Black Carbon Research Articles

Treatment of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in stormwater using polishing columns with biochar and granular activated carbon.

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are recalcitrant organic pollutants often detected in stormwater. Various stormwater control measures (SCMs) can remove PAHs and PCBs by filtration, adsorption, and biodegradation. However, dissolved PAHs and PCBs remain present in the treated outflow of SCMs. To provide further treatment, two types of biochar (biochar A and biochar B), a granular activated carbon (GAC), and a regenerated GAC (RAC) were tested in a column study with synthetic stormwater containing PAHs and PCBs in low concentrations. Results showed that PAH concentrations were reduced by 98.2-99.8% (range: <limit of quantification (LOQ) - 1.89μg/L), while PCB concentrations were reduced by 86.0-97.9% (range: <LOQ - 0.7μg/L). The extraction of PCBs from the media showed that >62% of the PCBs accumulated at the first third of the column due to adsorption onto the black carbon material thus providing information for management. The difference in treatment performances of different PAHs and PCBs may be caused by the molecular structure of the contaminants. Lifetime calculations indicated that biochar had lifetimes >36-51 years, while GAC and RAC showed lifetimes longer than 147 and 206 years, respectively, based on predicted precipitation for scaled up designs. The results showed that biochar and activated carbons can be efficient adsorbents for stormwater polishing treatment. With consideration of efficiency, sustainability and cost, RAC is recommended for polishing treatment of dissolved PAHs and PCBs.

Long-term exposure to air pollution and greenness in association with respiratory emergency room visits and hospitalizations: The Life-GAP project.

Air pollution has been linked to respiratory diseases, while the effects of greenness remain inconclusive. We investigated the associations between exposure to particulate matter (PM2.5 and PM10), black carbon (BC), nitrogen dioxide (NO2), ozone (O3), and greenness (normalized difference vegetation index, NDVI) with respiratory emergency room visits and hospitalizations across seven Northern European centers in the European Community Respiratory Health Survey (ECRHS) study. We used modified mixed-effects Poisson regression to analyze associations of exposure in 1990, 2000 and mean exposure 1990-2000 with respiratory outcomes recorded duing ECRHS phases II and III. We assessed interactions of air pollution and greenness, and of atopic status (defined by nasal allergies and hay fever status) and greenness, on these outcomes. The analysis included 1,675 participants, resulting in 119 emergency visits and 48 hospitalizations. Increased PM2.5 by 5 μg/m³ was associated with higher relative risk (RR) of emergency visits (1990: RR 1.16, 95% CI: 1.00-1.35; 2000: RR 1.24, 95% CI: 0.98-1.57; 1990-2000: RR 1.17, 95% CI: 0.97-1.41) and hospitalizations (1990: RR 1.42, 95% CI: 1.00-2.01; 2000: RR 2.20, 95% CI: 1.43-3.38; 1990-2000: RR 1.44, 95% CI: 1.04-2.00). Similar trends were observed for PM10, BC, and NO2, with only PM10 showing significant associations with hospitalizations across all periods. No associations were found for O3. Greenness exposure was linked to more emergency visits in 2000 but to fewer hospitalizations in 1990. Significant interactions were observed between greenness and atopic status for emergency visits, and between NDVI with O3 and BC for some time windows. Long-term exposure to particulate matter was associated with increased emergency room visits and hospitalizations. Significant associations were observed for BC and NO2 with hospitalizations. No link was found with O3. Greenness indicated a lower risk of hospitalizations, but increased risks for emergency visits for those with atopic status.

Near-Time Measurement of Aerosol Optical Depth and Black Carbon Concentration at Socheongcho Ocean Research Station: Aerosol Episode Case Analysis

Near-Time Measurement of Aerosol Optical Depth and Black Carbon Concentration at Socheongcho Ocean Research Station: Aerosol Episode Case Analysis

Carbon residue from co-pyrolysis of cartons and plastics: Characteristics, environmental behaviors and applications.

