Measured Ozone Concentrations Research Articles

Optimization of the concentration of ozone generated by DBD using PSO algorithm for water treatment process

The water treatment process with ozone is influenced by various operating parameters and environmental factors that can impact its efficiency. In this study, experiments were conducted using a Venturi pumping frame to investigate the effects of three controllable variables: oxygen flow height, applied voltage level, and water flow rate. The tests aimed to develop a mathematical model that accurately represents the relationship between these input variables and the resulting ozone concentration in the treated water. The experimental data was analyzed using the MODDE 5.0 software, a specialized application for statistical modeling and design of experiments. By fitting the data to appropriate model equations, a mathematical model was obtained that quantifies the influence of each variable and their interactions on the ozone concentration response. To optimize the process performance, a particle swarm optimization (PSO) algorithm was employed to extract the best-fit parameters for the mathematical model. PSO is a computational technique inspired by the social behavior of bird flocks or fish schools, utilizing a population of candidate solutions that evolve iteratively to converge on the global optimum solution. In this case, PSO searched for the model parameter values that minimized the error between predicted and experimentally measured ozone concentrations, rapidly converging to an accurate solution. The optimized mathematical model enables predicting the ozone concentration under any combination of oxygen flow height, voltage, and water flow rate within the experimental range. This predictive capability facilitates identifying the optimum operating conditions to maximize ozone concentration, thereby enhancing the efficiency of the water treatment process. The model serves as a valuable tool for process control, monitoring, and optimization, ensuring consistent treatment quality while minimizing resource consumption and operational costs.

Measurement and Risk Analysis of Ozone (O3) Concentrations in the 9 MeV and 12 MeV Electron Mode LINAC

This study investigates potential non-radiation hazards, specifically Ozone (O3) production, during Linear Accelerator (LINAC) electron mode radiotherapy. The research uses experimental measurements to determine Ozone concentration in the LINAC patient waiting room and control room. Measurements are taken assuming a ±2-hour delay in one working day, using 9 MeV and 12 MeV energy, 400 MU dose rate, and illumination angles of 0o, 90o, and 270o. Maximum Ozone concentrations in the LINAC patient waiting room and control room are found to be 6.6 ppb (12 MeV) and 8.3 ppb (12 MeV), respectively. These concentrations fall below the chemical threshold limit and are deemed safe for human exposure. Notably, potentially detectable Ozone levels are observed in the LINAC banker. Overall, this research highlights the importance of monitoring Ozone levels to ensure the safety of both patients and personnel in LINAC facilities.

Novel Compact Polarized Martian Wind Imaging Interferometer

The Mars Atmospheric Wind Imaging Interferometer offers several advantages, notably its high throughput, enabling the acquisition of precise and high vertical resolution data on the temperature and wind fields in the Martian atmosphere. Considering the current absence of such an Interferometer, this paper introduces a novel Mars wind field imaging interferometer. In analyzing the photochemical model of O2 (a1Δg) 1.27 μm molecular airglow radiation in the Martian atmosphere and considering the impact of instrument signal-to-noise ratio (SNR), we have chosen an optical path difference (OPD) of 8.6 cm for the interferometer. The all-solid-state polarized wind imaging interferometer is miniaturized by incorporating two arm glasses as the compensation medium in its construction, achieving the effects of field-widening and temperature compensation. Additionally, an F-P Etalon is designed to selectively filter the desired three spectral lines of O2 dayglow, and its effect is evaluated through simulations. The accuracy of the proposed compact Mars polarized wind imaging interferometer for detecting Mars’ wind field and temperature field has been validated through rigorous theoretical derivation and comprehensive computer simulations. The interferometer boasts several advantages, including its compact and small size, static stability, minimal stray light, and absence of moving parts. It establishes the theoretical, technological, and instrumental engineering foundations for future simultaneous static measurement of Martian global atmospheric wind fields, temperature fields, and ozone concentrations from spacecraft, thereby significantly contributing to the dataset for investigating Martian atmospheric dynamics.

