High O3 Levels Research Articles

Association Between Short-Term Exposure to Air Pollutants and Emergency Attendance for Upper Gastrointestinal Bleeding in Hong Kong: A Time-Series Study.

The relationship between exposure to ambient air pollutants and emergency attendance for upper gastrointestinal bleeding (UGIB) remains inconclusive. This study examines the association between short-term exposure to various ambient pollutants and the risk of UGIB emergency attendance. Data on daily UGIB emergency attendance, ambient pollutants, and meteorological conditions in Hong Kong were collected from 2017 to 2022. A time-series study using a distributed lag non-linear model to analyze the data, considering lag days. Stratified analysis was performed based on sex, seasons, and the COVID-19 pandemic period. The burden was quantified using attributable fraction (AF) and number (AN). The study included 31,577 UGIB emergency records. Exposure to high levels of PM2.5 significantly increased the risk of UGIB emergency attendance from lag day 3 (RR: 1.012) to day 6 (RR: 1.008). High NO2 exposure also posed a significant risk from lag day 0 (RR: 1.026) to day 2 (RR: 1.014), and from lag day 5 (RR: 1.013) to day 7 (RR: 1.024). However, there was no association between UGIB and high O3 levels. The attributable burden of high-concentration NO2 exposure was higher compared to those of PM2.5. Males and elderly individuals (≥65years) faced a higher risk of UGIB emergencies, particularly during cold seasons. Our study suggests that both PM2.5 and NO2 exposure are associated with an increased risk of emergency attendance for UGIB. Ambient pollutant exposure has a stronger effect on UGIB in males and the elderly, particularly during cold seasons.

ANALYSIS OF THE DYNAMIC RELATIONSHIPS BETWEEN INDUSTRIAL, ENVIRONMENTAL FACTORS, AND THE UNEMPLOYMENT RATE. AN ECONOMETRIC APPROACH

ABSTRACT: The sustainability of socio-economic and industrial systems is a key concern, particularly within the framework of the 2030 agenda. A holistic understanding of the functioning and relationships of these systems is essential if we want to implement practical actions to achieve sustainability. This study uses econometric techniques, such as the distributed lag autoregressive model, to explore the interactions between industrial and environmental factors and the unemployment rate. The variables analyzed include working hours, wage costs, and tropospheric ozone concentration, over two periods: 2008-2020 (reduced period) and 2008-2024 (extended period). Between both periods, substantial differences have been found in the variables significantly influencing the unemployment rate. The significance of working hours and ozone (O3) concentration, determinants of the unemployment rate in the reduced period, are replaced by wage costs, determining the unemployment rate in the extended period. The results show that an initial increase in worked hours reduces unemployment, while wage increases and high levels of O3 tend to increase the unemployment rate. Granger causality analysis suggests bidirectional relationships between unemployment, wage costs, and O3 concentration, highlighting the connection between the different aspects and feedback collateral effects. The study underscores the need for balanced socioeconomic policies that promote both economic growth and environmental sustainability and the promotion of fostering of technological innovations. The importance of policies that mitigate the adverse effects of wage increases on employment is underlined, and that favor a more sustainable development model capable of decoupling economic well-being from intensive resource consumption. Keywords: Sustainability, Socioeconomic systems, ARDL techniques, Granger causality, unemployment, O3 concentration, working hours, hourly wage.

Effect modification of air pollution on the association between heat and mortality in five European countries

