Search Results (60)

People spend the majority of their time indoors; however, most previous studies on the health effects of particulate matter (PM) and ozone (O₃) have used outdoor concentrations as a proxy for personal exposure, which may introduce misclassification bias. Since indoor PM and O₃ originate primarily from outdoors, estimating their indoor infiltration levels provides a closer approximation of true personal exposure. This study used data on approximately four million deaths occurring over an eight-year period in Jiangsu Province, China. The infiltration factor method and time-series analysis were employed to assess the linear and nonlinear associations of short-term indoor exposure to outdoor-origin PM₁, PM_2.5, PM₁₀, and O₃ with all-cause, cardiovascular, and respiratory mortality. In addition, the interactions between indoor PM and O₃ were investigated. The results indicate that indoor exposure to outdoor-origin PM and O₃ was positively associated with mortality, and these associations were stronger than those observed for direct outdoor exposure. Each 10 μg/m³ increase in the 2-day moving average concentration of indoor PM₁, PM_2.5, PM₁₀, and O₃ was associated with a 1.82% (95% confidence interval [CI]: 1.64, 2.01), 1.02% (95% CI: 0.91, 1.13), 0.69% (95% CI: 0.62, 0.77), and 1.79% (95% CI: 1.60, 1.99) increase in all-cause mortality, respectively. No threshold was observed in the exposure-response associations. Furthermore, significant multiplicative and additive interactions were identified between infiltrated PM and O₃. Consequently, greater attention should be directed toward indoor air quality, particularly the coordinated management of combined exposure to indoor PM and O₃, in order to better protect public health. Full article

Cooking-related emissions represent a major contributor to indoor air pollution in residential kitchens, producing complex mixtures of volatile organic compounds (VOCs), odor-causing gases, oil vapors, particulate matter (PM_2.5), and combustion-related pollutants (CO and NO_x). In this study, a controlled ozone-assisted oxidation approach was integrated into a recirculating (ductless) domestic kitchen hood equipped with a confined reaction chamber and experimentally evaluated under closed-loop operating conditions where treated air was returned to the indoor environment after post-treatment. A multivariate Response Surface Methodology (RSM) framework based on the Box–Behnken design was employed to quantify and optimize the coupled effects of temperature (20–30 °C), relative humidity (40–60%), ozone dosage (1–3 ppm within the confined reaction zone), and airflow rate (150–250 m³/h) on multi-pollutant removal performance. The results demonstrate that ozone assistance substantially improves the abatement of oxidation-sensitive pollutants, particularly VOCs and odor, while airflow rate strongly governs transport-dominated pollutants such as PM_2.5 and oil vapors. In contrast, CO and NO_x exhibited limited improvement, indicating that ozone-assisted oxidation alone is insufficient for comprehensive control of combustion-related gases under short-residence-time recirculating hood conditions. The main contribution of this work is the implementation of a demand-driven ozone management strategy, supported by dual ozone sensing for reaction-zone control and outlet safety verification, where ozone generation is activated only in the presence of reactive gaseous pollutants and automatically reduced or terminated once pollutant concentrations fall below predefined thresholds, minimizing unnecessary oxidant release. Residual ozone downstream of the reaction stage was continuously monitored to prevent excess ozone return to the occupied zone. Overall, the proposed closed-loop, feedback-controlled ozone-assisted recirculating range hood concept demonstrated device-level reductions in measured VOC/odor signals under controlled conditions, while also highlighting the need for complementary post-treatment components for particle- and combustion-related pollutants. However, the potential formation of secondary oxidation byproducts was not characterized in this study, and therefore the results should be interpreted with respect to device-level pollutant removal rather than comprehensive indoor air quality improvement. Full article

Data on various air-quality metrics are collected repeatedly by numerous monitoring stations worldwide to closely assess the severity of pollution. Particle pollution from fine particulate matter ${\mathrm{P}\mathrm{M}}_{2.5}$ is one such measure used as an indicator of whether air quality is unhealthy. ${\mathrm{P}\mathrm{M}}_{2.5}$ is a specific form of air contamination that negatively impacts the environment and human health when levels are above a certain threshold. As data are collected repeatedly over time at multiple locations, there may be a temporal dependence among repeated outcomes and spatial dependence between neighboring stations. Thus, it is important to assess the impact of risk factors on trajectory risk prediction. However, due to the temporal and spatial dependencies, trajectory risk prediction for such data becomes complicated, as both types of dependences must be accounted for during model building. In this paper, we propose a modeling framework that accounts for both types of dependences by incorporating Markov chains and Markov regression, using autologistics for model fitting and trajectory risk prediction. The proposed model fitting and trajectory risk prediction are illustrated using ${\mathrm{P}\mathrm{M}}_{2.5}$ outdoor air pollution data from the United States from 2000 to 2020. Full article