Analysis of Ozone Production Reaction Rate and Partial Discharge Power in a Dielectric-Barrier Acrylic Chamber with 60 Hz High-Voltage Electrodes: CFD and Experimental Investigations

We present a synergistic investigation into ozone production dynamics within a high-voltage reaction chamber operating from 1.75 kV to 10 kV, at 60 Hz. The output ozone concentration dependence on a 60 Hz root mean square high-voltage for an air input pressure of 0.1 bar was measured using an ultraviolet-based sensor. A finite-element numerical model of the reaction chamber was developed and used for obtaining the reaction rate for the generated ozone for each level of input voltage and the internal distribution of the gas vector velocity field and ozone concentration. An expression to estimate the ozone reaction rates from the measured ozone concentrations was also derived. It was then compared and validated using the developed computational model. Therefore, in this work, a formula is proposed to estimate the ozone production by providing the experimental reaction rates. The other objective is to analyze the hysteresis phenomena observed in the partial discharges’ levels in the reaction chamber and in the output ozone concentration. Finally, we establish a connection between the total power of partial discharges and the consequent ozone production, clarifying the role of cumulative partial discharges’ power levels in governing the resultant output ozone concentration.

The effect of VOC and environmental parameters on ozone sensors performance

ABSTRACT Accurate measurement of ozone concentration, especially in workplaces is a crucial component of managing indoor air quality and protecting workers’ and building occupants’ health and safety. Some factors such as gaseous pollutants (like volatile organic compounds (VOCs)), relative humidity, and air velocity and direction could interfere with monitor readings. This study examined the impact of these environmental factors on the responses of six commercial ozone monitors: three UV photometry, two electrochemical and one semiconductor metal oxide. The results demonstrated that environmental physical parameters (i.e. air velocity and relative humidity) often slightly affected UV instrument’s performance, while significant effects were seen in electrochemical and semiconductor monitors. Furthermore, chemical parameters (only VOCs including ethanol, acetone and toluene) had more influence on UV ozone monitors than those using electrochemical and metal oxide techniques.

Ozone Concentration Measurement of an Atmospheric Pressure Air Plasma Jet by Ultraviolet Absorption Spectroscopy

Atmospheric pressure plasma jets have great potentials for various biomedical applications due to abundance with active oxygen species. In this article, an air plasma jet with a geometry of microhollow cathode discharge has been developed, which operates in a pulsed mode or a continuous mode depending on the dissipated power of the plasma jet. There are some continuous spectra emitted from the plasma jet, whose integrated intensity indicates that electron density increases with the increase of dissipated power, while decreases with increasing air flow rate for both of the two modes. Moreover, the electron density in the continuous mode is higher than that in the pulsed mode. Gas temperature of the plasma jet is obtained by the best fitting of the simulated and the experimental optical emission spectrum of OH (A-X), and ozone concentration produced by the plasma jet is measured by means of ultraviolet absorption spectroscopy. Results indicate that both ozone concentration and gas temperature decrease with increasing distance from the jet nozzle. At the jet nozzle, both of them increase with increasing dissipated power. However, ozone concentration decreases, while gas temperature increases with increasing air flow rate. The results are very important for the biomedical application of plasma jet.

Evidence of NOx and O3 concentration reduction by kudzu (Pueraria lobata) invasion at a Japanese highway

Generally, urban green infrastructure aids in the mitigation of air pollution. However, little is known about the role of densely packed vegetation canopies, such as Pueraria lobata (Willd.) Ohwi (kudzu) in air pollution mitigation. Here, we conducted field measurements of tropospheric ozone (O3) and nitrogen oxides (NOx) concentrations on a highway embankment slope with and without kudzu canopies in Japan. We measured O3 and NOx concentrations above and within the kudzu canopies by using a passive sampler several times during the growing season in 2019. The results demonstrated that both O3 and NOx concentrations reduced within the kudzu canopy throughout the growing season, suggesting that kudzu generally acts as “vegetation barrier” for both gas pollutants along the highway roadside. Depending on meteorological and vegetative surface conditions, the reduction rate within the canopy ranged from 11% to 64% and from −2% to 33% for O3 and NOx concentrations, respectively. Considering lower canopy height but higher leaf area density of kudzu than those for urban tree plantations or forest patches along the roadside, kudzu can be useful as green infrastructure depending on situations. We also found that the higher the leaf area index of kudzu canopies, the higher the reduction rates of O3 and NOx. Depending on the maintenance cost for roadside tree planting, the minimal management without targeting the eradication of kudzu over a certain area can be an option for realizing green infrastructure at least for maintaining local air quality during the growing season.

