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To investigate particle characteristics and find an effective measure to control severe particle pollution, year-round observation of size-segregated inorganic aerosols was conducted in Beijing from January to December, 2016. The sampled atmospheric particles all presented bimodal size distribution at four pollution levels (clear, slight pollution, moderate pollution and severe pollution), and peak values appeared at the size range of 0.7-2.1 μm and9.0 μm, respectively. As dominant particle compositions, NO

Funding Information: This research was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (MSIT) (NRF2020M3G1A111499813). S. Lim was supported by the National Research Foundation of Korea (NRF) from the Ministry of Science and ICT (2018R1D1A1B07050849 and 2021R1C1C2011543). M. Lee thanks to the support by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF2020R1A2C301459213). S.-W. Kim was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (2017R1D1A1B06032548). Funding to K.-S. Kang was provided by the National Institute of Environmental Research (NIER-RP2017-166). Funding Information: This research was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (MSIT) (NRF2020M3G1A111499813). S. Lim was supported by the National Research Foundation of Korea (NRF) from the Ministry of Science and ICT (2018R1D1A1B07050849 and 2021R1C1C2011543). M. Lee thanks to the support by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF2020R1A2C301459213). S.-W. Kim was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (2017R1D1A1B06032548). Funding to K.-S. Kang was provided by the National Institute of Environmental Research (NIER-RP2017-166). Publisher Copyright: © 2022 The Author(s) Northeast Asia has suffered from severe PM2.5 pollution and the exact mechanisms have yet to be fully understood. Here, we investigated the transformation processes of submicron aerosols using a 4-year data set obtained at Jeju, a Northeast Asian background site. The diurnal-cycle constrained empirical orthogonal function analysis of nanoparticle size-number distribution distinguished 2 modes: burst of nucleation-Aitken particles and increase in accumulation mode particles, representing “new particle formation and growth” and “PM2.5 mass increase,” respectively. In these events, aerosol and meteorological characteristics changed progressively over several days, revealing that the PM2.5 mass increase is an episodic event occurring on a regional scale. The increase in PM2.5 mass was accompanied by an increase in aerosol liquid water content, which correlated well with SO4-2 and NO3, and a decrease in incoming solar radiation (-14.1 Wm-2 day-1) constituting a positive feedback. The “transport/haze” episode of KOREA-U.S. Air Quality campaign corresponds to “PM2.5 mass increase,” during which the vertical evolution of particles demonstrates that nanoparticles ≥3.5 nm were entrained into the shallow boundary layer upon vertical mixing and converted to accumulation-mode particles ≥0.3 mm at relative humidity (RH) exceeding the deliquescence RH of secondary inorganic aerosol (SIA). Coincidently, at ground, the coating thickness of refractory black carbon (rBC) (48 ± 39 nm) and SIA concentration increased. Furthermore, the diameter of rBC (180-220 nm)-containing particle in core-shell configuration linearly increased with PM2.5 mass, reaching 300-400 nm at PM2.5 ≥ 40 mg m-3.This observational evidence suggests that the thick coating of rBCs resulted from the active conversion of condensable gases into the particulate phase on the rBC surface, thereby increasing the mass of the accumulation-mode aerosol. Consequently, this result complies with the strategy to reduce primary emissions of gaseous precursors for SIA and particulates such as rBC as a way to effectively mitigate haze pollution as well as climate change in Northeast Asia.

The secondary treated effluents of pulp and paper mills contain high chemical oxygen demand (COD) that is associated with organic matter. Therefore, this study explores the adsorption of substances contributing to COD using CoFe2O4 and quartz sand-coated CoFe2O4 in batch and fixed-bed column experiments. X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller analysis, and X-ray photoelectron spectroscopy were used to characterize the adsorbents. The quartz sand-loaded CoFe2O4 exhibited a larger pore volume and average pore size. Batch experiments revealed that adsorption on CoFe2O4 closely fit the pseudo-second-order model. To explore the effects of bed depth, feed flow rate, and initial solution pH on the breakthrough characteristics of CoFe2O4-coated sand, fixed-bed column experiments were conducted, and the breakthrough curves were drawn from the ratio of influent COD concentration to effluent COD concentration. The breakthrough time decreased with an increase in the feed flow rate and initial pH but increased with the bed depth. According to the X-ray photoelectron spectroscopy analysis, CoFe2O4-coated sand showed excellent stability due to negligible leaching of metallic elements. These findings have important implications for the advanced treatment of industrial wastewater.

