Exposure to particulate matter (PM) and its chemical constituents in residential microenvironments has become a major health concern worldwide. The oxidative potential (OP) has been proposed as a metric for estimating the PM capacity to induce oxidative stress and, consequently, health effects. In the present study, PM10 was daily monitored simultaneously in the bedroom, living room and kitchen of three dwellings for one week in a small town of Portugal, to perform a detailed characterisation of its organic and inorganic constituents and the determination of the OP. Bedrooms (B) were found to be a hotspot of PM10 concentrations (B1 = 22.7 mu g m(-3); B2 = 19.5 mu g m(-3); B3 = 68.1 mu g m(-3)). PM10-bound elements varied significantly between microenvironments in all dwellings. Lower molecular weight polycyclic aromatic hydrocarbons (PAHs) were found to be between 14 and 72 times higher than high molecular weight PAHs in bedrooms. The mean volume-normalised OP determined by the dithiothreitol and ascorbic acid assays varied within the 0.01-0.38 nmol min(-1) m(-3) and 0.03-0.53 nmol(-1) m(-3) ranges, respectively. Quinones, oxy-aromatic, aromatic and alkyl-aromatic compounds stood out in bedrooms. Strong and significantly positive relationship between OP and black carbon, Cu and Br were observed, indicating common redox active species mainly associated with traffic emissions. Sr, Fe, Zn and Zr presented higher concentrations in dwelling 3, exhibiting excellent positive correlation with OP, indicating that the Sahara dust intrusion recorded in that house may have contributed to the formation of more redox active species thought to drive antioxidant depletion responses.

Wildfires are becoming increasingly frequent and severe, particularly in Southern Europe. In addition to their immediate environmental and socioeconomic impacts, wildfires release significant amounts of particulate matter (PM), which poses serious health and ecological risks. Gaseous (CO and CO2) and PM2.5 samples were collected directly from smoke plumes, and the modified combustion efficiency (MCE) was calculated to characterise combustion conditions. This study aims to assess the cytotoxicity, mutagenicity and ecotoxicity of PM2.5 collected during wildfires in Portugal, with a focus on how varying biomass types and combustion conditions impact these effects. Ecotoxicity assessments using Aliivibrio fischeri showed that PM2.5 samples ranged from toxic to extremely toxic, with mixed vegetation burns (eucalyptus, acacia, ferns) exhibiting the highest toxicity levels. Cytotoxicity tests on human lung epithelial cells (A549) demonstrated a dose-dependent decrease in metabolic activity and no membrane damage, while mutagenicity assays identified direct-acting mutagens from smouldering acacia debris combustion, specifically inducing frameshift mutations in Salmonella typhimurium strain TA98. Root growth inhibition tests showed no toxicity, with some samples, instead, promoting growth probably due to nutrient content. Peroxidase activity responses indicated that, at higher concentrations, the enzyme function could be reduced if defence mechanisms are overwhelmed or stimulated due to high nutrient levels. These findings highlight the complex and varying toxicological profiles of wildfire PM, emphasising the need for further research.

Despite the numerous studies on particulate matter and gaseous pollutants in school environments in developed countries, air quality in African schools has been largely neglected. In this work, the atmospheric concentrations of particulate matter (PM10) were evaluated in various classrooms and outdoor courtyards of four primary schools in Luanda, Angola, using photometric monitors and gravimetric samplers. Comfort parameters, carbon oxides (CO and CO2) and total volatile organic compounds (TVOCs) were measured in real time. Passive sampling was also used to assess the levels of various gaseous pollutants: benzene, toluene, ethylbenzene, and xylenes (BTEX), ozone (O3), nitrogen dioxide (NO2), and carbonyl compounds. The daily PM10 concentrations (62.0 ± 37.0 μg/m3) exceeded the WHO guideline value on 68% of the days. Indoor PM10 levels were usually lower than outdoors, except at one school with poor structural conditions and unpaved roads in the vicinity. Average temperature and relative humidity levels consistently exceeded recommended standards, potentially impacting academic performance. CO2 and TVOCs levels followed occupancy patterns, with elevated concentrations exceeding international standards in just one classroom due to poor ventilation. NO2 concentrations in the classrooms were very similar to those recorded outdoors, whereas BTEX levels slightly exceeded those measured in the courtyards. These compounds were primarily attributed to emissions from road traffic. O3 levels in the classrooms were, on average, 2.3 times lower than those outdoors. For most carbonyl compounds, indoor concentrations were 1.8-3.8 times higher than those measured outdoors, suggesting the presence of active emission sources indoors. Butyraldehyde, formaldehyde, and hexaldehyde were the most abundant carbonyl compounds. While BTEX, O3, and NO2 levels in Luanda aligned with those reported for European schools, formaldehyde concentrations were lower, likely due to better natural ventilation supported by the milder climate.