Preterm birth (PTB) has been increasingly linked to maternal exposure to fine particulate matter (PM_2.5) during pregnancy. However, the contribution of individual PM_2.5 constituents risk remains unclear. This research investigated associations between prenatal exposure to PM_2.5 constituents and PTB risk using a hypothetical intervention approach. A birth cohort of 148,068 mother–child pairs from Foshan, China was constructed from health records. Maternal exposure to PM_2.5 constituents—including black carbon (BC), organic matter (OM), nitrate (NO₃⁻), ammonium (NH₄⁺), and sulfate (SO₄²⁻)—was estimated based on satellite-derived spatial and temporal modeling. Parametric G-computation and distributed lag nonlinear models were used to estimate the cumulative risks of PTB under hypothetical reductions of PM_2.5 constituents during pregnancy. Potential benefits (preventable PTB cases) were also estimated. Among the cohort, 9757 (6.59%) PTBs were observed. Hypothetical reductions in all five constituents during pregnancy were associated with decreased cumulative risks of birth at week 36 (i.e., the threshold for PTB). For instance, a 40% reduction (reducing PM_2.5 to the WHO recommended levels) yielded risk differences of −2.29 (BC), −3.70 (OM), −4.74 (NH₄⁺), −5.00 (NO₃⁻), and −2.11 (SO₄²⁻) per thousand births, corresponding to 312 (3.20%) to 740 (7.58%) preventable cases. Our results indicate that reductions in PM_2.5 constituents, especially NO₃⁻ and NH₄⁺, were associated with lower risks of PTB. Full article

Microbiological contamination in public buildings is closely linked to human presence, such as airborne bacteria, fungi, and particulate matter, which strongly influence indoor air quality (IAQ). This study examined the distribution of microorganisms in a museum building in relation to time of day, air-handling unit (AHU) type, and ventilation operating mode. Exhibition rooms without natural light relied entirely on a central heating, ventilation and air conditioning (HVAC) system. Microbiological contamination was assessed using Koch’s passive sedimentation method over a 24 h cycle for two AHUs (I and III) and selected rooms, while CO₂ levels were monitored as indicators of occupancy and ventilation demand in line with EN 16798-1:2019 and ASHRAE 62.1-2022. Although the demand-controlled ventilation system increased the outdoor air fraction from 40% to 70–100% during peak visitor density, localized increases in microbial contamination occurred. AHU I showed higher loads of Staphylococcus sp. and fungi, while AHU III exhibited pronounced fungal peaks influenced by elevated humidity from an open water reservoir. Psychrophilic bacteria reached 140–230 CFU·m⁻³, mesophilic bacteria 230–320 CFU·m⁻³, and fungi up to 740 CFU·m⁻³. Most CFU values remained below commonly referenced upper limits (<1000 CFU·m⁻³), but several peaks exceeded lower recommended thresholds, indicating a need for improvements. Enhanced filtration, humidity control, increased airflow during high occupancy, and reducing moisture sources in AHUs may mitigate microbial growth and improve IAQ in public buildings. Full article

This study compares Ordinary Least Squares (OLS) regression and Random Forest models to analyze particulate matter (PM₁, PM_2.5, and PM₁₀) concentrations based on meteorological and traffic data collected on major arterials in Karachi, Pakistan. OLS regression highlights temperature and humidity as significant contributors to PM levels, while wind speed shows an inverse relationship, especially with PM₁. Random Forest regression demonstrates superior performance with higher R² values and a lower RMSE, effectively capturing complex, non-linear relationships among variables. Wind speed thresholds for PM dispersion are identified, providing critical benchmarks for air quality management. This comparative analysis underscores the effectiveness of machine learning methods for accurate environmental modeling. Full article

