Mass Concentration Research Articles

Properties and mechanism analysis of a novel construction dust suppressant based on polymer blending

To address the poor suppression efficacy and limited mechanical properties enhancement of traditional dust suppressants in relation to construction dust, this study adopted polymer blending to prepare binding agent SA-PVA-CMC (SPC) utilizing sodium alginate (SA), polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC). Using a response surface methodology, the optimal mass concentrations of SPC, dodecyl dimethyl betaine (BS-12), and carboxymethyl chitosan (CMCS) were determined to be 0.317 %, 0.197 %, and 0.626 %, respectively, and a novel dust suppressant (SPC/CMCS/BS-12) was developed. The performance testing revealed the outstanding capabilities of the dust suppressant in binding, wetting, water retention, and moisture absorption. Dust treated with SPC/CMCS/BS-12 attained a compressive strength of 313.93 kPa, experiencing only a 2.73 % wind erosion rate under strong wind conditions (12 m/s). Furthermore, the dust suppressant achieved an 86.67 % efficiency in removing respirable dust and up to 93.21 % for total dust. The hydrogen bonding between polymer molecular chains and the adsorption between SPC/CMCS/BS-12 and the surface of construction dust enhance the mechanical properties of the construction dust.

Virtual Instruments for Peak-Overlapping Studies to Determine Low- and High-Concentration Components with Ion Chromatography: Potassium and Sodium.

We developed the LabVIEW-based virtual instruments (VIs) to bridge a gap in commercial software and to enable systematic peak-overlapping studies to recognise the concentration levels enabling reliable simultaneous determination of major and minor constituents in samples with wide concentration proportions. The VIs were applied to a case study of the ion chromatographic determination of potassium as minor and sodium as a major ion with an IonPac CS12A column and 50 μL injection loop. Two successive studies based on multilevel two-factorial response surface experimental designs, (1) a model peak-overlapping study based on single-ion injections, and (2) an accuracy and precision study, provided guidelines for real sample analyses. By adjusting sample dilutions so that the sodium mass concentration was set to 340 mg/L, the simultaneous determination of potassium in the presence of sodium was possible in samples with sodium over potassium concentration ratios between 14 and 341. The relative expanded uncertainty associated with potassium ion determination was between 0.52 and 4.4%, and the relative bias was between -3.8 and 1.9%. We analysed Ringer's physiologic solutions, standard sea, trisodium citrate anticoagulant, and buffered citrate anticoagulant solutions. We confirmed that the VI-supported peak-overlapping studies contributed to the quality of results by enabling the evidence-based choices of concentration levels adjusted by a dilution.

Reference Material for the Composition of Fuel Oil

Electrical transformers are a key element in the process of distributing electricity from the producer to the final consumer. The reliability of electrical transformers is ensured through systematic monitoring of the structural condition using chemical analysis of fuel (transformer) oil used for electrical insulation and cooling of transformers. The working life of energy oil and paper insulation can be assessed by evaluating the content of antioxidant additive (ionol) and furan derivatives (furfuryl alcohol, furfural, 2-acetylfuran and 5-methylfurfural). The article provides a critical analysis of methods for measuring ionol and furan derivatives in oils. In particular, it has been established that the most widely used methods for the identification of ionol and furan derivatives are liquid and gas chromatography methods with preliminary isolation of analytes based on the principles of liquid/solid-phase extraction. At the same time, the need for matrix reference materials with established metrological traceability was identified for metrological support of methods for measuring the content of ionol and furan derivatives in oils. Therefore, the purpose of this study was the development of a certified reference material (CRM) for the composition of fuel oil. The technology for producing such a CRM makes it possible to prepare the material with the required concentrations of analytes. The article describes the sequence of preparation of a CRM batch and presents the conclusions of studying the stability and between-bottle homogeneity of the material. The given calculation of the standard uncertainty for the certified value of the CRM from the characterization method, heterogeneity, and instability of the material in accordance with GOST ISO Guide 35–2015 deserves attention. The metrological traceability of certified values of the CRM to the unit of value «mass fraction of a component» reproduced by the State Primary Standard of units of mass (molar) fraction and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotope dilution and gravimetry (GET 208–2019). The competence of the study is confirmed by the fact that the CRM was recognized as GSO 12232–2023.

