Ambient air pollution, namely exposure to air particulate matter (PM), has been shown to be connected with a number of adverse health effects. At least part of the effects can be caused by organic pollutant mixtures associated with PM, which can elicit a wide range of specific toxic potentials. These potentials could be affected by seasonal variation of pollutant mixtures and PM size fraction. To examine this, six size subfractions of PM₁₀ were collected at rural and urban site in the Czech Republic in a year-long sampling campaign. The samples were assessed for aryl hydrocarbon (AhR)-mediated activity, estrogenicity and anti-androgenicity using mammalian cell models. The concentrations of detected toxic potentials differed among seasons. The greatest levels were observed in samples collected during winter when AhR-mediated effects and estrogenicity were at least 10-times greater than in summer. While the observed potentials were mostly less pronounced in samples from rural area, during winter, their AhR-mediated activity was twice as great as at the urban site. This was probably caused by the low-quality of fuel used for heating at the rural site. Assessed toxic potentials were associated mainly with PM size fractions with lesser aerodynamic diameters (<1 μm). Toxic potentials were compared with data from chemical analyses covering 102 chemicals from different pollutant groups to model their contribution to the observed effects. For AhR-mediated activity, chemical analyses explained on average 44% of the effect and the main identified effect-drivers were polycyclic aromatic hydrocarbons. For estrogenicity and anti-androgenicity, detected chemicals were able to explain on average less than 1.6% and 11% of the potentials, with their highest explicability reaching 13% and 57%, respectively. This was affected by the lack of data on specific toxic potency of some detected air pollutants, but also indicates a possible role of further not analyzed chemicals in these effects.

Exposure to Aluminum oxide nanoparticles (Al₂O₃ NPs) has been associated with pulmonary inflammation in recent years; however, the underlying mechanism that causes adverse effects remains unclear. In the present study, we characterized microRNA (miRNA) expression profiling in human bronchial epithelial (HBE) cells exposed to Al₂O₃ NPs by miRNA microarray. Among the differentially expressed miRNAs, miR-297, a homologous miRNA in Homo sapiens and Mus musculus, was significantly up-regulated following exposure to Al₂O₃ NPs, compared with that in control. On combined bioinformatic analysis, proteomics analysis, and mRNA microarray, NF-κB-activating protein (NKAP) was found to be a target gene of miR-297 and it was significantly down-regulated in Al₂O₃ NPs-exposed HBE cells and murine lungs, compared with that in control. Meanwhile, inflammatory cytokines, including IL-1β and TNF-α, were significantly increased in bronchoalveolar lavage fluid (BALF) from mice exposed to Al₂O₃ NPs. Then we set up a mouse model with intranasal instillation of antagomiR-297 to further confirm that inhibition of miR-297 expression can rescue pulmonary inflammation via Notch pathway suppression. Collectively, our findings suggested that up-regulation of miR-297 expression was an upstream driver of Notch pathway activation, which might be the underlying mechanism involved in lung inflammation induced by exposure to Al₂O₃ NPs.

Interactions between aromatic pollutants (APs) and porphyrin nucleus as physiological receptors have a significant effect on biological functions of porphyrin-based systems in organism. However, the details on the interaction at molecule level are still elusive. Herein, interaction mechanisms between two typical APs (methylene blue, MB and benzo[a]pyrene, B[a]P) and meso-tetra (4-carboxyphenyl) porphine (TCPP) as physiological receptors were systematically investigated. Adsorption behaviors of TCPP to B[a]P was dominated by pi-pi interaction, while interaction between TCPP and MB coupled with a multi-force field including hydrophobic, pi-pi, electrostatic, and H-bonding interactions. The relative contributions of these four forces obeyed an order: H-bonding > pi-pi > electrostatic > hydrophobic, regardless of the pH value and the initial concentration of MB. H-bonding assisted by hydrogen/hydroxide ion was the most influential force. According to the effect of pH and temperature, organisms exposed to cellular environment with high alkalinity and high temperature might uptake more APs molecules with chemical properties similar to MB and suffered greater health risks. In detail, APs might replace amino acid molecules surrounding porphyrin and change the distortion type of porphyrin molecule, and then affect biological functions of porphyrin and related proteins. This study facilitates a better understanding of potential toxicity of organisms in contaminated environment.

