Hybrid attention based deep learning for forecasting boundary layer ozone using satellite derived profiles.

Multi-scale impacts of Indochina biomass burnings on tropospheric ozone in coastal South China: Insights from long-term (2000–2024) observations

Differential ozone sensitivity and mechanistic insights into lipid remodelling and antioxidant responses in two mustard cultivars.

Do downdrafts always induce near-surface ozone enhancements above the Amazon region?

A novel approach to identify the spatial characteristics of ozone-precursor sensitivity based on interpretable machine learning.

Impact of temperature on the biogenic volatile organic compound (BVOC) emissions in China: A review.

Aerosols influence forest ecosystems through changes in radiation and climate affecting plant physiology and structure. Conversely, forests also contribute to aerosol formation. They emit primary aerosol particles and volatile organic compounds, which promote secondary organic aerosol formation in the atmosphere. This forest-aerosol coupling is highly dynamic, influenced by temperature, radiation, humidity, and trace gases. Wildfires add further complexity via smoke plumes altering radiation and ecosystem functioning, tropospheric ozone levels and stratospheric chemistry. Aerosols modify the quantity, directionality, and composition of solar radiation. The type of diffuse light produced by aerosol particles is however strongly dissimilar to the one produced under clouds, and the relevance of the traditional diffuse/direct binary paradigm is discussed. Therefore, potential benefits from increased diffuse radiation are contingent on aerosol load, canopy structure, and prevailing environmental conditions. Beyond photosynthetic responses, aerosols alter forest water-use efficiency and microclimate, yet their long-term effects on plant development, architecture, and community composition remain poorly understood. This review highlights significant knowledge gaps and recent advances in understanding aerosol-forest interactions across temporal and spatial scales. We underline the urgent need for improved experiments with realistic diffuse shading, extensive in situ observations, mechanistic model intercomparison, and global validation to guide future research and policy.

Plant leaves help with air pollution by absorbing pollutants through both their surface and their tiny pores (stomata) and by participating in photosynthesis, which removes carbon dioxide and releases oxygen. Plants are exposed to various harmful air pollutants, which cause oxidative stress and pose a threat to plant health, agriculture production, and vitality of ecosystems. Despite the climate actions and technological development, most ecosystems and agricultural areas are exposed to high levels of tropospheric ozone, nitrogen oxides, and particulate matters (PMs). To use plant trees to investigate the air pollution. Leaf surfaces were heavily loaded by dust particles but the stomata were not occluded, the cuticle was thinner, other anatomical properties were unaffected.

Association of Essential Hypertension Cases and Ground-Level Ozone Concentrations in Tbilisi (2015-2018)

Knowledge of ground-level ozone (O3) formation in the Southern Hemisphere is limited due to the lack of long-term in situ O3 observations. Here, we analyzed the ground-based measurement data of O3, formaldehyde (HCHO), nitrogen dioxide (NO2), and benzene, toluene, and xylene (BTX) collected from 2011 to 2020 at two sites in eastern Australia, namely, Memorial Park and Springwood. Only HCHO at Memorial Park showed a statistically significant upward trend (0.19 ppb yr-1). Compared with the sea-influenced air masses, the land-influenced air masses were observed to enhance all pollutant concentrations at two sites. According to the site-specific sensitivity of the O3 to the HCHO-to-NO2 ratio (FNR), the daytime formation of the O3 at two sites was mainly in the volatile organic compound (VOC)-limited regime. When the long-term variability of NO2 was weak, HCHO, particularly from primary emissions indicated by BTX, was observed to predominantly control the monthly FNR at each site over time. Our work underscores the importance of long-term in situ measurements in interpreting ground-level O3 formation and potentially informs future O3 studies in other areas in the Southern Hemisphere.

ABSTRACT This study assessed long-term trends of tropospheric ozone (O3) concentrations in Tehran, Iran, over the time period 2015–2024, and quantified the non-carcinogenic health risks across different age groups by applying the United States Environmental Protection Agency (U.S. EPA) human health risk assessment methodology. The O3 data from 22 air-quality monitoring stations and satellite-retrieved columnar from Copernicus Sentinel-5P were analyzed. Annual O3 mean concentrations exhibited a slight non-statistically significant decreasing trend (-0.11% year−1). Peak concentrations were recorded in 2021, corresponding to post-COVID-19 socio-economic recovery and rising precursor emissions. Age-specific Hazard Quotients (HQ) remained <1.0 in all years, indicating acceptable non-carcinogenic risk for any single life stage. However, the cumulative lifetime Hazard Index (HI), obtained by summing age-specific HQs, ranged from 5.48 to 8.10 and consistently exceeded the U.S. EPA safe threshold of 1.0, showing potential adverse non-carcinogenic health effects from chronic O3 exposure over a full lifetime. These results underline the importance of controlling O3 precursors in densely populated cities and demonstrate the value of combining ground and satellite observations with lifetime exposure modeling for urban air-quality management.