The reaction of alkenes with ozone has great effect on atmospheric oxidation, its transient species can produce OH radicals and contribute to the formation of secondary organic aerosols (SOA). In the present study, the reaction of tetramethylethene (TME) with ozone was investigated using self-assembled low temperature matrix isolation system. The TME and ozone were co-deposited on a salt plate at 15 K, and then slowly warmed up the plate. The first transient species primary ozonide (POZ) was detected, indicating that the reaction followed Criegee mechanism. Then POZ began to decompose at 180 K. However, secondary ozonide (SOZ) was not observed according to Criegee mechanism. Probably, Criegee Intermediate (CI) did not react with inert carbonyl of acetone, but with remaining TME formed tetra-methyl epoxide (EPO).

Dust and pollution are frequently mixed together in East Asia, causing large uncertainties in assessing climate change and environmental influence and in relevant policymaking. To discern the dust effect on particle mass, we carried out long-term measurements of the mass and key chemical compositions of PM10, PM2.5, and PM1 from August 2007 to February 2012 and collected hourly data of PM10 and PM2.5 concentrations from January 2012 to October 2020 at Gosan, South Korea. The principal component analysis of measured species reveals two dominant factors, pollution and dust, accounting for 46% and 16% of the total variance, respectively. The mode distribution of PM10, PM2.5, and PM1 mass in addition to the dust events helps to provide a robust criterion of the dust impact. Dust can be identified by the mean + standard deviation (σ) of PM10, while the threshold is down to the mean concentration when dust particles experience precipitation. High PM2.5 concentration also presents dust impact, however, the criterion decreases from mean + σ in 2007–2012 to mean in 2012–2020. It indicates that dust is no longer a high-concentration event of PM2.5, but its influence gradually appears in low-concentration particles. Therefore, the dust criterion obtained from long-term PM10 concentration data is robust, however, the standard is based on PM2.5 changes over time and still needs to be determined by follow-up long-term observations.

International audience; Severe volatile organic compound (VOC) pollution has become an urgent problem during the heating season in the North China Plain (NCP), as exposure to hazardous VOCs can lead to chronic or acute diseases. A campaign with online VOC measurements was conducted at a rural site in Wangdu, NCP during the 2018 heating season to characterize the compositions and associated sources of VOCs and to assess their potential health risks. The total concentration of VOCs with 94 identified species was 77.21 ± 54.39 ppb. Seven source factors were identified by non-negative matrix factorization, including coal combustion (36.1%), LPG usage (21.1%), solvent usage (13.9%), biomass burning and secondary formation (14.2%), background (7.0%), industrial emissions (4.5%), and vehicle emissions (3.3%). The point estimate approach and Monte Carlo simulation were used to estimate the carcinogenic and non-carcinogenic risks of harzadous VOCs. The results showed that the cumulative health risk of VOCs was above the safety level. Acrolein, 1.2-dichloroethane, 1,2-dichloropropane, chloroform, 1,3-butadiene, and benzene were identified as the key hazardous VOCs in Wangdu. Benzene had the highest average carcinogenic risk. Solvent usage and secondary formation were the dominant sources of adverse health effects. During the Spring Festival, most sources were sharply reduced; and VOC concentration declined by 49%. However, coal and biomass consumptions remained relatively large, probably due to heating demand. This study provides important references for the control strategies of VOCs during the heating season in heavily polluted rural areas in the NCP.

International audience

The receptor model is an effectively and widely used tool for analyzing the source of PM2.5, and its development and improvement have always been focused and challenged. In this study, approaches of source analysis is applied and compared. The PM2.5 samples were collected in spring of 2015 at a remote background site of Weizhou, South China and were analyzed for water-soluble ions, trace metals, and sugars. The 28 measurement species were introduced into the positive matrix factorization (PMF) and a non-negative matrix factorization (NMF) model for inter-comparison of PM2.5 prediction. Results showed that the NMF model is a more robust tool to identify source types and source apportionment in the case of a small sample size (n = 31). In NMF, four source variants were obtained as dust (15.6%), biomass combustion (11.8%), secondary formation (17.6%), and coal combustion (54.9%), corresponding to four main source areas. These were Southeast Asia, South China Sea, Taiwan Strait, as well as Pearl River Delta, respectively. The areas were distinguished based on hybrid receptor models, potential source contribution function (PSCF) and concentration weighted trajectory (CWT), by introducing the daily loadings of each source factor from NMF method. These model results were highly consistent with categorized chemical characteristics of PM2.5, suggesting that NMF linking with hybrid receptor models provides valuable implications for exploring source types and source areas of PM2.5. Meanwhile, biomass combustion and coal combustion comparably contributed to the high PM2.5 concentrations indicating control strategy in South China in spring.

