気体粘性計測用振動子のオゾンガス暴露による周波数-圧力特性の変化

Effect of ozone exposure on prostacyclin synthesis in lung

To investigate the effects of subchronic ozone exposure on rat lung ventilation using hyperpolarized (HP) (3)He MRI. A total of 24 Sprague-Dawley rats, distributed in one control group and four groups exposed to 0.5 ppm ozone concentration for two days or six days, either continuously (22 hours/day) or alternatingly (12 hours/day). A three-step MRI protocol was designed and applied to each animal, including: 1) (3)He gas distribution images acquired at inspiratory capacity, 2) measurements of intrapulmonary (3)He diffusion coefficients, and 3) dynamic ventilation acquisitions performed during lung filling with (3)He. No differentiation between animals exposed to ozone and control animals was observed from the ventilation images obtained at inspiratory capacity. The (3)He diffusion coefficients were not statistically different from one group to another. Ventilation defects, appearing as delayed lung filling regions and heterogeneous lung filling, were observed in the dynamic lung ventilation image series. The percentage of animals with ventilation defects in the control, two-day, and six-day exposed groups were equal to 20%, 43% and 75%, respectively. In the subgroup of the animals exposed six days for 12 hours per day, the percentage of animals exhibiting ventilation defects was equal to 85%. Heterogeneous obstructive patterns in an experimental animal model of subchronic ozone exposure were observed using HP (3)He MRI.

Anxiety and depression are severe public health problems worldwide. The effects of ozone exposure on anxious and depressive symptoms remain largely unknown, especially in China. We evaluated the associations between ozone exposure and depression and anxiety among middle-aged and older adults across China. A multi-center community-based repeated measurement study among middle-aged and older adults was conducted from 2017 to 2018 in 11 provinces in China. The status of depression and anxiety was measured using Patient Health Questionnaire-9 (PHQ-9) and the generalized anxiety disorder seven-item (GAD-7) scale at the cut-off point of five, respectively. Concentrations of multiple ozone metrics were collected from real-time monitoring stations. The multilevel logistic regression model with random intercept was used to evaluate the effects of ambient ozone on anxiety and depression over different exposure windows. After adjusting for potential confounders, a 10 μg /m3 increase in the three months moving average of ozone was associated with the risk of anxiety [odds ratio (OR) = 1.25; 95% confidence interval (CI): 1.15; 1.37] and depression (OR = 1.17; 95% CI: 1.08; 1.27). A significantly positive modification effect of temperature on associations between ozone and anxiety was also found, while there is no interaction for depression. Exposure-response curves showed that there may be a threshold for the effect of ozone exposure on anxiety and depression over the three months moving average concentrations, with similar patterns observed at different temperature levels. People over 65 years old were at significantly higher risks of ozone-associated depression, while anxiety was more strongly associated with ozone in hypertensive patients. Our study supports the theory that anxiety and depression is associated with mid-term ozone exposure in China, and temperatures significantly enhanced their associations. These findings may have significant implications for promoting prevention activities regarding mental disorders and approaches in reducing the disease burden by simultaneously controlling air pollution and mitigating climate change.

Ozone is a photochemical pollutant, with exposure levels typically peaking during warm seasons in urban areas with intense sunlight and high traffic emissions. The rising annual average tropospheric ozone concentration risks children's health. This paper provided an in-depth overview of research on ambient ozone exposure and child health. A meticulous search was conducted within the PubMed database from 1 January 1964 to 4 October 2024 to identify epidemiological studies on the association between ambient ozone exposure and children's health. In addition, this study innovatively compiled the average ozone exposure levels from each epidemiological investigation. In total, 85 papers were included. Ambient ozone exposure's effects remain controversial in most diseases. Consistent evidence exists that ambient ozone exposure is a risk factor for low birth weight, asthma, respiratory disease and obesity in children, even if ozone concentrations are below the World Health Organization (WHO) standard. Both long-term ozone exposure and short-term spikes in ozone concentrations can harm children's health. Current ambient ozone air quality standards inadequately protect children's health and urgently require revision. Further research is needed to furnish evidence concerning the contentious aspects of research and to offer guidance to child health practitioners and public health policymakers.