Research has consistently linked exposure to particulate matter (PM) with adverse health outcomes, including cardiovascular and pulmonary morbidity and mortality. Understanding the mechanisms by which PM leads to these effects on human health is crucial for developing effective mitigation strategies. One aspect of PM research that has gained increasing attention in the past few years is the bioaccessibility of inhaled PM-bound pollutants that have potential to cause adverse health effects. To assess the bioaccessibility of PM-bound pollutants, such as polycyclic aromatic hydrocarbons, phthalate esters, organophosphorus flame retardants and metal(loid)s, simulated lung fluids (SLF) are used as a tool to mimic the conditions in the human respiratory system. In addition to different SLF, various extraction methodologies and experimental conditions (e.g., incubation period, solid to liquid ratio, and pH) have been employed to extract the bioaccessible part of these pollutants, though there is not yet a standardised procedure to do so. This review aims to critically evaluate existing inhalation bioaccessibility methodologies and explore their connection with PM characteristics. More research is needed, and a standardised procedure should be implemented to allow the comparation of data between studies. Better in vitro-in vivo relationships need to be established to enhance the feasibility of in vitro bioaccessibility assays as surrogates in human health exposure assessments. Long-term effects of bioaccessible pollutants and any potential synergetic effects between multiple contaminants should also be explored to assess health repercussions more thoroughly.

This paper provides a comprehensive assessment of indoor and outdoor air quality within a home improvement and gardening store chain in northeastern Portugal. In December 2021 and January 2022, two multipollutant systems were installed in the store and outdoors to assess air quality. Continuous monitoring included particulate matter below 10 mu m (PM10), CO2 and comfort parameters. PM10 samples were collected using gravimetric samplers during both occupied and vacant periods. These samples were then analysed for carbonaceous constituents and metal(loid)s. Additionally, volatile organic compounds (VOCs), carbonyls, bacteria, and fungi were passively sampled. Results showed higher indoor concentrations of PM10 during labour hours (45.4 f 15.2 mu g/ m3), while outdoor values of 27.1 f 9.96 mu g/m3 were recorded. The elemental characterisation of PM10 revealed a high abundance of soil-related elements indoors, suggesting that resuspension is one of the primary sources. The most abundant elements were Ca, Fe, and Zn, with concentrations of 658 f 297, 273 f 141, and 172 f 67.4 ng/m3, respectively. Outdoors, elements related to tyre and brake wear and road dust were predominant, indicating emissions from non-exhaust traffic emissions as the main source. A prevalence of alpha-pinene, limonene, and hexanal was found indoors, most likely related to wood products. Fungi with clinical relevance and toxigenic potential, and higher bacterial loads were observed in the gardening and heating sectors of the store. This study underscores the importance of investigating less-studied stores, as they may exhibit pollutant levels that exceed health protection thresholds.

This study applied Positive Matrix Factorization (PMF) to PM10 speciation datasets from 24 urban sites across six European countries (France, Greece, Italy, Portugal, Spain, and Switzerland) to perform a detailed source apportionment (SA) analysis. By using a consistent source apportionment tool for all datasets, the study enhances the comparability of PM10 SA results across urban Europe. The results identified seven major PM10 sources including road traffic, biomass burning, crustal/mineral sources, secondary aerosols, industrial emissions, sea salt, and heavy oil combustion (HOC). Road traffic emerged as the predominant source of PM10 in urban areas, with contributions varying by location, but representing as much as 41