Globally, lakes are increasingly recognized as sensitive indicators of climate change and ecosystem stress. Qaraoun Lake, Lebanon’s largest artificial reservoir, is a critical resource for irrigation, hydropower generation, and domestic water supply. Over the past 25 years, satellite remote sensing has enabled consistent monitoring of its hydrological and environmental dynamics. This study leverages the advanced cloud-based processing capabilities of Google Earth Engine (GEE) to analyze over 180 cloud-free scenes from Landsat 7 (Enhanced Thematic Mapper Plus) (ETM+) from 2000 to present, Landsat 8 Operational Land Imager and Thermal Infrared Sensor (OLI/TIRS) from 2013 to present, and Landsat 9 OLI-2/TIRS-2 from 2021 to present, quantifying changes in lake surface area, water volume, and pollution levels. Water extent was delineated using the Modified Normalized Difference Water Index (MNDWI), enhanced through pansharpening to improve spatial resolution from 30 m to 15 m. Water quality was evaluated using a composite pollution index that integrates three spectral indicators—the Normalized Difference Chlorophyll Index (NDCI), the Floating Algae Index (FAI), and a normalized Shortwave Infrared (SWIR) band—which serves as a proxy for turbidity and organic matter. This index was further standardized against a conservative Normalized Difference Vegetation Index (NDVI) threshold to reduce vegetation interference. The resulting index ranges from near-zero (minimal pollution) to values exceeding 1.0 (severe pollution), with higher values indicating elevated chlorophyll concentrations, surface reflectance anomalies, and suspended particulate matter. Results indicate a significant decline in mean annual water volume, from a peak of 174.07 million m³ in 2003 to a low of 106.62 million m³ in 2025 (until mid-November). Concurrently, pollution levels increased markedly, with the average index rising from 0.0028 in 2000 to a peak of 0.2465 in 2024. Episodic spikes exceeding 1.0 were detected in 2005, 2016, and 2024, corresponding to documented contamination events. These findings were validated against multiple institutional and international reports, confirming the reliability and efficiency of the GEE-based methodology. Time-series visualizations generated through GEE underscore a dual deterioration, both hydrological and qualitative, highlighting the lake’s growing vulnerability to anthropogenic pressures and climate variability. The study emphasizes the urgent need for integrated watershed management, pollution control measures, and long-term environmental monitoring to safeguard Lebanon’s water security and ecological resilience. Full article

Ensuring good air quality in indoor environments of historical and artistic significance is essential not only for protecting valuable artworks but also for safeguarding human health. While many studies in this field tend to focus on the preservation of cultural heritage, fewer have addressed the impact on visitors and worshippers. Yet, places such as museums, galleries, churches, and other religious sites attract large numbers of people, making indoor air quality a key factor for their well-being. This study focused on evaluating air quality within the Santuario della Beata Vergine dei Miracoli in Saronno, Italy, a religious site that welcomes large numbers of visitors and worshippers each year. A detailed analysis of particulate matter was conducted, including chemical characterization by ICP-MS for metals, ion chromatography for water-soluble ions, and thermal–optical analysis for the carbonaceous fraction, as well as assessments of size distribution and radiometric properties. The results indicated overall good air quality conditions: concentrations of heavy metals were below levels of concern (<35 ng m⁻³), and gross alpha, beta, and ¹³⁷Cs activity concentrations remained below the minimum detectable thresholds. Hence, no significant health risks were identified. Full article

Widespread residential wood burning in southern Chile combined with cold climate conditions cause severe episodes of particulate matter (PM_2.5 and PM₁₀) pollution. In this study, we used logistic regression to predict daily exceedances of fine (PM_2.5) and coarse (PM₁₀) particulate levels at multiple urban sites, assessing model performance under different air quality standards. Results showed a clear latitudinal gradient in air pollution, with communities further south experiencing significantly higher PM levels and more frequent threshold exceedances, likely due to higher per capita firewood use and cooler temperatures. The logistic models achieved their best predictive accuracy under the strictest European (ESP) air quality standards (F1-scores up to ~0.72 for PM₁₀ and ~0.59 for PM_2.5), while Chile’s national (NCh) thresholds significantly underestimated pollution events. Additionally, annual per capita wood energy consumption in the far south was several times higher than in central Chile, contributing to disproportionately high emissions. These findings highlight the need to adopt more protective air quality standards and reduce wood-fueled emissions to improve early warning systems and decrease particulate exposure in southern Chile. Full article