The response of rice grain quality to ozone exposure during growth depends on ozone level and genotype

Biogenic volatile organic compounds (BVOCs) play an important role in ecological and atmospheric processes, including production of secondary air pollutants in urban areas. BVOC emission rates and composition are highly context-dependent and can change dramatically under conditions that elicit plant stress. This is particularly concerning given proposed expansion of urban forests where plants could regularly be exposed to spikes of atmospheric pollution stress, such as tropospheric ozone. However, few studies have investigated the effects of ozone exposure on plants commonly found in urban forests. This study characterized the effect of acute ozone exposure on BVOC emission rates in Canary Island pines (Pinus canariensis), which are often used in urban landscaping in Southern California. Pine saplings were exposed to four different ozone doses (control, 200 ppb, 300 ppb, 400 ppb) for 2 h. BVOC emission measurements were collected both pre-treatment and 24 h after exposure. Emission rates of total monoterpenes and several individual monoterpene and sesquiterpene compounds decreased when treated with 200 ppb of ozone. Total sesquiterpene emissions decreased significantly only after exposure to 300 ppb ozone, an effect that was largely driven by reduced emissions of the dominant sesquiterpene, α-farnesene. These findings indicate that landscaping with the pines used in this study would not exacerbate urban air quality degradation due to acute ozone stress. Future studies should investigate the effect of other major stressors and combinations of stressors for this and other common urban trees.

Previous studies show variable ozone cytotoxicity and genotoxicity in cell cultures, laboratory animals and humans directly exposed to tropospheric ozone. The aim of this study was therefore to investigate and compare the cyto and genotoxic effects of ozone using adenocarcinoma human alveolar basal epithelial cells A549 and normal human fibroblasts Hs27. A cell culture chamber with controlled atmosphere (a simulation reactor) was built to inject a flow of 120 ppb of ozone, which is two times the threshold value for the protection of human health, fixed by the EU legislation. Cell proliferation was evaluated by a luminescent cell viability assay while we assessed the genotoxic potential of ozone by the induction of micronuclei as well as evaluating DNA strand breaks by the induction of micronuclei evaluated by means of the cytokinesis-block micronucleus (CBMN) assay as well as evaluating DNA strand breaks by Alkaline Comet Assay (CA) or Comet Assay. A549 cells viability decreases significantly at 24 hours treatment with 120 ppb of O3 while at 48 hours and 72 hours O3 treated cells viability doesn’t differ in respect to the control. However a significative decrease of A549 viability is shown at 72 hours vs. 48 hours in both treated and not-treated cells. The viability trend in the Hs27 cells did not show any significant changes in treated samples compared to the control in all conditions. The two genotoxicity biomarkers, the micronucleus and the comet tests, showed in both the cell types exposed to ozone, a significant increase in the number of micronuclei and in the tail DNA % in respect to the control even if at different times/cell type. Moreover, we found that O3 provokes genotoxic effects more evident in A549 cancer cells than in normal fibroblasts Hs27 ones. We applied a cell growth simulation model referred to ozone treated or not cell lines to confirm that the ozone exposure causes a slackening in the cells replication.

The effects of ambient and elevated ozone levels on growth and photosynthesis of beech (Fagus sylvatica) were studied by exposing seedlings in open-top chambers for one growing season to three treatments: charcoal-filtered (CF), non-filtered (NF) and non-filtered air with addition of ozone (30 ppb ozone) on clear days for 8-10 h d-1 (NF +). Ambient levels were relatively low and accumulated to an AOT40 (accumulated exposure over a threshold of 40 ppb) of 4055 ppb h (for the period 23 Apr-30 Sept). The NF + chambers received an AOT40 of 8880 ppb h. Throughout the growing season we measured growth and photosynthetic properties. The treatments did not cause strong effects: measurements of gas exchange (light-saturated assimilation rate, CO2 and light-response curves) and chlorophyll fluorescence showed slight and mostly non-significant reductions of several parameters. No significant differences were found for growth, though in the NF + treatment (AOT40 8880 ppb h) the relative growth rate for diameter increment was at times reduced by 12% compared with the control treatment.

The aim of our study was to clarify the effect of ozone exposure on several phytopathogenic fungi on stored apple fruits under different storage conditions. The study was conducted at Bistrita, Romania, in the storehouse of an experimental apple orchard in 2002 and 2003. Two widely grown apple cultivars (‘Jonathan’ and ‘Golden Delicious’) were used. General microbial examination of the fruits was made during storage in order to identify the most important storage pathogens. Efficacy of six ozone treatments was evaluted on fruit decay caused by phytopathogenic fungi. Monthly observations (January, February, March and April) were made of the degree of decay and three measurements were assessed (disease frequency, disease intensity and degree of attack). Our results showed that the most important phytopathogenic fungi during storage was blue mold, caused by species of Penicillium. Disease frequency of apple fruits was very high on cv. ‘Jonathan’, much higher than on cv. ‘Golden delicious’. Ozone treatments (25 ppm ozone for 0.5 and 1.5 hours in November) caused significantly lower disease incidence on stored apple than all other ozone treatments. For longer storage, it seems that additional ozone treatments in February increased treatment efficacy. Cv. ‘Golden delicious’ seemed to be more resistant to storage diseases than cv. ‘Jonathan’ both on the untreated and treated fruits. The effect of the ozone treatments was also the most effective when 25 ppm ozone was applied for 0.5 and 1.5 hours in November.