Airborne fine particulate matter (PM2.5) has been linked to neurological diseases, but its cellular and metabolic effects remain incompletely understood. This study assessed the cytotoxic and metabolic impact of PM2.5 samples from São Paulo, Brazil, on SH-SY5Y neuroblastoma cells. Even at low toxicity levels (IC10-IC30), PM2.5 organic extracts induced apoptosis, increased TNF-α secretion, and triggered moderate oxidative responses. Metabolomic analyses revealed a downregulation of energy-producing pathways, including glycolysis and the TCA cycle, along with decreased ATP and phosphocreatine levels. Compensatory adaptations were evident, such as increased proline oxidation, lipid accumulation, and activation of the creatine-phosphocreatine system. One-carbon metabolism was also affected, with changes suggesting suppression of the folate and methionine cycles. Elevated glutathione levels indicated an enhanced antioxidant response. These findings highlight how PM2.5 disrupts neuronal energy homeostasis and redox balance, offering new insights into the cellular mechanisms of air pollution-related neurotoxicity.

This exploratory pilot study examines the potential impact of indoor environmental exposures on sleep quality, with a particular focus on a comprehensive characterization of indoor air quality (IAQ) parameters and their association with sleep architecture assessed through polysomnography. The study was conducted during the cold seasons of 2016 and 2017 with a small sample of 10 subjects from the urban area of Lisbon, Portugal. Polysomnography was performed over two consecutive weeknights, while IAQ monitoring took place over three consecutive nights using typical real-time instruments. Additionally, bioburden was assessed in each bedroom before and after the sleep period using active methods. The analysis was based on correlations between the environmental parameters and the sleep data from these 10 subjects. Parametric and non-parametric statistics were employed to examine potential associations, with a significance level set at alpha = 0.05. The findings showed that higher bedroom temperatures during sleep were associated with a decrease in REM sleep. Both minimum and mean heart rates (HR) increased with higher levels of CO and CO2, while post-sleep bacteria levels were linked to a decrease in maximum HR. Fungal levels in the bedrooms were associated with a reduction in NREM2, and higher formaldehyde exposure was found to increase REM sleep latency. Exposure to PM2.5 negatively impacted NREM1, RDI, and snoring, while PM10 levels were negatively correlated with WASO and RDI. Although these findings provide a preliminary baseline, they are based on a small sample and may not be representative, highlighting the need for future studies to confirm the effects of various IAQ parameters on sleep quality in a larger and more diverse population.

An unprecedented study was carried out in the megacity of Luanda, Angola, involving daily sampling of particulate matter (PM10) from June to November 2023. The analysis was focused on the detection of 56 metal(loid)s and complemented by the application of several contamination and health risk indices. PM10 levels ranged from 23.6 to 108 μg/m3, averaging 59.3 μg/m3, exceeding WHO's 24-h guideline on 83% of days. In addition to crustal elements, the most abundant constituents were Zn (159 ng/m3), Ba (43.2 ng/m3), Pb (17.8 ng/m3), Cu (10.5 ng/m3), Sr (7.0 ng/m3), Ni (4.5 ng/m3), Sb (3.7 ng/m3) and Cr (3.5 ng/m3). Mineral dust, primarily from unpaved roads and local soils, accounted for 31 wt% of PM10, while sea salt contributed 6%. Geochemical markers (e.g., Ce-La-V relationships) suggest that vanadium originates predominantly from upper crust weathering. Elemental ratios such as Fe/Cu, Cu/Sb, and Zn/Sb indicate significant contributions from traffic-related emissions (e.g., brake and tyre wear) and industrial sources. Sulphur, an important PM10 component, likely stems from fossil fuel combustion and petroleum refining. Luanda experiences severe air pollution, with high inputs from Sb, Cd, Zn, and other elements linked to traffic, industrial emissions, and biomass burning. The extremely high ecological risk (RI = 4360 ± 2440) highlights critical contamination, driven primarily by Cd and Sb, while the Nemerow risk index (1990 ± 1530) underscores urgent public health concerns. Non-cancer hazard indices (HI) exceeded safe thresholds for children (2.29) and adults (2.18), with Fe, Mn, Be, Pb, Ni, Co, and Sb identified as key contributors. Carcinogenic risks from PM10 inhalation (2.34 × 10-3 for children and 1.36 × 10-3 for adults) also exceeded acceptable levels, emphasising the need for targeted pollution mitigation strategies.

