Source Of Matter Research Articles

Evaluate climate change and anthropogenic activities influencing geochemical variations in sediment between and within the avulsion period in the Lower Yellow River avulsion channels

The geochemical data from sediments in avulsion channels provide historical evidence of climate change and human-induced alterations in river basin environments. The present study focused on the particle size of sediments in cores and the level of geochemical variation in avulsion channels of the Lower Yellow River Delta (YRD), China. The sediment samples were collected in a depth range of 20–400 cm in avulsion channels. The collected samples were analyzed for sediment particle size and geochemical composition using standard methods. The results demonstrated rapid increases in agriculture practices, rainfall pattern changes, and terrestrial sediment runoff reduction in river basins after the 1960s. The reduced sediment loads in the Sanmenxia Reservoir significantly changed the sediment grain size and geochemical levels in the avulsion channel from August 1960.8 to January −1961.1. In particular, TC, TN, and C/N levels decreased with increasing sediment depth. The C/N values of <12 denoted completely reduced terrestrial sources of organic matter in the channel during the August 1960–January 1961 period compared to the July 1953–August 1960 period. The two-way ANOVA p-values were (p <0.016-p<0.001) strong between the avulsion periods but had no significant variation within the avulsion periods. We emphasize that this study provides a close interplay of different historical periods of geochemical variation in avulsion channel sediments in the alluvial fan YRD, and we argue that the evolution of the middle upstream river basin was subjective by climate change and human developmental actions, which impacted the YRD. In particular, reservoir-interrupted water flow and sediment reduction impacts associated with geochemical fluctuations are documented in the YRD.

The Effect of Organic Materials on the Acidity and Organic Carbon for Floating Media in Lebak Swampland

The potential of floating cultivation in lebak swampland, particularly during flood periods, is underscored by this study. Composted aquatic weeds, a rich source of organic matter, are a key component of this potential. The study measures the nutrient content in the compost and chicken manure and analyzes the effect of both on the nutrient content in floating systems. The compost and chicken manure, with their slightly acidic pH and very high organic-C content, hold significant promise. The best-growing medium, a blend of compost (375 g) and chicken manure (375 g), demonstrates optimal pH and organic-C content. Soil treatment (500 g) and compost (250 g) show the most significant effect on eggplant plant height, while the best yield is obtained from the treatment of compost (375 g) and chicken manure (375 g).

Molecular organic geochemistry and origin of oil in the Potwar Basin, Pakistan

The Potwar Basin (PTB) is a prominent geological feature located in northern part of Pakistan, and is considered as one of the active and productive regions for petroleum and gas exploration in Pakistan. In this study, eight crude oil specimens originating from three distinct fields within the PTB were comprehensively examined to decipher the environmental conditions, source of organic matter (OM) and oil-oil correlations using gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC–MS). The molecular marker and hierarchical cluster analysis of PTB oils reveal two different crude oil families. Family-I showed relatively low values of Pr/Ph, C19TT/C23TT and C25TT/C24TeT, C27-C29 regular steranes, dibenzothiophene (DBT), fluorene (FL) and dibenzofuran (DBF), as well as C26/C28 TAS (20S) and C27/C28 TAS (20R). These results suggest that Family-I crude oils derived from marine environment of suboxic water bodies with higher contribution from green algae or planktonic microbes. However, Family II contains comparatively high values of the aforementioned molecular parameters, indicating that crude oils mainly originated from a lacustrine environment with a higher contribution of plant organisms under oxidizing conditions. Saturated hydrocarbon maturity parameters such as CPI and OEP, and C3122S/(C3122S + C3122R) and C3222S/(C3222S + C3222R) indicate PTB crude oils are thermally mature, while aromatic indices reveal that Family-II crude oils are high mature. The present research defines that PTB crude oils contributed from mixed organic matter sources of marine and lacustrine majorly from marine sedimentary environment with the bloom of algae and/or higher plants.