Background Climate variability and air pollution adversely affect stroke, yet comprehensive global assessments are lacking. This study investigates their impact on age-standardized stroke mortality rates (ASMR) from 2000–2020. Methods We analyzed 179 countries using the Global Burden of Disease Study 2021 (GBD 2021) data for stroke ASMR, European Center for Medium-Range Weather Forecasts Reanalysis v5 (ERA5) climate data, and air pollution data (nitrogen dioxide [NO2], fine particulate matter [PM2.5], ground-level ozone [O3]). Climate variability indicators included temperature and humidity deviance percentages, extreme weather events, and variability measures. Linear mixed-effects models examined associations between stroke ASMR and climate variability indicators, air pollution, Socio-Demographic Index (SDI), smoking, and alcohol consumption. Results Global stroke ASMR substantially decreased from 2000–2020, driven by increased SDI and reduced smoking. Each 2.34% decrease in negative humidity deviance increased ASMR by 0.98/100,000 (95% CI: 0.21–1.76; p < 0.05). Each 13.16-day increase in extreme hot days raised ASMR by 0.59/100,000 (95% CI: 0.14–1.04; p < 0.05). Each 14.01-day increase in extreme cold days elevated ASMR by 0.67/100,000 (95% CI: 0.24–1.11; p < 0.05). Each 9.7 ppb ozone increase statistically significantly raised ASMR by 7.41/100,000 (95% CI: 6.02–8.80; p < 0.05). Conclusion These associations suggest potential benefits from addressing climate variability mitigation, air pollution control, and stroke prevention to reduce global stroke mortality burden.

Time Series–Based Forecasting of Ground-Level Ozone Concentration Using Machine Learning and Deep Learning Models

Abstract. Tropospheric ozone trends are important indicators of climate forcing and surface pollution, yet relevant satellite observations are too uncertain for assessments. The assessment project TOAR-II has used multi-instrument, ground-based data for global trends over 2000–2022 (Van Malderen et al., 2025a, b). For the tropics, trends are derived from SHADOZ ozonesonde profiles (Thompson et al., 2021, “T21”; Stauffer et al., 2024) or combinations of satellite, SHADOZ and IAGOS aircraft measurements (Gaudel et al., 2024). We extend T21 that covered 1998–2019, analyzing SHADOZ data at five sites with a Multiple Linear Regression (MLR) model for 1998–2023 and reporting trends for two free-tropospheric (FT) segments, the lowermost stratosphere and the total tropospheric column (TrCOsonde). Trends for the Aura period, 2005–2023, are computed from OMI/MLS TrCOsatellite. We find the following: Extending SHADOZ analyses 4 years shows little change from T21; TrCOsonde trends are small (0.5–1 DU/decade) except over SE Asia. Annual trends for TrCOsonde and OMI/MLS TrCOsatellite agree within uncertainties at four of five sites, with the largest differences at Samoa. Sensitivity tests show the following: (a) Adding thousands of FT IAGOS profiles to SHADOZ yields little change in trends; SHADOZ sampling is sufficient. (b) Quantile Regression (QR) and MLR median trends are both near zero, but QR captures extremes (5th percentile, 95th percentile) with changes up to ±1 DU/decade (p&lt; 0.10). (c) Twelve-year analyses for trends lead to uncertainty changes too large for an assessment. This study and Van Malderen et al. (2025a, b) provide the most reliable TOAR-II trends to date: over the past ∼ 25 years, tropical FT ozone changes have been modest, ∼ (−3–+3) %/decade, except over SE Asia.

Surface ozone (O3) substantially and adversely impacts public health and ecosystems. Despite China's air quality improvements, pre-2013 ozone records in central-eastern China (CEC) remain scarce. To address this temporal gap, we constructed a 0.5° resolution daily maximum 8-h average (MDA8) ozone concentration dataset spanning 1980-2012 by employing a light gradient boosting machine (LightGBM, LGBM) model based on multisource datasets. Tenfold cross-validation (2013-2023) demonstrated robust spatiotemporal reconstruction capability, with 88% of grids exhibiting correlation coefficients (R2) > 0.8 versus observations (42% exceeding 0.9) and root mean square errors (RMSE) of 7.5-7.9 μg⋅m-3. The reconstructed climatology revealed a regional mean of 87.6 μg⋅m-3 with a north-south gradient and significant annual increase (0.14 μg⋅m-3⋅yr-1, p < 0.01). μg⋅m-3 Mechanistic attribution identified synergistic forcing from global warming (0.32 °C decade-1), industrial expansion, and urbanization-induced emission growth as primary drivers of long-term ozone elevation. The LightGBM-reconstructed dataset exhibits exceptional stability (interannual variability < 5%), providing critical baseline data for quantifying multidecadal ozone pollution-climate interactions and informing regional air quality management strategies.