This study investigates the environmental impact of combined missile and drone attacks on Kyiv, the capital of Ukraine, with a focus on the release of particulate matter (PM) into the urban atmosphere. These military strikes frequently result in the destruction of residential and industrial infrastructure, as well as fires, leading to acute increases in ambient concentrations of fine particulate matter (PM2.5). Observational data were collected between 1 and 30 June 2025 using a distributed network of low-cost air quality monitoring stations aggregated by the SaveEcoBot platform. The optical particle counters, based on light scattering technology, enable real-time monitoring of airborne particulate fractions of PM2.5 along with meteorological parameters and gas pollutants. The study period included two significant attacks (10 and 17 June), during which the temporal and spatial dynamics of PM2.5 concentrations were analyzed in comparison to baseline levels observed under non-attack conditions. Raw concentrations of PM2.5 up to 241 μg/m³ were observed in the epicenters of air-strike-induced fires, while smog plumes covered half of the city area. Elevated PM2.5 concentrations were recorded during and for several hours following the attacks and corresponding air raid alerts. The findings show days of PM2.5 exceedances above the World Health Organization (WHO) daily threshold of 15 μg/m³. These results underscore the acute environmental and public health hazards posed by military assaults on urban centers. Furthermore, this research highlights the role of citizen-driven environmental monitoring as a valuable tool for both scientific documentation and potential evidentiary support in assessing the environmental impacts of warfare. Full article

When driving at highway speeds, the airtightness and ventilation mode of the cabin can significantly affect the in-cabin air quality. Accordingly, this study conducted on-road driving experiments along four highways in Tainan City, Taiwan, to examine the effects of different ventilation strategies and driving speeds on the concentrations of three pollutants (carbon dioxide (CO₂), PM_2.5, and PM₁₀) in the cabin of a mid-size sedan. During the test, the vehicle will travel at a constant speed of 60, 70, 80, 90, 100, 110 and 120 km/h depending on the traffic conditions. When driving on the system interchanges, the vehicle speed was maintained at 40 and 50 km/h. Ventilation strategies are divided into fresh air mode and recirculation air mode. The results revealed that leakage ventilation at high speeds allowed more outdoor air to infiltrate the cabin. This reduced the CO₂ concentration but slightly increased the particulate matter (PM) when the ventilation system was operated in the recirculation mode. The continuous use of the recirculation air mode for extended periods resulted in a potentially hazardous increase in the CO₂ concentration. Thus, periodic switching to the fresh air mode is recommended to ensure that the in-cabin CO₂ concentration remains below the ASHRAE threshold of 1000 ppm. In the fresh air mode, the PM_2.5 and PM₁₀ concentrations decreased as the vehicle speed increased. In the recirculation mode, the cabin filters maintained lower in-cabin PM levels than in the fresh-air mode. The experimental data were fitted using a curve-fitting technique to quantify the relationships between the vehicle speed and the in-cabin CO₂, PM_2.5, and PM₁₀ concentrations under the two ventilation strategies. The findings of this study provide useful practical guidelines for optimizing the vehicle ventilation strategy to improve the in-cabin air quality and enhance occupant health and safety during highway driving. Full article

Air quality is a vital factor for safeguarding public and environmental health. Particulate matter (i.e., PM2.5 and PM10) and nitrogen dioxide are among the most harmful air pollutants leading to severe health risks such as respiratory and cardiovascular diseases, while also affecting the environment negatively by contributing to the formation of acid rains and ground level ozone. The European Union has introduced new thresholds on those pollutants to be met by the year 2030, taking into consideration the guidelines set by the World Health Organization, aiming for a healthier environment for humans and living species. Cyprus is an island that is vulnerable to those pollutants mostly due to its geographic location, facilitating shipping activities and dust transport from Sahara Desert, and the methods used to produce electricity which primarily rely on petroleum products. Furthermore, the country suffers from heavy traffic conditions, making it susceptible to high levels of nitrogen dioxide. Thus, the projection of air pollutants according to different scenarios based on regulations and policies of the European Union are necessary towards clean air and better practices. The Screening for High Emission Reduction Potential on Air (SHERPA) is a tool developed by the European Commission which allows the simulation of emission reduction scenarios and their effect on the following key pollutants: NO, NO₂, O₃, PM2.5, PM10. This study aims to assess the potential of the SHERPA simulation tool to support air quality related decision and policy planning in Cyprus to ensure that the country will remain within the thresholds that will be applicable in 2030. Full article