Indoor/Outdoor particulate matter (respirable dust) and respirable crystalline silica source tracking in households located proximal to gold mine tailings in Johannesburg, South Africa

Introduction: This study aimed to investigate the concentration of Respirable Crystalline Silica (RCS) and respirable dust, Particulate matters (PM4) concentration in samples measured indoors and outdoors of the nine(9) selected households located proximal to gold mine tailings in Riverlea, Johannesburg. Materials and methods: Sampling locations were separated according to grids, based on distance from the tailings; A (<500 m from the dump), B (>500m<1 km) and C (1 km-3 km). Three households were selected from each grid zone to measure indoor and outdoor PM4 samples continuously over 24 h using GilAir constant sampling pumps. Samples were collected during dry and wet seasons, and respirable crystalline silica in PM4 samples were analysed by an X-ray diffraction method. Results: The mean indoor and outdoor PM4 mass concentrations ranged from 2.02±0.02 µg/m3 to 2.26±0.02 µg/m3, respectively. The dry season mean for PM4 mass concentrations were higher than the wet season PM4 mass concentrations in all zones. The pairwise comparison of PM4 mass concentration for dry and wet seasons revealed no statistically significant difference (p<0.05). The dry season means the indoor/outdoor ratio was greater than one across all zones, suggesting indoor activities as the primary source of PM. In both seasons, the mean indoor and outdoor RCS ranged from 0.02±0.01% to 0.06±0.03%. The mean indoor and outdoor 24 h RCS concentrations in both seasons were below the California Office of Environmental Health Hazard Assessment (OEHHA) defined 24 h ambient exposure threshold of 3 µg/m3. Conclusion: The study found that PM4 concentration was directly proportional to distance from the gold mine tailings. Using RCS as a signature chemical, we found a similar chemical composition in all samples collected in winter and dry season at varied distances. It is concluded that the gold mine tailings are the significant source of PM4 emissions. Therefore, further dust control measures needs to be implemented at the gold mine tailings.

Interaction between marine and terrestrial biogenic volatile organic compounds: Non-linear effect on secondary organic aerosol formation

Biogenic volatile organic compounds (BVOCs) are the largest source of secondary organic aerosols (SOA) globally. However, the complex interactions between marine and terrestrial BVOCs remain unclear, inhibiting our in-depth understanding of the SOA formation in the coastal areas and its environmental impacts. Here, we performed smog chamber experiments with mixed α-pinene (a typical monoterpene) and dimethyl sulfide (DMS, a typical marine emission BVOC) to investigate their possible interactions and subsequent SOA formation. It is found that DMS has a non-linear effect on SOA generation: The mass concentration and yield of SOA show increasing and then decreasing trends with the increase of the initial concentration of DMS. The increasing trend can be attributed to OH regeneration from isomerization of the CH3SCH2OO radical together with acid-catalyzed heterogeneous reactions by the oxidation of DMS, while the decreasing trend is explained by the less contribution of isomerization reaction and the high OH reactivity that inhibits the formation of low volatility products. The results from infrared spectra and mass spectra together reveal the contribution of sulfur-containing molecules in the mixed system. Moreover, the mass spectra results indicate that acidic products generated by DMS photooxidation enhance the O:C ratio, while organosulfates are produced to contribute to the formation of mixed SOA. In addition, the trends in relative abundance of highly oxygenated organic molecules (HOMs) with C8 - C10 multiple functional groups in different mixed systems agree well with the turning point of the SOA yield. The findings of this study have significant implications for understanding binary or more complex systems in the atmosphere in the coastal areas.

The Characteristics of the Chemical Composition of PM2.5 during a Severe Haze Episode in Suzhou, China

During the past decade, the air quality has been greatly improved in China since the implementation of the “Clean Air Act”. However, haze events are still being reported in some regions of China, and the pollution mechanism remains unclear. In this study, we investigate the chemical characteristics of the pollution mechanism of the PM2.5 composition in Suzhou from October 18 to December 15, 2020. A notable declining trend in temperature was observed from 18 to 27 November, which indicates the seasonal transition from fall to the winter season. Four representative periods were identified based on meteorological parameters and the PM2.5 mass concentrations. The heavy pollution period had the typical characteristics of a relatively low temperature, a high relative humidity, and mass loadings of atmospheric pollutants; nitrate was the dominant contributor to the haze pollution during this period. The nitrate formation mechanism was driven by the planetary boundary layer dynamics. The potential source contribution function model (PSCF) showed that the major PM2.5 composition originated from the northwest direction of the sampling site. The aerosol liquid water content presented increasing trends with an increasing relative humidity. The pH was the highest during the heavy pollution period, which was influenced by the aerosol liquid water content and the mass loadings of NO3−, SO42−, NH4+, and Cl−. The comprehensive analysis in this paper could improve our understanding of the nitrate pollution mechanism and environmental effects in this region.