Isoprene (C5H8), the most abundant biogenic volatile organic compound (400–600 Tg C yr−1), exerts complex NOx-dependent influence on tropospheric ozone, yet its representation remains absent in many climate models. This study aims to quantify isoprene’s impact on tropospheric chemical composition using the Russian Earth system model INM-CM6.0 with newly implemented isoprene oxidation chemistry. Two 12-year experiments (2008–2019) were conducted: a control run without isoprene and an experiment with the Mainz Isoprene Mechanism (MIM1: 44 reactions, 16 species). Results reveal a NOx-dependent two-layer vertical structure. In the tropical surface layer (0–5 km, 20° S–20° N), ozone decreases by 10–15 ppb through radical termination under low-NOx (&lt;100 ppt), with 15–30% OH reduction and 30–60% CO increase. In the middle troposphere (8–12 km), ozone increases by 10–15 ppb through thermal decomposition of vertically transported PAN and MPAN. In subtropics (20–35°) with elevated NOx (&gt;500 ppt), isoprene stimulates ozone formation at all altitudes (+3–12 ppb). Oxidation product distributions establish a spatial hierarchy: local (ISON, NALD: 0–5 km), regional (MPAN: to 8 km), and global (PAN: reaching high latitudes at 8–12 km). Comparison with CAMS, MERRA-2, and ERA5 reanalyses shows substantial improvement: tropical CO discrepancies decrease from 20–30% to 10–15%, OH by factors of 2–3, and ozone overestimation from 30–40% to 10–15%. These findings demonstrate that explicit isoprene chemistry is essential for accurate tropospheric composition simulation, particularly given the projected 21–57% emission increases by 2100 under climate warming.

This study aimed to comprehensively review and synthesize results specific to the Indonesian archipelago from the IPCC Sixth Assessment Report (AR6) Working Group I, "The Physical Science Basis." At the heart of the Indo-Pacific maritime continent, Indonesia's climate was undergoing significant anthropogenic alteration owing to complex atmospheric and oceanic processes. The review distilled pertinent observations, trends, and projections, while also offering a detailed analysis of the underlying physical science. The observed changes included a significant rise in tropospheric ozone since the 1990s, a persistent trend towards a La Niña-like state in the Pacific Walker Circulation, accelerated warming of surrounding tropical oceans, and increased multi-decadal variability in the Indonesian Throughflow. The regional water cycle was also intensifying, marked by an increase in rainfall extremes which occurred against a background of powerful climate variability modes such as El Niño-Southern Oscillation and Indian Ocean Dipole, contributing to severe events such as the 2015-2016 drought and fire crisis. Future projections assessed with high confidence pointed towards a decrease in annual mean precipitation with particularly severe drying of up to 30% projected for the summer months over key islands. These multifaceted changes have profound implications for Indonesia's environmental stability, socioeconomic development, and population well-being, underscoring the critical urgency for science-informed, targeted climate adaptation and mitigation strategies.

Ground-level ozone (O3), a criteria air pollutant, can cause significant adverse effects on lung health, including airway inflammation, compromised lung function, and increased susceptibility to lung infections. This study was conceived to determine whether a history of high-concentration O3-induced acute lung injury responsiveness of respiratory tract to low-concentration repetitive O3exposures. Accordingly, we hypothesized that prior acute O3exposure would modulate the lung’s Th2 responses to subsequent repetitive O3exposures. We exposed 8-10-week-old C57BL6/J mice to either filtered air (FA) or 2 ppm O3for three hours, followed by a three-week recovery period, after which the mice received daily exposures to FA or 1 ppm O3for four hours over 9 days. We evaluated immune cell recruitment, inflammatory mediators in cell-free bronchoalveolar lavage fluid (BALF) and examined mucous cell metaplasia and epithelial cell injury in lung tissue sections. As expected, FA-FA (no O3exposure) mice did not exhibit any signs of injury or inflammation. The O3-FA (acute O3exposure only) groups exhibited baseline immune cell populations and no evidence of MCM suggesting almost complete recovery from acute lung injury. In contrast, FA-O3group (repetitive O3exposure only) demonstrated loss of body weight, marked immune cell recruitment, and prominent MCM. These mice also displayed elevated BALF levels of eotaxin, IL-1α, IL-1β, and IL-4, along with increased number of mast cells and FIZZ1+epithelial cells in the lungs. Compared with FA-O3group, the O3-O3group (both acute and repetitive O3) exhibited attenuated responses, as evidenced by diminished eosinophil and lymphocyte counts, and attenuated MCM. BALF analysis revealed lower levels of eotaxin, IL-1α, IL-1β, and IL-4, but elevated levels of G-CSF, KC, IL-6, IL-10, and IL-12 in the O3-O3group. Furthermore, these mice displayed reduced numbers of mast cells and FIZZ1+epithelial cells. These findings suggest that prior exposure to acute high-concentration O3modulates inflammatory and remodeling responses induced by subsequent repeated low-concentration O3exposures. The findings from this study highlight the health impacts of O3pollution, particularly in populations experiencing intermittent high-level exposures.