A more selective and accurate method than indigo method for measuring dissolved ozone concentration (p-vinylbenzoic acid method)

Dissolved ozone concentration measurement is crucial for ozone treatment. In the most used conventional indigo method, the ozone concentration is measured by the decrease in absorbance due to the loss of the C–C double bond of indigotrisulfonic acid. However, measurement of ozone concentration is difficult when water contains substances that react with C–C double bonds other than ozone. To address this concern, we developed a novel breakthrough method to measure ozone concentration by measuring the p-formylbenzoic acid (p-FBA) produced after the reaction of p-vinylbenzoic acid and ozone. The formation of p-FBA was almost not caused by other substances (hypochlorous acid, hypobromous acid, permanganate ion and hydrogen peroxide), and its yield to ozone was maintained at 1 in river water, treated wastewater and seawater. In addition, the experimental error is smaller with the new method than with indigo. Furthermore, the new method does not require cumbersome calibration unlike indigo method because highly pure forms of p-FBA are commercially available. p-FBA can be separated by liquid chromatography and detected with highly sensitive ultraviolet and mass spectrometric detectors, and hence easily analyzed simultaneously with other substances. Our new method contributes to extensive ozone treatment and ozonation management.

Simulation of ozone concentrations inside 60CO industrial irradiator

The motivation of this work is to study the relationship between gamma radiation and also ozone concentration in 60CO industrial irradiators. Because ozone is considered to be one of the most important safety issues, because it has a destructive effect on the human body and has a corrosive effect on metal parts in the irradiated area. Moreover, due to its high reactivity. So first using ozone monogram method to measure ozone concentration, and also the effect of the factor on ozone concentration was determined. MATLAB computer code was used to calculate the ozone concentration-response with completely different statistics. Among them, ozone concentration in the 60CO irradiation area is in a completely different state. These conditions include: different gamma emitters, completely different irradiators, airflow correction, and engine failure. It is suggested that ozone formation may be a direct effect of gamma radiations. the result show also that the health hazards due to the ozone produced during irradiation are significant and should not be overlooked. It was observed that in case of 1Ci motor failure, the detection time is 67.5 minutes. While, for 0.1Ci motor failure, the detection time is 32.2 minutes. To fulfill the employee safety limits. it is recommended to have a second control system with ventilation

Measurement of Ambient Ozone Concentration using Passive Sampler

<p>Measurement of ozone concentration in ambient air was carried out using the passive sampling method in Cipedes, Bandung, from 2012 – 2020. Sample analysis was done using ICS 1500 Dionex ion chromatography. The results showed a fluctuating concentration from 2012 -2020 with the highest average value in 2015 of 29.94 g/m³. The monthly pattern shows the highest ozone concentration in September and the lowest in December; this condition was related to the intensity of rainfall that can clean ozone in the atmosphere. The seasonal pattern showed in the dry season ozone concentration is relatively higher than in the rainy season. A comparison of passive and continuous sampling was made to see the performance of the passive sampler showing a similar pattern with a correlation coefficient of r = 0.48. This difference in value was related to the absorption of ozone gas in the passive sampler absorbing filter and the meteorological factors.</p>

Generation of ozone during irradiation using medical linear accelerators: an experimental study

