Toxicological Effects of Fine Particulate Matter (PM2.5): Health Risks and Associated Systemic Injuries-Systematic Review

Sources and characterisation of organic pollutants in airborne particle fractions in an urban area, Bab Ezzaour, Algeria: A focus on n-alkanes and polar substances

The main objective of this study was to determine the loads, sources and behaviour of n-alkanes and several polar organics, including plasticisers (phthalates, [bis]2-ethylhexyl adipate), psychotropic substances (both legal and illegal) and the mosquito repellent DEET, in the atmosphere of the city of Bab Ezzouar, northern Algeria. Particulate matter was classified into three fractions according to aerodynamic diameter: coarse (PM10-2.5), fine (PM2.5-1) and ultrafine (PM1-0.01) particles. s. Particulate samples were collected from the atmosphere using a high-volume sampler (HVS), and target compounds were characterised using gas chromatography coupled with mass spectrometry detection (GC-MS) over a one-year period (January 2018 to January 2019). In detail, 41 organic compounds were analysed. The total content of n-alkanes, considering the three particle size fractions, was found to be 43.8 ± 18.0 ng/m3, while the phthalate reached 27.4 ± 13.6 ng/m3. The incremental risk to human health was assessed using a model in accordance with USEPA guidelines. The results indicate that the carcinogenic risk for BBP and DEHP were 1.49 × 10-10 and 7.72 × 10-8, respectively. The study of psychotropic substances revealed the occurrence of significant concentrations of nicotine and caffeine (up to tens of ng/m3), accompanied by cotinine and cannabinol. According to principal component analysis and three molecular indices (i.e. carbon preference index [CPI], carbon number of n-alkane maximum concentration [Cmax] and natural wax percentage [NW%]), PVC combustion and vehicle exhaust were the main sources of organic pollutants associated with airborne particles at Bab Ezzouar. Tabacco smoke and biogenic emissions (microorganisms/bacteria and high vegetation) contribute less to the formation of organic contaminants, although they cannot be ignored.

Region-specific characterization and ecotoxicity assessment of PAH compounds in winter PM2.5 from three capital cities in Northeast Asia

Industrialization and urbanization in Northeast Asia have heightened PM2.5 pollution, posing significant public health risks. This study examined the spatial and chemical variability of polycyclic aromatic hydrocarbons (PAHs) and their ecotoxicity in winter PM2.5 from three capitals-Ulaanbaatar (UB, Mongolia), Beijing (BJ, China), and Seoul (SE, South Korea)-using two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOF MS). PM2.5 samples collected between December 15, 2020 and January 14, 2021 revealed UB had the highest concentrations (85.7 ± 36.7 μg m-3) and PAH levels (758.9 ± 224.7 ng m-3), primarily from coal combustion and biomass burning. BJ (30.3 ± 16.9 μg m-3; 41.4 ± 18.4 ng m-3) and SE (26.0 ± 14.4 μg m-3; 6.2 ± 2.4 ng m-3) had lower PAH levels but a higher share of secondary products, including oxygenated (OPAHs) and nitrogen-containing PAHs (NPAHs). Overall, 646 PAH compounds were identified: UB was dominated by methylated alkyl and sulfur-containing PAHs, while BJ and SE had more hydroxylated and carbonylated PAHs. QSAR ecotoxicity analysis indicated the highest toxicity in SE from hydroxylated PAHs and a broader toxic range in UB. These findings support air quality strategies to reduce coal combustion in UB and secondary PAH formation in BJ and SE.

Renewable energy reduces domestic depression but increases depression for neighboring countries: evidence of spatial effects from 181 countries worldwide

BACKGROUND

Depression poses a significant global public health challenge, affecting millions of people worldwide. The utilization of renewable energy holds potential for improving mental health by reducing air pollution and promoting green spaces.

PURPOSE

This study aims to investigate the impact of renewable energy use on depression, with a focus on its spatial effects and the mediating roles of air pollution reduction and green space expansion.

METHODS

Data from 181 countries were analyzed using a two-way fixed effects model and the Spatial Durbin Model (SDM). Depression-related metrics, including Disability-Adjusted Life Years (DALYs), Age-Standardized Disability-Adjusted Life Years Rate (ASDR), prevalence, and Age-Standardized Prevalence Rate (ASPR), were evaluated.

RESULTS

Renewable energy use significantly reduces DALYs, ASDR, prevalence, and ASPR within a country, but it also significantly increases the risk of depression in neighboring countries. The impact of renewable energy on depression varies by gender, age, and SDI level, being more pronounced for males and the 50-74 age group. The effect is significant in high and low SDI countries but not in middle SDI countries, indicating a "middle-income trap."

CONCLUSION

Renewable energy can improve mental health by reducing air pollution and promoting green spaces. However, policymakers need to consider spatial effects and tailor policies accordingly to maximize health benefits.

κ-Carrageenan from Grateloupia filicina protects against PM2.5-induced intraocular pressure elevation

This study investigates the efficacy of GFP01, an almost pure κ-carrageenan derived from Grateloupia filicina, in counteracting intraocular pressure (IOP) elevation induced by PM2.5 exposure. GFP01, characterized by a molecular weight of 97.8 kDa, exhibits a linear backbone composed of 4-O-sulfated-β-D-galactose and 3,6-anhydro-α-D-galactose. In a murine model subjected to PM2.5-induced high IOP, GFP01 treatment significantly mitigated IOP compared to the PM2.5 group (n = 12, p < 0.01). In vitro assays revealed a 27.7 % increase in cell viability in human trabecular meshwork cells (HTMCs) treated with GFP01 compared to controls exposed to PM2.5 (p < 0.001, n = 5 cell lines). Additionally, GFP01 decreased PM2.5-induced transendothelial electrical resistance (TEER) of angular aqueous plexus (AAP) cells by 35.8 % at 48 h post-treatment (p < 0.05, n = 3 cell lines). Western blot analysis further demonstrated GFP01's role in inhibiting NLRP3/caspase-1/GSDMD/IL-1β axis in ocular tissues and HTMCs. Cytotoxicity assessment and slit-lamp imaging confirmed the safety of GFP01. In conclusion, GFP01 demonstrates a significant protective effect against PM2.5-induced IOP elevation, making it a promising therapeutic candidate for clinical applications.