New models of d-dimensional black holes without inner horizon and with an integrable singularity

Theoretically, it has been proposed that objects traveling radially along regular black holes (RBHs) would not be destroyed because of finite tidal forces and the absence of a singularity. However, the matter source allows the creation of an inner horizon linked to an unstable de Sitter core due to mass inflation instability. This inner horizon also gives rise to the appearance of a remnant, inhibiting complete evaporation. We introduce here a d-dimensional black hole model with Localized Sources of Matter (LSM), characterized by the absence of an inner horizon and featuring a central integrable singularity instead of an unstable de Sitter core. In our model, any object tracing a radial and timelike world-line would not be crushed by the singularity. This is attributed to finite tidal forces, the extendability of radial geodesics, and the weak nature of the singularity. Our LSM model enables the potential complete evaporation down to r h = 0 without forming a remnant. In higher dimensions, complete evaporation occurs through a phase transition, which could occur at Planck scales and be speculatively driven by the Generalized Uncertainty Principle (GUP). Unlike RBHs, our model satisfies the energy conditions. We demonstrate a linear correction to the conventional area law of entropy, distinct from the RBH's correction. Additionally, we investigate the stability of the solutions through the speed of sound.

LiteBIRD science goals and forecasts. A case study of the origin of primordial gravitational waves using large-scale CMB polarization

We study the possibility of using the LiteBIRD satellite B-mode survey to constrain models of inflation producing specific features in CMB angular power spectra. We explore a particular model example, i.e. spectator axion-SU(2) gauge field inflation. This model can source parity-violating gravitational waves from the amplification of gauge field fluctuations driven by a pseudoscalar “axionlike” field, rolling for a few e-folds during inflation. The sourced gravitational waves can exceed the vacuum contribution at reionization bump scales by about an order of magnitude and can be comparable to the vacuum contribution at recombination bump scales. We argue that a satellite mission with full sky coverage and access to the reionization bump scales is necessary to understand the origin of the primordial gravitational wave signal and distinguish among two production mechanisms: quantum vacuum fluctuations of spacetime and matter sources during inflation. We present the expected constraints on model parameters from LiteBIRD satellite simulations, which complement and expand previous studies in the literature. We find that LiteBIRD will be able to exclude with high significance standard single-field slow-roll models, such as the Starobinsky model, if the true model is the axion-SU(2) model with a feature at CMB scales. We further investigate the possibility of using the parity-violating signature of the model, such as the TB and EB angular power spectra, to disentangle it from the standard single-field slow-roll scenario. We find that most of the discriminating power of LiteBIRD will reside in BB angular power spectra rather than in TB and EB correlations.

Nutrient and organic substances emissions from diffuse sources to the rivers of Ukrainian Carpathians

Formulation of the problem. The transition from territorial-administrative to basin-based water resources management in Ukraine requires an assessment of the load of water bodies with pollutants from diffuse and point sources. Among the various components of the chemical composition of water entering water bodies, organic matter and nutrients are the most important. The Danube is the second largest river in Europe, with a basin covering the territories of 19 countries and is an important transportation waterway. Within Ukraine, the Danube is divided into the Lower Danube sub-catchment and the Tisza, Prut, and Siret River basins within the Carpathian region. The scientific results presented in this paper were obtained during research within the framework of state budgetary research works of the UHMI, the implementation of which will contribute to the further development of knowledge in the field of hydrometeorology. The results presented in the publication are important for supplementing information when writing the Danube River Basin Management Plan, which is being developed in accordance with Ukraine's obligations under the Association Agreement with the European Union. Aim of the study. To calculate the supply of nutrients and organic matter from diffuse sources to the rivers of the Danube basin within the Ukrainian Carpathians. Methods. Monitoring data of organic substances and nutrients provided by the Danube Hydrometeorological Observatory (the state surface water monitoring network of the State Emergency Service of Ukraine) for 2018 were used for calculations. To assess the load of water bodies by diffuse sources, a conceptual scheme was developed that allowed to take into account the main pathways of substances supply, i.e precipitation; water runoff from arable land, forests, meadows and pastures, built-up areas, rock outcrops, as well as from the population of rural regions without sewage systems. Scientific novelty. For the first time: the load of nutrients and organic matter in the Danube rivers within the Ukrainian Carpathians by the sources of their income was evaluated; it was found that agricultural land is the main source of emissions of inorganic nitrogen and phosphorus compounds. Practical value. The analysis of the diffuse load by nutrients and organic matter in the Danube rivers can be used as an important part of the River Basin Management Plan. The results of the calculations can also be used to develop measures to achieve certain environmental objectives. Results. The main source of organic matter in the water of rivers of the Carpathian region ere agricultural enterprises locating within rural settlements that are not equipped with sewage systems. Surface water of Prut and Tisza River basins is the most polluted by organic matter. By source, the nutrient emissions are distributed as follows. For the Tisza and Prut rivers, more than 50% of the total nitrogen compounds emissions come from agricultural land, while for the Siret River the source of nitrogen compounds are forests (46% of the total nitrogen emissions). Accordingly, the total phosphorus runoff for the Tisza and Prut rivers was distributed as follows: the dominant share (up to 45%) comes from agricultural land, the load caused by population not connected to the sewerage systems is 36%. For the Siret River, agricultural land and forested areas are of equal shares (33%) among the sources of phosphorus compounds.