In this study, indoor air quality was assessed in a store belonging to one of Portugal's largest commercial retail groups. A variety of methodologies was used, including gravimetric analysis for particulate matter (PM), optical monitors for real-time PM measurements, gas sensors and analysers for CO2 and other gaseous pollutants, diffusion tubes for VOCs, and passive deposition for microorganisms. The average PM10 concentration indoors was 16.5 +/- 3.87 mu g/m3, well below the exposure limits set by various international organisations. A significant portion of indoor PM10 - 69%- was originated from outdoor sources. Outdoor PM10 concentrations were substantially higher, averaging 29.4 +/- 14.6 mu g/m3. Metal concentrations were also higher outdoors than indoors, and the associated cancer risk and hazard quotient were not exceeded, indicating favourable air quality conditions within the store. Among VOCs, alpha-pinene and tetrachloroethylene were detected in notable concentrations. alpha-Pinene likely originated from cleaning products and fragrances, while tetrachloroethylene was attributed to emissions from a dry-cleaning establishment located in the same building, but did not exceed protection thresholds. Microbial analysis showed low concentrations of both fungi and bacteria. However, fungal species with clinical and toxigenic potential were found. The most common fungal species were Trichoderma sp. and Penicillium sp., depending on the culture media. Overall, the clothing store demonstrated good air quality. However, to further reduce the impact of outdoor pollutants on indoor air quality, enhancements to the ventilation system are recommended. These improvements can help create a healthier indoor environment by filtering and managing the intake of external contaminants more effectively.

Indoor and outdoor air pollution is related to adverse human health effects, especially in children due to their ongoing physical development. This study assesses airborne microplastics (MP) concentrations and associated inhalation risks in a school in Estarreja, Portugal, near a large industrial complex producing polyvinylchloride (PVC). PM10 samples were collected over two campaigns (winter and spring) in four classrooms (ages 3-11 years) and adjacent outdoor areas. Airborne MP were determined by pyrolysis-gas chromatography coupled to Orbitrap-mass spectrometry (Pyr-GC-Orbitrap-MS) targeting ten common polymers. Six polymers, including polymethyl methacrylate, nylon-6,6, polypropylene, nitrile butadiene rubber, polyvinyl chloride and polystyrene were identified. Indoor MP average concentrations (21.8 ± 16.3 ng/m3, n = 35) were significantly higher than outdoor levels (13.4 ± 13.6 ng/m3, n = 36). Seasonal differences were observed, with higher MP concentrations in spring compared to winter. Based on the concentrations detected indoors, the daily inhalation dose was evaluated and revealed a median daily exposure to MP in children of 1.57 ± 0.93 ng kg bw-1 d-1. Additionally, a non-targeted chemometric method using Regions of Interest-Multivariate Curve Resolution-Alternating least squares (ROIMCR) identified co-occurring pollutants such as phthalates, pesticides, and nicotine. This is the first study to apply Pyr-GC-Orbitrap-MS combined with ROIMCR for simultaneous targeted and untargeted analysis of airborne MP in a school setting. The findings reveal continuous exposure of children to a complex mixture of MP and hazardous additives, emphasizing the need to include these compounds in indoor air quality assessments and to protect sensitive populations in educational environments.

University cafeterias are popular spaces where students and staff can have quick meals and snacks, socialise and relax. Despite their frequent use, the health impacts of airborne particles in these environments remain unexplored. This study aimed to evaluate the mutagenicity and the potential toxicological effects of PM10 in a university cafeteria using human alveolar epithelial cells (A549). PM10 samples were collected both indoors, during periods of activity and when unoccupied (background air), and outdoors. The MTT assay was used to assess the metabolic activity of A549 cells following PM10 exposure, while flow cytometry was used to evaluate the intracellular reactive oxygen species (ROS) levels and disruptions in cell cycle dynamics. Additionally, the Ames test was performed to determine the mutagenic activity of PM10-bound polycyclic aromatic hydrocarbon (PAH) extracts using the Salmonella typhimurium TA98 with and without metabolic activation. The findings revealed a significant decrease in A549 metabolic activity, particularly with PM10 extracts collected indoors during occupancy. Elevated ROS levels and cell cycle arrest in the G0/G1 phase were observed for these indoor samples. Moreover, the concentration of specific organic compounds detected in the PM10 extracts were significantly correlated with the observed biological effects. None of the PAH extracts tested showed mutagenic effects, both with and without metabolic activation. These findings suggest that PM10 exposure in cafeterias, particularly during occupancy, may cause oxidative stress and disrupt cell cycle dynamics, highlighting potential health risks. While no mutagenic effects were detected, further research is needed to explore long-term impacts and develop strategies to enhance indoor air quality in these environments.