Perfluorooctane sulfonate (PFOS) is one of the perfluorinated compounds (PFCs), and has been used in industrial and consumer products. It has already been shown that PFOS could be detected in the environmental media and biological species including humans, due to its resistance to environmental degradation. PFOS is known to induce a series of adverse impacts on human health, e.g., as a potential neurotoxic substance. Recent studies suggest that astrocytes act as the mediator in PFOS-induced neurotoxicity; however, the underlying molecular mechanism needs further investigation. Under the physiological condition, astrocytes play an important role in maintaining brain functions through releasing and up-taking of neurotransmitters between astrocytes and neurons. In the present study, astrocytes-derived d -serine was shown to be involved in PFOS-induced apoptosis and death in the rat primary hippocampal neurons. Significant alterations in d -serine were found in astrocytes, mediated by the molecules in d -serine synthesis (serine racemase), metabolism ( d -amino acid oxidase) and delivery (calcium, vacuolar type H+-ATPase, alanine–serine–cysteine transporter and connexin 43 hemichannels). Meanwhile, the N-methyl- d -aspartate receptor (NMDAR) subunits (NR1, NR2 A and NR2B) gene and protein expressions were significantly increased in the hippocampal neurons exposed to the PFOS-activated astrocytes-conditional medium (ACM). Further, the adverse effects of PFOS could be attenuated by the fluorocitrate (an inhibitor for d -serine up-taken by the glial cells) application. Our data indicated that astrocytes-derived d -serine was involved in PFOS-induced neurotoxicity through the NMDARs in the rat primary hippocampal neurons.

Bagasse spraying wastewater (BSW) is a source of organic pollutants during bagasse processing. In this study, the feasibility of anaerobic treatment of BSW under different calcium concentrations (60 to 2400 mg/L) was studied. The experiment was performed in a lab-scale up-flow multistage anaerobic reactor (UMAR) inoculated with granular sludge, and operated for 160 days at a constant organic loading rate of 6 kg COD/(m3·d). Treatment of BSW with 60 to 800 mg Ca2+/L resulted in 80.7 to 82.7% of COD removal, 161 to 232.7 mg COD/L of volatile fatty acid (VFA) yield, 0.56 to 0.79 m3/(kgCOD·d) of biogas production rate, and 2.4 to 2.66 m3/(m3·d) of volume loading rate (VLR). The pH remained within the optimal range for anaerobic digestion (adjust to pH = 6.8 to 7.0). The VFAs were composed of 77 to 85% acetic acid, 8.4 to 13.2% butyric acid, and 6.6 to 9.6% propionic acid. At higher influent calcium concentrations (> 800 mg/L), the hydrolysis process appeared to be inhibited, affecting the anaerobic digestion performance of the reactor. In particular, the COD removal efficiency decreased to 55.5%, and the VFA content in the effluent significantly increased due to the lower pH. Microbial community analysis showed that at the end of anaerobic digestion, the Syntrophobacter disappeared, and Clostridium and Anerolineaceae were the main genus and family, respectively. Overall, the results indicated that low calcium (< 300 mg/L) had a positive effect on the UMAR performance.

Carbonaceous aerosols (CAs) are major components of fine particulate matter (PM

Particulate nitrite is a critical source of hydroxyl radicals; however, it lacks high-resolution methods due to its low abundance and stability to explore its formation mechanism. In this study, a modified versatile aerosol concentration enrichment system (VACES) coupled with ion chromatography (IC) was used to measure particulate NO

Based on source-specific saccharide tracers, the characteristic of biomass burning (BB) and biogenic emissions to saccharides was investigated in three rural sites at Lincang, where covered with 65 % of forest in the southwest border of China. The total saccharides accounted for 8.4 ± 2.7 % of OC, and 1.6 ± 0.6 % of PM2.5. The measured anhydrosugars accounted for 48.5 % of total saccharides, among which levoglucosan was the most dominant species. The high level of levoglucosan was both attributed to the local BB activities and biomass combustion smoke transported from the neighboring regions of Southeast Asia (Myanmar) and the northern Indian Peninsula. The measured mono (di) saccharides and sugar alcohols accounted for 24.9 ± 8.3 % and 26.6 ± 9.9 % of the total saccharides, respectively, were both proved to be mostly emitted by direct biogenic volatilization from plant materials/surface soils, rather than as byproducts of polysaccharides breakdown during BB processes. Five sources of saccharides were resolved by non-negative matrix factorization (NMF) analysis, including BB, soil microbiota, plant senescence, airborne pollen and plant detritus with the contribution of 34.0 %, 16.0 %, 21.0 %, 23.7 % and 5.3 %, respectively. The results provide the information on the magnitude of levoglucosan and contributions of BB, as well as the characteristic of biogenic saccharides, at the remote sites of Southwest China, which can be further applied to regional source apportionment models and global climate models.