Optimizing microgreen cultivation through post-crosslinked alginate-gellan gum hydrogel substrates with enhanced porosity and structural integrity

Hydrogels present a promising alternative to soil and traditional hydroponic substrates for indoor and space farming due to their high water retention capacity, non-toxicity, biodegradability, and capacity to fix microgreen seeds in place. However, conventional hydrogels typically suffer from poor porosity in their native state and often experience mechanical instability, which leads to the collapse of critical porous networks necessary for root zone oxygenation. To address these challenges, we developed a hydrogel-based growth substrate from alginate and gellan gum, using a sequential process involving directional freezing, lyophilization, and post-crosslinking in a CaCl2 solution. The as-prepared substrate retained the porous architecture upon rehydration as evidenced by SEM and Micro-CT imaging, as well as a 14-fold increase in the median pore diameter compared to pre-crosslinked control at hydrated state. The post-crosslinked hydrogels also exhibited superior mechanical stability, with an average compression stress of 6.08 kPa compared to 3.35 kPa for the control. In a growth study using Brassica juncea microgreens, the as-prepared hydrogel sustained a 12-day growth cycle without additional watering, achieving similar germination rates and fresh weights to regularly hydrated rockwool. Notably, the hydrogels treated with slow freezing and crosslinked in 5 % CaCl2 solution yielded higher fresh weight of harvested microgreens than those prepared under other conditions. This work presents a simple and effective approach to developing a plant growth substrate with significant potential for low-maintenance crop production in future space exploration missions.

What are the consequences of PM air pollution exposure on elderly behavior? A systematic review

Environmental pollution poses a significant risk to human health. Particulate matter (PM) found in polluted air is particularly of concern due to its ability to penetrate the blood-brain barrier (BBB) and impact the central nervous system (CNS), affecting sensory, cognitive, and emotional well-being. The aim of this review is to provide a comprehensive overview on the latest evidence regarding the association between PM exposure and behavioral outcomes in adult and older populations. Searches were conducted across PubMed, Web of Science, and Scopus up to August 2023, with articles selected and screened following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 27 articles meeting the criteria were included, and their risk of bias was evaluated using the Newcastle Ottawa Scale. The studies primarily focused on PM2.5 and PM10 in regions such as Europe, the USA, and Asia. While data on the impact of PM exposure on sensory variables were limited, suggesting an adverse effect, overall findings indicated a link between PM exposure and worsened cognitive function, increased risk of dementia, depressive symptoms, and anxiety. Some studies highlighted sex-dependent effects of PM exposure, with women experiencing a higher prevalence of adverse effects. This review underscores the importance of further research to understand the specific cognitive aspects affected by PM exposure, particularly in relation to dementia risk.

The spatio-temporal distribution characteristics and influencing factors of airborne microbial components in ambient PM2.5 within a city scale

PM2.5-carried microorganisms, widely dispersed in the atmosphere, have garnered significant attention for their potential health impacts. However, the impact of spatio-temporal variations on bioaerosol distribution remains unclear. In this study, we collected PM2.5 samples across all seasons from industrial, urban, and rural areas of Nanjing, a Chinese megacity, and analyzed the spatio-temporal distribution of microorganisms and their influencing factors. Results revealed significant spatio-temporal variations in microbial diversity and abundance. Bacterial diversity and abundance were higher in autumn and winter, with notable seasonal differences in industrial and rural areas. Fungi exhibited regional variations, with higher diversity and abundance in industrial areas during spring and autumn, and peak abundance in urban and rural areas in winter. Additionally, key genera responded variably to spatio-temporal changes. Broadly adapted genera, such as Achromobacter (bacterium) and Cladosporium (fungus) remained stable across seasons, while taxa like Chloroplast and Epicoccum showed significant abundance fluctuations with environmental changes. Multifactorial analyses revealed bacterial communities were primarily influenced by temperature, wind speed, and air quality index (AQI), while fungi were also significantly impacted by humidity and population density. Correlation network analyses linked metals, carbon and nitrogen contents in PM2.5 to microbial abundance. Most bacterial genera were negatively correlated with chemical constituents, while fungi were more adaptive to these constituents and were positively correlated. This study offers insights into the spatio-temporal distribution of PM2.5 microbial components and the influence of environmental factors and aerosol chemistry on microbial communities, highlighting implications for air quality and pollution management in public health.

Exploration of the impact of air pollutants on the influenza epidemic after the emergence of COVID-19: based on Jiangsu Province, China (2020-2024)

Background

Non-pharmaceutical interventions (NPIs) during the COVID-19 pandemic altered influenza transmission patterns, yet the age-specific effects of air pollutants on influenza dynamics remain unclear.

Methods

Utilizing influenza surveillance data of Jiangsu Province from 2020 to 2024, we integrated generalized additive quasi-Poisson regression model and distributed lag non-linear models (DLNM) to quantify lagged effects and exposure-response relationships between air pollutants (NO2, SO2, PM2.5) and influenza risk across young, middle-aged, and older adult groups. Meteorological factors, including temperature and humidity, as well as the implementation stages of NPIs, were controlled in the model to isolate the impact of pollutants on influenza transmission.

Results

The NO2 and SO2 both showed significant positive effects in all age groups. The effect of NO2 is most significant in the young group (RR = 5.02, 95% CI: 4.69-5.37), while SO2 exhibited the most pronounced effects in middle-aged and older adult groups (RR = 4.22, 95% CI: 3.36-5.30; RR = 8.31, 95% CI: 5.77-11.96, respectively). PM2.5 elevated risks in young (RR = 1.99, 95% CI: 1.87-2.12) and older adult (RR = 1.45, 95% CI: 1.07-1.94) groups. Interactions between meteorological factors (temperature, humidity) and pollutants were statistically insignificant.

Conclusions

Air pollutant impacts on influenza transmission are age-dependent: NO2 dominates in younger populations, whereas SO2 disproportionately affects older adults. These findings highlight age-related vulnerability to air pollution and the need for targeted public health strategies for different population subgroups.