Distribution and sources of sedimentary organic matter in different aquaculture areas of northeastern Zhanjiang Bay using stable carbon and nitrogen isotopes

Distribution and sources of sedimentary organic matter in different aquaculture areas of northeastern Zhanjiang Bay using stable carbon and nitrogen isotopes

Developing an ecological stoichiometry-based framework for tracing the sources of soil organic matter.

Developing an ecological stoichiometry-based framework for tracing the sources of soil organic matter.

Insights into the morphology, composition, and sources of atmospheric particulate matter on Mount Qomolangma (Everest)

Aerosol category and its physicochemical properties are key factors influencing its climate and environmental effects. To further enhance our understanding of aerosols in the Himalayas-Tibetan Plateau region, atmospheric particulate matter samples were collected at three different altitudes on Mount Qomolangma (Everest). Using an automated scanning electron microscope system, the composition, size, and morphology of 52,349 particles were analyzed. The average mass concentrations of PM1, PM2.5, and PM10 were 0.678, 5.054, and 16.698 µg/m3, respectively. Aluminosilicate particles dominated the samples, accounting for 71.5 % to 82.8 % of PM10 mass and 34.7 % to 62.4 % of the particle number. Quartz particles, carbonate particles, metal oxides, and sulfates were also observed at different periods. Carbonaceous particles made up a significant portion of aerosols, comprising 2.1 % to 9.7 % of PM10 mass and 10.4 % to 45.4 % of particle number, with their concentration showing an upward trend with altitude. Small amounts of tar ball particles and fly ash particles were also observed, providing direct evidence of anthropogenic influences on high-altitude regions, even at altitudes exceeding 6000 m. The size distribution and abundance of different particle categories were closely related to the transport trajectories of air masses. The morphology of different particle categories varied, with fly ash particles mainly spherical and carbonaceous particles exhibiting higher irregularity.

Composition and Bioreactivity of Dissolved Organic Matter Leachates From End Members in a Mountain to Prairie Transitional River Valley

AbstractRiver organic matter transformations impact the cycling of energy, carbon, and nutrients. The delivery of distinct dissolved organic matter (DOM) sources can alter aquatic DOM cycling and associated biogeochemical processes. Yet DOM source and reactivity are not well‐defined for many river systems, including in western Canada. Here, we explore DOM cycling in the mainstem of the Oldman River (stream order 6–7), a heavily regulated river network in southern Alberta (Canada). We compared seasonal river DOM content, composition, and bioavailability with nine endmember leachates from the river valley using optical properties and incubations to estimate biodegradable dissolved organic carbon (BDOC). River DOM composition was most similar to terrestrial soil leachates, followed by autochthonous DOM leachates. River DOM bioavailability was low (BDOC = 0%–16.6%, mean of 7.1%). Endmember leachate bioavailability increased from soils (BDOC = 23.9%–53.7%), to autochthonous sources (fish excretion, macrophytes, biofilm; BDOC = 49.9%–80.0%), to terrestrial vegetation (leaves, shrubs, grass; BDOC &gt; 80%), scaling positively with protein‐like DOM content and amount of leachable dissolved organic carbon (DOC), and negatively with aromaticity. Seasonally, DOC concentrations changed little despite &gt;15‐fold increases in discharge during spring. River DOM composition shifted modestly toward soil‐like endmembers in spring and more bioavailable autochthonous end members in autumn and winter. Low DOM bioavailability in the river mainstem and low DOC yields shown in previous work point to limited internal processing of DOM and limited bioavailable DOM delivery to downstream habitats, possibly due to upstream flow regulation. Our observations provide important insights into the functioning of western Canadian aquatic networks.