Over the past few decades, northeast Asia has suffered from the extreme levels of PM2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 μm). Despite extensive efforts and the scientific advances in understanding PM2.5 pollution, the fundamental mechanisms responsible for the occurrence of high PM2.5 concentrations have not been comprehensively understood. In this study, we investigated the physical and chemical drivers for the formation and transformation of atmospheric particles using a four-year dataset of nanoparticle number size distributions, PM2.5 chemical composition, gaseous precursors, and meteorological variables in northeast Asia outflows. The empirical orthogonal function (EOF) analyses of size-separated particle numbers extracted two modes representing a burst of nanoparticles (EOF1) and an increase in PM2.5 mass (EOF2) associated with persistent anticyclone and synoptic-scale stagnation, respectively. The vertical structure of the particles demonstrated that the synoptic conditions also affected the daily evolution of boundary layer, promoting either the formation of nanoparticles through deep mixing or conversion into accumulation-mode particles in shallow mixed layers. In the haze-development episode equivalent to EOF2 during the KORUS-AQ (KORea-US Air Quality) campaign, the PM2.5 mass reached 63 μg m−3 with the highest contribution from inorganic constituents, which was accompanied by a thick coating of refractory black carbon (rBC) that linearly increased with condensation-mode particles. This observational evidence suggests that the thick coating of rBC resulted from an active conversion of condensable gases into particle-phase on the BC surface, thereby increasing the mass of the accumulation-mode aerosol. Consequently, this result complies with the strategy to reduce black carbon as a way to effectively mitigate haze pollution as well as climate change in northeast Asia.

Commodity plastic is ubiquitous in daily life and commonly disposed of via unregulated burning, particularly in developing regions. We report here the much higher emission factors (13.1 ± 7.5 g/kg) and toxicities of inhalable aerosols emitted from the unregulated burning of plastic waste based on field measurements and cellular experiments, including oxidative stress and cytotoxic tests in A549 cells. Plastic foam burning emitted aerosols possesses the highest EFs (34.8 ± 4.5 g/kg) and toxicities, which are 4.2- to 13.4-fold and 1.1- to 2.7-fold higher than those emitted from the burning of other waste types. These quantified toxicities are mainly attributed to aerosols containing carbonaceous matter, especially persistent organic pollutants, including polycyclic aromatic hydrocarbons and dioxins, which originate from incomplete combustion processes. The aerosol emission amounts were estimated from the obtained experimental results. Approximately 70.2 million tons (29%) of plastic waste was burned without regulation worldwide in 2016, leading to 0.92 ± 0.53 million tons of toxic aerosols being released into the air, a majority of which occurred in developing regions. The results indicate improved combustion technology and control strategies are urgently needed in developing regions for discarded plastic -waste to mitigate toxic exposure risks and achieve sustainable development.

Particulate nitrite is a critical source of hydroxyl radicals; however, it lacks high-resolution methods due to its low abundance and stability to explore its formation mechanism. In this study, a modified versatile aerosol concentration enrichment system (VACES) coupled with ion chromatography (IC) was used to measure particulate NO2- hourly online and achieve a lowered detection limit of 10-3 μg m-3. VACES-IC was used to observe a high- and low-concentration events of PM1.0-NO2- in Shanghai, corresponding to the ambient-level concentrations of 0.34 and 0.05 μg m-3, respectively. The morning peak concentrations of NO2- even exceeded 3σ (standard deviation) in the high-concentration event due to the reduction of NO2 by aerosol SO32- based on kinetics and regression analysis. This implies that controlling SO2 emissions would be an effective strategy to decrease morning NO2- concentrations, correspondingly reducing the kinetic formation of SO42- by 20.8-34.8%. However, after sunrise, NO2- formation was primarily attributed to NO2 hydrolysis at pH 4.97-6.14. In the low-concentration event, NO2 hydrolysis also accounted for an overwhelming proportion (∼90%) of NO2- formation. This work estimates the contribution of different paths to particulate NO2- formation based on newly established high-resolution measurements.