Pregnancy as a Susceptible Period to Ambient Air Pollution Exposure on the Maternal Postpartum Metabolome

Pregnancy is a potential critical window to air pollution exposure for long-term maternal metabolic effects. However, little is known about potential early metabolic mechanisms linking air pollution to maternal metabolic health. We included 544 pregnant Mexican women with both ambient PM2.5 levels during pregnancy and untargeted serum metabolomics to examine associations between pregnancy PM2.5 exposure (overall and monthly) and postpartum metabolites, implementing FDR-adjusted robust linear regression controlling for covariates. Pathway enrichment analyses (in Reactome and MetaboAnalyst) and effect modification by fetal sex and folic acid supplementation were also evaluated. Higher PM2.5 exposure levels throughout pregnancy were associated with higher bile acids and amino acids, dysregulated glycerophospholipids, or lower fatty acyl levels (FDR < 0.05), among other metabolites. Potential critical windows of susceptibility to monthly PM2.5 on metabolites were observed in early to midpregnancy (FDR < 0.005). Main findings were consistent by strata of fetal sex and folic acid supplementation. Metabolic pathways corresponding to positive PM2.5-metabolite associations indicated enriched bile acid, dietary lipid, and transmembrane transport metabolism, whereas for negative PM2.5-metabolite associations, we identified altered pathways involving adipogenesis, incretin peptide hormone, GLP-1, PPAR-alpha, and fatty acid receptors (FDR < 0.05). PM2.5 exposures during pregnancy, especially in early gestation, altered maternal postpartum lipids as well as amino acid metabolism.

Effects of chronic particulate matter exposure on endometriosis-associated signaling pathways and disease progression

Exposure to PM2.5 (particulate matter <2.5 μm) has been implicated in increasing the risk of endometriosis and worsening its symptoms. However, the molecular mechanisms and direct associations remain unclear. This study explored whether PM2.5 contributes to the onset or progression of endometriosis using in vitro and in vivo models. Endometrial (EM) cells from women without endometriosis were cultured to the second passages (P2) with or without exposure to PM2.5 at a concentration of 200 µg/ml (N = 5 for each group). Z-stack confocal imaging confirmed PM accumulation in the nucleus and cytoplasm of exposed EM cells. Initial PM exposure at the primary passage (P0) led to decreased proliferation, migration, anti-apoptosis, and oxidative stress, accompanied by downregulation of associated pathways. However, repeated PM exposure during subculturing to P2 led to increased proliferation, enhanced anti-apoptotic activity, and elevated oxidative stress. Given the similarity of these gene expression alterations to those observed in endometriosis, an endometriosis-induced mouse model was established to assess the potential of repeated PM exposure to exacerbate the condition in vivo. To investigate the in vivo effects, an endometriosis-induced mouse model was developed using female C57BL/6 mice exposed to low (10 mg/kg/day) or high (20 mg/kg/day) doses of PM2.5 for 4 weeks (n = 6 for each group). PM exposure significantly enlarged endometriotic lesions compared to controls (no PM exposure). Upregulated gene expression in endometriotic lesions included anti-apoptotic (Bcl2/Bax), proliferative (p-ERK), inflammatory (p-NF-κB, p-c-jun, IL-6, IL-1β), and migration (MMP-2, MMP-9) markers. PM exposure altered estrogen receptor (ER) expression, resulting in a decreased ERα/ERβ ratio in both dose groups. The control group exhibited a ratio of 1.03 ± 0.09, while the low-dose and high-dose mice had ratios of 0.57 ± 0.08 (P = 0.02) and 0.46 ± 0.26 (P = 0.03), respectively. In conclusion, PM2.5 exposure alters gene expression related to cell growth, survival, oxidative stress, and migration in EM cells and exacerbates endometriotic lesions in vivo, likely through ER modulation. These findings suggest PM2.5 may contribute to other estrogen-dependent conditions, such as leiomyoma or adenomyosis, by influencing ER pathways.

Tagetes erecta Linn flower extract inhibits particulate matter 2.5-promoted epithelial-mesenchymal transition by attenuating reactive oxygen species generation in human retinal pigment epithelial ARPE-19 cells

BACKGROUND/OBJECTIVES

Particulate matter 2.5 (PM2.5) exposure can promote epithelial-mesenchymal transition (EMT) in human retinal pigment epithelial (RPE) cells. The flowers of Tagetes erecta Linn, commonly known as marigold, are rich in diverse flavonoids and carotenoids and play a significant role in preventing cellular damage induced by oxidative stress, but the role of their extracts in RPE cells has not been reported. This study aimed to evaluate the influence of an ethanol extract of T. erecta Linn flower (TE) on PM2.5-induced EMT processes in RPE ARPE-19 cells.

MATERIALS/METHODS

To investigate the protective effect of TE against ARPE-19 cell damage following PM2.5 treatment, cells were exposed to TE for 1 h before exposure to PM2.5 for 24 h. We investigated whether the efficacy of TE on suppressing PM2.5-induced EMT was related to antioxidant activity and the effect on the expression changes of factors involved in EMT regulation. Additionally, we further explored the role of intracellular signaling pathways associated with EMT inhibition.

RESULTS

TE significantly blocked PM2.5-induced cytotoxicity while effectively preventing mitochondrial dysfunction, increased reactive oxygen species (ROS) generation, and mitochondrial membrane potential disruption. TE inhibited PM2.5-induced EMT and inflammatory response by suppressing the ROS-mediated transforming growth factor-β/suppressor of mothers against decapentaplegic/mitogen-activated protein kinases signaling pathway.

CONCLUSION

Our results suggest that marigold extract is a highly effective in protection against PM2.5-induced eye damage.

Comparing UV and Diesel Cutaneous Damage and Evaluating the Protective Role of a Topical Antioxidant Mixture Containing Vitamin C, E and Ferulic Acid

Cutaneous tissue is one of the main targets of outdoor stressors, and nowadays, the effect of pollution on skin conditions and premature skin ageing has been well correlated, although the exact effect that different pollutants have on the skin has not been well defined, especially when compared to other stressors. Among the air pollutants, UV radiation and particulate matter (PM) have been found among the most aggressive in terms of skin damage, inducing oxinflammatory responses, promoting degradation of extracellular matrix (ECM) components, and compromising the cutaneous defensive barrier. Topical application of technologies able to prevent oxidative damage is still one of the best approaches to protect our skin, and considering the well-known antioxidant network, application of an antioxidant mixture is more recommended than a single compound. In the present study, human skin explants were exposed every day for 4 days to diesel particles (DEE) or to UV after the daily pre-treatment with a topical application of a commercially available antioxidant mixture (AOX Mix), containing 15% ascorbic acid, 0.5% ferulic acid and 1% tocopherol. Oxidative stress markers such as 4-hydroxynonenal, skin barrier proteins such as involucrin, filaggrin, claudin-1 and desmocollin-1, resilience markers such as elastin and tropoelastin, and the levels of Type I and Type III collagens were assessed. Topical application was able to prevent most of the damage induced by the outdoor stressors, confirming that daily protection is needed to prevent cutaneous premature ageing.