BackgroundEvidence suggests that air pollution modifies the association between heat and mortality. However, most studies have been conducted in cities without rural data. This time-series study examined potential effect modification of particulate matter (PM) and ozone (O3) on heat-related mortality using small-area data from five European countries, and explored the influence of area characteristics. MethodsWe obtained daily non-accidental death counts from both urban and rural areas in Norway, England and Wales, Germany, Italy, and the Attica region of Greece during the warm season (2000–2018). Daily mean temperatures and air pollutant concentrations were estimated by spatial-temporal models. Heat effect modification by air pollution was assessed in each small area by over-dispersed Poisson regression models with a tensor smoother between temperature and air pollution. We extracted temperature-mortality relationships at the 5th (low), 50th (medium), and 95th (high) percentiles of pollutant distributions. At each air pollution level, we estimated heat-related mortality for a temperature increase from the 75th to the 99th percentile. We applied random-effects meta-analysis to derive the country-specific and overall associations, and mixed-effects meta-regression to examine the influence of urban-rural and coastal typologies and greenness on the heat effect modification by air pollution. ResultsHeat-related mortality risks increased with higher PM levels, rising by 6.4% (95% CI: −2.0%–15.7%), 10.7% (2.6%–19.5%), and 14.1% (4.4%–24.6%) at low, medium, and high PM levels, respectively. This effect modification was consistent in urban and rural regions but more pronounced in non-coastal regions. In addition, heat-mortality associations were slightly stronger at high O3 levels, particularly in regions with low greenness. ConclusionOur analyses of both urban and rural data indicate that air pollution may intensify heat-related mortality, particularly in non-coastal and less green regions. The synergistic effect of heat and air pollution implies a potential pathway of reducing heat-related health impacts by improving air quality.

Adverse effects of meteorological factors and air pollutants on dry eye disease: a hospital-based retrospective cohort study

Although previous studies have suggested that meteorological factors and air pollutants can cause dry eye disease (DED), few clinical cohort studies have determined the individual and combined effects of these factors on DED. We investigated the effects of meteorological factors (humidity and temperature) and air pollutants [particles with a diameter ≤ 2.5 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}m (PM2.5), ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO)] on DED. A retrospective cohort study was conducted on 53 DED patients. DED was evaluated by Symptom Assessment in Dry Eye (SANDE), tear secretion, tear film break-up time (TBUT), ocular staining score (OSS), and tear osmolarity. To explore the individual, non-linear, and joint associations between meteorological factors, air pollutants, and DED parameters, we used generalized linear mixed model (GLMM) and Bayesian kernel machine regression (BKMR). After adjusting for all covariates, lower relative humidity or temperature was associated with a higher SANDE (p < 0.05). Higher PM2.5, O3, and NO2 levels were associated with higher SANDE and tear osmolarity (p < 0.05). Higher O3 levels were associated with lower tear secretion and TBUT, whereas higher NO2 levels were associated with higher OSS (p < 0.05). BKMR analyses indicated that a mixture of meteorological factors and air pollutants was significantly associated with increased SANDE, OSS, tear osmolarity, and decreased tear secretion.

Formation and Transport of Secondary Contaminants Associated with Germicidal Ultraviolet Light Systems in an Occupied Classroom.

Germicidal ultraviolet light (GUV) systems are designed to control airborne pathogen transmission in buildings. However, it is important to acknowledge that certain conditions and system configurations may lead GUV systems to produce air contaminants including oxidants and secondary organic aerosols (SOA). In this study, we modeled the formation and dispersion of oxidants and secondary contaminants generated by the operation of GUV systems employing ultraviolet C 254 and 222 nm. Using a three-dimensional computational fluid dynamics model, we examined the breathing zone concentrations of chemical species in an occupied classroom. Our findings indicate that operating GUV 222 leads to an approximate increase of 10 ppb in O3 concentration and 5.2 μg·m-3 in SOA concentration compared to a condition without GUV operation, while GUV 254 increases the SOA concentration by about 1.2 μg·m-3, with a minimal impact on the O3 concentration. Furthermore, increasing the UV fluence rate of GUV 222 from 1 to 5 μW·cm-2 results in up to 80% increase in the oxidants and SOA concentrations. For GUV 254, elevating the UV fluence rate from 30 to 50 μW·cm-2 or doubling the radiating volume results in up to 50% increase in the SOA concentration. Note that indoor airflow patterns, particularly buoyancy-driven airflow (or displacement ventilation), lead to 15-45% lower SOA concentrations in the breathing zone compared to well-mixed airflow. The results also reveal that when the ventilation rate is below 2 h-1, operating GUV 254 has a smaller impact on human exposure to secondary contaminants than GUV 222. However, GUV 254 may generate more contaminants than GUV 222 when operating at high indoor O3 levels (>15 ppb). These results suggest that the design of GUV systems should consider indoor O3 levels and room ventilation conditions.