Abstract Elevated ground-level ozone (O3) is known to inhibit plant growth and development, but its interactive effects with other climate factors, such as elevated carbon dioxide, warming, drought, and nitrogen deposition, remain poorly understood. Here, a comprehensive meta-analysis was conducted to investigate the main and interactive effects of O3 and multiple climate factors on plant photosynthetic rate, stomatal conductance, biomass production, and allocation. Our findings revealed a consistent pattern of O3-induced overall reduction in plant photosynthesis, stomatal conductance, and biomass production across different CO2, temperature, drought, and nitrogen deposition conditions. Elevated O3 exposure caused significant declines in biomass production, with crops experiencing the largest reduction, followed by trees and grasses. The greater biomass loss in crops and trees may be due to their physiological traits, longer exposure durations, or agronomic management practices. Elevated CO2 alleviated the negative effects of O3 on plants, but it is reflected in the photosynthetic rate. Although the O3-induced decrease in stomatal conductance and root biomass was reduced by increasing temperatures, warming had a limited effect on improving plant resistance to O3. Interestingly, O3 damage was reduced by drought through decreased stomatal conductance, whereas nitrogen addition did not affect the harm caused by O3. Our findings provide insights into plant gas exchange, biomass, and allocation responses to the interaction of O3 and climate factors, improving the understanding of plant adaptative mechanisms in the context of global change.

Introduction. Over 40 years after the introduction of the first mitigation regulations and strategies, managing exposure to aromatic solvents and volatile organic compounds (VOCs) still presents a challenge in the field of environmental and occupational prevention. Aromatic solvents – particularly benzene, toluene, ethylbenzene, and xylenes (BTEX) – are substances widely used in industrial processes due to their physicochemical properties. These substances are associated with short- and long-term toxic effects, including, in the case of benzene, an increased incidence of leukemia. VOCs also contribute to the formation of tropospheric ozone and photochemical smog, with a resulting impact on public health. Objectives. The evaluation of the effectiveness of the preventive actions adopted over the years, including the definition of occupational exposure limits, with the aim of progressively reducing total emissions and partially replacing substances. Identification of actions to be taken. Methods. Literature analysis for the toxicological characterization of the main VOCs, particularly BTEX, and subsequent derivation of exposure limits. Analysis of the effects on exposed workers. Analysis of monitoring techniques, particularly for complex mixtures. Analysis of regulations and adopted limits. Results and Conclusions. In the past, especially in Scandinavian countries, chronic effects of organic solvents on the central nervous system were reported. These effects had been attributed to the lipophilic properties of the solvents and were defined as “psycho-organic syndrome”, with symptoms including irritability, mood reduction, and anxiety, often summarized as “nervousness” and occasionally accompanied by peripheral nerve symptoms. The actual existence of this syndrome has often been questioned. In any case, the reporting of these cases has greatly decreased, likely also in relation to the reduction in exposure levels. According to paragraph 11, article 268 of Legislative Decree 152/2006, VOCs are defined as any organic compound that has a vapor pressure of 0.01 kPa or higher at 293.15 K (20°C). This definition of VOCs includes compounds that, in addition to the similar physicochemical characteristic of volatility and lipophilicity, exhibit different toxicological characteristics, both qualitatively (different effects) and quantitatively (different potency in causing the same effect). In the near future, priorities will need to include: updating the limit thresholds based on the latest evidence, extending preventive measures to indoor and semi-confined environments, and a better understanding of the effects related to exposure to mixtures. In particular, exposure measurements should assess the reliability and level of uncertainty associated with the determination of a portion of the compounds, considered as tracers of total exposure. For this, it will be necessary to better understand the emission sources and their characteristics, taking into account the technological evolution that could lead to the introduction of new, less studied compounds.