Depth‐Partitioning of Particulate Organic Carbon Composition in the Rising and Falling Stages of the Amazon River

AbstractThe Amazon River mobilizes organic carbon across one of the world's largest terrestrial carbon reservoirs. Quantifying the sources of particulate organic carbon (POC) to this flux is typically challenging in large systems such as the Amazon River due to hydrodynamic sorting of sediments. Here, we analyze the composition of POC collected from multiple total suspended sediment (TSS) profiles in the mainstem at Óbidos, and surface samples from the Madeira, Solimões and Tapajós Rivers. As hypothesized, TSS and POC concentrations in the mainstem increased with depth and fit well to Rouse models for sediment sorting by grain size. Coupling these profiles with Acoustic Doppler Current Profiler discharge data, we estimate a large decrease in POC flux (from 540 to 370 kg per second) between the rising and falling stages of the Amazon River mainstem. The C/N ratio and stable and radiocarbon signatures of bulk POC are less variable within the cross‐section at Óbidos and suggest that riverine POC in the Amazon River is predominantly soil‐derived. However, smaller shifts in these compositional metrics with depth, including leaf wax n‐alkanes and fatty acids, are consistent with the perspective that deeper and larger particles carry fresher, less degraded organic matter sources (i.e., vegetation debris) through the mainstem. Overall, our cross‐sectional surveys at Óbidos highlight the importance of depth‐specific sampling for estimating riverine export fluxes. At the same time, they imply that this approach to sampling is perhaps less essential with respect to characterizing the composition of POC sources exported by the river.

Variability of Dissolved Organic Matter Sources in the Upper Eurasian Arctic Ocean

AbstractChromophoric dissolved organic matter (CDOM) is a ubiquitous component in marine environments, and substantial changes in its sources and distribution, related to the carbon cycle in the Arctic Ocean, are expected due to Arctic warming. In this study, we present unique CDOM data in the Eurasian Arctic Ocean derived from the year‐round MOSAiC expedition. We used CDOM absorbance spectra and fluorescence excitation‐emission matrices in combination with parallel factor analysis to characterize differences in DOM sources and composition. Our results suggested that terrestrial DOM was less sensitive to seasonal changes but controlled by regionality in hydrography. Elevated dissolved organic carbon (DOC) levels in polar surface water were primarily derived from terrigenous sources as identified by CDOM absorption and fluorescence characteristics. In the Amundsen Basin and western Fram Strait surface waters, to which terrestrial DOM is primarily transported by the Transpolar Drift, we found, on average, a 188% larger meteoric water fraction and a 40% higher DOC concentration compared to the Atlantic water that dominated western Nansen Basin and Yermak Plateau. In the Amundsen Basin, the DOC concentration in summer of surface water was only 13% higher compared to winter season. Additionally, autochthonous DOM and chlorophyll‐a concentrations were relatively low in surface water and exhibited significant differences compared to those observed in summer, while there were significant differences between autochthonous DOM and chlorophyll‐a. We also observed that sea ice melt contributed to autochthonous DOM in summer, while storms in winter affected the vertical distribution of terrestrial and autochthonous DOM in the subsurface.