Atmospheric particulate matter (PM), as a leading part of air pollution, affects health in many ways. Thus, identifying and quantifying the contribution of atmospheric particulate matter sources of PM is vital for developing effective air quality management strategies. Positive Matrix Factorization (PMF) is one of the most common methods for source apportionment. However, PMF has some limitations, particularly its assumption that each source contributes linearly. In reality, some sources may exhibit nonlinear behaviors, which can compromise the accuracy of source apportionment. This study introduces a Lung Performance Optimization-based XGBoost (LPO-XGBoost) model, which leverages adaptive optimization principles inspired by lung function to enhance classic PM source apportionment. We demonstrate the potential for efficient, real-time application of the LPO-XGBoost model across 21 monitoring sites in 6 European countries. Trained and validated on extensive environmental datasets, the model is capable of predicting major pollution sources, including road traffic, biomass burning, crustal, industrial, nitrate-rich particles, sulfate-rich particles, heavy fuel oil, and sea salt. It outperforms other machine learning models with an overall predictive coefficient of determination (r2 = 0.88). Notably, the model performs exceptionally well in predicting sources such as sea salt (r2 = 0.97) and biomass burning (r2 = 0.89), but shows lower accuracy for the sulfate-rich particles source (r2 = 0.75). Comparative analyses with models including Random Forest (RF), Support Vector Machine (SVM), and their LPO-enhanced variants confirm that LPO-XGBoost provides the most reliable performance in estimating pollution source contributions, offering scalability and robustness ideal for high-time-resolution observational data. This model has significant potential to support targeted air quality management strategies. Future research should focus on expanding key species measurements at monitoring sites, ensuring consistent temporal coverage, and optimizing the model for improved mixed-source predictions to strengthen its applicability in comprehensive urban air quality assessments.

Indoor air quality is crucial for human health due to the significant time people spend at home, and it is mainly affected by internal sources such as solid fuel combustion for heating. This study investigated the indoor air quality and health implications associated with residential coal burning covering gaseous pollutants (CO, CO2 and total volatile organic compounds), particulate matter, and toxicity. The PM10 chemical composition was obtained by ICP-MS/OES (elements), ion chromatography (water-soluble ions) and thermal-optical analysis (organic and elemental carbon). During coal combustion, PM10 levels were higher (up to 8.8 times) than background levels and the indoor-to-outdoor ratios were, on average, greater than unity, confirming the existence of a significant indoor source. The chemical characterisation of PM10 revealed increased concentrations of organic carbon and elemental carbon during coal combustion as well as arsenic, cadmium and lead. Carcinogenic risks associated with exposure to arsenic exceeded safety thresholds. Indoor air quality fluctuated during the study, with varying toxicity levels assessed using the Aliivibrio fischeri bioluminescence inhibition assay. These findings underscore the importance of mitigating indoor air pollution associated with coal burning and highlight the potential health risks from long-term exposure. Effective interventions are needed to improve indoor air quality and reduce health risks in coal-burning households.

