Search Results (105)

This study investigates the health impacts of air pollution in the Greater Athens Area (GAA), Greece, by estimating the Relative Risk (RR) of hospital admissions (HA) for cardiovascular (CVD) and respiratory diseases (RD) from 2018 to 2020. The analysis focuses on daily exceedances of key air pollutants—PM₁₀, O₃, and NO₂—based on the “Fair” threshold and above, as defined by the European Union Air Quality Index (EU AQI). Data from ten monitoring stations operated by the Ministry of Environment and Energy were spatially matched with six hospitals across the GAA. A Distributed Lag Non-linear Model (DLNM) was employed to capture both the delayed and non-linear exposure–response (ER) relationships between pollutant exceedances and daily HA. Additionally, the synergistic effects of pollutant interactions were assessed to provide a more comprehensive understanding of cumulative health risks. The combined exposure term showed a peak RR of 1.49 (95% CI: 0.79–2.78), indicating a notable amplification of risk when multiple pollutants exceed thresholds simultaneously. The study utilizes R for data processing and statistical modeling. Findings aim to inform public health strategies by identifying critical exposure thresholds and time-lagged effects, ultimately supporting targeted interventions in urban environments experiencing air quality challenges. Full article

We surveyed the air quality conditions in 18 homes with gas stoves for PM_2.5, CO₂, NO₂ and CO using calibrated low-cost sensors. In each home, participants were asked to cook as usual, but to record their cooking activities and mitigation efforts (windows, ventilation fans, etc.). All homes showed enhanced pollutants during, and immediately after, times of cooking or stove use. For each home, we quantified the minutes per day and minutes per minute of cooking over known health thresholds for each pollutant. On average, homes exhibited 38 min per day over one or more of these thresholds, with PM_2.5 and NO₂ being the pollutants of greatest concern. Six homes had much higher occurrences over the health thresholds, averaging 73 min per day. We found an average of 1.0 min over one or more of the health thresholds per minute of cooking when no mitigation was used, whereas when mitigation was used (filtration or vent fan), this value was reduced by 34%. We further investigated several mitigation methods including natural diffusion, a commercial HEPA filter unit, a commercial O₃ scrubber and a ventilation fan. We found that the HEPA unit was highly effective for PM_2.5 but had no impact on any of the gaseous pollutants. The O₃ scrubber was moderately effective for NO₂ but had little impact on the other pollutants. The ventilation fan was highly effective for all pollutants and reduced the average pollutant lifetime significantly. Under controlled test conditions, the pollutant lifetime (or time to reach 37% of the original concentration), was reduced from an average of 45 min (with no ventilation) to 7 min. While no commercial filter showed efficacy for both PM_2.5 and NO₂, the fact that each could be removed individually suggests that a combined filter for both pollutants could be developed, which would significantly reduce health impacts in homes with gas stoves. Full article

Agricultural production in Northwest China is widely constrained by residual plastic film pollution, excessive greenhouse gas emissions, and low productivity. Integrating biodegradable film with controlled-release nitrogen fertilizer offers a promising approach to optimize crop management, enhance yield, and improve environmental outcomes. In this study, three planting patterns (conventional flat planting, FP; ridge mulching with biodegradable film, BM; and ridge mulching with conventional plastic film, PM), two nitrogen fertilizer types (urea, U, and controlled-release nitrogen fertilizer, C), and four nitrogen application rates (0, 80, 160, and 240 kg·hm⁻²) were applied to systematically investigate their effects on alfalfa yield and N₂O emissions from grasslands. The results showed that BM and PM increased alfalfa yield by 23.49% and 18.65%, respectively, compared to FP, while C increased yield by 8.46% compared to urea. The highest yield (24.84 t·hm⁻²) was recorded under the BMC2 treatment, which was 97.11% higher than that of FPN0. N₂O emission flux and cumulative emissions increased with nitrogen application rate. Compared with U, C reduced cumulative N₂O emissions and greenhouse gas emission intensity (GHGI) by 23.89% and 25.84%, respectively. Compared to PM, BM reduced cumulative N₂O emissions and GHGI by 11.58% and 20.15%, respectively. Principal component analysis indicated that the combination of ridge mulching with biodegradable film and 160 kg·hm⁻² of C was optimal for simultaneously increasing alfalfa yield and reducing N₂O emissions, making it a suitable planting–fertilization strategy for the Yellow River irrigation district in Gansu and similar ecological regions. Full article