Constraints on Bianchi-I type universe with SH0ES anchored Pantheon+ SNIa data

We study the Bianchi-I cosmological model motivated by signals of statistical isotropy violation seen in cosmic microwave background (CMB) observations and others. To that end, we consider various kinds of anisotropic matter that source anisotropy in our model, specifically Cosmic strings, Magnetic fields, Domain walls and Lorentz violation generated magnetic fields. These anisotropic matter sources, taking one at a time, are studied for their co-evolution with standard model (isotropic) sources viz., dust-like (dark/normal) matter, and dark energy modelled as cosmological constant. We constrain the Hubble parameter, density fractions of anisotropic matter, cold dark matter (CDM), and dark energy (Λ) in a Bianchi-I universe with planar symmetry i.e., which has a global ellipsoidal geometry, and try to find signatures of a cosmic preferred axis if any.The latest compilation of Type Ia Supernova (SNIa) data from Pantheon+SH0ES collaboration is used in our analysis to obtain constraints on cosmological parameters and any preferred axis for our universe.In our analysis, we found mild evidence for a cosmic preferred axis. It is interesting to note that this preferred axis lies broadly in the vicinity of other prominent cosmic anisotropy axes reported in the literature from diverse data sets.Also we find some evidence for non-zero (negative) cosmic shear and eccentricity that characterize different expansion rates in different directions and deviation from an isotropic scale factor respectively.The energy density fractions of two of the sources considered are found to be non-zero at a2σ confidence level.To be more conclusive, we require more SNIa host galaxy data for tighter constraints on distance and absolute magnitude calibration which are expected to be available from the future JWST observations and others.

Infinitely degenerate slowly rotating solutions in f(R) gravity

This work tests the no-hair conjecture in f(R) gravity models. No-hair conjecture asserts that all black holes in general relativity coupled to any matter must be Kerr–Newman type. However, the conjecture fails in some cases with non-linear matter sources. Here, we address this by explicitly constructing multiple slow-rotating black hole solutions, up to second order in rotational parameter, for a class of f(R) models ( f(R)=(α0+α1R)p,p>1 ). Such an f(R) includes all higher-powers of R. We analytically show that multiple vacuum solutions satisfy the field equations up to the second order in the rotational parameter. In other words, we show that the multiple vacuum solutions depend on arbitrary constants, which depend on the coupling parameters of the model. Hence, our results indicate that the no-hair theorem for modified gravity theories merits extending to include the coupling constants. The uniqueness of our result stems from the fact that these are obtained directly from metric formalism without conformal transformation. We discuss the kinematical properties of these black hole solutions and compare them with slow-rotating Kerr. Specifically, we show that the circular orbits for the black holes in f(R) are smaller than that of Kerr. This implies that the inner-most stable circular orbit for black holes in f(R) is smaller than Kerr’s; hence, the shadow radius might also be smaller. Finally, we discuss the implications of our results for future observations.

Rates of sedimentary organic carbon preservation in the Bering Sea and Chukchi Sea, and their response to climate change over the past 75 years

The Arctic Ocean is rapidly warming. In this paper, we document changes in the source, distribution, and accumulation rate of organic matter (OM) for three sediment cores in the Bering and Chukchi seas to investigate changes to the oceanic carbon cycle over the past ∼75 years. Analyses were undertaken using bulk properties, such as total organic carbon (OC), total nitrogen (TN), stable carbon isotope (δ13C), OC to TN molar ratio (C/N), and biomarkers (lignin phenols). The OC, TN, and lignin (Σ8, in mg (g sediment)−1) contents were found to be significantly related to the fraction of sand (Sand%) as a result of sediment sorting and/or different sediment sources. Using an end-member mixing model, we estimated marine OM accounted for ∼67% of all organic matter in all cores, being the dominant source. Moreover, terrestrial OM mainly originated from angiosperm non-woody tissue, while moss contribution was negligible. In the Bering Sea shelf, OC% has not changed over time, but there have been some extreme peaks around the 1960s–1970s and in 2005, which correspond to increased terrestrial input from North American rivers. In the southern core from the Chukchi Sea, the OC% showed an apparent decrease after 2000, accompanied by an increase in sand content, likely due to enhanced delivery of volcanic rocks by the Pacific Inflow from the Bering Sea. In contrast, in the northern core from the Chukchi Sea, the OC% showed a significant increasing trend, with some peaks occurring at the same time as in the Bering Sea core. The mean increase rate was compared to the increase in Siberian riverine discharge, which both could be caused by long-term climate changes. The results highlight the regional differences in the response of OC preservation to climate change and other controlling factors. Further studies with higher spatial resolution are required to better understand the preservation of OC in response to climate change.