In this study, pot-culture experiments were conducted to investigate the single effect of Cd, PCBs, and the combined effect of Cd-PCBs with Tagetes patula L. The study highlights that the minimum concentration of PCBs (100 µg kg−1) could enable the growth of the plant with an increase in biomass by 27.76% when compared with the control. In all the experiments performed, the Cd concentrations over the surface parts were found to be above 100 mg kg−1. Significant positive correlations were observed between the Cd and PCBs concentrations accumulated in tissues of the soil and plants (p

Acute toxicity assay presents vital significance in modern environmental monitoring, including online detection and in-situ assay for emergency events. Although photobacteria related detection methods were established and verified in the past decades with combination of photomultiplier tube (PMT), the price and size of PMT sensor hampered application of rapid acute toxicity assay and detection system miniaturization, especially in the resource-limited occasions. Wide application of smartphones with great low-light performance cameras could be used in photobacteria-based toxicity assay instead of the PMT methods. Herein a box-type portable detection system had been successfully established, including a disc-chip for detection, detection device, and smartphones with a high-performance camera. The system performed well showing stable temperature and rotation control. Results captured by CMOS-based camera presented a linear relationship with PMT-based detection method. An image progress algorithm was also established and tested by series diluted zinc sulfate solution as a reference substance. The system also performed well for toxicity analysis for real Atmospheric particle matter sample. The system could be used in some environmental monitoring scenarios as an alternative solution.

The toxicity of atmospheric particles directly associates to health effects, but its online monitoring has not yet been implemented due to low-concentration toxic components and high measurement detection limit. To solve the detection problem, we extended a versatile aerosol concentration enrichment system (VACES) for toxicity aerosol measurement and firstly used VACES to provide a comparison of toxicity between non-concentrated and concentrated aerosols in ambient air. Through optimizing the technical parameters, the total concentration (number or mass), the concentration of chemical components, and the toxicity were all increased by approximately 7 to 10 times in VACES. In particular, ambient aerosols with toxicity below the detection limit, were detected significantly after concentration. Moreover, comparable enrichment factors and similar trends before and after enrichment in toxicity were observed over time, suggesting that the toxic properties of ambient aerosols do not change in VACES. Whereas, changes in PM2.5 concentrations and their toxicity do not always correlate well, which was probably driven by the combined toxicity effect of chemical components. Thereby, it hints a necessity to further study on the toxicity effects of chemical compositions. All above also imply that VACES could provide technical support for the future measurement of online atmospheric particulate toxicity, which is currently performed at high-concentration environment, long sampling duration, and offline.

For PM2.5 filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China) from December of 2013 to February of 2014 (the winter period), chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the 3 months, the average PM2.5 concentration was 89 µg m−3, exceeding the Chinese national standard of 75 µg m−3 in 24  h. The maximum PM2.5 concentration was 307 µg m−3, which characterizes developed-type pollution (PM2.5 / PM10>0.5) in the World Health Organization criteria. PM2.5 was dominated by SO42−, NO3−, and pseudo-carbonaceous compounds with obvious differences in concentrations and proportions between non-haze and haze episodes. The non-negative matrix factorization (NMF) analysis provided reasonable PM2.5 source profiles, by which five sources were identified: soil dust, traffic emission, biomass combustion, industrial emission, and coal combustion accounting for 13, 22, 12, 28, and 25  % of the total, respectively. The dust impact increased with northwesterlies during non-haze periods and decreased under stagnant conditions during haze periods. A blue alert of heavy air pollution was characterized by the greatest contribution from industrial emissions (61  %). During the Chinese Lantern Festival, an orange alert was issued and biomass combustion was found to be the major source owing to firework explosions. Red-alert haze was almost equally contributed by local traffic and transported coal combustion emissions from the vicinity of Beijing (approximately 40  % each) that was distinguished by the highest levels of NO3− and SO42−, respectively. This study also reveals that the severity and source of haze are largely dependent on meteorological conditions.

From October till November in 2010 and during March of 2011, when Chinese outflow events were frequently encountered, the chemical composition of submicron particles (PM1.0) was determined hourly using a particle-into-liquid sampler at the Gosan Climate Observatory. Three distinctive pollution plume types were identified: haze aerosols impacted by biomass combustion, nanoparticle bursts associated with outflow from Beijing, and saline soil particles from salt deposits. The highest PM1.0 concentration was observed in a fall haze event, under near-stagnant high-pressure synoptic conditions that were characterized by the lowest visibility ( 104 cm–3 with highly elevated SO2 levels, even during the night. When air masses move rapidly from northeastern China to Gosan under strong wind conditions, the Ca2+ concentration, along with that of Cl– and Na+, is enhanced in PM1.0, which is attributed to the influence of saline transport from dry lakes. The results of this study reveal compositional details and information on both number and mass concentration for different PM1.0 plumes from anthropogenic and natural sources, all of which are associated with different kinds of Chinese outflow events.