PM2.5 exposure deteriorates Th1/Th2 balance in pediatric asthma by downregulating ALKBH5 and enhancing SRSF1 m6A methylation

Accumulating evidence has shown that long-term exposure to particulate matter with aerodynamic diameter of less than 2.5 μm (PM2.5) causes Th1/Th2 imbalance and increases the risk of allergic asthma (AA) in children. However, the mechanism underlying such effect remains elusive. Here, an AA mouse model was developed by intranasal administration of ovalbumin (OVA) and uncovered that OVA-sensitized mice exhibited pathological damage of lung tissues, mucus production, augmented serum IgE levels, enhanced Th2 cells and associated cytokine levels, and diminished Th1 cells and associated cytokine levels. Meanwhile, OVA induction led to upregulation of SRSF1 in mice. Moreover, shRNA-mediated knockdown of SRSF1 suppressed AA and Th1/Th2 imbalance in OVA-sensitized mice. After PM2.5 exposure, AA and Th1/Th2 imbalance were exacerbated and SRSF1 expression was increased in OVA-sensitized mice. Mechanistic experiments demonstrated that PM2.5-mediated inhibition of ALKBH5 expression augmented SRSF1 m6A modification in human bronchial epithelial cells treated with house dust mite. In this process, the m6A-reading protein YTHDF1 bound to SRSF1 mRNA and increased its stability. Furthermore, ALKBH5 overexpression neutralized PM2.5-aggravated Th1/Th2 imbalance in OVA-sensitized mice. Altogether, PM2.5 fosters Th1/Th2 imbalance in pediatric asthma by increasing SRSF1 m6A methylation through ALKBH5 downregulation.

Spatiotemporal evolution of PM2.5 and its components and drivers in China, 2000-2023: effects of air pollution prevention and control actions in China

This study evaluated the Air Pollution Prevention and Control Action Plan (APPCAP) in China using 2000-2023 data. The average annual PM2.5 concentration dropped from 46.11 ± 16.18 µg/m3 to 31.75 ± 14.22 µg/m3 (P < 0.05) after APPCAP, with components showing a similar decline. Temporal analysis via Mann-Kendall test indicated a decreasing trend (Z < 0, P < 0.05), seasonally peaking in winter and lowest in summer. Spatially, APPCAP reduced concentration distribution, with key regions improving but areas like Shandong and Henan still facing severe pollution. The main PM2.5 driver shifted from human (e.g., population density) to meteorological (e.g., temperature) factors post-APPCAP, and anthropogenic influence varied across regions. In summary, APPCAP has curbed PM2.5 pollution, yet SO42-, NO3-, and NH4+ remain relatively high, and the increasing human impact in central and southeastern China demands attention in future policies.

Accelerated aging as a mediator of the association between co-exposure to multiple air pollutants and risk of chronic kidney disease

BACKGROUND

The association between co-exposure to multiple air pollutants and the occurrence of chronic kidney disease (CKD) was not well-established, and the mediating role of accelerated aging in this association remained uncertain.

METHODS

Using a cohort of 313,908 participants without CKD at baseline from the UK Biobank, we examined the potential association between co-exposure to multiple air pollutants, including PM2.5, PM10, PM2.5-10, NO2 and NOx, and the incidence of CKD by calculating an air pollution score. Mediation analyses were performed to examine the mediating role of accelerated aging (PhenoAgeAccel or KDM-BioAgeAccel) in this association.

RESULTS

During the median follow-up time of 12.9 years, 11,117 participants developed CKD. The results showed that per interquartile range (IQR) increment in air pollution score led to an approximately 9.0 % (6.6-11.4 %) elevated risk of occurring CKD. Compared to the first quartile (Q1) of air pollution score, those in the highest quartile (Q4) had a 21.2 % (14.8-27.9 %) higher risk of developing CKD (Ptrend<0.001). Mediation analyses suggested that PhenoAgeAccel and KDM-BioAgeAccel significantly mediated 1.5 % and 5.7 % of the association between air pollution score and incident CKD, respectively.

CONCLUSION

Co-exposure to multiple air pollutants could increase the risk of developing CKD, with accelerated aging serving as a partial mechanism in the relationship between air pollution and CKD. These findings highlight the importance of reducing air pollution, and suggest a possible mechanism from air pollution to CKD through accelerated aging.

Effects of particulate air pollution on BPDE-DNA adducts, telomere length, and mitochondrial DNA copy number in human exhaled breath condensate and BEAS-2B cells

Traffic-related particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) have been linked to respiratory diseases and cancer risk in humans. Genomic damage, including benzo[a]pyrene diolepoxide (BPDE)-DNA adducts as well as alterations in telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN) are associated with respiratory diseases. This study aimed to investigate the association between exposure to traffic-related particulate pollutants and genomic damage in exhaled breath condensate (EBC) in human subjects and a bronchial epithelial cell line (BEAS-2B). Among the 60 healthy recruited subjects, residents living in high-traffic-congested areas were exposed to higher concentrations of PM2.5 (1.66-fold, p < 0.01), UFPs (1.79-fold, p < 0.01), PM2.5-PAHs (1.50-fold, p < 0.01), and UFPs-PAHs (1.35-fold, p < 0.05), than those in low-traffic-congested areas. In line with increased exposure to particulate air pollution, the high-traffic-exposed group had significantly increased BPDE-DNA adducts (1.40-fold, p < 0.05), TL shortening (1.24-fold, p < 0.05), and lower mtDNA-CN (1.38-fold, p < 0.05) in EBC. The observations in the human study linking exposure to PM2.5, UFPs, PM2.5-PAHs, and UFPs-PAHs with the aforementioned biological effects were confirmed by an in vitro cell-based study, in which BEAS-2B cells were treated with diesel exhaust particulate matter (DEP) containing fine and ultrafine PM and PAHs. Increased BPDE-DNA adducts levels, shortened TL, and decreased mtDNA-CN were also found in treated BEAS-2B cells. The shortened TL and decreased mtDNA-CN were in part mediated by decreased transcript levels of hTERT, and SIRT1, which are involved in telomerase activity and mitochondrial biogenesis, respectively. These results suggest that exposure to traffic-related particulate pollutants can cause genomic instability in respiratory cells, which may increase the health risk of respiratory diseases and the development of cancer.