The continuously growing of municipal solid waste (MSW) has posed a threat to human-being. Pyrolysis is a promising technique for MSW disposal, as it can reduce its volume and produce valuable products as well. This study evaluated the potential of carbon residue (CR) derived from waste carton as soil amendment. Additionally, considering the waste plastics, such as plastic bags, plastic tape, etc., can mix with carton in MSW, the effect of polyvinyl chloride (PVC) addition on the characteristics of CR and its environmental behavior was measured. Results showed that the CR derived from carton exhibited notable efficacy in adsorbing Cd2+ (56.111mg/g), pesticides and PO43- (0.231mmol/g), thereby mitigating pollutants and immobilizing nutrient in soil environment. The introduction of PVC was found to enhance the adsorption of CR for Cd2+ (65.623mg/g) and PO43- (0.524mmol/g), albeit exhibiting diminished performance in the removal of pesticides. Different from previous studies, this study revealed that the dissolved black carbon (DBC) released from CRs did not generate reactive oxygen species (ROS) effectively under solar irradiation, and the light screening of DBC can mitigate the photodegradation of pollutants. Furthermore, both CRs increased bacterial luminescence by approximately 70%, which indicated that no toxicity produced during the pyrolysis process. And gas chromatography-mass spectrometry (GC-MS) revealed the absence of polyaromatic hydrocarbon (PAH) in CRs. In summary, this study may provide some new insights on the disposal of MSW, and the CR made by MSW could be effective in soil amendment and reduce the leaching of pollutants and nutrient.

Imprint of incomplete combustion processes on the water column of the anthropogenic-pressured Baltic Sea.

This study evaluates the distribution and sources of thermogenic organic matter in the Baltic Sea water column, focusing on polycyclic aromatic hydrocarbons (PAH), dissolved black carbon (DBC), and the imprint of thermogenic organic matter on the dissolved organic matter (DOM) pool. The spatial patterns and complex interactions between land-based and atmospheric sources were assessed from Kiel Bay to Pomeranian Bight within the water column with the combined targeted and untargeted approaches. The findings emphasize the significant influence of terrestrial inputs from the Oder River and autochthonous production composing DOM. In the Pomeranian Bight, PAH and DBC concentrations strongly correlate with land-based discharge, while shipping emissions play a more prominent role in the Arkona Sea. The sea surface microlayer shows unique characteristics in DOM composition, with potential combustion products as an important source revealed by PAH and DOM analyses. Ultrahigh-resolution mass spectrometry identified combustion products, in the DOM pool, providing insights into anthropogenic impacts. This research contributes to a better understanding of the complex dynamics of thermogenic organic matter in coastal environments, highlighting the interplay between land-based sources, shipping emissions, and in-situ processes in the Baltic Sea region.

Multi-platform observations and constraints reveal overlooked urban sources of black carbon in Xuzhou and Dhaka

Here we use multi-waveband single scattering albedo observations from ground-based instruments and satellite to constrain black carbon aerosol's physical properties and loading over Xuzhou, China, and Dhaka, Bangladesh. Our daily high-resolution findings reveal smaller black carbon cores and spatially variable morphology dominate both regions. Column loadings reveal higher black carbon mass in Dhaka, while higher total aerosol mass and number are observed in Xuzhou. These findings reflect differences in emission sources, atmospheric conditions, and regulatory policies. Spatial analysis reveals notable enhanced black carbon along Dhaka’s urban riverbanks (8–9 mg m−2), and over rapidly changing, small industrial sites in China, indicating overlooked sources. Complex daily interactions between wind, accumulation, and dispersion challenge traditional seasonal dynamics. These findings demonstrate high-resolution data can be tailored from available remote sensing platforms, providing nuanced insights into regional air quality, enhancing assessment capabilities and informing targeted mitigation strategies.

Long-term exposure to fine particulate matter constituents and the prognosis of oral cancer patients: A prospective study in Southeastern China.