Thyroid hormones are key hormones involved in growth and development. Changes in their levels can cause embryonic brain developmental damage in the first trimester. Studies have shown that polybrominated diphenyl ethers (PBDEs) have developmental neurotoxicity as environmental pollutants, and exposure during pregnancy can cause irreversible brain damage in offspring, similar to the interference effects of thyroid hormones, but its mechanism has not yet been understood. Since the physiological environment for placental cells is highly hypoxic, in the current study, the human placenta-derived JEG cells were cultured at 1% oxygen, 4% carbon dioxide and 94% nitrogen, to reflect in vivo scenario, and the possible protection of taurine on BDE 209-mediated toxicity in JEG cells was studied. Our data showed that different concentrations of BDE 209 can have profound effects on cell viability and placental deiodinase 3 expression under hypoxic culture condition. Taurine was found to improve BDE 209-induced reductions in cell viability and altered gene and protein expressions of placental deiodinases. The results provide a reference for the establishment of early biomarkers and effective preventive measures.

PBDEs (stands for polybrominated diphenyl ethers) are extensively utilized flame retardants, and BDE 209 is one of the most widely used congeners. Studies have suggested the general toxic effects of PBDEs on the endocrine system and neural development. Our previous studies found that BDE 209 changed Type 3 iodothyronine deiodinase (Dio 3) expression in human SK-N-AS neuroblastoma cells. The current study was designed to examine the potential protection of taurine on alterations of Dio 3 expression induced by BDE 209 in SK-N-AS cells. Briefly, SK-N-AS cells were pretreated with taurine prior to the BDE 209 treatment, and the cell viability was evaluated by the MTT (methyl-thiazolyl-tetrazolium) assay. The disturbance or restoration in the levels of Dio 3 proteins and mRNA were observed separately by the western blot and qRT-PCR. Our data showed that taurine moderately attenuated BDE 209-mediated the loss of cell viability. Also, taurine moderately prevented the reduction in the Dio 3 protein expression and mRNA expression induced by BDE 209 in the SK-N-AS cells. Our findings indicated that taurine potentially provide the protection on PBDEs-induced toxicity on endocrine and neuro-development.

Taurine is an important amino acid for the growth and development of the central nervous system and plays an important role in the development of the nervous system. Many studies have shown that taurine can prevent and repair neurodevelopmental damage, and its mechanism has also become a research hotspot. While most studies focus on nerve cells, less on placental cells that are closely related to early neurodevelopment (developmental neurotoxicity) by modulating fetal circulation level of thyroid hormones. Studies have shown that exposure of placental cells to the common environmental endocrine disruptor BDE 209 during early pregnancy may lead to developmental neurotoxicity due to thyroid hormone interference caused by abnormal expression of deiodinases. Therefore, in this study, the placenta-derived JEG cells cultured at 95% air/5% CO2 was used as a in vitro model, and the potential protection from taurine on BDE 209-mediated cytotoxicity was examined. When BDE 209 was found to cause a decrease in cell viability and disturbance in the gene and protein expressions of placental deiodinase 3, pretreatment of the JEG cells with taurine can moderately reduce the BDE 209-meditated cytotoxicity, and restore gene and protein expressions of placental deiodinase, so that thyroid hormone levels tend to be normal in cell culture medium. Our data suggest that taurine may have some protection on the developmental neurotoxicity caused by BDE 209.

Measuring isotopic ratios in aerosol particles is a powerful tool for identifying major sources, particularly in separating fossil from non-fossil sources and investigating aerosol formation processes. We measured the radiocarbon, stable carbon, and stable nitrogen isotopic composition of PM

Decabromodiphenyl ether (BDE209) has been widely used as a flame retardant in the past four decades, leading to human health consequences, especially neurological impairments. Our previous in vivo studies have suggested that developmental neurotoxicity in offspring may be the result of BDE209-induced placental type III iodothyronine deiodinase (Dio3) disturbance and consequent thyroid hormone (TH) instability. Dio3 is paternally imprinted gene, and its balanced expression is crucial in directing normal development and growth. In this study, we used placenta-derived cells to investigate how BDE209 affected Dio3 expression through interfering imprinting mechanisms in the delta-like homolog 1 (Dlk1)-Dio3 imprinted region. Gene chip analysis and RT-qPCR identified miR409-3p, miR410-5p, miR494-3p, miR668-3p and miR889-5p as potential candidates involved in Dio3 deregulation. The sodium bisulfite-clonal sequencing revealed the BDE209 affect methylation status of two differentially methylated regions (DMRs), intergenic-DMR (IG-DMR) and maternally expressed gene 3-DMR (MEG3-DMR). Our data indicate that placental Dio3 may be a potential molecular target for future study of BDE209 developmental toxicity. In particular, miRNAs, IG-DMR and MEG3-DMR in the Dlk1-Dio3 imprinted locus may be informative in directing studies in TH disturbance and developmental toxicity induced by in utero exposure to environmental persistent organic pollutants (POPs), and those candidate miRNAs may prove to be convenient and noninvasive biomarkers for future large-scale population studies.