Role of AhR-Hsp90-MDM2-mediated VDR ubiquitination in PM2.5-induced renal toxicity

BACKGROUND AND OBJECTIVES

The kidney is a primary target for the accumulation of particulate matter (PM2.5). This study aimed to investigate PM2.5-induced renal toxicity mechanisms, focusing on the aryl hydrocarbon receptor (AhR)-Hsp90-MDM2 axis and its impact on vitamin D receptor (VDR) ubiquitination.

METHODS

PM2.5's role in activating the AhR and its downstream pathways was investigated using in vitro and in vivo models. Renal damage and therapeutic effects in PM2.5-exposed and paricalcitol-treated mice were evaluated using weight measurements, histopathology, and scanning electron microscopy. AhR, Hsp90, and VDR localization and expression in renal cells were assessed using FISH and Western blot. Protein interactions were examined using co-immunoprecipitation. Differentially expressed gene (DEG) analysis of GEO datasets was used to identify related proteins and genes.

RESULTS

PM2.5 exposure caused significant renal damage in mice, including increased serum creatinine, albuminuria, and histopathological deterioration, which were alleviated by paricalcitol. PM2.5 induced the nuclear translocation of AhR and Hsp90 and reduced nuclear VDR expression; paricalcitol reversed these effects. Immunohistochemistry confirmed these findings. PM2.5 upregulated the NLRP3/caspase-1/IL-1β/IL-18 axis, which was reversed by paricalcitol treatment. Inhibition of Hsp90 increased nuclear VDR expression through MDM2 mediation. DEG analysis identified VDR-regulated genes; PM2.5 increased the mRNA levels of IL-6, IL-2, and CXCL8, which were downregulated by Hsp90 and MDM2 inhibitors, with VDR agonists further decreasing these levels.

CONCLUSION

This study reveals a novel mechanism of PM2.5-induced renal toxicity through the AhR-Hsp90-MDM2 axis, promoting VDR ubiquitination and degradation and increasing inflammation. These findings provide a foundation for future studies and lay the groundwork for developing targeted interventions to mitigate the public health impact of PM2.5 exposure.

Effect of high-efficiency particulate air filter on children with asthma: a systematic review protocol of RCTs

INTRODUCTION

Asthma has been classified as a major non-communicable disease by the WHO. With the worsening air quality index worldwide, the burden of asthma has increased specifically in children. The focus of the management strategy of asthma has shifted from traditional pharmacological treatments towards non-pharmacological preventive and control therapy in recent decades. The use of high-efficiency particulate air (HEPA) filters is one of the methods to achieve that, despite extensive research, the efficacy of HEPA filters in this context of effectiveness and usage guidelines remains unclear. Our study aims to examine the effect of HEPA filters in (1) reducing clinical visits or hospital admissions or the number of exacerbation events, (2) reducing asthma symptoms, (3) increasing asthma symptom-free days, (4) reducing indoor particulate matter 2.5 levels for children with asthma aged 5-17 years and (5) improving quality of life.

METHODS

We will conduct a systematic review using MEDLINE, Google Scholar and Scopus as databases, article selection is planned to be restricted to randomised controlled trials only (2002-2025). We are following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines developed specifically for the protocol(s). Two reviewers will screen the studies independently and assess study quality using the Cochrane Risk of Bias Tool for Randomised Trials, V.2. The results of outcome measure(s) will be summarised in tables. If the studies are sufficient, we will also perform a quantitative analysis by creating forest plots and subgroup analysis will be performed if required. Lastly, publication bias will be assessed using a funnel plot and Egger's test and reported accordingly.

ETHICS AND DISSEMINATION

We will conduct a systematic review, therefore there is no need for a formal ethical review. After successful completion, our results will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CR42024494949.

Global Trends and Hotspots in the Research of the Effects of PM2.5 on Asthma: A Bibliometric and Visualized Analysis

BACKGROUND

Fine particulate matter (PM2.5) has been identified as a significant environmental and public health challenge, particularly due to its association with respiratory diseases like asthma. With the global rise in urbanization and industrialization, PM2.5-related asthma research has grown substantially over the past two decades. This study aims to provide a comprehensive bibliometric analysis to map global research trends, highlight key contributors, and identify emerging hotspots in the relationship between PM2.5 and asthma.

METHODS

We performed a bibliometric analysis using the Web of Science Core Collection database, covering research from January 2004 to September 2024. The selected studies were analyzed using CiteSpace and VOSviewer to assess publication trends, global collaborations, and research hotspots through visualized networks and co-occurrence analyses.

RESULTS

A total of 2035 publications were identified, demonstrating a steady increase in research output over the past two decades. The United States and China emerged as dominant contributors, frequently collaborating with countries like Canada, Australia, and South Korea. Key research areas focused on air quality, particulate matter exposure, and asthma exacerbation, with an increasing emphasis on indoor air pollution and long-term exposure risks. Institutional collaborations were led by prominent universities such as the University of California System and Harvard University. Additionally, research on vulnerable populations, particularly children, and the impact of early-life exposure to PM2.5 has gained attention in recent years.

CONCLUSIONS

The global research landscape on PM2.5 and asthma has expanded significantly, with growing attention to interdisciplinary approaches that combine environmental science and public health. Future studies should focus on the global burden of air pollution, particularly in low- and middle-income countries, and address the long-term health impacts of PM2.5 exposure, especially in vulnerable populations.