Evidence on the association of long-term exposure to fine particular matter (PM2.5) and its chemical constituents with the prognosis of oral cancer patients is limited. We identified 1673 oral cancer patients from 2011 to 2021 in Fujian, China. We evaluated annual average concentrations of PM2.5 and constituents, including nitrate, sulfate, ammonium, black carbon (BC), and organic matter (OM), using bilinear interpolation based on the patients' residential address. Cox proportional hazard models were used to calculate the hazard ratio (HR) and 95 % confidence interval. We used counterfactual analyses to evaluate the population attributable fractions (PAF). During a median follow-up duration of 3.58 years, 484 (28.93 %) died. For per-SD increase in PM2.5, nitrate, sulfate, ammonium, OM, and BC, the adjusted HRs were 1.18, 1.16, 1.18, 1.19, 1.17, and 1.20 for all-cause mortality, and 1.26, 1.22, 1.27, 1.28, 1.24, and 1.29 for oral cancer-specific mortality, respectively. The corresponding PAFs of PM2.5, nitrate, sulfate, ammonium, OM, and BC were 25.43 %, 24.19 %, 25.73 %, 25.78 %, 25.28 %, and 26.59 % for all-cause mortality, and 26.61 %, 24.19 %, 27.15 %, 27.01 %, 26.19 %, and 28.41 % for oral cancer-specific mortality, respectively. Our study showed that long-term exposure to PM2.5 and constituents might be an important risk factor for mortality among oral cancer patients.

Impact of gas flaring on acute respiratory distress among pregnant women and newborn babies in Delta State Central Senatorial District, Nigeria

Introduction: Gas flaring is a vital environmental issue that has a negative influence on health of population that host natural gases and oil wells. Exacerbated risk of abnormal outcomes for pregnant women and newborn babies are of great concern in maternal and child health. The researchers aimed to examine how gas flaring impact acute Respiratory Distress Syndrome (RDS) in women that were pregnant and newborn babies. Materials and methods: A descriptive cross-sectional survey involving 483 pregnant women of reproductive age, antenatal caregivers and healthcare professionals at health facilities in Delta State Central Senatorial District. Using a multi-stage random sampling technique, a structured survey questionnaire was used to collect respondents’ RDS experiences and that of their new borne. Data were statistically analysed with the use of SPSS. Significant level was considered at P&lt;0.05 Results: Among the 326 children recruited, 205 (42.4%) had experienced respiratory distress. Of the 483 women, 54% suffered from respiratory disease and 33% of the children had been admitted for respiratory distress on a weekly basis. While the age, educational level, gender, and marital status of women were not significant statistically with having children experiencing RDS, bearing children was statistically significant (P&lt;0.001). Health professional reported that developing severe lung infection, release of black carbon and asthma sufferers were major risk factors to RDS. Conclusion: Findings showed that there was an increased prevalence of RDS among the study sub-population. RDS contributes more to cardiovascular disease and diabetes, hence it is important to address this public health issue

High-resolution analyses of concentrations and sizes of refractory black carbon particles deposited in northwestern Greenland over the past 350 years – Part 2: Seasonal and temporal trends in refractory black carbon originated from fossil fuel combustion and biomass burning

High-resolution analyses of concentrations and sizes of refractory black carbon particles deposited in northwestern Greenland over the past 350 years – Part 2: Seasonal and temporal trends in refractory black carbon originated from fossil fuel combustion and biomass burning

Assessment of Air Pollution and Lagged Meteorological Effects in an Urban Residential Area of Kenitra City, Morocco