Measuring isotopic ratios in aerosol particles is a powerful tool for identifying major sources, particularly in separating fossil from non-fossil sources and investigating aerosol formation processes. We measured the radiocarbon, stable carbon, and stable nitrogen isotopic composition of PM2.5 in Beijing (BJ) and Changdao (CD) in the North China Plain (NCP) from May to mid-June 2016. The mean PM2.5 concentrations were 48.6 ± 28.2 μg m−3 and 71.2 ± 29.0 μg m−3 in BJ and CD, respectively, with a high contribution (∼66%) from secondary inorganic aerosol (SIA; NO3−, NH4+, and SO42−). The mean δ13C of total carbon (TC) and δ15N of total nitrogen (TN) values differed significantly between the two sites (p-value of

The North China Plain (NCP) is the most heavily polluted region in China and the explosive growth (EG) events of PM2.5 frequently occur in winter in this region. A campaign from 17 Nov. 2018 to 1 Mar. 2019 was conducted at a rural site in NCP. EG events of PM2.5 were defined as the dynamic increase in PM2.5 concentration by 100 μg/m3 within half day. The intensity of EG events were then graded by the time cost, i.e. 3, 6 and 9 h. EG events with a total number of 120 were identified during the study. Mean growth rates and corresponding standard deviations of PM2.5 of 3 h-, 6 h- and 9 h-EG events were 43.4 ± 6.9, 19.3 ± 1.8 and 12.5 ± 0.5 μg/m3/h, respectively. All of them except one 3 h-EG event occurred with windspeed lower than 2 m/s. Based on the evolution of hourly chemical composition of PM2.5, the EG events were investigated on their formation mechanism. The average mass fraction ratios of SNA (sulphate, SO42−; nitrate, NO3−; ammonium, NH4+) in PM2.5 were 26.3%/18.7%, 32.6%/18.0% and 33.6%/26.9% in 3 h-, 6 h- and 9 h-EG events in the daytime/nighttime, respectively. About two thirds of EG events occurred in the nighttime with a significant increase in the concentrations of organic matter (OM) and chloride (Cl−), which is attributable to nocturnal primary emissions such as coal combustion. In addition, CO-scaled growth rate was calculated as chemical growth rate, the results indicate that OM was the dominant components in EG events.

The measurement of volatile organic compounds (VOCs) was carried out using an online GC-FID/MS at a rural site in North China Plain from 1 Nov. 2017 to 21 Jan. 2018. Their concentrations, emission ratios and source apportionment are investigated. During the entire experiment period, the average mixing ratio of VOCs was 69.5 ± 51.9 ppb, among which alkanes contributed the most (37% on average). Eight sources were identified in the non-negative matrix factorization (NMF) model as short-chain alkanes (13.3%), biomass burning (4.6%), solvent (10.8%), industry (3.7%), coal combustion (41.1%), background (4.5%), vehicular emission (7.7%) and secondary formation (14.2%). In addition to the formation of OVOCs through photochemical reactions, the primary sources, such as coal combustion, biomass burning, vehicular emission, solvent and industry, can also contribute to OVOCs emissions. High OVOCs emission ratios thus were observed at Wangdu site. Primary emission was estimated to contribute 50%, 45%, 73%, 77%, 40%, and 29% on average to acrolein, acetone, methylvinylketone (MVK), methylethylketone (MEK), methacrolein and n-hexanal according to NMF analysis, respectively, which was well consistent with the contribution from photochemical age method. Secondary organic aerosol formation potential (SOAFP) was evaluated by SOA yield, which was significantly higher under low-NOx condition (13.4 μg m−3 ppm−1) than that under high-NOx condition (3.2 μg m−3 ppm−1). Moreover, the photochemical reactivity and sources of VOCs showed differences in seven observed pollution episodes. Among, the largest OH loss rate and SOAFP were found in severe pollution plumes, which were induced primarily by coal combustion. Therefore, mitigation strategies for severe pollution formation should focus on reducing coal combustion emitted VOCs that lead to SOA formation.