PM2.5-mediated cardiovascular disease in aging: Cardiometabolic risks, molecular mechanisms and potential interventions

Air pollution, particularly fine particulate matter (PM2.5) with <2.5 μm in diameter, is a major public health concern. Studies have consistently linked PM2.5 exposure to a heightened risk of cardiovascular diseases (CVDs) such as ischemic heart disease (IHD), heart failure (HF), and cardiac arrhythmias. Notably, individuals with pre-existing age-related cardiometabolic conditions appear more susceptible. However, the specific impact of PM2.5 on CVDs susceptibility in older adults remains unclear. Therefore, this review addresses this gap by discussing the factors that make the elderly more vulnerable to PM2.5-induced CVDs. Accordingly, we focused on physiological aging, increased susceptibility, cardiometabolic risk factors, CVDs, and biological mechanisms. This review concludes by examining potential interventions to reduce exposure and the adverse health effects of PM2.5 in the elderly population. The latter includes dietary modifications, medications, and exploration of the potential benefits of supplements. By comprehensively analyzing these factors, this review aims to provide a deeper understanding of the detrimental effects of PM2.5 on cardiovascular health in older adults. This knowledge can inform future research and guide strategies to protect vulnerable populations from the adverse effects of air pollution.

Review of in vitro studies evaluating respiratory toxicity of aerosols: impact of cell types, chemical composition, and atmospheric processing

In recent decades, several cell-based and acellular methods have been developed to evaluate ambient particulate matter (PM) toxicity. Although cell-based methods provide a more comprehensive assessment of PM toxicity, their results are difficult to comprehend due to the diversity in cellular endpoints, cell types, and assays and the interference of PM chemical components with some of the assays' techniques. In this review, we attempt to clarify some of these issues. We first discuss the morphological and immunological differences among various macrophage and epithelial cells, belonging to the respiratory systems of human and murine species, used in the in vitro studies evaluating PM toxicity. Then, we review the current state of knowledge on the role of different PM chemical components and the relevance of atmospheric processing and aging of aerosols in the respiratory toxicity of PM. Our review demonstrates the need to adopt more physiologically relevant cellular models such as epithelial (or endothelial) cells instead of macrophages for oxidative stress measurement. We suggest limiting macrophages for investigating other cellular responses (e.g., phagocytosis, inflammation, and DNA damage). Unlike monocultures (of macrophages and epithelial cells), which are generally used to study the direct effects of PM on a given cell type, the use of co-culture systems should be encouraged to investigate a more comprehensive effect of PM in the presence of other cells. Our review has identified two major groups of toxic PM chemical species from the existing literature, i.e., metals (Fe, Cu, Mn, Cr, Ni, and Zn) and organic compounds (PAHs, ketones, aliphatic and chlorinated hydrocarbons, and quinones). However, the relative toxicities of these species are still a matter of debate. Finally, the results of the existing studies investigating the effect of aging on PM toxicity are ambiguous, with varying results due to different cell types, different aging conditions, and the presence/absence of specific oxidants. More systematic studies are necessary to understand the role of different SOA precursors, interactions between different PM components, and aging conditions in the overall toxicity of PM. We anticipate that our review will guide future investigations by helping researchers choose appropriate cell models, resulting in a more meaningful interpretation of cell-based assays and thus ultimately leading to a better understanding of the health effects of PM exposure.

Quantifying the noncarcinogenic and carcinogenic risks resulting from the inhalation of PM2.5-bound metals: A multicity analysis and implications for public health

Toxic metals in PM2.5 represent a growing public health concern because of their potential health effects. Ambient PM2.5 samples were collected from five provinces around Bangkok from December 2020 to December 2021. The concentrations of PM2.5 and metals (arsenic, cadmium, chromium, cobalt, nickel, lead, and vanadium) were analyzed. The noncarcinogenic and carcinogenic risks were evaluated via Monte Carlo simulations in four age groups (0 to <6, 6 to <12, 12 to <18, 18-70 years), with a dataset comprising 2282 heavy metal assays within the particulate matter. Significantly higher PM2.5 concentrations were detected in provinces with higher factory densities, as well as higher concentrations during haze periods than during non-haze periods. The HI values for all age groups and provinces were lower than 1, indicating acceptable noncarcinogenic risks. The carcinogenic risks from PM2.5-bound metals varied between 7.08×10-7 and 4.29×10-6, indicating increased cancer risks, for preschool children and adults. Cancer risk was highest in industrial areas, followed by areas with dense traffic, and lowest in agricultural areas. The results indicated that Thailand's current air quality regulations, which primarily provide only lead limits, are insufficient considering the high carcinogenic potential of other metals. The Monte Carlo simulation results confirmed that lowering Thailand's 24-h PM2.5 standard from 37.5 to either 25 or 15 µg m-3, as specified in the 2021 World Health Organization guidelines, would decrease cancer risk by 9.63-43.18 %.

Spatial associations of daily PM2.5 concentration with cardiovascular and pulmonary morbidity in Korea

Air pollution, particularly fine particulate matter less than 2.5 μm in diameter (PM2.5), contributes to respiratory and cardiovascular diseases and poses significant public health risks worldwide. This study evaluated the short-term effects of PM2.5 on hospital admissions for cardiovascular and respiratory diseases, with additional analyses to identify vulnerable populations based on regional characteristics. The present study analyzed data from 249 Korean communities between 2006 and 2021. Data on daily hospital admissions for cardiovascular and respiratory diseases were obtained from the National Health Insurance Service. Data on PM2.5 concentrations were sourced from air quality modeling. Additional data on regional characteristics, including the regional deprivation index, proportion of elderly residents, education levels, and greenness levels, were also collected. We used case time series analysis to assess the associations between PM2.5 concentrations and hospital admissions for cardiovascular and respiratory diseases and explored effect modification by regional characteristics with stratified analyses. The mean numbers of daily cardiovascular admissions and respiratory admissions were 5.68 ± 5.46 and 6.46 ± 8.03, respectively. The mean PM2.5 concentrations were 23.58 ± 13.66 μg/m3. A10 μg/m³ increment in daily PM2.5 concentration was associated with increase of cardiovascular and respiratory hospitalization by 0.94% (95% CI: 0.84%, 1.04%) and 1.43% (95% CI: 1.34%, 1.52%), respectively. Regional characteristics analysis showed significant disparities, with higher risks for hospital admissions in areas with lower deprivation and low greenness. This study highlights the significant short-term health impacts of PM2.5 on respiratory and cardiovascular hospital admissions in Korean communities. The findings underscore the critical role of regional and demographic factors in modulating these effects, identifying socio-economic areas, age structure of the population, lower education levels, and low greenness as key vulnerability factors.