Complex mixtures of air pollutants, including ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), black carbon (BC), and fine particulate matter (PM2.5), present significant health risks. To understand the factors influencing air pollution levels and their temporal variations, comprehensive high-resolution long-term air pollution data are essential. This study analyzed the characteristics, lagged meteorological effects, and temporal patterns of six air pollutant concentrations over a one-year period at an urban residential site in Kenitra, Morocco. The results reveal pronounced seasonal and diurnal variations in pollutant levels, shaped by meteorological factors, emission sources, and local geographic conditions. PM2.5, SO2, and CO concentrations peaked during winter, while NO2 and CO exhibited consistent diurnal peaks during morning and evening rush hours across all seasons, driven by traffic emissions and nocturnal pollutant accumulation. In contrast, O3 concentrations were highest during summer afternoons due to photochemical reactions fueled by strong UV radiation, while winter levels were the lowest due to reduced sunlight. Lagged meteorological effects further highlighted the complexity of air pollutant dynamics. Meteorological factors, including temperature, wind speed, humidity, and pressure, significantly influenced pollutant levels, with both immediate and lagged effects observed. Lag analyses revealed that PM2.5 and BC levels responded to wind speed, temperature, and humidity over time, highlighting the temporal dynamics of dispersion and accumulation. CO is sensitive to temperature and pressure changes, with delayed impacts, while O3 formation was primarily influenced by temperature and wind speed, reflecting complex photochemical processes. SO2 concentrations were shaped by both immediate and lagged meteorological effects, with wind direction playing a key role in pollutant transport. These findings emphasize the importance of considering both immediate and lagged meteorological effects, as well as seasonal and diurnal variations, in developing air quality management strategies.

Concentrations and origins of ultrafine particles at a major European harbor.

The maritime transport sector poses significant air quality concerns, particularly in nearby cities. Ultrafine particles (UFP, diameter<100nm) are of particular concern due to their potential health impacts. This study measured particle number concentrations (PNC), size distributions (PNSD), and other pollutants including particulate matter (PM), nitrogen oxides (NOX), black carbon (BC), sulfur dioxide (SO2) and ozone (O3), organic markers and trace elements at a major European harbor and an urban background (UB) location. The average PNC at the harbor was 1.8-fold higher than at the UB, with particularly marked differences in the Aitken mode (2.4-fold higher). NOx levels were 10.5-fold higher at the harbor, and NO2, NOX and BC concentrations were 2.0 to 2.9 times greater compared to the UB site. SO2 concentrations were also 1.7-fold higher at the harbor. Two distinct types of PNC peaks were observed: daytime peaks with high Aitken mode particles likely linked to transit ship emissions, and late afternoon/nighttime peaks with higher nucleation mode particles likely linked to thermal power plant emissions, docked cruise ships, and vehicular traffic related to ferry boarding. Source apportionment of PNC-PNSD through Positive Matrix Factorization (PMF) identified four key contributors to PNC at the harbor: Regional recirculation (9%, modes: 100nm and 35nm), Nucleation (30%, mode: 18nm), Coastal background (22%, mode: 75nm), and Ship transit (33%, mode, 35nm). Concentrations of Ti, V, Cr, Ni, Cu, Zn, As, Sb, Pb and Na in the quasi-UFP range were more than twice at the harbor compared to the UB. This study provides insights into UFP concentrations and their sources within a major touristic and commercial harbor, highlighting the complexity of identifying specific contributions from various UFP emission sources in large harbors.

In Situ Characterization of Dust Storms and Their Snow‐Darkening Effect Over Himalayas

AbstractIn this study, we used satellite observations to identify 10 typical dust‐loading events over the Indian Himalayas. Next, the aerosol microphysical and optical properties during these identified dust storms are characterized using cotemporal in situ measurements over Mukteshwar, a representative site in Indian Himalayas. Relative to the background values, the mass of coarse particles (size range between 2.5 and 10 μm) and the extinction coefficient were found to be enhanced by 400% (from 24 ± 15 to 98 ± 40 μg/m3) and 175% (from 89 ± 57 Mm−1 to 156 ± 79 Mm−1), respectively, during these premonsoonal dust‐loading events. Moreover, based on the air mass trajectory, these dust storms can be categorized into two categories: (a) mineral dust events (MDEs), which involve long‐range transported dust plumes traversing through the lower troposphere to reach the Himalayas and (b) polluted dust events (PDEs), which involve short‐range transported dust plumes originating from the arid western regions of the Indian subcontinent and traveling within the heavily polluted boundary layer of the Gangetic plains before reaching the Himalayas. Interestingly, compared to the background, the SSA and AAE decrease during PDEs but increase during MDEs. More importantly, we observe a twofold increase in black carbon concentrations and the aerosol absorption coefficient (relative to the background values) during the PDEs with negligible changes during MDEs. Consequently, the aerosol‐induced snow albedo reduction (SAR) also doubles during MDEs and PDEs relative to background conditions. Thus, our findings provide robust observational evidence of substantial dust‐induced snow and glacier melting over the Himalayas.