Spatial variations of PM2.5-bound parent, nitrated and oxygenated PAHs at urban and suburban sites in the Ili River Valley: Characteristics, sources and health risks

Polycyclic Aromatic Hydrocarbons (PAHs), along with their derivatives nitro-PAHs and oxy-PAHs, are globally recognized toxic pollutants. This research conducted daily PM2.5 sampling in winter 2021 at three urban (YNCE, SWP, and NG) and three suburban sites (HC, CTV, and YNE) in the Ili River Valley (IRV). For the first time in the IRV, a comprehensive study on 39 PAHs and derivatives was carried out. The results showed that the average ∑PAHs concentration was 130.21 ± 98.94 ng/m3, with ∑16PAHs constituting the dominant fraction (112.51 ± 86.48 ng/m3). The mean BaP and the total BaP equivalent quotient (TEQ) concentrations were 10.28 ± 8.85 ng/m3 and 19.74 ± 16.70 ng/m3, respectively. Approximately 88 % of the daily BaP averages and 98 % of the daily TEQ averages exceeded the national daily average standard of BaP (2.5 ng/m3), indicating severe local BaP pollution. Urban sites had notably higher ∑PAHs and TEQ concentrations than suburban sites, attributed to increased vehicular traffic and coal combustion in urban areas. PMF results showed that traffic emissions (32.7 %–60.5 %), coal combustion (13.9 %–24.3 %) and secondary formation (14.7 %–22.7 %) were the primary contributors to ∑PAHs. Urban sites experienced a greater influence from traffic, while suburban sites were more impacted by coal and biomass burning. On polluted days, traffic sources' contributions increased significantly at HC, YNE, NG and YNCE sites, and secondary formation sources' contributions grew at CTV and YNCE sites. The source-dependent BaPeq results underscored the role of secondary-formed PAH derivatives in TEQ. Enhanced secondary reactions in winter were facilitated by high NO2 and O3 levels, relative humidity (RH), and elevated temperatures (T). The findings of this study provide valuable insights for devising emission control strategies to safeguard both the environment and human health in the IRV.

Investigating ground-level ozone pollution in semi-arid and arid regions of Arizona using WRF-Chem v4.4 modeling

Abstract. Ground-level ozone (O3) pollution is a persistent environmental concern, even in regions that have made efforts to reduce emissions. This study focuses on the state of Arizona, which has experienced elevated O3 concentrations over past decades and contains two non-attainment areas as designated by the U.S. Environmental Protection Agency. Using the Weather Research and Forecasting with Chemistry (WRF-Chem) model, we examine O3 levels in the semi-arid and arid regions of Arizona. Our analysis focuses on the month of June between 2017 and 2021, a period characterized by high O3 levels before the onset of the North American Monsoon (NAM). Our evaluation of the WRF-Chem model against surface Air Quality System (AQS) observations reveals that the model adeptly captures the diurnal variation of hourly O3 levels and the episodes of O3 exceedance through the maximum daily 8 h average (MDA8) O3 concentrations. However, the model tends to overestimate surface NO2 concentrations, particularly during nighttime hours. Among the three cities studied, Phoenix (PHX) and Tucson (TUS) exhibit a negative bias in both hourly and MDA8 O3 levels, while Yuma demonstrates a relatively large positive bias. The simulated mean hourly and MDA8 O3 concentrations in Phoenix are 44.6 and 64.7 parts per billion (ppb), respectively, compared to observed values of 47.5 and 65.7 ppb, resulting in mean negative biases of −2.9 and −1.0 ppb, respectively. Furthermore, the analysis of the simulated ratio of formaldehyde (HCHO) to NO2 (HCHO/NO2; FNR), reveals interesting insights of the sensitivity of O3 to its precursors. In Phoenix, the FNR varies from a VOC (volatile organic compound)-limited regime in the most populated areas to a transition between VOC-limited and NOx-limited regimes throughout the metro area, with an average FNR of 1.15. In conclusion, this study sheds light on the persistent challenge of ground-level O3 pollution in semi-arid and arid regions, using the state of Arizona as a case study.