Optimising the Particulate Emission Characteristics of a Dual-Fuel Spark Ignition Engine by Changing the Gasoline Direct Injection Strategy

In the current global scenario, it is essential to find more effective and practical solutions to mitigate the problem of particulate emissions from vehicles. In this research, particulate emission characteristics with changing GDI pressure or applying a split GDI strategy with different second injection timings were initially explored in a Dual-Fuel Spark Ignition (DFSI) engine, which employs Ethanol Port Injection (EPI) plus Gasoline Direct Injection (GDI). The experimental results show that by increasing GDI pressure (PGDI) from 5.5 MPa to 18 MPa, ignition delay (θF) shows a small decrease of 0.68 degrees. The parameters, such as maximum in-cylinder temperature (TMI) and exhaust gas temperature (TEG), each increase by 53.75 K and 13.84 K. An apparent reduction of 59.5% and 36.26% was achieved for the concentrations of particulate number (NP) and particulate mass (MP), respectively. Particulate emissions are effectively reduced by a split GDI strategy with an appropriate range of second injection timing (tGDI2). Under tGDI2 = −260 ºCA, NP and MP concentrations exhibit a relatively lower level. However, by delaying tGDI2 from −260 ºCA to −140 ºCA, there is an increase of more than 60% in NP concentration. The research findings help offer new and valuable insights into optimising particulate number and mass emissions from DFSI engines. Moreover, the findings could contribute novel and valuable insights into the optimisation of particulate emission characteristics in DFSI engines.

Spatiotemporal Characterization and Driving Factors of Fine Particulate Matter and Its Chemical Components in the Huaihe River Basin

According to the data sets of fine particulate matter （PM2.5） and its components in 35 cities in the Huaihe River Basin from 2015 to 2021, the temporal and spatial distribution patterns of pollutants were analyzed. The influence of meteorological factors on PM2.5 concentrations was examined using a random forest model. The original series of PM2.5, sulfate （SO42-）, nitrate （NO3-）, ammonium salt （NH4+）, organic matter （OM）, and black carbon （BC） were rebuilt using KZ （Kolmogorov-Zurbenko） filtering and multiple linear regression （MLR） to quantify the effects of meteorological conditions. The results demonstrated that from 2015 to 2021, the declining rates of PM2.5, SO42-, NO3-, NH4+, OM, and BC in the Huaihe River Basin were 4.71, 0.99, 1.05, 0.77, 1.01, and 0.19 μg·（m3·a）-1, respectively. The high mass concentrations of PM2.5 and its components were concentrated in the central and western regions of the HRB, whereas those in coastal and southern cities were lower. The variance contributions of the short-term, seasonal, and long-term components of PM2.5 to the original PM2.5 sequences in 35 cities were 51.6%, 35.9%, and 7.0%, respectively. The PM2.5 in coastal cities were more affected by the short-term components. The meteorological conditions were unfavorable for PM2.5 reduction in the HRB from 2015 to 2018, whereas the meteorological conditions supported the PM2.5 decrease from 2019 to 2021. From 2015 to 2021, the contribution rates of meteorological conditions to the long-term component reductions of PM2.5, SO42-, NO3-, NH4+, OM, and BC were 28.3%, 29.1%, 31.0%, 29.3%, 27.8%, and 28.6%, respectively. The contribution rates of meteorological conditions to the long-term PM2.5 reduction were 43.4%, 25.6%, 25.5%, and 20.6% in the HRB cities in Anhui, Shandong, Jiangsu, and Henan Provinces, respectively. With the decrease in PM2.5 concentration in the HRB, the sulfur oxidation rate （SOR） increased significantly, while the nitrogen oxide oxidation rate （NOR） changed little.