This study explores the generation of ultrafine particle emissions, measured in particle number (PN), based on a portable emissions measurement system (PEMS) in the City of Toronto between October and December 2019. Two driving routes were designed to include busy arterial roads and highways. All measurements were conducted between 10 a.m. and 4 p.m. Altogether, emissions from 31 drives were collected, leading to approximately 200,000 s of data. A spike detection algorithm was employed to isolate PN spikes in time series data. A sensitivity analysis was also conducted to identify the most optimum method for spike detection. The results indicate that the average emission rate during a PN spike is approximately 8 times the emission rate along the rest of the drive. In each test trip, about 25% of the duration was attributed to spike events, contributing 75% of total PN emissions. A Pearson correlation of 0.45 was estimated between the number of PN spikes and the number of sharp accelerations (above 8.5 km/h/s). The Pearson correlation between the occurrence of high engine torque (above 65.0 Nm) and the number of PN spikes was estimated at 0.80. The number of PN spikes was highest on arterial roads where the vehicle speed was relatively low, but with high variability, and including a high number of sharp accelerations. This pattern of UFP emissions leads to high UFP concentrations along arterial roads in the inner city core.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are cancerogenic organic pollutants that priority controlled by Stockholm Convention with globally 183 signatories now. Secondary nonferrous smelting plants are confirmed to be important sources in China due to its large industrial activities and high emissions of PCDD/Fs. It is important to prioritize source to achieve source emission reduction by conducting field monitoring on typical case plants. Here, the emission profiles and levels of PCDD/Fs were investigated in 25 stack gas samples collected from three secondary copper production (SeCu), two secondary zinc production (SeZn) and two secondary lead production (SePb). Both average mass concentration and toxic equivalency quantity (TEQ) concentrations of PCDD/Fs all generally decreased in the order: SeCu > SeZn > SePb. It is noteworthy that the mean TEQ concentration in stack gas from SeCu with oxygen-enrich melting furnace technology, at 2.7 ng I-TEQ/Nm³, was much higher than the concentrations of other smelting processes. The average emission factors and annual release amounts of PCDD/Fs from SeCu, SePb and SeZn investigated were 28.4, 1.5, 10.4 μg I-TEQ/t and 1.03, 0.023, 0.17 g I-TEQ/year, respectively. The ratios of 2,3,7,8-TCDF to 1,2,3,7,8-PeCDF and OCDD to 1,2,3,7,8,9-HxCDD varied to large extent for three metal smelting, which could be used as diagnostic ratios of tracing specific PCDD/Fs sources. Addition of copper-containing sludge into the raw materials might lead to higher PCDD/Fs emissions. It is important to emphasize and reduce the PCDD/Fs emissions from oxygen-enrich melting furnace from secondary copper productions.

Field observations have suggested that particulate nitrate can promote the aging of black carbon (BC), yet the mechanisms of the aging process and its impacts on BC’s light absorption are undetermined. Here we performed laboratory simulation of internal mixing of flame-generated BC aggregates with ammonium nitrate. Variations in particle size, mass, coating thickness, effective density, dynamic shape factor, and optical properties were determined online by a suite of instruments. With the development of coatings, the particle size initially decreased until reaching a coating thickness of ∼10 nm and then started increasing, accompanied by an increase in effective density and a decrease in dynamic shape factor, reflecting the transformation of BC particles from highly fractal to near-spherical morphology. This is partially attributable to the restructuring of BC cores to more compact forms. Exposing coated particles to elevated relative humidity (RH) led to additional BC morphology changes, even after drying. Particle light absorption and scattering were also amplified with ammonium nitrate coating, increasing with coating thickness and RH. For BC particles with a 17.8 nm coating, absorption and scattering were increased by 1.5- and 7.9-fold when cycled through 70% RH (5-70-5% RH), respectively. The irreversible restructuring of the BC core caused by condensation of ammonium nitrate and water altered both absorption and scattering, with a magnitude comparable to or even exceeding the effects of increased coating. Results show that ammonium nitrate is among the most efficient coating materials with respect to modifying BC morphology and optical properties compared with other inorganic and organic species investigated previously. Accordingly, mitigation of nitrate aerosols is necessary for the benefits of both air pollution control and reducing the impacts of BC on visibility impairment and radiative forcing on climate change. Our results also pointed out that the effect of BC core restructuring needs to be considered when evaluating BC’s light absorption enhancement.

Little is known about how forests adjust their gas-exchange mode while atmospheric CO₂ rises globally and air quality changes regionally. The present study aims at addressing this research gap for boreal spruce trees growing in three different regions of Canada, submitted to distinct levels of atmospheric emissions, by examining the amount of carbon gained per unit of water lost in trees, i.e., the intrinsic water use efficiency (iWUE).Under pristine air quality conditions, middle-to long-term trends passed from no-reaction mode to passive strategies due to atmospheric CO₂, and short-term iWUE variations mostly ensue from year-to-year climatic conditions. In contrast, in trees exposed to pollutants from a copper smelter and an oil-sands mining region, air quality deterioration generated swift, long-term iWUE rises immediately at the onset of operations. In this case, the very active foliar strategy sharply reduced the intra-foliar CO₂ (Ci) pressure. Statistical modeling allowed identifying emissions as the main trigger for the iWUE swift shifts; subsequent combined effects of emissions and rising CO₂ led to passive foliar modes in the recent decades, and short-term variations due to climatic conditions appeared all along the series.Overall, boreal trees under different regional conditions modified their foliar strategies mostly without changing their stem growth. These findings underline the potential of acidifying emissions for prompting major iWUE increases due to lowering the stomatal apertures in leaves, and the combined influence of rising CO₂ in modulating other foliar responses. A fallout of this research is that degrading air quality may create true divergences in the relationship between tree-ring isotopes and climatic conditions, an impact to consider prior to using isotopic series for paleo-climatic modeling.