Summertime tropospheric ozone source apportionment study in the Madrid region (Spain).

The design of emission abatement measures to effectively reduce high ground-level ozone (O3) concentrations in urban areas is very complex. In addition to the strongly non-linear chemistry of this secondary pollutant, precursors can be released by a variety of sources in different regions, and locally produced O3 is mixed with that transported from the regional or continental scales. All of these processes depend also on the specific meteorological conditions and topography of the study area. Consequently, high-resolution comprehensive modeling tools are needed to understand the drivers of photochemical pollution and to assess the potential of local strategies to reduce adverse impacts from high tropospheric O3 levels. In this study, we apply the Integrated Source Apportionment Method (ISAM) implemented in the Community Multiscale Air Quality (CMAQ v5.3.2) model to investigate the origin of summertime O3 in the Madrid region (Spain). Consistent with previous studies, our results confirm that O3 levels are dominated by non-local contributions, representing around 70 % of mean values across the region. Nonetheless, precursors emitted by local sources, mainly road traffic, play a more important role during O3 peaks, with contributions as high as 25 ppb. The potential impact of local measures is higher under unfavorable meteorological conditions associated with regional accumulation patterns. These findings suggest that this modeling system may be used in the future to simulate the potential outcomes of specific emission abatement measures to prevent high-O3 episodes in the Madrid metropolitan area.

Allocation of Nutrients and Leaf Turnover Rate in Poplar under Ambient and Enriched Ozone Exposure and Soil Nutrient Manipulation.

An excess of ozone (O3) is currently stressing plant ecosystems and may negatively affect the nutrient use of plants. Plants may modify leaf turnover rates and nutrient allocation at the organ level to counteract O3 damage. We investigated leaf turnover rate and allocation of primary (C, N, P, K) and secondary macronutrients (Ca, S, Mg) under various O3 treatments (ambient concentration, AA, with a daily hourly average of 35 ppb; 1.5 × AA; 2.0 × AA) and fertilization levels (N: 0 and 80 kg N ha-1 y-1; P: 0 and 80 kg N ha-1 y-1) in an O3-sensitive poplar clone (Oxford: Populus maximowiczii Henry × P. berolinensis Dippel) in a Free-Air Controlled Exposure (FACE) experiment. The results indicated that both fertilization and O3 had a significant impact on the nutrient content. Specifically, fertilization and O3 increased foliar C and N contents (+5.8% and +34.2%, respectively) and root Ca and Mg contents (+46.3% and +70.2%, respectively). Plants are known to increase the content of certain elements to mitigate the damage caused by high levels of O3. The leaf turnover rate was accelerated as a result of increased O3 exposure, indicating that O3 plays a main role in influencing this physiological parameter. A PCA result showed that O3 fumigation affected the overall allocation of primary and secondary elements depending on the organ (leaves, stems, roots). As a conclusion, such different patterns of element allocation in plant leaves in response to elevated O3 levels can have significant ecological implications.

Geometric anisotropic Semi-variogram analysis of ozone levels in Daerah Istimewa Yogyakarta, Indonesia

Identification of areas with high O3 levels that pose a risk to public health is necessary. Ordinary co-kriging is a geostatistical method that determines the value of primary variables at specific locations using weighted values of secondary parameters. A Semi-variogram is required to demonstrate the spatial correlation between the observations measured using this method. This study aims to determine the best Semi-variogram model and produce a map of the predicted O3 level interpolation results using the ordinary co-kriging method with a geometric anisotropic Semi-variogram. Data from the first quarter of 2018’s air quality monitoring in Daerah Istimewa Yogyakarta (DIY) were used to interpolate O3 levels, with 72 points for CO levels and 53 points for O3 levels. The results showed that the Semi-variogram model with the lowest mean error (ME) value is a gaussian model that differs from the spherical model by only 0.003. The Gaussian model has the lowest root mean squared error (RMSE), but it is only 0.002 different from the spherical model. However, by comparing the mean squared deviation ratio (MSDR) values of the three models, the spherical model’s MSDR value is the lowest. A comprehensive analysis showed that the spherical geometric anisotropic Semi-variogram model performed superior, resulting in the smallest minimum mean error (ME), root mean square error (RMSE) and minimum squared deviation ratio (MSDR) values. These findings highlight the potential of this approach to accurately map the spatial distribution of O3 and support evidence-based decision-making related to public health.