Application End Evaluation of Electrostatic Precipitation for Control PM and NOx Emissions from Small-Scale Combustions

Electrostatic precipitators (ESPs) have shown promise in reducing particulate matter (PM) emissions, but their potential for simultaneous NOx reduction in small-scale combustion systems remains underexplored. This study focuses on using non-thermal plasma generated in a corona discharge to reduce PM and NOx emissions from small-scale combustion. ESP was specifically designed for a commercially available 15 kW boiler with wood pellet combustion and used with both positive and negative discharge polarity to control emissions without any chemical additives. ESP performance was evaluated across a range of specific input energies (SIE) in terms of particle mass and number concentrations and NOx concentrations obtained by continuous gas analysis. ESP ensured the reduction in PM concentrations from 48 mg/m3 to the magnitude of PM content in the ambient air. The highest precipitation efficiency was observed for particles in the 20–200 nm range. Concurrently, NOx emissions were reduced by up to 78%, from 178 mg/m3 to 39 mg/m3. These results were achieved at specific input energies of 36 for positive and 48 J/L for negative corona, which is significantly lower than those reported for many existing separate PM and NOx control systems. This study demonstrates the potential of ESPs as a compact, energy-efficient solution for simultaneous PM and NOx removal in small-scale combustion systems, offering promising implications for improving air pollution control technologies for small-scale combustion systems.

Flocculation of fiber suspensions studied by Rheo-OCT

When dealing with papermaking fiber suspensions, particle flocculation takes place even before the paper web is formed. The particle flocculation depends on several aspects, including particle mass concentration (consistency), particle collisions, electrochemical interactions promoted by chemical additives, etc. Due to its impor-tance, fiber suspension flocculation has been studied for a long time in papermaking, and several methods have been developed for this purpose. The traditional techniques include, for example, focused beam reflectance micros-copy (FBRM) and high-speed video imaging (HSVI). Recently, a new optical method, optical coherence tomography (OCT), has emerged for flocculation analysis. The advantages of OCT are the possibility to study opaque suspensions, its micron-level resolution, and its high data acquisition speed. The OCT measurements can be combined with rheological (Rheo) measurements, allowing simul-taneous measurement of both the time evolution of the floc size and the suspension viscosity. In this work, we used this approach, Rheo-OCT, to study the flocculation of suspensions of various papermaking furnishes. We analyzed the time evolution of the floc size and the fiber suspension viscosity when the studied paper-making suspensions were treated with highly refined furnish (HRF) — a furnish that contained a significant amount of micofibrillated cellulose (MFC)-type fibrils — and/or chemical additives. Such studies can lead to a better under-standing of the impact of flocculation on the produced paper web in terms of qualities like formation, drainage potential, and strength behavior.

Dominant influence of biomass combustion and cross-border transport on nitrogen-containing organic compound levels in the southeastern Tibetan Plateau

Abstract. The Tibetan Plateau (TP) is highly susceptible to climate change, and nitrogen-containing organic compounds (NOCs) in fine particulate matter (PM2.5) represent one of the largest uncertainties with respect to their impact on the climate in high-altitude areas. Previous studies have shown that NOCs play a vital role in the nitrogen budget of PM2.5. However, our understanding of the composition and sources of NOCs in PM2.5, particularly in the TP, is limited. Here, we aim to enhance our understanding of NOCs in the TP region by examining their identification, concentration levels, sources, and origins. We conducted field sampling at a regional background sampling site in Gaomeigu, in the southeastern margin of the TP from 11 March to 13 May 2017, followed by laboratory analysis of the NOCs collected on the filters. The daily mass concentrations of NOCs ranged from 714.4 to 3887.1 ng m−3, with an average of 2119.4 ± 875.0 ng m−3 during the campaign. This average concentration was approximately 40 % higher than that reported at a typical regional site in the North China Plain (NCP), highlighting a more significant presence of NOCs in the Tibetan area. Biomass burning and secondary sources were identified as the major contributors to total NOCs. This was further substantiated by a regional air quality model, which indicated that over 80 % of the aerosol in the southeast of the TP originated from neighboring countries. This study improves our understanding of NOCs' contribution to PM2.5 in the TP and their potential impacts on climate stability in high-altitude areas.