Taurine is an important amino acid for the growth and development of the central nervous system and plays an important role in the development of the nervous system. Many studies have shown that taurine can prevent and repair neurodevelopmental damage, and its mechanism has also become a research hotspot. While most studies focus on nerve cells, less on placental cells that are closely related to early neurodevelopment (developmental neurotoxicity) by modulating fetal circulation level of thyroid hormones. Studies have shown that exposure of placental cells to the common environmental endocrine disruptor BDE 209 during early pregnancy may lead to developmental neurotoxicity due to thyroid hormone interference caused by abnormal expression of deiodinases. Therefore, in this study, the placenta-derived JEG cells cultured at 95% air/5% CO2 was used as a in vitro model, and the potential protection from taurine on BDE 209-mediated cytotoxicity was examined. When BDE 209 was found to cause a decrease in cell viability and disturbance in the gene and protein expressions of placental deiodinase 3, pretreatment of the JEG cells with taurine can moderately reduce the BDE 209-meditated cytotoxicity, and restore gene and protein expressions of placental deiodinase, so that thyroid hormone levels tend to be normal in cell culture medium. Our data suggest that taurine may have some protection on the developmental neurotoxicity caused by BDE 209.

PBDEs (stands for polybrominated diphenyl ethers) are extensively utilized flame retardants, and BDE 209 is one of the most widely used congeners. Studies have suggested the general toxic effects of PBDEs on the endocrine system and neural development. Our previous studies found that BDE 209 changed Type 3 iodothyronine deiodinase (Dio 3) expression in human SK-N-AS neuroblastoma cells. The current study was designed to examine the potential protection of taurine on alterations of Dio 3 expression induced by BDE 209 in SK-N-AS cells. Briefly, SK-N-AS cells were pretreated with taurine prior to the BDE 209 treatment, and the cell viability was evaluated by the MTT (methyl-thiazolyl-tetrazolium) assay. The disturbance or restoration in the levels of Dio 3 proteins and mRNA were observed separately by the western blot and qRT-PCR. Our data showed that taurine moderately attenuated BDE 209-mediated the loss of cell viability. Also, taurine moderately prevented the reduction in the Dio 3 protein expression and mRNA expression induced by BDE 209 in the SK-N-AS cells. Our findings indicated that taurine potentially provide the protection on PBDEs-induced toxicity on endocrine and neuro-development.

In East Asia, soil dust is a major component of aerosols and is mixed with various pollutants during transport, resulting in large uncertainty in climate and environmental impact assessment and relevant policymaking. To diagnose the influence of soil dust and anthropogenic pollution on bulk aerosol, we conducted long-term measurements of mass, water-soluble ions, and carbonaceous compounds of PM10, PM2.5, and PM1 at Gosan Climate Observatory, South Korea, from August 2007 to February 2012. The principle component analyses of all measured species reveal that the impact of anthropogenic pollution, soil dust, and agricultural fertilizer accounts for 46 %, 16 %, and 9 % of the total variance, respectively. Particularly, the loadings of agricultural component were high in the warmer months with the least occurrence of high concentration events and have increased over time. In mode analysis of PM10, PM2.5, and PM1 mass concentrations, the mean + σ was comparable to the 90th percentile and thus, suggested as a robust criterion that determines the substantial impact of soil dust and haze pollution on particulate matter. The results of this study imply that non-combustion sources such as soil dust will impose constraints to the reduction of PM2.5 as well as PM10 concentrations. In addition, questions are raised as to whether the yearly average concentration is suitable for environmental standard in northeast Asian region.

For PM2.5 filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China) from December of 2013 to February of 2014 (the winter period), chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the three months, the average PM2.5 concentration was 89 µg m−3, exceeding the Chinese national standard of 75 µg m−3 in 24 h. The maximum PM2.5 concentration was 307 µg m−3, which characterizes developed-type pollution (PM2.5/PM10 > 0.5) in the World Health Organization criteria. PM2.5 was dominated by SO42−, NO3−, and pseudo-carbonaceous compounds with obvious differences in concentrations and proportions between non-haze and haze episodes. The non-negative matrix factorization (NMF) analysis provided reasonable PM2.5 source profiles, by which five sources were identified: soil dust, traffic emission, biomass combustion, industrial emission, and coal combustion accounting for 13 %, 22 %, 12 %, 28 %, and 25 %, respectively. The dust impact increased with northwesterlies during non-haze periods and decreased under stagnant condition during haze periods. A blue alert of heavy air pollution was characterized by the greatest contribution from industrial emissions (61 %). During the Chinese Lantern Festival, an orange-alert was issued and biomass combustion was found to be the major source owing to firecraker explosions. Red-alert haze was almost equally contributed by local traffic and transported coal combustion emissions from Beijing vicinities (approximately 40 % each) that was distinguished by the highest levels of NO3− and SO42−, respectively. This study also reveals that the severity and source of haze are largely dependent on meteorological conditions.