treated air-supplied water

This study aimed to develop a technique to accelerate fish growth without using genetic modification or genome editing. We have prepared a reactor with four pairs of opposed electrodes and a high-voltage power supply for the discharge. An arc discharge generates a plasma-treated gas in the reactor. Plasma-treated gas containing active species such as nitric oxide (NO) was generated via an arc discharge in the atmosphere and inserted into an aquarium containing Nile tilapia. No ozone was detected in the plasma-treated gas. Plasma treatment gas was supplied to the 20 L tank at a flow rate of 10 L per minute for varying supply times. The supply duration of plasma-treated air to the water tank was 0.5, 2, 5, and 15 min. Tanks were prepared for each of these four conditions, and gas was supplied daily at the same time. We observed that on supplying plasma-treated gas to tilapia from the 16th week of age for 5 min daily, the average length of the fish at 31 weeks of age was ∼1.5 times longer than that of the control fish. All other supply time conditions were also found to grow acceleration over the control. In the 15-minute supply time condition, individual differences in body length were more significant. A sample had more growth suppression than controls. In other words, the results suggest that an excess supply of active species can cause growth inhibition. These results suggest that an optimal supply of plasma-treated gas has a growth-promoting effect on fish. Key policy highlights The fish growth was accelerated by supplying plasma-treated air to the tank. The amount of ozone in the plasma-treated air was below the detection limit, and a large amount of RNS, such as nitric oxide, was generated. After an experimental period of 16 to 31 weeks, the average length of fish in the most significant growth condition was 1.5 times that of the control fish.