Polychlorinated biphenyls (PCBs) in the air are predominantly the less chlorinated congeners. Non-dioxin-like (NDL) low-chlorinated PCBs are more neurotoxic, and cause neurodevelopmental and neurobehavioral alterations in humans. However, the underlying mechanisms for this neurodevelopmental toxicity remain unknown. In the present study, Wistar rats were treated by gavage with PCB52 (1 mg/kg body weight) or corn oil from gestational day 7 to postnatal day 21. Both the body lengths and weights of the suckling rats at birth were significantly decreased by PCB52 treatment, suggesting developmental toxicity. Although no obvious histopathological changes were observed in the brain, using RNA-sequencing, 208 differentially expressed genes (DEGs) were identified in the striatum of PCB52-treated male offspring, while just 13 DEGs were identified in female offspring, suggesting sex-specific effects. Furthermore, using Gene Ontology enrichment analysis, neurodevelopmental processes, neurobehavioral alterations, and neurotransmission changes were enriched from the 208 DEGs in male offspring. Similarly, using Kyoto Encyclopedia of Genes and Genomes enrichment analysis, neuroactive ligand receptor interactions and multiple synapse pathways were enriched in male offspring, implying dysfunction of the neurotransmission system. Reductions in the protein expressions of these ligand receptors were also identified in the striatum, cerebral cortex, and hippocampus using western blotting methods. Taken together, our findings indicate that PCB52 exposure during gestation and lactation results in the abnormal expression of neurotransmission ligand-receptors in male offspring with a sex bias, and that this may contribute to neurodevelopmental toxicity.

In recent years, implementation of aggressive and strict clean air policies has resulted in significant decline in observed PM₂.₅ concentration in the Beijing–Tianjin–Hebei (BTH) region and its surrounding areas (i.e., the “2 + 26” region). To eliminate the effects of interannual and seasonal meteorological variation, and to evaluate the effectiveness of emission abatement policies, we applied a boosted regression tree model to remove confounding meteorological factors. Results showed that the annual average PM2.5 concentration normalized by meteorology for the “2 + 26” region declined by 38% during 2014–2019 (i.e., from 96 to 60 μg/m³); however, the BTH region exhibited the most remarkable decrease in PM₂.₅ concentration (i.e., a 60% reduction). Certain seasonal trend in normalized PM₂.₅ level remained for four target subregions owing to the effects of anthropogenic emissions in autumn and winter. Although strong interannual variations of meteorological conditions were unfavorable for pollutant dispersion during the heating seasons of 2016–2018, the aggressive abatement policies were estimated to have contributed to reductions in normalized PM₂.₅ concentration of 19%, 10%, 19%, and 17% in the BTH, Henan, Shandong, and Shanxi subregions, respectively. Our study eliminated the meteorological contribution to concentration variation and confirmed the effectiveness of the implemented clean air policies.

A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m³, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2–5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a ‘reference city’ for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.

Atmospheric levels of chlorinated paraffins (CPs) at five remote, six rural and four urban sites in Australia were measured using XAD-2 passive air samplers (XAD-PAS). While long-chain CP (LCCP, C>₁₇) levels were below method detection limits (MDLs), short-chain CPs (SCCPs, C₁₀₋₁₃) and, for the first time, medium-chain CPs (MCCPs, C₁₄₋₁₇) and CPs with a carbon chain length of nine (CP–C9) were found at many sites (88%, 81% and 88%, respectively) across the Australian continent, representing a range of environmental conditions. Applying preliminary sampling rates of the XAD-PAS for CPs, gaseous CP levels in Australian air were <MDL-1.3 and <MDL-1.8 ng/m³ for ΣSCCPs and ΣMCCPs, respectively, with a significant decreasing trend from more densely to less densely populated areas. Atmospheric median levels in this study (0.37 and 0.47 ng/m³ for SCCPs and MCCPs, respectively) were at the lower end of the median range (0.32–10 and 3.0–4.2 ng/m³ for SCCPs and MCCPs, respectively) reported for CPs at predominantly urban or industrial sites elsewhere (apart from China and extremely remote sites such as Antarctica). Principal component analysis matched the SCCP and MCCP congener group patterns in samples with those found in commercial mixtures, indicating a prevalence of less chlorinated congener groups in the Australian atmosphere. Information about the Australian production, use and disposal of CPs as well as their levels in other environmental matrices, including humans, is needed for assessing their emissions, behaviour, fate and potential exposure.