Controllable generation of engine exhaust similar soot particles using an inverted nitrogen-diluted flame burner for calibration purpose

The calibration of vehicle engine exhaust PN analyzers has been a challenge due to the significant difference in properties between calibration particles and measured particles. In this study, an inverted nitrogen-diluted flame burner was designed to generate engine exhaust similar soot particles and evaluated for calibration use. The burner can produce reference-unimodal soot particles at 61–311 nm and total number concentration up to 108 #/cm3 by adjusting the flow rate of ethylene, nitrogen and air. Excellent stability of 0.91 % enables it to generate a fairly stable calibration particle flow. Mixing nitrogen in ethylene makes burner have a high degree of variability in generating smaller particles. The properties of size distribution, morphology, effective density indicate that the generated soot particles can simulate well with engine exhaust particles. TOA results indicate that the soot have high TC mass concentration of over 559.26 mg/m3 and EC/TC fraction of over 90 %.

Numerical study of the vortex-induced vibrations of a cantilevered pipe with a concentrated mass end using a wake oscillator model

In this paper, a numerical study based on a wake oscillator model has been carried out to determine the vortex-induced vibration (VIV) response characteristics of a flexible cantilevered pipe with a concentrated mass at the free end. First, a coupled model consisting of a cantilevered pipe and a wake oscillator is established, followed by discretization of the model and an iterative solution using the second-order central difference method. The displacement response and frequency response characteristics for different flow velocities and concentrated end masses have been compared. The numerical results reveal that the maximum value of the structural vibration displacement occurs at the bottom; i.e., free boundary end, for the cantilevered pipe with a concentrated mass at the free end. The dominant vibration mode typically shows a stepwise increase for an increase of the maximum flow velocity. As the vibration mode is transmitted from a lower order to a higher one, the vibration displacement of the structural end decreases fast. As the concentrated end mass increases, the dominant vibration mode shows a stepwise decrease, and as the vibration mode is transmitted from a higher order to a lower one, the vibration displacement of the structural end experiences a sharp increase.

Variations of black carbon, particulate matter and nitrogen oxides mass concentrations in urban environment with respect to winter heating period and meteorological conditions

The atmospheric concentrations of particulate pollution are of great scientific concern due to their impact on both human health and environment. This study aimed to investigate the concentration of black carbon (BC), particulate matter with an aerodynamic diameter of less than 10 micrometres (PM10) and nitrogen oxides (NOx) at an urban background environment throughout the year, and understand the impact of winter heating and meteorology on its concentration level. The campaign covered heating and non-heating periods, from 1 June 2021 to 31 May 2022. During the heating period, the mass concentrations of BC, PM10 and NOx were 1.17, 24.9 and 19.4 µg m–3, respectively. The analysis revealed that the mass concentrations of BC and NOx were 1.9 and 1.4 times greater during the heating period, respectively, compared to the non-heating period. In contrast, PM10 remained almost constant during the heating (19.4 µg m–3) and non-heating periods (20.0 µg m–3). Throughout the year, the BC mass concentration was dominated by BCFF (71.2%) originating from fossil fuel combustion with a maximum (8.43 µg m–3) during the heating period. Moreover, wind speed presented a weak negative correlation with BC (r = –0.40), PM10 (r = –0.19) and NOx (r = –0.40) during the heating period.

Free vibrations of a Continuous-discrete multi-span Beam taking into account inertial Rotation Forces

Objective. The aim of the study is to estimate free vibrations of a continuousdiscrete multi-span beam taking into account the inertial forces of rotation. The goal is to determine the spectra of natural frequencies, damping coefficients and natural modes. Method. The study is based on the methods of linear mechanics of structures; numerical and numericalanalytical calculation methods. The solution to the problem is found using the method of separation of variables. Rotational movements of particles of continuous sections are taken into account according to one of the models of the Timoshenko beam. The D'Alembert principle and hypotheses on the smallness of displacements and angles of rotation of sections are used. Result. A system of equations in matrix-vector form is obtained. The mathematical model of transverse vibrations consists of three systems of differential equations. The equation includes transverse forces, external concentrated forces, d'Alembert inertial forcesi, and linear-viscous resistance forces. The inertial forces of rotation of concentrated masses are taken into account. The boundary and other additional conditions to the equations correspond to the calculation scheme. The left end of the beam is hinged. The conjugation conditions are met at the junction of the sections. Conclusions. This random process of disturbances is very close to the processes used in deterministic problems. The amplitudes and standard deviations of displacements in the deterministic and stochastic problems almost coincide, which confirms the reliability of the proposed calculation theory. Analysis of the curves shows that the standard deviations significantly depend on the degree of correlation of the components of the vector random process of disturbances. The use of modern computing computer systems such as Matlab allows us to successfully combine the advantages of both numerical and graphical methods.