The aim of this study is to examine the impact of poor air quality and adverse meteorological conditions on health risks in the Greater Athens Area (GAA), Greece, during the period from 2018 to 2022. Specifically, the aim is to assess the Relative Risk (RR) of hospital admissions (HAs) for cardiovascular diseases (CVDs) and respiratory diseases (RDs), due to air pollution in combination with thermal discomfort, as well as to identify the time lag effect on admissions. For this purpose, data from six (6) different hospitals within the GAA were collected and used. Statistical analysis of hourly measurements of key pollutants (NO₂, O₃, PM_2.5, and PM₁₀) obtained from the Directorate of Climate Change and Air Quality (DCCAQ), which falls under the auspices of the Ministry of Environment and Energy (MEE), and meteorological parameters (T, RH, and wind velocity), is performed to calculate the daily air quality and human thermal comfort–discomfort levels, respectively. These conditions were examined using appropriate indexes for both air quality and human thermal comfort–discomfort, as independent variables in a Negative Binomial regression model developed in R, with daily HAs (not including scheduled cases or pre-existing health conditions) as the response variable. Moreover, a spatiotemporal analysis of air quality and meteorological parameters is conducted to identify associated variations in health risks. This analysis highlights key risk patterns linked to environmental conditions and the relevant measures to both manage and mitigate the risk. Findings indicate that extreme environmental conditions significantly elevate health risks, with cumulative RR over a one-week period peaking at 1.540 (95% CI: 1.158–2.050) during the warm season, while prolonged increases in the RR are also observed during the cold season, reaching 1.214 (95% CI: 0.937–1.572) under extreme cold exposures. Full article

During the intense heatwaves of late summer 2024, Washington, D.C.’s urban landscape revealed the powerful influence of urban morphology on microclimates and air quality. This study investigates the impact of building height-to-width (H/W) ratios on the urban heat island (UHI) effect, using a combination of field measurements and Computational Fluid Dynamics (CFD) simulations to understand the dynamics. Street-level data collected from late August to November 2024 across three sites in Washington, D.C., indicate that high H/W ratios (1.5–2.0) increased temperatures by approximately 2–3 °C and reduced wind speeds to around 0.8 m/s. These conditions led to elevated pollutant concentrations, with ozone (O₃) ranging from 1.8 to 7.3 ppb, nitrogen dioxide (NO₂) from 0.3 to 0.5 ppm, and carbon monoxide (CO) remaining relatively constant at approximately 2.1 ppm. PM_2.5 concentrations fluctuated between 2.8 and 0.4 $\mathsf{\mu }$g/m³. Meanwhile, lower H/W ratios (less than 1.5) demonstrated better air circulation and lower pollution levels. The CFD simulations are in agreement with the experimental data, yielding an RMSE of 0.75 for temperature, demonstrating its utility for forecasting UHI effects under varying urban layouts. These results demonstrate the potential of Computational Fluid Dynamics in not only modeling but also predicting UHI dynamics. Full article

The combined pollution of fine particulate matter (PM_2.5) and ozone (O₃) is increasing synergistically on a global scale, posing a serious threat to human health. However, the joint toxicity and the underlying mechanisms associated with co-exposure to PM_2.5 and O₃ remain poorly understood. Through complementary in vivo animal models and in vitro cellular assays, the results demonstrate that although there was no synergistic cytotoxicity effect between PM_2.5 and O₃, the presence of O₃ significantly enhanced the genotoxicity of PM_2.5 by inducing severe DNA double-strand breaks. Furthermore, O₃ exposure significantly exacerbated the bioaccumulation of PM_2.5 by disturbing the cellular membrane integrity, thus leading to synergistic toxicity in bronchial cells and mouse lungs. Astaxanthin (AST) effectively antagonized the adverse effects of PM_2.5 and O₃ co-exposure by maintaining cell membrane integrity. These findings enhance our understanding of the pathophysiological mechanisms induced by co-exposure to PM_2.5 and O₃, and provide a promising therapeutic strategy for treating respiratory diseases caused by unavoidable exposure to these pollutants. Full article