An air quality monitoring campaign for gaseous pollutants using passive sampling techniques was carried out, for the first time, at 25 locations in the metropolitan area of Luanda, Angola, in June 2023. Concentrations of benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes, SO2 and NO2 were generally higher in locations more impacted by traffic. Benzene, SO2 and NO2 levels did not exceed the World Health Organisation guidelines. Ozone concentrations surpassed those documented for other African regions. Higher O3 formation potential values were recorded at heavy-trafficked roads. The top 5 species with potential for ozone formation were m,p-xylene, toluene, formaldehyde, propionaldehyde and butyraldehyde. The Mulenvos landfill presented a distinctive behaviour with a very low toluene/benzene ratio (0.47), while values close to 5 were obtained at traffic sites. The maximum levels of α-pinene, D-limonene, formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, butyraldehyde, benzaldehyde, valeraldehyde, hexaldehyde and crotonaldehyde were recorded at the landfill. The formaldehyde/acetaldehyde ratio ranged from 0.40 at the Mulenvos landfill to 3.0, averaging 1.8, which is a typical value for urban atmospheres. Acetaldehyde/propionaldehyde ratios around 0.4-0.6 were found in locations heavily impacted by traffic, whereas values between 0.7 and 1.2 were observed in green residential areas and in places with more rural characteristics. All hazard quotient (HQ) values were in the range from 1 to 10, indicating moderate risk of developing non-cancer diseases. The exception was the Mulenvos landfill for which a HQ of 11 was obtained (high risk). The cancer risks exceeded the tolerable level of 1 × 10-4, with special concern for the landfill and sites most impacted by traffic. A mean lifetime cancer risk of 9 × 10-4 was obtained. The cancer risk was mainly due to naphthalene, which accounted, on average, for 94.6% of the total.

Five-stage Sioutas impactors were used to collect particulate matter (PM) in 4 classrooms and the playground of a school with various educational levels near the largest industrial chemical complex in Portugal. Monitoring was carried out over a total period of 8 weeks split equally between winter and spring. Samples were analysed for its elemental composition by PIXE. The prevalence of respiratory symptoms in schoolchildren was assessed by applying the International Study of Asthma and Allergies in Childhood (ISAAC) standardised questionnaire. The mass concentration of quasi-ultrafine particles (PM0.25) 0.25 ) was higher in winter, but lower than those reported in other studies. Elements accounted for 15.3-17.3 % and 25.6-34.1 % of the total PM10 10 mass in winter and spring, respectively. Elements such as K, S, Zn, Cu and Br presented a dominant mode in PM 0.25 , while Al, Mg, Ca, Fe and Si peaked at 2.5 mu m. Throughout the campaign, Cl was the main component of the mass of PM greater than 0.5 mu m in the schoolyard, while in classrooms Ca constituted the most abundant element of PM 2.5-10 . The results indicate that soil dust, cleaning products, biomass burning, traffic, the chemical complex and railway affected PM levels at the school. Taking paracetamol and living near roads with intense traffic of heavy vehicles were found to be statistically significant predictors of asthma symptoms, while the frequent consumption of antibiotics and children exposure to parental smoking during the first year of their life were found to increase the odds of developing symptoms of rhinitis.

Gaseous and PM10 10 samples were collected during the open burning of pruning residues (olive branches and garden waste) and characterised by distinct analytical techniques to obtain comprehensive chemical emission profiles. Oxidative potential (dithiothreoitol and ascorbic acid assays) and cell viability tests were also performed with the aim of evaluating aerosol toxicity. Emission factors (EFs) were as follows (g kg(-1) biofuel, dry basis): 1537-1672 for CO2, 2 , 41.9-80 for CO, 2.74-6.6 for CH4, 4 , 0.89-3.51 for ethane, 0.79-1.78 for ethylene and 0.56-3.47 for formaldehyde. Emissions of PM10, 10 , organic carbon (OC) and elemental carbon (EC) were in the ranges 8-41, 3-18, and 0.4-1.5 g kg(-1) biofuel, dry basis, respectively. OC accounted for 35-45% of the total PM10 10 mass, while EC contributed between around 3% and 5%. WSOC/OC ratios varied from 0.4 to 0.6, revealing that a substantial portion of the carbon emitted was hydrosoluble. Water soluble ions constituted around 8-21% of the PM10 10 mass, with potassium and chloride as the most abundant ions in all samples. Levoglucosan, widely used a reliable biomass burning tracer, was found in significant amounts in all samples (up to 1.2% of the PM10 10 mass). Retene, generally pointed out as a biomass combustion biomarker, was the predominant PAH. WSOC and some PAHs showed significant positive correlations with the intrinsic OP measured with the DTT assay, while the OPAA AA was significantly correlated with some trace metals, such as Fe or Ni. All samples significantly reduced the viability of alveolar epithelial cells.