Indoor sports facilities present unique challenges for air quality management due to high crowd densities and limited ventilation. This study investigated air quality in a municipal athletic facility in Komotini, Greece, focusing on concentrations of airborne particulate matter (PM_1.0, PM_2.5, PM₁₀), humidity, and temperature across spectator zones, under varying mask scenarios. Sensing devices were installed in the stands to collect high-frequency environmental data. The system, based on optical particle counters and cloud-enabled analytics, enabled real-time data capture and retrospective analysis. The main experiment investigated the impact of spectators wearing medical masks during two basketball games. The results show consistently elevated PM levels during games, often exceeding recommended international thresholds in the spectator area. Notably, the use of masks by spectators led to measurable reductions in PM_1.0 and PM_2.5 concentrations, because they seem to have limited the release of human-generated aerosols as well as the amount of movement among spectators, supporting their effectiveness in limiting fine particulate exposure in inadequately ventilated environments. Humidity emerged as a reliable indicator of occupancy and potential high-risk periods, making it a valuable parameter for real-time monitoring. The findings underscore the urgent need for improved ventilation strategies in small to medium-sized indoor sports facilities and support the deployment of low-cost sensor networks for actionable environmental health management. Full article

This study evaluates occupational exposure to respirable particulate matter (PM2.5) and crystalline silica (c-silica) among workers in five ceramic industries in Indonesia. Personal sampling revealed that 55.3% of workers were exposed to c-silica levels exceeding the Threshold Limit Value (TLV) of 50 µg/m³, with concentrations ranging from 1.5 to 1395.3 µg/m³. PM2.5 levels reached as high as 4152.4 µg/m³ in certain production zones. Health surveys identified frequent respiratory symptoms such as shortness of breath (27.1%) and chronic cough (14.6%), with 6.4% of workers showing lung abnormalities on chest X-rays. Risk assessments based on chronic daily intake (CDI), hazard quotient (HQ), and risk quotient (RQ) revealed that 63.8% of workers faced unsafe exposure, particularly those with longer job tenures, older age, and poor compliance with personal protective equipment (PPE). To mitigate risks, the study recommends engineering controls such as more local exhaust ventilation, improved PPE usage, and administrative measures including job rotation and regular health monitoring. These findings highlight the urgent need for improved occupational health strategies in silica-intensive industries and call for further research on long-term health impacts and effective intervention programs. Full article

Indoor sports facilities face distinctive indoor air quality (IAQ) challenges due to high occupant density, elevated metabolic emissions, and diverse pollutant sources associated with physical activity. This review presents a narrative synthesis of multidisciplinary evidence concerning IAQ in sports environments. It explores major pollutant categories, including carbon dioxide (CO₂), particulate matter (PM), volatile organic compounds (VOCs), and airborne microbial agents, highlighting their sources, behavior during exercise, and associated health risks. Research shows that physical activity can increase PM concentrations by up to 300%, and CO₂ levels frequently exceed 1000 ppm in inadequately ventilated spaces. The presence of semi-volatile organics and bioaerosols further complicates pollutant dynamics, especially in humid and densely occupied areas. Measurement technologies such as optical sensors, chromatographic methods, and molecular techniques are reviewed and compared for their applicability to dynamic indoor settings. Existing IAQ standards across China, the USA, the EU, the UK, and WHO are examined, revealing a lack of activity-specific thresholds and insufficient responsiveness to real-time conditions. Mitigation strategies (e.g., including demand-controlled ventilation, use of low-emission materials, liquid chalk substitutes, and integrated HEPA-UVGI purification systems) are evaluated, many demonstrating pollutant removal efficiencies over 80%. The integration of intelligent building management systems is emphasized for enabling real-time monitoring and adaptive control. This review concludes by identifying research priorities, including the development of activity-sensitive IAQ control frameworks and long-term health impact assessments for athletes and vulnerable users. Full article