BackgroundSome patients have noted a foul odor during radiation therapy sessions, but the cause of the odor remains unknown. Since we suspected that this phenomenon is due to ozone generated by ionizing radiation, this experimental study measured ozone concentrations in the treatment room and in a coiled polyvinyl chloride (PVC) tube placed within the radiation field.MethodsWe measured ozone concentrations using an ultraviolet absorption method and an ozone monitor. A PVC tube (inner diameter 7 mm, outer diameter 10 mm) was used to mimic the environment of the nasal cavity. The tube (790 cm) was coiled and set between two 4-cm-thick (for X-rays) or 2-cm-thick (for electron beams) water-equivalent solid phantoms. The sampling tube of the ozone monitor was inserted into the PVC tube, and the joint was sealed to prevent environmental air contamination. To measure ozone concentrations in the atmosphere, the sampling tube supplied with the unit was used. A linac was used on a full-sized treatment field (40 cm × 40 cm at a source-to-axis distance of 100 cm). The effect of an electron beam on ozone concentrations was also evaluated with a full-sized treatment field (40 cm × 40 cm at a source-to-surface distance of 100 cm).ResultsOzone levels in the treatment room were undetectable before the start of daily treatment but reached 0.008 parts per million (ppm) or more at 1 h after the start of treatment. Concentrations then remained nearly constant at 0.010–0.015 ppm throughout the day. The maximum ozone concentration in the PVC tube was only 0.006 ppm, even when it was irradiated at 2400 monitor units/min. Depending on the X-ray dose rate, the concentration increased to a maximum of 0.010 ppm with oxygen flowing into the other end of the tube at 1.5 L/min. Ozone concentrations in the PVC tube did not differ significantly between X-ray and electron-beam irradiation.ConclusionsOnly traces of ozone were found in the PVC tube that was used to mimic the nasal passages during radiation, these concentrations were too low for human perception. However, ozone concentrations did reach potentially detectable levels in the treatment room.

The effect of built-in and portable ionizers on in-cabin ozone concentrations in light-duty vehicles.

This paper investigates the effects of ionizers on the ozone concentration within vehicle cabins by using a series of measurements combined with a kinetic box model. Testing consisted of measuring ozone concentration during static tests where the ventilation of the test vehicle was turned on and off depending on the test. This testing was repeated for three different portable ionizers and two vehicles with built-in ionizers. Ionizer A produced ozone at a rate of ∼0.04 ppb s-1 (∼0.68 mg h-1), which increased the in-cabin O3 concentrations of a Mitsubishi Mirage to ∼10 ppb with the fan off and ∼6 ppb in the recirculation mode. In the fresh air mode, in-cabin O3 concentrations were dominated by outdoor-to-indoor transport. Ionizer B and C produced O3 at a rate of less than 0.008 ppb s-1 (<0.14 mg h-1); however, during retesting, ionizer C was shown to emit large amounts of ozone for short amounts of time while being tested up close. The same testing was completed on vehicles with built-in ionizers; these produced <0.01 ppb s-1 (<0.32 mg h-1 in the Buick Enclave and <0.25 mg h-1 in the Hyundai Genesis), and in-cabin O3 concentrations were again dominated by outdoor-to-indoor transport with fresh air ventilation. While ionizers are currently regulated, the negative impact they have on in cabin air quality is important to continue monitoring.

Photochemical reactions and surface ozone measurements in Tehran city center

Efforts have been made for surface ozone concentration measurements considering secondary reactions via actinometry. Pyro heliometry, pyranometry and spectrophotometry, idometry in Amir Abad station of Tehran city center in parallel. In actinometry method consideration were made to show solar radiation in all different filters of green, yellow, red and dark red by means of 525 nm, 630 nm, 695 nm and 721 nm in parallel by the same time during 1991–1992. Resulted as solar radiation reduction in all filters and concluded for secondary reactions at Amirabad station for the first time in Iran. Measurements were made daily and seasonally at midday in Amirabad station. Where in idometry and spectrophotometry method consideration were made in certain wavelengths of 276.5 nm and 301 nm, for surface ozone measurements during autumn winter considering, October, November, December 1991–1992 and 1999–2001, using rain samples. Which has shown a concentration range of 30–60 (ppb) and 80–115 (ppb), respectively. The concentration measurements of surface ozone were made as a function of photochemical reactions of NO2. NO and photon rays in agreement with the results of spectrometry method by the same time due to F.M. Shahrtash for the first time in Iran. This study was in agreements with the works in Montreal, Ca (1992). Other consideration was made for surface ozone data collection analysis of (MOI) from Mehrabad station of Tehran city center via Dobson method during summer–autumn 2015. Which has shown a range of concentration of 80–92 (ppb), in comparison with the measurements of Amirabad station. Besides consideration was made for recent research work in China, which has detected the surface ozone concentration of 70–100 ppb during 2013–2018, mainly in North China and Yangtze river plain” by means of “photochemical reactions and surface ozone” in agreement with this study as a whole.