Nocturnal ozone enhancement in Shandong Province, China, in 2020–2022: Spatiotemporal distribution and formation mechanisms

Nighttime ozone enhancement (NOE) can increase the oxidation capacity of the atmosphere by stimulating nitrate radical formation and subsequently facilitating the formation of secondary pollutants, thereby affecting air quality in the following days. Previous studies have demonstrated that when nocturnal ozone (O3) concentrations exceed 80 μg/m3, it leads to water loss and reduction of plant yields. In this study, the characteristics and mechanisms of NOE over Shandong Province as well as its 16 cities were analyzed based on observed hourly O3 concentrations from 2020 to 2022. The analysis results show that NOE predominantly occurred in the periods of 0:00–3:00 (41 %). The annual mean frequency of NOE events was ~64 days/year, approximately 4–7 days per month. The average concentration of nocturnal O3 peak (NOP) was ~72.6 μg/m3. Notably, high NOP was observed in the period from April to September with the maximum in June. Coastal cities experienced more NOE events. Typical NOE events characterized by high NOP concentrations in the coastal cities of QingDao, WeiHai and YanTai in June 2021 were selected for detailed analysis with a regional chemical transport model. The results showed that high levels of O3 in eastern coastal cities during NOE events primarily originate from horizontal transport over the sea, followed by vertical transport. During the daytime, O3 and its precursors are transported to the Yellow Sea by westerly winds, leading to the accumulation of O3 near the sea and coastline. Consequently, under the influence of prevailing winds, the movement of O3 pollution belts from the sea to land causes rapid increases in near-surface O3 levels. Meanwhile, vertical transport can also contribute to NOE in coastal areas. The high-level O3 in the upper atmosphere generally originates from long-distance transport and turbulent transport of O3 produced near the ground during the daytime. At night, the absence of chemicals that consume O3 in the upper air and descending air flow carries O3 to the near-surface. The impacts of other O3-depletion processes (such as dry deposition) on NOE are less pronounced than those of transport processes.

Direct Measurement of Aerosol Liquid Water Content: A Case Study in Summer in Nanjing, China.

Aerosol liquid water content (ALWC) affects the mass loading, optical properties, and toxicity of aerosols. However, the measurement of ALWC is very rare due to its requirement of sophisticated instruments and its high operational costs. In this work, we improved on our previous simple, low-cost method by using a combination of one real-time fine particulate matter (PM2.5) monitor and two turbidimeters and successfully applied these for the direct measurement of ALWC in PM2.5 in Nanjing during the summer of 2023. The average ALWC during this measurement period occupied ~1/6 of the total PM2.5 mass, and this contribution was even greater with the elevation in the PM2.5 concentration. The ALWC was, as anticipated, closely related to the relative humidity (RH) and PM2.5 concentrations, but it did not always increase with the air quality index (AQI) due to the fact that polluted periods in summer were often governed by high O3 levels, not PM2.5 levels. The ALWC also had a great impact on visibility; it could decrease the visibility rapidly to hazy conditions when the dry PM2.5 was not high (~30 μg m-3) or the AQI was "good" (75~100), indicating that the air quality classified as "good" using the dry PM2.5 concentration might actually be "lightly polluted" if the ALWC is included. We also found that the air mass originating from Northeast China had the lowest PM2.5 mass concentration yet the highest ALWC values due to its high RH. Moreover, the quantification of ALWC levels can help us understand the solubility/bioavailability and thus the toxic effects of some specific components (for example, heavy metals or organics). Moreover, the influence of ALWC on air quality classifications should also be considered in the assessment of the health effects of air pollution and in public health early warning and protection.