Glyphosate and other plant protection products in size-segregated urban aerosol: Occurrence and dimensional trend

Plant protection products (PPPs) play a fundamental role in the maintenance of agricultural fields and private/public green areas, however they can contaminate zones nearby the application point due to wind drift, resuspension, and evaporation. Several studied have deepened the relationship between PPPs and living beings' health, suggesting that these products might have a negative influence. Some PPPs belong to the class of Emergent Contaminants, which are compounds whose knowledge on the environmental distribution and influence is limited. These issues are even more stressed in urban aerosol, due to the high residential density that characterizes this area. Therefore, this study assessed the contamination caused by polar PPPs, such as herbicides (i.e., Glyphosate), fungicides (i.e., Fosetyl Aluminium), and growth regulators (i.e. Maleic Hydrazide), in size-segregated urban aerosol and evaluated their concentration variability with respect to atmospheric parameters (humidity, temperature, rain). Moreover, hypotheses on possible sources were formulated, exploiting also back-trajectories of air masses. A total of six PPPs were found in the samples: glyphosate was more present in the coarse fraction (2.5-10 μm), Fosetyl Aluminium, chlorate and perchlorate were more present in the coarse/fine fractions (10-1 μm), while cyanuric acid and phosphonic acid were mostly concentrated in the fine/ultrafine fractions (<1 μm). While for the first four we suspect of local sources, such as private gardening, the two latter might derive from the entire Po Valley, a highly polluted area in the North of Italy, and from degradation of other substances.

Particulate matter 2.5 accelerates aging: Exploring cellular senescence and age-related diseases

Exposure to Particulate matter 2.5 (PM2.5) accelerates aging, causing declines in tissue and organ function, and leading to diseases such as cardiovascular, neurodegenerative, and musculoskeletal disorders. PM2.5 is a major environmental pollutant and an exogenous pathogen in air pollution that is now recognized as an accelerator of human aging and a predisposing factor for several age-related diseases. In this paper, we seek to elucidate the mechanisms by which PM2.5 induces cellular senescence, such as genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, and mitochondrial dysfunction, and age-related diseases. Our goal is to increase awareness among researchers within the field of the toxicity of environmental pollutants and to advocate for personal and public health initiatives to curb their production and enhance population protection. Through these endeavors, we aim to promote longevity and health in older adults.

Single-cell RNA sequencing of estrual mice reveals PM2.5-induced uterine cell heterogeneity and reproductive toxicity

Fine particulate matter (PM2.5) exposure has been extensively linked to reproductive and developmental dysfunctions, yet the underlying mechanisms remain elusive. This study employed single-cell RNA sequencing (scRNA-seq) to investigate PM2.5-induced changes in uterine cell populations and gene expression profiles in mice during estrus and early pregnancy. Methodologically, we intranasally inoculated mice with 20 μL of 4.0 mg/mL PM2.5 suspension during their estrus and early pregnancy periods. Utilizing scRNA-seq analysis, we revealed significant alterations in cell type composition following PM2.5 exposure. Notably, we observed a marked decrease in the proportion of natural killer (NK) cells in PM2.5-exposed mice (2.00 % vs. 8.97 % in controls). Further functional enrichment analysis identified suppression of the IL-17 signaling pathway in NK cells as a key mechanism of PM2.5-induced toxicity. GSEA analysis showed in-depth details of the downregulated genes in this pathway, including Fosb, S100a8, Tnfaip3, IL-17a, and S100a9. PM2.5 exposure also disrupted intercellular communication within the uterine microenvironment, with the number of cell interactions decreasing from 483 to 315 and interaction strength reducing from 12.43 to 6.78 compared to controls. Histological examination revealed that PM2.5 exposure led to thinning of the endometrium and less prominent main branches in uterine tissues, and immunofluorescence assays corroborated the altered expression of IL-17 pathway components, showing enhanced Hsp90ab1 expression and reduced FOSB, S100A8, and S100A9 expression in PM2.5-exposed uterine tissues. These findings provide novel insights into the cellular mechanisms of PM2.5-induced reproductive toxicity, highlighting the IL-17 signaling pathway in uterine NK cells as a potential target for therapeutic interventions. Our results underscore the need for air quality regulations and open new avenues for developing biomarkers and targeted therapies to mitigate the reproductive risks associated with PM2.5 exposure.

Photobiomodulation Mitigates PM2.5-Exacerbated Pathologies in a Mouse Model of Allergic Asthma

Exposure to particulate matter (PM), especially PM2.5, is known to exacerbate asthma, posing a significant public health risk. This study investigated the asthma-reducing effects of photobiomodulation (PBM) in a mice model mimicking allergic airway inflammation exacerbated by PM2.5 exposure. The mice received sensitization with ovalbumin (OVA) and were subsequently treated with PM2.5 at a dose of 0.1 mg/kg every 3 days, for 9 times over 3 weeks during the challenge. PBM, using a 610 nm wavelength LED, was applied at 1.7 mW/cm2 to the respiratory tract via direct skin contact for 20 min daily for 19 days. Results showed that PBM significantly reduced airway hyperresponsiveness, plasma immunoglobulin E (IgE) and OVA-specific IgE, airway inflammation, T-helper type 2 cytokine, histamine and tryptase in bronchoalveolar lavage fluid (BALF), and goblet cell hyperplasia in PM2.5-exposed asthmatic mice. Moreover, PBM alleviated subepithelial fibrosis by reducing collagen deposition, airway smooth muscle mass, and expression of fibrosis-related genes. It mitigated reactive oxygen species generation, oxidative stress, endoplasmic reticulum stress, apoptotic cell death, ferroptosis, and modulated autophagic signals in the asthmatic mice exposed to PM2.5. These findings suggest that PBM could be a promising intervention for PM2.5-induced respiratory complications in patients with allergic asthma.