This paper presents the results of the study on columnar aerosol optical and physical properties and radiative effects directly observed over Dushanbe, the capital city of Tajikistan, a NASA AERONET site (equipped with a CIMEL sunphotometer) in Central Asia. The average aerosol optical depth (AOD) and Ångström exponent (AE) during the observation period from July 2010 to April 2018 were found to be 0.28 ± 0.20 and 0.82 ± 0.40, respectively. The highest seasonal AOD (0.32 ± 0.24), accompanied by the lowest average AE (0.61 ± 0.25) and fine-mode fraction in AOD (0.39), was observed during summer due to the influence of coarse particles like dust from arid regions. Fine particles were found in significant amounts during winter. The ‘mixed aerosol’ was identified as the dominant aerosol type with presence of ‘dust aerosol’ during summer and autumn seasons. Aerosol properties like volume size distribution, single scattering albedo, asymmetry parameter and refractive index suggested the influence of coarse particles (during summer and autumn). Most of the air masses reaching this site transported local and regional emissions, including from beyond Central Asia, explaining the presence of various aerosol types in Dushanbe’s atmosphere. The seasonal aerosol radiative forcing efficiency (ARFE) in the atmosphere was found high (>100 Wm⁻²) and consistent throughout the year. Consequently, this resulted in similar seasonally coherent high atmospheric solar heating rate (HR) of 1.5 K day⁻¹ during summer-autumn-winter, and ca. 0.9 K day⁻¹ during spring season. High ARFE and HR values indicate that atmospheric aerosols could exert significant implications to regional air quality, climate and cryosphere over the central Asian region and downwind Tianshan and Himalaya-Tibetan Plateau mountain regions with sensitive ecosystems.

Microbiota associated with airborne particulate matter (PM) is an important indicator of indoor pollution as they can be pathogenic and cause serious health threats to the exposed occupants. Present study aimed to investigate the level of culturable microbes associated with PM and their toxicological characterization in urban and rural houses of Pune city. Highest concentration of bacterial aerosols observed to be associated with PM₁₀ size fraction in urban site (2136 ± 285 CFU/m³) whereas maximum fungal concentration has been measured in rural houses (1521 ± 302 CFU/m³). Predominantly found bacterial species were Bacillus sp., S. aureus, and Pseudomonas aeruginosa and fungal species were Aspergillus sp., Cladosporium sp., and Penicillium sp. in both urban and rural residential premises. Concentration of endotoxin measured using the kinetic Limulus Amebocyte Lysate assay exhibited that the level of endotoxin in both urban and rural sites are associated with household characteristics and the activities performed in indoor as well as outdoor. Cell free DTT assay confirmed the ability of these airborne microbes to induce the production of reactive oxygen species (ROS) varying along with the types of microorganisms. On exposure of A549 cells to airborne microbes, a significant decrease in cell viability was observed in terms of both necrosis and apoptosis pathway. Elevated production of nitric oxide (NO) and proinflammatory cytokines in epithelial cells and macrophages clearly suggest the inflammatory nature of these airborne microbes. Results derived from the present study demonstrated that the indoor air of urban and rural houses of Pune is contaminated in terms of microbial load. Therefore, attention should be paid to control the factors favoring the microbial growth in order to safeguard the health of exposed inhabitants.

Cylindrospermopsin (CYN) is an important cyanobacterial toxin posing a major threat to surface waters during cyanobacterial blooms. Hence, methods for cyanotoxin removal are required to confront seasonal or local incidences to sustain the safety of potable water reservoirs. Non-thermal plasmas provide the possibility for an environmentally benign treatment which can be adapted to specific concentrations and environmental conditions without the need of additional chemicals. We therefore investigated the potential of two different non-thermal plasma approaches for CYN degradation, operated either in a water mist, i.e. in air, or submerged in water. A degradation efficacy of 0.03 ± 0.00 g kWh⁻¹ L⁻¹ was found for a dielectric barrier discharge (DBD) operated in air, while a submerged pulsed corona-like discharge resulted in an efficacy of 0.24 ± 0.02 g kWh⁻¹ L⁻¹. CYN degradation followed a pseudo zeroth order or pseudo first order reaction kinetic, respectively. Treatment efficacy of the corona-like discharge submerged in water increased with pH values of the initial solution changing from 5.0 to 7.5. Notably, a pH-depending residual oxidative effect was observed for the submerged discharge, resulting in ongoing CYN degradation, even without further plasma treatment. In this case hydroxyl radicals were identified as the dominant oxidants of CYN at acidic pH values. In comparison, degradation by the DBD could be related primarily to the generation of ozone.