AI-NAOS: an AI-based nonspherical aerosol optical scheme for the chemical weather model GRAPES_Meso5.1/CUACE

Abstract. The Artificial-Intelligence-based Nonspherical Aerosol Optical Scheme (AI-NAOS) is a newly developed aerosol optical module that improves the representation of aerosol optical properties for radiative transfer simulations in atmospheric models. It incorporates the nonsphericity and inhomogeneity (NSIH) of internally mixed aerosol particles through a deep learning method. Specifically, the AI-NAOS considers black carbon (BC) to be fractal aggregates and models soil dust (SD) as super-spheroids, encapsulated partially or completely with hygroscopic aerosols such as sulfate, nitrate, and aerosol water. To obtain AI-NAOS, a database of the optical properties for the models was constructed using the invariant imbedding T-matrix method (IITM), and deep neural networks (DNN) were trained based on this database. In this study, the AI-NAOS was integrated into the mesoscale version 5.1 of Global/Regional Assimilation and Prediction System with Chinese Unified Atmospheric Chemistry Environment (GRAPES_Meso5.1/CUACE). Real-case simulations were conducted during a winter with high pollution, comparing BC aerosols evaluated using three schemes with spherical aerosol models (external-mixing, core-shell, and volume-mixing schemes) and the AI-NAOS scheme. The results showed that the NSIH effect led to a moderate estimation of absorbing aerosol optical depth (AAOD) and obvious changes in aerosol radiative effects, shortwave heating rates, temperature profiles, and boundary layer height. The AAOD values based on three spherical schemes were 70.4 %, 125.3 %, and 129.3 % over the Sichuan Basin, benchmarked to AI-NAOS results. Compared to the external-mixing scheme, the direct radiative effect (DRE) induced by the NSIH effect reached +1.6 W m−2 at the top of the atmosphere (TOA) and −2.9 W m−2 at the surface. The NSIH effect could enhance the shortwave heating rate, reaching 23 %. Thus, the warming effect at 700 hPa and the cooling effect on the ground were strengthened by 21 % and 13 %, reaching +0.04 and −0.10 K, which led to a change in the height of the planetary boundary layer (PBL) by −11 m. In addition, the precipitation was inhibited by the NSIH effect, causing a 15 % further decrease. Therefore, the NSIH effects demonstrated their non-negligible impacts and highlighted the importance of incorporating them into chemical weather models.

Optimizing Exposure Measures in Large-Scale Household Air Pollution Studies: Results from the Multicountry HAPIN Trial.

Repeated measurements of household air pollution may provide better estimates of average exposure but can add to costs and participant burden. In a randomized trial of gas versus biomass cookstoves in four countries, we took supplemental personal 24-h measurements on a 10% subsample for mothers and infants, interspersed between protocol samples. Mothers had up to five postrandomization protocol measurements over 16 months, while infants had three measurements over one year. For the subsample, we added up to 6 supplemental postrandomization samples for mothers and 3 for infants, measuring PM2.5, black carbon (BC) (mothers only), and carbon monoxide (CO) at each visit. 310 mothers had both protocol (n = 1026) and supplemental (n = 1099) valid exposure measurements. For children, supplemental data sufficient for analysis were collected in only two countries; 94 infants had both protocol (n = 317) and supplemental (n = 234) samples. The geometric means for protocol and supplemental samples for mothers for PM2.5 were 37 μg/m3 and 38 μg/m3, respectively, while for infants, they were 42 μg/m3 and 46 μg/m3. Mixed models comparing supplemental to protocol samples, controlling for covariates, found few differences between protocol and supplemental samples. Supplemental analyses among control mothers with complete protocol measurements found that an average of three measurements explained 81% of the variance of the average of all six measurements.