Development of ozone monitoring system in ozone-treated water.

An ozone concentration meter in ozonated water has been developed and manufactured. The measurement of ozone concentration is based on the use of a photometric method. The range of measured ozone concentration is varied from 0.1 to 10 mg/l. The principle of operation of the meter is based on recording the difference in the absorption coefficients of ultraviolet radiation by the analyzed ozonated water and the reference (ozone-free) water. The meter was calibrated on an automated measuring stand using a monochromator and a photomultiplier tube. Such a device could be very useful in water purification systems or wastewater treatment plants. The developed meter provided high accuracy and stability of readings, operation without maintenance, full automation of measurement, and automatic correction of zero drift.

Comparative study of variation of ground level ozone concentrations and total column ozone concentrations over Klang Valley

Ozone is a gas that plays important role in balancing the Earth’s atmosphere thermal and chemical. Ozone is capable of absorbing the harmful sun’s ultraviolet (UV) radiation. The stratospheric ozone has protecting humans and the ecosystems on Earth from solar radiation. However, ground level ozone (GLO) has been related to secondary pollutants and greenhouse gases that give adverse impacts on human health and crop yield. Hence, determining ozone concentration measurement is important for air quality status for the environmental and public health warnings. Variations of ground level ozone (GLO) and total column ozone (TCO) concentrations over Klang Valley, Malaysia in 2014 and 2015 were determined in this study. The GLO measurement data was acquired from Department of Environment (DOE) Malaysia and is measured using standard method instrument, UV Absorption Ozone Analyzer Model 400A while, TCO measurement using Ozone Monitoring Instrument (OMI). The analysis suggests that GLO concentrations in all four stations in Klang Valley exceeded the Malaysia Ambient Air Quality Standard (NMAAQS) 2020 prescribed limit of 90 ppb per hour. In both 2014 and 2015, TCO concentration observed higher from May to August with the highest concentration of 290 DU and lowest from November to February with the lowest concentration of 230 DU, suggesting that there is seasonal fluctuation caused by Northeast Monsoon (NEM) and Southwest Monsoon (SWM). This is due to environmental factors during SWM that favour a rise in TCO concentration, such as low precipitation, low relative humidity, high temperature, and prolonged sunshine hours. On the other hand, NEM results in lower TCO concentration due to high precipitation, high relative humidity, cold temperature, and short sunshine hours. Meanwhile, GLO peaks are usually seen towards the end of March through April and in October, according to GLO trend research (40 to 50 ppb). This is during the transitional monsoon season, where the west part of Peninsular Malaysia received precipitation lower than usual.

Development of an Experimental Setup for Real-Time In-Line Dissolved Ozone Measurement for Medical Therapy

ABSTRACT Ozone therapy is established in clinical applications since many decades, such as treatment of infections or herniated discs. However, in-line monitoring of ozone concentrations is challenging and therefore not performed by default. We developed an experimental setup to measure the in-line ozone concentration in water in real-time with a spectroscopic sensor. Thereby, the experimental setup enables the calibration and evaluation of newly evolved ozone sensors. The results for ozone concentration measurement with the spectroscopic sensor and the colorimetric photometer show a very good correlation. Furthermore, the ozone decay curves measured with our experimental setup highly correlate with those of previous research.