Observational Evidence of the Vertical Exchange of Ozone within the Urban Planetary Boundary Layer in Shanghai, China

The vertical mass exchange of ozone (O3) plays an important role in determining surface O3 air quality, the understanding of which, however, is greatly limited by the lack of continuous measurements in the vertical direction. Here, we characterize O3 variations at a high-altitude monitoring site at the top of Shanghai Tower (SHT) and discuss the potential impacts of the vertical exchange of air pollutants on O3 air quality within the urban planetary boundary layer (PBL) based on continuous measurements during 2017–2018. During the daytime, two distinct patterns of vertical O3 gradient are detected. In summer, the daytime O3 formation at SHT is observed to be more limited by nitrogen oxides (NOx) than the surface, which, together with the efficient vertical mixings, results in higher O3 levels in the upper mixing layer. In cold months, the opposite vertical gradient is observed, which is associated with weak vertical exchange and NOx-saturated O3 formation. A nighttime O3 reservoir layer and consistent morning O3 entrainments are detected all year round. These results provide direct evidence of the vertical mixings within the urban PBL, underscoring the pressing need for improving vertical resolution in near-surface layers of air quality models.

Ozone alters the chemical signal required for plant – insect pollination: The case of the Mediterranean fig tree and its specific pollinator

Tropospheric ozone (O3) is likely to affect the chemical signal emitted by flowers to attract their pollinators through its effects on the emission of volatile organic compounds (VOCs) and its high reactivity with these compounds in the atmosphere. We investigated these possible effects using a plant-pollinator interaction where the VOCs responsible for pollinator attraction are known and which is commonly exposed to high O3 concentration episodes: the Mediterranean fig tree (Ficus carica) and its unique pollinator, the fig wasp (Blastophaga psenes). In controlled conditions, we exposed fig trees bearing receptive figs to a high-O3 episode (5 h) of 200 ppb and analyzed VOC emission. In addition, we investigated the chemical reactions occurring in the atmosphere between O3 and pollinator-attractive VOCs using real-time monitoring. Finally, we tested the response of fig wasps to the chemical signal when exposed to increasing O3 mixing ratios (0, 40, 80, 120 and 200 ppb). The exposure of the fig tree to high O3 levels induced a significant decrease in leaf stomatal conductance, a limited change in the emission by receptive figs of VOCs not involved in pollinator attraction, but a major change in the relative abundances of the compounds among pollinator-attractive VOCs in O3-enriched atmosphere. Fig VOCs reacted with O3 in the atmosphere even at the lowest level tested (40 ppb) and the resulting changes in VOC composition significantly disrupted the attraction of the specific pollinator. These results strongly suggest that current O3 episodes are probably already affecting the interaction between the fig tree and its specific pollinator.

Understanding the spatial and seasonal variation of the ground-level ozone in Southeast China with an interpretable machine learning and multi-source remote sensing

Ground-level ozone (O3) pollution poses significant threats to both human health and air quality. This study uses ground observations and satellite retrievals to explore the spatiotemporal characteristics of ground-level O3 in Zhejiang Province, China. We created data-driven machine learning models that include meteorological, geographical and atmospheric parameters from multi-source remote sensing products, achieving good performance (Pearson's r of 0.81) in explaining regional O3 dynamics. Analyses revealed the crucial roles of temperature, relative humidity, total column O3, and the distributions and interactions of precursor (volatile organic compounds and nitrogen oxides) in driving the varied O3 patterns observed in Zhejiang. Furthermore, the interpretable modeling quantified multifactor interactions that sustain high O3 levels in spring and autumn, suppress O3 levels in summer, and inhibit O3 formation in winter. This work demonstrates the value of a combined approach using satellite and machine learning as an effective novel tool for regional air quality assessment and control.