Tissue trace elements and lung superoxide dismutase activity in mice exposed to ozone

The effects of ozone exposure on lettuce leaves were investigated by means of gas exchange, modulated chlorophyll a fluorescence and antioxidants systems. High ozone concentration decreased the rate of photosynthesis at light saturation level and changes in stomatal conductance and transpiration rate. However, an increase in intercellular CO2 concentration indicated a decrease in the carboxylation efficiency. These data agreed with a reduction of non‐cyclic electron flow and lower capacity to reduce the quinone pool. Ozone affected the ascorbate pool and decreased ascorbate peroxidase activity, increased lipid peroxidation, altered membrane properties and reduced the development of non‐photochemical quenching.

ナメコ栽培におけるO3暴露(対照区およびO3試験区: 0.03ppm区, 0.1ppm区)の有効性を脂肪酸組成を介して検討した.O3暴露により増加したものは,傘,柄および全子実体のパルミチン酸とO/L比,傘および全子実体のオレイン酸であった. O3暴露により減少したものは,傘,柄および全子実体ともにリノール酸およびP/S比であった.傘は柄に比べO3暴露の影響を受けやすいことが分かった.

Ozone is a principal component of photochemical air pollution endogenous to numerous metropolitan areas, which may induce irritant effects on the respiratory tract which impair pulmonary function, result in subjective symptoms of respiratory discomfort, including cough and shortness of breath, and can limit exercise performance. The effects of moderate ambient photochemical air pollution observed in a mobile laboratory have also been shown to be similar to those induced in laboratory chamber exposures to the same level of ozone alone. The metabolic demand of exercise increases minute ventilation (VE) and thus, the rate of ozone inhalation over that at rest. Potentially, exercise can also enhance the effects of ozone by: (a) reducing nasal passage absorption; (b) increasing the uniformity of ventilation throughout the lungs; and (c) replacing reacted ozone at a faster rate. However, results from 2-hour intermittent exercise and 1-hour continuous exercise exposures at the same total ventilation and ozone concentration have been shown to yield similar pulmonary function effects. It has been shown via significant variation in exercise intensity, and thus VE, that the simple product of ozone concentration, VE and exposure time (termed the ozone effective dose) predicts pulmonary function and exercise ventilatory pattern (induced rapid, shallow breathing) effects more precisely than ozone concentration alone. Better prediction of pulmonary function effects has been achieved via multiple regression analysis in which ozone concentration is given a greater weighting than VE and exposure time. Light intermittent exercise was first studied in 2-hour laboratory exposures to ozone at concentrations rarely seen in the ambient environment. In recent studies, heavy continuous exercise has been used in 1-hour exposures to ozone at levels routinely observed in photochemical episodes (less than or equal to 0.35 ppm). Statistically significant impairment of exercise performance has been observed at 0.18 ppm, a level reached for 1 hour, or more, on about 180 days per year in the Los Angeles basin. Responses of subpopulation groups, such as children, young adult females, older adults, and those with pre-existing pulmonary disease are not notably different from those of young adult males provided that the ozone effective dose is proportional to body size. Conversely, highly trained endurance athletes demonstrate significant responses at rather low ozone concentrations due to their ability to sustain very high VE over prolonged periods.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of Ozone Exposure on Asthma Severity, Lung Function and Bronchial Responsiveness in 371 Adult Asthmatics From the EGEA Study

Ozone or triatomic oxygen, is a powerful disinfectant and oxidizing agent. Despite the fact that the application of ozone for the disinfection of fresh fruits and vegetables has been studied widely, comparatively little information is presented on the potential of ozone to reduce microbial populations in papaya fruit. In this study, ozone was applied in gaseous form to papaya fruit at five concentrations (0.05, 0.5, 2.0, 3.5 and 5.8 ppm) for five different periods (0.5, 1, 3, 5 and 24 h) and the reduction in the total bacterial count (coliforms, yeasts and moulds) was assessed. The effect of ozone on weight loss, firmness, fruit peel colour, soluble solids concentration and titratable acidity were also determined. Total mesophilic bacteria on papaya fruit were reduced by 83.3 to 99.7% after exposure to 0.05 to 5.8 ppm ozone for 24 h. Ozone treatments did not affect peel colour and titratable acidity, but significantly reduced weight loss, retained firmness and increased soluble solids concentration during ambient storage. In summary, ozone treatments can be useful for maintaining quality attributes and reducing microbial flora in papaya fruit.