Short-term control measures are often implemented during major events to improve air quality and protect public health. In preparation for the 11th National Traditional Games of Ethnic Minorities of China (denoted as “NMG”), held from 8 to 16 September 2019 in Zhengzhou, China, the authorities introduced several air pollution control measures, including traffic restrictions and dust control. In the study presented herein, we applied automated machine learning-based weather normalisation combined with an augmented synthetic control method (ASCM) to evaluate the effectiveness of these interventions. Our results show that the impacts of the NMG control measures were not uniform, varying significantly across pollutants and monitoring stations. On average, nitrogen dioxide (NO₂) concentrations decreased by 8.6% and those of coarse particles (PM₁₀) decreased by 3.0%. However, the interventions had little overall effect on fine particles (PM_2.5), despite clear reductions observed at the traffic site, where NO₂ and PM_2.5 levels decreased by 7.2 and 5.2 μg m⁻³, respectively. These reductions accounted for 56.3% of the NMG policy’s effect on NO₂ concentration and 73.2% of its effect on PM_2.5 concentration at the traffic site. Notably, the control measures led to an increase in ozone (O₃) concentrations. Our results demonstrate the moderate effect of the short-term NMG intervention, emphasising the necessity for holistic strategies that address pollutant interactions, such as nitrogen oxides (NO_X) and volatile organic compounds (VOCs), as well as location-specific variability to achieve sustained air quality improvements. Full article

Loofah is deemed a promising candidate for the purification of oily fumes. Our research utilized H₃PO₄ for initial activation of loofah (TCS), producing loofahderived carbon (TGSC-0). Subsequently, Fenton’s reagent was utilized for further modification to yield loofah-derived carbon (TGSC-1). TGSC-1 was used in the form of an adsorption column to simultaneously treat multiple pollutants from oily fumes, with surface Fe³⁺, Fe²⁺, and H₂O₂ catalyzing ·OH and ·OOH generation to enhance adsorption of the oils and non-methane hydrocarbon (NMHC). Characterization showed that the specific surface area of TGSC-1 was 427.97 m²/g and pore sizes ranged from 0.50 to 3.50 nm. The rich mesoporous and macroporous structures of TGSC-1 enhanced the capability of carbon layer adsorption. Langmuir adsorption kinetics suggested that adsorption proceeded via monolayer adsorption pathways, while L-τ lines revealed shorter protective effect times for adsorbing PM₁₀ and PM_2.5 than for oils and NMHC. The results indicated that TGSC-1 exhibited maximum saturated adsorption capacities of 25.79, 13.02, 9.82, and 15.99 mg/g for oils, NMHC, PM_2.5, and PM₁₀, respectively. Increasing resistance of the adsorption column exhibited a notable synergistic effect of filtration and adsorption in treating oily fumes. It combines renewable materials with low-energy processing, delivering eco-economic benefits for sustainable development and application. Full article

Air pollution is a significant and widespread issue that presents serious challenges for both human health and the environment because of the presence of a variety of harmful substances in the air, such as tropospheric ozone (O₃), particulate matter (PM₁₀), nitrogen oxides (NOx), sulfur dioxide (SO₂), and carbon monoxide (CO). In this research, the aim is to evaluate the current evidence for the harmful effects of air pollution on human health, focusing on tropospheric ozone, and to highlight the need for further research in the future. The objective is to evaluate recent data on the respiratory and cardiovascular risks caused by air pollution, the potential association between climate change due to air pollution and human disorders, and the subsequent economic burden. A systematic search of the literature is conducted using PubMed, Scopus, Web of Science, and regulatory reports (EPA), focusing on peer-reviewed studies, epidemiological analyses, and clinical and experimental studies. The key findings indicate that O₃ exposure contributes to inflammatory lung injury and to the worsening of preexisting conditions like asthma and COPD, is associated with cancer, and also has numerous negative impacts on neurological, metabolic, and reproductive health, combined with increased healthcare costs. These findings highlight the significance of O₃ pollution as a major public health concern, emphasizing the need for immediate measures to decrease emissions and effective policies to protect the climate and the health of the individuals. Full article