Exposure to benzo(a)pyrene (BaP) has been shown to cause mitochondrial dysfunction and injury to neural cells. Resveratrol (RSV) has been studied as an antioxidant, anti-inflammatory, anti-apoptotic, and anticancer agent and can modulate mitochondrial function in vitro and in vivo. However, the molecular mechanisms underlying RSV’s protection against mitochondrial dysfunction have not been fully elucidated. To investigate whether RSV can effectively prevent BaP-induced mitochondrial dysfunction, we tested the effects of RSV in primary neuronal models. Our results confirmed that neurons exhibited mitochondrial dysfunction and apoptosis in the mitochondrial pathway after BaP-treatment, and that pretreatment with RSV could reduce that dysfunction. Further, our results indicated that RSV pretreatment enhanced mitochondrial biogenesis via the AMPK/PGC-1α pathway and activated mitophagy via the PINK1-Parkin and AMPK/ULK1 pathways, thereby coordinating mitochondrial homeostasis. We also found that RSV could alleviate mitochondrial network fragmentation caused by BaP. This work provided insights into the role of RSV in preventing BaP-induced primary neuronal apoptosis in the mitochondrial pathway, mainly via regulation of mitochondrial biogenesis and mitophagy through AMPK pathway, thus maintaining the integrity of the mitochondrial network.

Antibiotic resistance surveillance data is lacking in many parts of the world, limiting effective therapy and management of resistance development. Analysis of urban wastewater, which contains bacteria from thousands of individuals, opens up possibilities to generate informative surveillance data in a standardized and resource-efficient way. Here, we evaluate the relationship between antibiotic resistance prevalence in E. coli from wastewater and clinical samples by studying countries with different resistance situations as assessed by traditional clinical surveillance. Composite, influent wastewater samples were collected over 24 h from treatment plants serving major cities in ten European countries. Using a broth screening method, resistance to six antibiotic classes was analyzed for 2507 E. coli isolates (n = 247–252 per country). Resistance prevalence in wastewater E. coli was compared to that in clinical E. coli reported by the European Antibiotic Resistance Surveillance Network. Resistance prevalence was lower in wastewater than clinical E. coli but followed similar geographic trends. Significant relationships were found for resistance to aminopenicillins (R² = 0.72, p = 0.0019) and fluoroquinolones (R² = 0.62, p = 0.0072), but not for aminoglycosides (R² = 0.13, p = 0.31) and third-generation cephalosporins (R² = 0.00, p = 0.99) where regression analyses were based on considerably fewer resistant isolates. When all four antibiotic classes were taken into account, the relationship was strong (R² = 0.85, p < 0.0001). Carbapenem resistance was rare in both wastewater and clinical isolates. Wastewater monitoring shows promise as method for generating surveillance data reflecting the clinical prevalence of antibiotic resistant bacteria. Such data may become especially valuable in regions where clinical surveillance is currently limited.

Adverse health effects of exposure to air pollution have been investigated in many previous studies. However, there is no study available on the association between maternal exposure to air pollution during pregnancy and cord blood lipid profile. This study, based on 150 mother-newborn pairs residing in Sabzevar, Iran (2018), evaluated the association of exposure to ambient air pollution as well as traffic indicators (total street length in different buffers around residential address and distance to major roads) during entire pregnancy with lipid levels cord blood lipid profile. Concentrations of PM₁₀, PM₂.₅, and PM₁ at maternal residential address were estimated using land use regression (LUR) models. We measured triglyceride (TAG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) levels and TC/HDL-C and TAG/HDL-C ratio in the cord blood samples to characterize their lipid profile. Multiple linear regression models were developed to estimate the association of exposure to air pollution and traffic indicators with cord blood lipid profile controlled for relevant covariates. Higher concentrations of PM₂.₅ and PM₁₀ were associated with higher levels of TAG, TC, HDL-C, TC/HDL-C, and TAG/HDL-C in cord blood samples. Moreover, higher concentration of PM₁ was associated with higher levels of TAG, TC and LDL-C. There was also a positive association between total street length in 100 m buffer around home and serum levels of TC, TAG, LDL-C and TC/HDL ratio (β = 3.73, 95% confidence intervals (CI): 1.76, 5.71; β = 2.75, 95% CI: 0.97, 4.53; β = 1.87, 95% CI: 0.64, 3.09; β = 0.06, 95% CI: 0.01, 0.11, respectively). However, the associations for total street length in larger buffers and distance to major roads were not statistically significant. Our findings support a relationship between exposure to air pollution during pregnancy and increase in cord blood lipid levels.