Geochemical implications of uranium-bearing thucholite aggregates in the Upper Permian Kupferschiefer shale, Lubin district, Poland

New inorganic and organic geochemical data from thucholite in the Upper Permian (Wuchiapingian) Kupferschiefer (T1) shale collected at the Polkowice-Sieroszowice Cu-Ag mine in Poland are presented. Thucholite, which forms spherical or granular clusters, appears scattered in the T1 dolomitic shale at the oxic-anoxic boundary occurring within the same shale member. The composition of thucholite concretions and the T1 shale differs by a higher content of U- and REE-enriched mineral phases within the thucholite concretions compared to the T1 shale, suggesting a different mineralising history. The differences also comprise higher Ntot, Ctot, Htot, Stot contents and higher C/N, C/S ratios in thucholite than in the T1 shale. The hydrocarbon composition of the thucholite and the surrounding T1 shale also varies. Both are dominated by polycyclic aromatic compounds and their phenyl derivatives. However, higher abundances of unsubstituted polycyclic aromatic hydrocarbons in the thucholite are indicative of its pyrogenic origin. Pyrolytic compounds such as benz[a]anthracene or benzo[a]pyrene are more typical of the thucholite than the T1 shale. Microscopic observations of the thucholite and its molecular composition suggest that it represents well-rounded small charcoal fragments. These charcoals were formed during low-temperature combustion, as confirmed by semifusinite reflectance values, indicating surface fire temperatures of about 400 °C, and the absence of the high-temperature pyrogenic polycyclic aromatic hydrocarbons. Charred detrital particles, likely the main source of insoluble organic matter in the thucholite, migrated to the sedimentary basin in the form of spherical carbonaceous particulates, which adsorbed uranium and REE in particular, which would further explain their different contents and sorption properties in the depositional environment. Finally, the difference in mineral content between thucholite and the T1 shale could also have been caused by microbes, which might have formed biofilms on mineral particles, and caused a change in the original mineral composition.

Heterogeneous coupling of δ13Corg and δ13Ccarb during the Shuram Excursion: Implications for a large dissolved organic carbon reservoir in the Ediacaran ocean

The Ediacaran ocean recorded the largest negative carbonate carbon isotope (δ13Ccarb) excursion in Earth's history, the Shuram Excursion (SE). The relatively invariant character of organic carbon isotope (δ13Corg) profiles during the SE has been attributed to buffering by a large dissolved organic carbon (DOC) reservoir in the ocean. However, recent studies suggest that the DOC buffering may have been highly heterogeneous, a hypothesis that can be tested by assessing variability in the spatial and temporal ranges of δ13Corg buffering during the SE. In this study, we evaluated δ13Corg and δ13Ccarb records from multiple regions globally to test the heterogeneous buffering hypothesis. Making use of a high-precision astrochronological framework, we found that the buffering effect of DOC persisted for ∼2.7 Myr in Oman, ∼4.9 Myr in South China, and ∼5.9 Myr in Australia, demonstrating its temporal heterogeneity. Heterogeneous buffering is also demonstrated at a small spatial scale for South China sections based on a correlation framework subdividing the SE into three intervals: EN3a (δ13Ccarb decline from baseline to nadir), EN3b (δ13Ccarb stabilized at nadir), and EN3c (δ13Ccarb recovery from nadir value). The duration of δ13Corg buffering increased with water depth from shallow neritic to deep pelagic areas. The buffering effect terminated within EN3a in inner-shelf areas, within EN3b in an intra-shelf basin, and within EN3c in slope areas. Spatial variation in the offset between δ13Ccarb and δ13Corg values (Δ13C(carb-org)) is consistent with multiple sources of sedimentary organic matter. An average of ∼26 ‰ in inner-shelf areas implies mainly fresh phytoplankton debris, whereas an average of ∼18 ‰ in slope areas is consistent with dominance of DOC, which is thought to have been present in abundance in deeper anoxic watermasses. Thus, our study supports a large DOC reservoir in the late Ediacaran ocean that led to heterogeneous buffering during the SE at both basinal and global scales. Large shallow-to-deep oceanic δ13Ccarb and δ13Corg gradients of similar magnitude existed both before and during the SE, indicating that the circulation and productivity dynamics of the Ediacaran ocean were not significantly changed by the SE. The downward expansion of oxidant-rich surface watermasses during the SE improved the ventilation of shelf oceans while leaving the deep ocean anoxic, setting the stage for rapid biological evolution on continental shelves during the Cambrian Explosion.