The air we breathe contains contaminants such as particulate matter (PM), carbon dioxide (${\mathrm{CO}}_2$), nitrogen dioxide (${\mathrm{NO}}_2$), and nitric oxide (NO), which, when inhaled, bring about several changes in the autonomous responses of our body. Our previous work showed that we can use the human body as a sensor by making use of autonomous responses (or biometrics), such as changes in electrical activity in the brain, measured via electroencephalogram (EEG) and physiological changes, including skin temperature, galvanic skin response (GSR), and blood oxygen saturation (${\mathrm{SpO}}_2$). These biometrics can be used to estimate pollutants, in particularly ${\mathrm{PM}}_1$ and ${\mathrm{CO}}_2$, with high degree of accuracy using machine learning. Our previous work made use of the Welch method (WM) to obtain a power spectral density (PSD) from the time series of EEG data. In this study, we introduce a novel approach for obtaining a PSD from the EEG time series, developed by Astrapi, called the Astrapi Spectrum Analyzer (ASA). The physiological responses of a participant cycling outdoors were measured using a biometric suite, and ambient ${\mathrm{CO}}_2$, ${\mathrm{NO}}_2$, and NO were measured simultaneously. We combined physiological responses with the PSD from the EEG time series using both the WM and the ASA to estimate the inhaled concentrations of ${\mathrm{CO}}_2$, ${\mathrm{NO}}_2$, and NO. This work shows that the PSD obtained from the ASA, when combined with other physiological responses, provides much better results (RMSE = 9.28 ppm in an independent test set) in estimating inhaled ${\mathrm{CO}}_2$ compared to making use of the same physiological responses and the PSD obtained by the WM (RMSE = 17.55 ppm in an independent test set). Small improvements were also seen in the estimation of ${\mathrm{NO}}_2$ and NO when using physiological responses and the PSD from the ASA, which can be further confirmed with a large number of dataset. Full article

Organic pollutants present a substantial risk to both ecological systems and human well-being. Activation of peroxymonosulfate (PMS) have emerged as an effective strategy for the degradation of organic pollutants. Bi-based heterojunction is commonly used as a photocatalyst for reductively activating PMS, but single-component Bi-based heterojunction frequently underperforms due to its restricted absorption spectrum and rapid combination of photogenerated electron–hole pairs. Herein, BiVO₄ was selected as the oxidative semiconductor to form an S-type heterojunction with CuBi₂O₄—x-CuBi₂O₄/BiVO₄ (x = 0.2, 0.5, and 0.8) for PMS photoactivation. The built-in electric field (BEF) in x-CuBi₂O₄/BiVO₄ promoted electron transfer to effectively activate PMS. The x-CuBi₂O₄/BiVO₄ heterojunctions also demonstrate stronger adsorption of the polar PMS than pure CuBi₂O₄ or BiVO₄. In addition, the BEF prompts photoelectrons able to reduce O₂ to •O₂⁻ and photogenerated holes in the valence band of BiVO₄ able to oxidize H₂O to generate •OH. Therefore, under visible light irradiation, 95.1% of ciprofloxacin (CIP) can be degraded. The 0.5-CuBi₂O₄/BiVO₄ demonstrated the best degradation efficiency and excellent stability in cyclic tests, as well as a broad applicability in degrading other common pollutants. The present work demonstrates the high-efficiency S-type heterojunctions in the coupled photocatalytic and PMS activation technology. Full article

Trees growing in urban areas face increasing stress from atmospheric pollutants, with limited attention given to the early responses of young seedlings. This study aimed to address the knowledge gap regarding the effects of simulated pollutant exposure, specifically particulate matter (PM), elevated ozone (O₃), and carbon dioxide (CO₂) concentrations, on young seedlings of five tree species: Scots pine (Pinus sylvestris L.); Norway spruce (Picea abies (L.) H.Karst.); silver birch (Betula pendula Roth); small-leaved lime (Tilia cordata Mill.); and Norway maple (Acer platanoides L.). The main objectives of this paper were to evaluate the seedling stem growth response and the biochemical response of seedling foliage to pollutant exposure. Four treatments were performed on two- to three-year-old seedlings of the selected tree species: with PM (0.4 g per seedling) under combined O₃ = 180 ppb + CO₂ = 650 ppm; without PM under combined O₃ = 180 ppb + CO₂ = 650 ppm; with PM (0.4 g per seedling) under combined O₃ < 40–45 ppb + CO₂ < 400 ppm; and without PM under combined O₃ < 40–45 ppb + CO₂ < 400 ppm. Scots pine and Norway maple showed no changes in growth (stem height and diameter) and biochemical parameters (photosynthetic pigments, total polyphenol content (TPC), total flavonoids content (TFC), and total soluble sugars (TSS)), indicating a neutral response to the combined PM, O₃, and CO₂ treatment. The chlorophyll response to PM alone and in combination with elevated O₃ and CO₂ exposure varied, with silver birch increasing, Norway maple—neutral to increasing, Scots pine—neutral to decreasing, and Norway spruce and small-leaved lime—decreasing. The TPC indicated stress responses in Scots pine, small-leaved lime, and Norway maple under increased combined O₃ and CO₂ and in Norway spruce under single PM treatment. Hence, Scots pine and Norway maple seedlings showed greater resistance to increased PM under combined O₃ and CO₂ with minimal change in growth, while silver birch seedlings showed adaptation potential with increasing chlorophyll under simulated pollutant stress. Full article