Improving Air Pollutant Metal Oxide Sensor Quantification Practices through: An Exploration of Sensor Signal Normalization, Multi-Sensor and Universal Calibration Model Generation, and Physical Factors Such as Co-Location Duration and Sensor Age

As low-cost sensors have become ubiquitous in air quality measurements, there is a need for more efficient calibration and quantification practices. Here, we deploy stationary low-cost monitors in Colorado and Southern California near oil and gas facilities, focusing our analysis on methane and ozone concentration measurement using metal oxide sensors. In comparing different sensor signal normalization techniques, we propose a z-scoring standardization approach to normalize all sensor signals, making our calibration results more easily transferable among sensor packages. We also attempt several different physical co-location schemes, and explore several calibration models in which only one sensor system needs to be co-located with a reference instrument, and can be used to calibrate the rest of the fleet of sensor systems. This approach greatly reduces the time and effort involved in field normalization without compromising goodness of fit of the calibration model to a significant extent. We also explore other factors affecting the performance of the sensor system quantification method, including the use of different reference instruments, duration of co-location, time averaging, transferability between different physical environments, and the age of metal oxide sensors. Our focus on methane and stationary monitors, in addition to the z-scoring standardization approach, has broad applications in low-cost sensor calibration and utility.

Long-term changes in northern mid-latitude tropospheric ozone concentrations: Synthesis of two recent analyses

The HTAP (Hemispheric Transport of Air Pollution) and TOAR (Tropospheric Ozone Assessment Report) programs synthesized historical ozone measurements and compared them with recent measurements to quantify the long-term increase of tropospheric ozone concentrations that occurred at northern mid-latitudes in the 20th century due to the increase and subsequent stabilization of anthropogenic ozone precursor emissions. The two studies disagree regarding the magnitude of the increase; the HTAP study found an approximate doubling of baseline ozone concentrations, while the TOAR study suggested a change of about half that magnitude in the well-mixed planetary boundary layer. Here we explore the reasons for this difference, and reconcile the results. The two efforts agree regarding measurements of historical ozone concentrations, but disagree on the comparison of the historical to the modern data. HTAP analyzed seasonal mean historical and modern data from the same or closely equivalent, baseline sites. TOAR selected pre-1975 measurement data sets based upon four data selection criteria; averages of these selected data sets from all seasons, site locations and site environments were compared with annual means of modern data collected at rural European surface sites. The TOAR comparison approach introduced several biases that led to underestimates of the overall change of baseline ozone. We conclude that northern mid-latitude tropospheric baseline ozone concentrations, which are relevant for radiative forcing, increased by a factor of 2.1 ± 0.2 over the 1950–2000 period.

Robust Inferential Techniques Applied to the Analysis of the Tropospheric Ozone Concentration in an Urban Area.

This paper analyzes 12 years of tropospheric ozone (O3) concentration measurements using robust techniques. The measurements were taken at an air quality monitoring station called Belisario, which is in Quito, Ecuador; the data collection time period was 1 January 2008 to 31 December 2019, and the measurements were carried out using photometric O3 analyzers. Here, the measurement results were used to build variables that represented hours, days, months, and years, and were then classified and categorized. The index of air quality (IAQ) of the city was used to make the classifications, and robust and nonrobust confidence intervals were used to make the categorizations. Furthermore, robust analysis methods were compared with classical methods, nonparametric methods, and bootstrap-based methods. The results showed that the analysis using robust methods is better than the analysis using nonrobust methods, which are not immune to the influence of extreme observations. Using all of the aforementioned methods, confidence intervals were used to both establish and quantify differences between categories of the groups of variables under study. In addition, the central tendency and variability of the O3 concentration at Belisario station were exhaustively analyzed, concluding that said concentration was stable for years, highly variable for months and hours, and slightly changing between the days of the week. Additionally, according to the criteria established by the IAQ, it was shown that in Quito, the O3 concentration levels during the study period were not harmful to human health.

Measurement of ozone and nitrogen oxide concentration emitted from household deodorizer using a developed colorimetric ozone detection paper and porous glass analytical chip

Measurement of ozone and nitrogen oxide concentration emitted from household deodorizer using a developed colorimetric ozone detection paper and porous glass analytical chip