Source identification of ultrafine particulate matter and ammonia emissions in the metropolitan area

Previous studies have estimated the sources of particulate matter in the atmosphere. Among these, studying the sources of secondary aerosols harmful to human health is important. However, there is a lack of research on ammonia (NH3), a precursor to secondary aerosol formation. This study uses positive matrix factorization (PMF) model and conditional bivariate probability function (CBPF) model to estimate the sources of particulate matter and ammonia. The results showed that about 40% of the PM2.5 mass at both sites was attributable to secondary aerosol. To estimate the emission sources of ammonia that contribute to the generation of secondary aerosols, CBPF was utilized to model and compare the emission characteristics of categorized pollution sources and ammonia, and it was found that SMA had similar emission trends to industry, road dust, oil combustion, and biomass combustion, while GRA had similar emission trends to oil combustion and vehicle (diesel). Considering the results from these two regions, ammonia in the metropolitan area is more likely to be emitted from daily activities than from long distances. The study results demonstrate the major role of secondary aerosols on ambient PM2.5 concentrations and can help develop effective management strategies and policies for air pollution mitigation.

Systemic effects of settleable atmospheric particulate matter (SePM) on swamp ghost crab Ucides cordatus

Metallurgical activities are a significant source of settleable atmospheric particulate matter (SePM). The material is exposed to wind action, leading to its deposition throughout terrestrial and aquatic ecosystems, thus promoting contamination by metals and metalloids. However, knowledge of the impacts on biota is scarce. In aquatic coastal zones, evaluating hemolymph in invertebrates makes it possible to have insights into the pre-pathogenic effects and health status of organisms. Our study aimed to evaluate bioaccumulation and the sublethal effects of SePM on the mangrove crab Ucides cordatus by assessing biomarkers of cito-genotoxicity in the hemolymph. Organisms underwent a 30-day experiment with four treatments: control; 0.01 g.L−1, 0.1 g.L−1, 1 g.L−1 of SePM, with hemolymph sampled at 2, 7, 15, and 30 days of exposure to assess lipid peroxidation (LPO), DNA damage (strand break), cholinesterase (ChE) and lysosomal membrane stability (LMS). The results revealed metals' bioaccumulation in soft tissues (Al, Fe+, Fe++, Cu, Zr, Nb) and dose-time-dependent responses for LPO, DNA strand break, ChE, and LMS. Significant correlation was found between LPO and Cu (tissue), reduced LMS and Al and Fe (tissue), and Cu, Zn, Ag, and Bi in water. Hemolymph was related to the toxicokinetic and toxicodynamic of metals and metalloids from SePM in Ucides cordatus. New toxicological evidence was obtained to shed light on the impacts of SePM on the ecological status of coastal zones.

Efficient particulate matter source localization in dynamic indoor environments: An experimental study by a multi-robot system

This study tackles the urgent issue of indoor particulate matter (PM) pollutants, highlighting the critical need for efficient source localization due to its significant health risks. Moving beyond traditional constant-rate gas emission research, we explore real-world PM releases using a multi-robot system, enabling effective PM source localization in dynamically ventilated environments. Initial data collection on airflow and PM concentrations helps optimize our system for mechanical ventilation challenges. Through 90 experiments across six scenarios, we evaluate the improved whale optimization algorithm (IWOA) and improved particle swarm optimization (IPSO) methods, assessing their ability to identify both constant and variable PM sources and their adaptability to different pollutants. The results show a success rate of 73.3 % for both methods in locating constant PM sources, with IPSO offering a slight edge in efficiency. Moreover, in tasks involving ethanol vapor, the methods exhibited higher success rates, indicating uniform performance across a variety of pollutants. This consistency, alongside the noted variations in success rates, is primarily attributed to the complexities of PM dispersion. Importantly, our study highlights the methods' adaptability to periodic PM sources with variable release rates, maintaining high success without extra localization steps. This research advances indoor air quality management and emphasizes the importance of flexible, effective pollutant control strategies for public health protection.