Short-term exposure to fine particulate matter exposure impairs innate immune and inflammatory responses to a pathogen stimulus: A functional study in the zebrafish model

Short-term exposure to fine particulate matter (PM2.5) is associated with the activation of adverse inflammatory responses, increasing the risk of developing acute respiratory diseases, such as those caused by pathogen infections. However, the functional mechanisms underlying this evidence remain unclear. In the present study, we generated a zebrafish model of short-term exposure to a specific PM2.5, collected in the northern metropolitan area of Milan, Italy. First, we assessed the immunomodulatory effects of short-term PM2.5 exposure and observed that it elicited pro-inflammatory effects by inducing the expression of cytokines and triggering hyper-activation of both neutrophil and macrophage cell populations. Moreover, we examined the impact of a secondary infectious pro-inflammatory stimulus induced through the injection of Pseudomonas aeruginosa lipopolysaccharide (Pa-LPS) molecules after exposure to short-term PM2.5. In this model, we demonstrated that the innate immune response was less responsive to a second pro-inflammatory infectious stimulus. Indeed, larvae exhibited dampened leukocyte activation and impaired production of reactive oxygen species. The obtained results indicate that short-term PM2.5 exposure alters the immune microenvironment and affects the inflammatory processes, thus potentially weakening the resistance to pathogen infections.

Pollution and endometriosis: A deep dive into the environmental impacts on women's health

BACKGROUND

The interaction between pollution and endometriosis is a pressing issue that demands immediate attention. The impact of pollution, particularly air and water pollution, or occupational hazards, on hormonal disruption and the initiation of endometriosis remains a major issue.

OBJECTIVES

This narrative review aims to delve into the intricate connection between pollution and endometriosis, shedding light on how environmental factors contribute to the onset and severity of this disease and, thus, the possible public health policy implications.

DISCUSSION

Endocrine-disrupting chemicals (EDCs) in pollutants dysregulate the hormonal balance, contributing to the progression of this major gynaecological disorder. Air pollution, specifically PM2.5 and PAHs, has been associated with an increased risk of endometriosis by enhancing chronic inflammation, oxidative stress, and hormonal imbalances. Chemical contaminants in water and work exposures, including heavy metals, dioxins, and PCBs, disrupt the hormonal regulation and potentially contribute to endometriosis. Mitigating the environmental impact of pollution is required to safeguard women's reproductive health. This requires a comprehensive approach involving stringent environmental regulations, sustainable practices, responsible waste management, research and innovation, public awareness, and collaboration among stakeholders.

CONCLUSION

Public health policies have a major role in addressing the interaction between pollution and endometriosis in a long-term commitment.

PM2.5 exposure exacerbates seizure symptoms and cognitive dysfunction by disrupting iron metabolism and the Nrf2-mediated ferroptosis pathway

In recent years, air pollution has garnered global attention due to its ability to traverse borders and regions, thereby impacting areas far removed from the emission sources. While prior studies predominantly focused on the deleterious effects of PM2.5 on the respiratory and cardiovascular systems, emerging evidence has highlighted the potential risks of PM2.5 exposure to the central nervous system. Nonetheless, research elucidating the potential influences of PM2.5 exposure on seizures, specifically in relation to neuronal ferroptosis, remains limited. In this study, we investigated the potential effects of PM2.5 exposure on seizure symptoms and seizures-induced hippocampal neuronal ferroptosis. Our findings suggest that seizure patients residing in regions with high PM2.5 levels are more likely to disturb iron homeostasis and the Nrf2 dependent ferroptosis pathway compared to those living in areas with lower PM2.5 levels. The Morris Water Maze test, Racine scores, and EEG recordings in epileptic mice suggest that PM2.5 exposure can exacerbate seizure symptoms and cognitive dysfunction. Neurotoxic effects of PM2.5 exposure were demonstrated via Nissl staining and CCK-8 assays. Direct evidence of PM2.5-induced hippocampal neuronal ferroptosis was provided through TEM images. Additionally, increased Fe2+ and lipid ROS levels indirectly supported the notion of PM2.5-induced hippocampal ferroptosis. Therefore, our study underscores the necessity of preventing and controlling PM2.5 levels, particularly for patients with seizures.

Acute exposure to diesel particulate matter promotes collective cell migration in thyroid cancer cells

Several ecological studies suggest that ambient air pollution is associated with the occurrence of thyroid cancer. In this study, we used certified diesel particulate matter as a proxy for fine particulate matter. Human thyroid cancer cell lines 8505C and TPC-1 were incubated with different concentrations of NIST1650b for 5 days and subjected to functional assays. We found that NIST1650b treatment did not affect short-term cell growth but reduced colony formation at high concentrations. Notably, NIST1650b-treated cells showed altered morphology toward cluster coalescence following treatment. Wound healing assays revealed that leading-edge cells formed protruding tips while maintaining cell-cell adhesion, and a significantly higher ratio of wound closure following treatment at 10 μg/mL was seen in both cell lines. A weak stimulatory effect on transwell cell migration was observed in 8505C cells. Taken together, our results suggest that fine particulate matter induced a coherent phenotype accompanied by augmented collective cell migration in thyroid cancer cells.

Biological Impact of Organic Extracts from Urban-Air Particulate Matter: An In Vitro Study of Cytotoxic and Metabolic Effects in Lung Cells

Atmospheric particulate matter (PM) with diameters below 10 µm (PM10) may enter the lungs through inhalation and are linked to various negative health consequences. Emergent evidence emphasizes the significance of cell metabolism as a sensitive target of PM exposure. However, the current understanding of the relationship between PM composition, conventional toxicity measures, and the rewiring of intracellular metabolic processes remains limited. In this work, PM10 sampled at a residential area (urban background, UB) and a traffic-impacted location (roadside, RS) of a Portuguese city was comprehensively characterized in terms of polycyclic aromatic hydrocarbons and plasticizers. Epithelial lung cells (A549) were then exposed for 72 h to PM10 organic extracts and different biological outcomes were assessed. UB and RS PM10 extracts dose-dependently decreased cell viability, induced reactive oxygen species (ROS), decreased mitochondrial membrane potential, caused cell cycle arrest at the G0/G1 phase, and modulated the intracellular metabolic profile. Interestingly, the RS sample, richer in particularly toxic PAHs and plasticizers, had a greater metabolic impact than the UB extract. Changes comprised significant increases in glutathione, reflecting activation of antioxidant defences to counterbalance ROS production, together with increases in lactate, NAD+, and ATP, which suggest stimulation of glycolytic energy production, possibly to compensate for reduced mitochondrial activity. Furthermore, a number of other metabolic variations hinted at changes in membrane turnover and TCA cycle dynamics, which represent novel clues on potential PM10 biological effects.