Given the increasing importance of effectively identifying synergistic changes between PM_2.5 and O₃ and comprehensively analyzing their impact on air quality management in China, we employ the Sen+Mann–Kendall (Sen+M-K) trend test in this study to examine the temporal and spatial variation trends of PM_2.5 and O₃ in the Yangtze River Delta (YRD), from 2003 to 2020. We identified the regions where these pollutants exhibited synergistic changes and established the pathways between the pollutants and their potential drivers, using geographically weighted random forest algorithms and structural equation modeling. The study results revealed as follows: (1) Overall, the PM_2.5 concentrations show a decreasing trend, while the O₃ concentrations exhibit an increasing trend, in the YRD. Analysis of the combined trends indicates that approximately 95% of the area displays opposing trends for PM_2.5 and O₃, with only about 4% in the southern region showing synergistic trends for both pollutants. (2) Drought and the average temperature are the main drivers of the changes in PM_2.5 and O₃ concentrations in areas experiencing synergistic changes. Their combined effects alleviate the aggregation of PM_2.5 and reduce the formation of VOCs, indirectly reducing the generation of pollutants. The negative effect of the average temperature on the O₃ concentration may indicate the existence of nonlinear effects and complex interaction effects between the drivers. NO_x and VOCs play important dual roles in the generation and conversion of pollutants, although their overall impact is smaller than meteorological factors. They produce significant indirect effects through their interaction with meteorological and other human factors, further affecting the concentrations of PM_2.5 and O₃. In areas without coordinated changes, the main impact of meteorological factors remains unchanged, and the relationship between the two anthropogenic emission sources and their effects on PM_2.5 and O₃ are complex, with different directions and levels involved. This study provides detailed insights into the drivers of air quality changes in the YRD and offers a scientific basis for environmental management authorities to develop more comprehensive and targeted strategies for balancing the control of PM_2.5 and O₃ pollution. Full article

This study investigated the influence of sea–land breezes on nocturnal spatial and temporal distribution of ozone (O₃) and its potential effects on particulate nitrate formation in Qingdao, a coastal city in northern China. Observation campaigns were conducted to measure surface air pollutants and meteorological factors during a typical sea–land breezes event from 22 to 23 July 2022. A coherent Doppler lidar (CDL) system was employed to continuously detect three-dimensional wind fields. The results revealed that nocturnal ozone levels were enhanced by a conversion of sea–land breezes. Initially, the prevailing northerly land breeze transported high concentrations of O₃ and other air pollutants from downtown to the Yellow Sea. As the sea breeze developed in the afternoon, the sea breeze front advanced northward, resulting in a flow of high O₃ concentrations back into inland areas. This penetration of the sea breeze front led to a notable spike in O₃ concentrations between 16:00 on 22 July and 02:00 on 23 July across downtown areas, with an average increase of over 70 μg/m³ within 10 min. Notably, a time lag in peak O₃ concentration was observed with southern downtown areas peaking before northern rural areas. During this period, combined pollution of O₃ and PM_2.5 was also observed. These findings indicated that the nighttime increase in O₃ concentrations, coupled with enhanced atmospheric oxidation, would likely promote the secondary conversion of gaseous precursors into PM_2.5. Full article

The ever-increasing industrialization of certain areas of the planet combined with the simultaneous degradation of the natural environment are alarming phenomena, especially in the field of human health. The concentration of particulate matter with an aerodynamic diameter of 2.5 μm (PM_2.5) and 10 μm (PM₁₀), nitrogen oxides (NO_x), carbon monoxide (CO), sulfur dioxide (SO₂), and ozone (O₃) needs constant monitoring, as they consist of the main cause for many diseases. Based on the existence of statutory limits from the World Health Organization (WHO) for the concentration of each of the aforementioned air pollutants, it is considered necessary to develop forecasting systems that have the ability to correlate the current meteorological data with the concentrations of the above pollutants. In this work, the attempt to predict air pollutant concentrations in the wider area of Beijing, China, is successfully carried out using artificial neural network (ANN) models. In the frame of a specific work, a significant number of ANNs are developed. For this purpose, an open-access meteorological and air pollution database was used. Finally, a statistical evaluation of the developed prognostic models was carried out. The results showed that ANNs present a remarkable prognostic ability in order to forecast air pollution levels in an urban environment. Full article