Air pollution exposure and its effects on idiopathic pulmonary fibrosis: clinical worsening, lung function decline, and radiological deterioration.

Major urban pollutants have a considerable influence on the natural history of lung disease. However, this effect is not well known in idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the effects of air pollution on clinical worsening, lung function, and radiological deterioration in patients with IPF. This exploratory retrospective cohort study included 69 patients with IPF, monitored from 2011 to 2020. Data on air pollution levels, including carbon monoxide (CO), nitrogen dioxide (NO2), particulate matter ≤ 2.5 μM (PM2.5), ozone (O3), and nitrogen oxides (NOx), were collected from the nearest air quality monitoring stations (<3.5 km from the patients' homes). Patient outcomes such as clinical worsening, lung function decline, and radiological deterioration were assessed over various exposure periods (1, 3, 6, 12, and 36 months). The statistical analyses were adjusted for various factors, including age, sex, smoking status, and treatment. There was an association between higher O3 levels and an increased likelihood of clinical worsening over 6 and 36 months of exposure (odds ratio [OR] and 95% confidence interval [CI] = 1.16 [1.01-1.33] and OR and 95% CI = 1.80 [1.07-3.01], respectively). Increased CO levels were linked to lung function decline over 12-month exposure periods (OR and 95% CI 1.63 = [1.01-2.63]). Lastly, radiological deterioration was significantly associated with higher CO, NO2, and NOx levels over 6-month exposure periods (OR and 95% CI = 2.14 [1.33-3.44], OR and 95% CI = 1.76 [1.15-2.66] and OR and 95% CI = 1.16 [1.03-1.3], respectively). This study suggests that air pollution, specifically O3, CO, NO2, and NOx, could affect clinical worsening, lung function, and radiological outcomes in patients with IPF. These findings highlight the potential role of air pollution in the progression of IPF, emphasizing the need for further research and air quality control measures to mitigate its effects on respiratory health.

The effect modification of PM2.5 and ozone on the short-term associations between temperature and mortality across the urban areas of Japan.

The acute effects of temperature and air pollution on mortality are well-known environmental factors that have been receiving more recognition lately. However, the health effects resulting from the interaction of air pollution and temperature remain uncertain, particularly in cities with low levels of pollution. This study aims to examine the modification effects of particulate matter with a diameter of 2.5 µm or less (PM2.5) and ozone (O3) on the association between temperature and mortality. We collected the daily number of all-cause, cardiovascular, and respiratory mortality from 20 major cities in Japan from 2012-2018. We obtained meteorological data from the Japan Meteorological Agency and air pollution data from the National Institute for Environmental Studies. We conducted analyses using a quasi-Poisson regression model with a distributed lag non-linear model for temperature in each city and subsequently performed a random-effects meta-analysis to derive average estimates. We found that high levels of O3 might positively modify the mortality risk of heat exposure, especially for cardiovascular diseases. Subgroups such as the elderly and females were susceptible. We did not observe consistent evidence of effect modification by PM2.5, including effect modification on cold by both pollutants. PM2.5 and O3 may positively modify the short-term association between heat and mortality in the urban areas of Japan. These results highlight the need for public health policies and interventions to address the collective impacts of both temperature and air pollution.

Growth, ultrastructural and physiological characteristics of Abelmoschus cytotypes under elevated ozone stress: a study on ploidy-specific responses.

Tropospheric ozone (O3 ) is a significant abiotic stressor whose rising concentration negatively influences plant growth. Studies related to the differential response of Abelmoschus cytotypes to elevated O3 treatment are scarce and need further exploration to recognise the role of polyploidisation in stress tolerance. In this study, we analysed the changes in growth pattern, ultrastructure, physiology and foliar protein profile occurring under O3 stress in Abelmoschus moschatus (monoploid), Abelmoschus esculentus (diploid) and Abelmoschus caillei (triploid). Our findings showed that higher stomatal conductance in A. moschatus triggered higher O3 intake, causing damage to stomatal cells and photosynthetic pigments. Additionally, it caused a reduction in photosynthetic rates, leading to reduced plant growth, total biomass and economic yield. This O3 -induced toxicity was less in diploid and triploid cytotypes of Abelmoschus . Protein profiling by sodium dodecyl sulpate-polyacrylamide gel electrophoresis showed a significant decrease in the commonly found RuBisCO larger and smaller subunits. The decrease was more prominent in monoploid compared to diploid and triploid. This study provides crucial data for research that aim to enhance plant ability to withstand O3 induced oxidative stress. Our findings may help in developing a tolerant variety through plant breeding techniques, which will be economically more advantageous in reaching the objective of sustainable production at the high O3 levels projected under a climate change scenario.