Validation of cantilever-enhanced photoacoustic particle-size-resolved light absorption measurement using nigrosin reference particles and Mie modelling

Abstract. Particle light absorption enhancement, also known as the lensing effect, is a complex phenomenon where particles undergo optical transformation as they age. This process is influenced by several factors, including particle size. To investigate the lensing effect, this study introduces and validates a novel method for size-resolved light absorption measurements using nigrosin particles as a model system. The method combines a three-wavelength cantilever-enhanced photoacoustic spectrometer (CEPAS) with a differential mobility analyser (DMA) to achieve particle-size-resolved measurements. Nigrosin, a well-characterised, spherically shaped, and water-soluble material, was selected to demonstrate the feasibility and precision of the approach. The system showed strong agreement (R2&gt;0.94) with Mie-modelled absorption, confirming its reliability. While the broader motivation for this work lies in advancing techniques for studying ageing, coating, and absorption enhancement in black carbon and other atmospheric aerosols, the present study serves as a foundational step by validating the methodology in a controlled and simplified context. Future studies will expand the application of this method to complex systems, including coated and aggregated black carbon particles, to explore phenomena such as absorption enhancement.

Implications of Pyrolytic Gas Dynamic Evolution on Dissolved Black Carbon Formed During Production of Biochar from Nitrogen-Rich Feedstock.

Gases and dissolved black carbon (DBC) formed during pyrolysis of nitrogen-rich feedstock would affect atmospheric and aquatic environments. Yet, the mechanisms driving biomass gas evolution and DBC formation are poorly understood. Using thermogravimetric-Fourier transform infrared spectrometry and two-dimensional correlation spectroscopy, we correlated the temperature-dependent primary noncondensable gas release sequence (H2O → CO2 → HCN, NH3 → CH4 → CO) with specific defunctionalization stages in the order: dehydration, decarboxylation, denitrogenation, demethylation, and decarbonylation. Our results revealed that proteins in feedstock mainly contributed to gas releases, and low-volatile pyrolytic products contributed to DBC. Combining mass difference analysis with Fourier transform ion cyclotron resonance mass spectrometry, we showed that 44-60% of DBC molecular compositions were correlated with primary gas-releasing reactions. Dehydration (-H2O), with lower reaction energy barrier, contributed to DBC formation most at 350 and 450 °C, whereas decarboxylation (-CO2) and deamidization (-HCNO) prevailed in contributing to DBC formation at 550 °C. The aromaticity changes of DBC products formed via gas emissions were deduced. Compared to their precursors, dehydration increased DBC aromaticity, while deamidization reduced the aromaticity of DBC products. These insights on pyrolytic byproducts help predict and tune DBC properties via changing gas formed during biochar production, minimizing their negative environmental impacts.

Unprecedented East Siberian wildfires intensify Arctic snow darkening through enhanced poleward transport of black carbon.

Summer Arctic black carbon (BC) predominantly originates from boreal wildfires, significantly contributing to Arctic warming. This study examined the impact of MODIS-detected extensive East Siberian wildfires from 2019 to 2021 on Arctic BC and the associated radiative effects using GEOS-Chem and SNICAR simulations. During these years, Arctic surface BC aerosol concentrations rose to 46ngm-3, 43ngm-3, and 59ngm-3, nearly doubling levels from the low-fire year of 2022. East Siberian wildfires accounted for 62%, 75%, and 79% of elevated BC levels in 2019, 2020, and 2021, respectively. These wildfires also increased BC deposition on snow and sea ice, particularly in the Laptev and East Siberian Seas. The resulting snow contamination (30.6±5.15ngg-1, 15.4±1.29ngg-1, and 33.8±5.24ngg-1) reduced surface snow albedo, increasing summer Arctic radiative forcing over snow and sea ice by +1.38±0.65Wm-2, +0.70±0.20Wm-2, and+1.46±0.73Wm-2 in 2019, 2020, and 2021, respectively. As climate warming intensifies, more frequent extreme wildfires in East Siberia could further amplify Arctic snow darkening, potentially accelerating Arctic warming.