Polybrominated biphenyl ethers (PBDEs) are commonly added to electronic products for flame-retardation effects, and are attracting more and more attentions due to their potential toxicity, durability and bioaccumulation. This study conducts a sysmtematic review to understand the human exposure to PBDEs from e-waste recycling, especially exploring the exposure pathways and human burden of PBDEs as well as investigating the temporal trend of PBDEs exposure worldwide. The results show that the particular foods (contaminated fish, poultry, meat and breast milk) ingestion, indoor dust ingestion and indoor air inhalation may be key factors leading to human health risks of PBDEs exposure in e-waste recycling regions. Residents and some vulnerable groups (occupational workers and children) in e-waste recycling areas may face higher exposure levels and health risks. PBDE exposure is closely related to exposure level, exposure duration, e-waste recycling methods, and dietary customs. High levels of PBDEs are found in human tissues (breast milk, hair, blood (serum), placenta and other tissues) in e-waste areas, at far higher levels than in other areas. Existing data indicate that PBDE exposure levels do not present any apparent downward trend, and will possibly cause serious human diseases. More epidemiological studies are still needed to provide a solid basis for health risk assessment.

To investigate chemical characteristics, abatement mechanisms and regional transport of atmospheric pollutants during the COVID-19 outbreak control period in the Yangtze River Delta (YRD) region, China, the measurements of air pollutants including fine particulate matter (PM₂.₅) and volatile organic compounds (VOCs) on non-control period (NCP, 24 December 2019–23 January 2020) and control period (CP, 24 January–23 February 2020) were analyzed at the urban Pudong Supersite (PD) and the regional Dianshan Lake Supersite (DSL). Due to the stricter outbreak control, the levels of PM₂.₅ and VOCs, and the occurrence frequencies of haze-fog episodes decreased substantially from NCP to CP, with average reduction rates of 31.6%, 38.9% and 35.1% at PD, and 34.5%, 50.7% and 37.9% at DSL, respectively. The major source for PM₂.₅ was secondary sulfate & nitrate in both periods, and the emission control of primary sources such as coal burning and vehicle exhaust decreased the levels of precursors gas sulfur dioxide and nitrogen oxide, which highly contributed to the abatement of PM₂.₅ from NCP to CP. The higher levels of ozone at both PD and DSL on CP might be due to the weak nitrogen monoxide titration, low relative humidity and high visibility compared with NCP. Vehicle exhaust and fugitive emission from petrochemical industry were the major contributors of ambient VOCs and their decreasing activities mainly accounted for VOCs abatement. Moreover, the high frequency of haze-fog events was closely impacted by medium-scale regional transport within Anhui and Jiangsu provinces. Therefore, the decreasing regional transported air pollutants coincided with the emission control of local sources to cause the abatement of haze-fog events in YRD region on CP. This study could improve the understanding of the change of atmospheric pollutants during the outbreak control period, and provide scientific base for haze-fog pollution control in YRD region, China.

Human exposure to particulate matter (PM) originating from air pollution is inevitable since more and more population is present in large cities that are characterized by poor air quality. The impact on human health is evident and we need to intensify research regarding this problem to get molecular insight into versatile effects of chronic exposure to PM inducing organism responses and initiating the development of selected disorders. Herein, the impact of standard PM representing urban pollution on the structure and function of human serum albumin (HSA) was evaluated by the application of various analytical techniques. HSA was selected due to its high likeliness of being exposed to PM because of the abundance of this protein in blood. The studies were focused mainly on the inorganic residue of PM resulting from removing organic components by a low-temperature plasma. To mimic physiological conditions, dialysis technique was used to simulate the release of nanoparticles and ions from PM to aqueous environment under, which in turn may interact with biomolecules inside the living system. Capture of metals from the bulk suspension was found for many metals like Al, Fe, Zn and Pb in quantities of more than 1 mol of metal ions per mole of HSA. No significant structural changes of the protein upon dialysis with PM were observed, however, an increase in the thermal stabilization of the HSA structure was observed. Moreover, the interaction of HSA dialyzed in the presence of PM with selected drugs (warfarin, aspirin) was negatively affected, indicating a lower affinity of drugs towards the protein, even though only small conformational changes of the PM exposed protein were observed. Our findings point to a possible interference of air pollutants with the drugs taken by patients living in highly polluted areas.