Meteorologically normalized spatial and temporal variations investigation using a machine learning-random forest model in criteria pollutants across Tehran, Iran

Investigating road traffic contribution to urban air pollution is helpful to determine traffic management approaches and environmental intervention policies that focus on better air quality. To this end, hourly average values of air pollutants collected from 2015 to 2021 from 20 monitoring sites including 10 traffic (TS) and 10 urban background (UB) sites in Tehran, Iran were retrieved. A machine learning-random forest (RF) model was applied to decouple the meteorology effects of the observed air pollutant values. The meteorologically normalized concentrations of air quality data were used for calculating the traffic increment and trend analysis. The seasonal component showed the greatest importance for predicting PM2.5 and PM10 and boundary layer heights (BLH) was the dominant explanatory variable for the predictions of CO, NO, NO2, and O3 concentrations. The overall annual average value of traffic increment during study period was found as PM10 (10.5 μg m−3), PM2.5 (0.19 μg m−3), NO (9.24 ppb), NO2 (3.67 ppb), NOx (15.6 ppb), and SO2 (0.33 ppb). Ozone indicates a traffic decrement in concentration (−0.70 ppb). The Theil-Sen estimated slopes showed meteorological normalized negative trends for PM2.5, PM10, CO, NO, NOx, and SO2, while meteorological normalized positive trends were observed for NO2 and O3. The PM10, CO, NO, NOx, and SO2 concentrations trends at the traffic sites that experience more anthropogenic emissions revealed greater reductions when emission interventions or control policies are used. The higher increase of NO2 at the UB sites than the traffic sites can be due to the weaker control policies, high traffic volume, higher number of diesel-fueled vehicles, and a higher NO to NO2 conversion because of the relatively high levels of temperature and O3. This quantitative summary provides useful information for decision-makers for evaluating the intervention policies related to road traffic pollutants.

Anomalous high ozone in the Pearl River Delta, China in 2019: A cause attribution analysis

Surface ozone (O3) pollution in the Pearl River Delta (PRD), especially persistent O3 pollution episodes lasting three days or longer (OPE3), showed an anomalous peak during the autumn of 2019 (bulge-2019). Our research reveals a robust connection between the occurrence of OPE3 events and days with low cloud cover. Specifically, low-cloud days comprised 55% of the total number of OPE3 events in the PRD during the autumn season spanning from 2015 to 2021. Notably, as much as 74% of the bulge-2019 is related to low-cloud days. However, establishing a direct causal link remains challenging. In autumn 2019, an anomalous cyclonic center developed over the Philippine Sea, with anomalous northerly winds on its northwestern flank, leading to anomalous downdraft over South China. This pattern was characterized by stagnant, low relative humidity, intensified solar radiation, and low cloud cover conditions that were conducive to the photochemical formation and accumulation of O3. Further analysis of the relationship between low-cloud days and El Niño–Southern Oscillation shows that eastern Pacific El Niño events are associated with fewer low-cloud days in the PRD in autumn, whereas central Pacific (CP) El Niño events result in more low-cloud days. In addition, the anomalous cyclonic center over the Philippine Sea serves as the crucial atmospheric circulation system connecting CP El Niño and high O3 level over southern China. Therefore, we propose that the increased downdraft of PRD brought by northward tropical cyclones (TCs) during more low-cloud days in 2019 is highly likely the primary cause of the occurrence of the bulge-2019.