Atmospheric Black Carbon Evaluation in Two Sites of San Luis Potosí City During the Years 2018–2020

Nevertheless, there is a lot to know about air pollutants in Mexico’s largest cities, like San Luis Potosi City, which is one of the 12 most crowded cities and is expected to grow in the next years; however, there is little information about air pollutant levels mainly particulate matter in their regulated size fractions (PM10 or PM2.5), and its main component of the Organic fraction: Black Carbon (BC), which is especially important because of its chemical properties and their effects on human health, air pollution, and climate change. This work presents a one-year BC monitoring in the northern part of the city (2018–2019) and another one-year BC monitoring in the southern area (2019–2020) during the health contingency situation due to the SARX-CoV-2 virus to obtain direct equivalent black carbon (eBC) concentrations and their main fractions related to fossil fuel and biomass burning using aethalometer AE-33, as well as other air pollutants concentrations measured at the same periods by the governmental local monitoring network (SEGAM). At the North, BC mass annual average concentration was (1.11 µg m−3), divided into seasonal stations, the cold season was the highest with (1.44 µg m−3), followed by the dry season (1.23 µg m−3), rainy season (0.94 µg m−3) and finally warm dry season (0.83 µg m−3). In the south, BC annual average concentration was (1.96 µg m−3); divided into seasons, the highest was the dry season with (2.73 µg m−3), followed by the cold season (2.37 µg m−3), dry warm season (1.61 µg m−3) and the rainy season (1.28 µg m−3). One of the main findings was the dominance of annual mean concentrations of BC originating from fossil fuels (BCff) on the north site in the city was 0.97 and on the south site (BCff) was 0.91 due to some forest fires during the monitoring period. This study presented information from two zones of a growing city in Mexico to generate new air pollutant indicators to have a better understanding of pollutant interactions in the city, to decrease the emission precursor sources, and reduce the health risks in the population.

Black carbon effects and seasonal isotope records in the Godwin-Austen snowpack and K2 high-altitude camps

Black carbon effects and seasonal isotope records in the Godwin-Austen snowpack and K2 high-altitude camps

Effects of colloids with different compositions on benzophenone-3 biotoxicity in zebrafish embryos.

The fate of the pollutants in aquatic environment is closely related to colloids, and the carrier effect of colloids on pollutants not only affects their bioaccumulation, but may also affect their toxicity. In this study, the effects of natural colloid with different components on the biological toxicity of benzophenone-3 (BP3) to zebrafish larvae (Diano rerio) were studied. BP3 caused oxidative stress damage, thyroid system disorders and neurotoxicity in zebrafish larvae. And in the co-exposure groups, the organic and black carbon mineral (BCM) colloids enhanced the organism's antioxidant system by regulating the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), reducing the lipid peroxidation damage in larvae. BCM colloids caused the thyroid system disorders in organisms, while organic colloids exacerbated the thyroid toxicity by transporting more BP3 into organisms, inducing severe abnormal heartbeats. The BCM and organic colloids regulated the acetylcholinesterase (AChE) activity and/or 5-hydroxytryptamine (5-ht) contents by affecting the neuroactive ligand receptor interaction pathway in zebrafish larvae, significantly increasing their swimming speed in co-exposure groups under the light condition. In addition, the effects of colloid-bound and freely dissolved BP3 absorbed by organisms on their physiological and biochemical activities were different. By analyzing the relative expression of the significant differential metabolites affected by BP3 in all experimental groups, it was found that colloid-bound and freely dissolved BP3 had a synergistic effect on most of these metabolites and pathways. However, the freely dissolved BP3 interfered with the purine metabolic pathway by mediating 2-(amidino)-n1-(5-phospho-d-ribosyl)acetamidine, and the tyrosine metabolic pathway by mediating choline and uranylacetic acid, while the colloid-bound BP3 has no or inverse regulatory effects on these three metabolites. This study provided a new perspective for the biotoxicity study of the pollutants in aquatic environment, necessitating a reconsideration of the real ecological risks of emerging pollutants in the presence of natural colloids.