Global Influence of Organic Aerosol Volatility on Aerosol Microphysical Processes: Composition and Number

AbstractWe present MATRIX‐VBS, a new aerosol scheme that simulates organic partitioning in an aerosol microphysics model, as part of the NASA GISS ModelE Earth System Model. MATRIX‐VBS builds on its predecessor aerosol microphysics model MATRIX (Bauer et al., 2008, https://doi.org/10.5194/acp‐8‐6003‐2008) and was developed in the box model framework (Gao et al., 2017, https://doi.org/10.5194/gmd‐10‐751‐2017). The scheme features the inclusion of organic partitioning between the gas and particle phases and the photochemical aging process using the volatility‐basis set (Donahue et al., 2006, https://doi.org/10.1021/es052297c). To assess the performance of the new model, we compared its mass concentration, number concentration, and activated number concentration to the original scheme MATRIX, and evaluated its mass concentrations in four seasons against data from the NASA Atmospheric Tomography Mission (ATom) aircraft campaign. Results from MATRIX‐VBS show that organics are transported further away from their source, and their mass concentration increases aloft and decreases at the surface compared to those in MATRIX. The mass concentration of organics at the surface agrees well with measurements, and there are discrepancies for vertical profiles aloft. In the new scheme, the global mass load of organic aerosols increased by 50%, there is also an increased number of particles at the surface and fewer activated ones in most regions. The new scheme presents advanced and more comprehensive capability in simulating aerosol processes.

Multi-site comparison and source apportionment of equivalent Black Carbon mass concentrations (eBC) in United States: Southern California Basin and Rochester, New York,

Spatial and temporal variability of equivalent black carbon (eBC) mass concentrations were studied using Aethalometers (AE33 and AE21) at 10 sites, including 5 urban and 5 near-road across the south coast of California and New York-Rochester. Statistical methods were applied to perform intra-urban and multi-site comparisons. Given that nominal eBC values provided by the Aethalometer were significantly overestimated, eBC concentrations were corrected using an appropriate multiple-scattering enhancement correction factor (C0) to accurately calculate light absorption. Annual and seasonal variations highlighted the significant contributions of traffic emissions to eBC mass concentrations at all sites. Source apportionment using the Aethalometer approach demonstrated that fuel combustion—primarily from gasoline and diesel vehicles— accounted for up to 80% of eBC emissions. Emission sources were found to be largely region specific. Our findings suggest that the implementation of restrictive regulations aimed at reducing gasoline and diesel vehicle emissions, such as California's Tier 3 (SULEV, 2015) and New York (2017), has led to a higher proportion of cleaner, emission-controlled vehicles in the South Coast Air Basin compared to Rochester. However, the effects of these measures may require more time to be fully observed in traffic-polluted areas across the US.

Multi-dimensional distribution prediction of PM2.5 concentration in urban residential areas based on CNN

Air pollution has been one of the major environmental health issues in urban residential areas. Enhancing the air quality of the human environment has become a relevant research topic, but the study of the distribution characteristics of air pollutants under the influence of multi-dimensional indicators of residential building design is rarely considered. Herein, the PM2.5 spatial distribution of residential environment in Hefei, China, was simulated using ENVI-met. This research explored the influence mechanism of different design indexes on PM2.5 in the residential environment. A fast prediction method was proposed for PM2.5 based on the convolutional neural network (CNN). Furthermore, 4183 test points in the residential environment were selected to explore the influence of design indexes on PM2.5. The morphological features around the test points were transform to the images as input datasets for CNN model training. Results indicated that the PM2.5 mass concentration in the residential area decreases with the increase in height, and it is correlated with the sky viewfactor, the average height of the building and the density of the building. The accuracy of the CNN prediction model exceeds that of the ANN prediction model by 14.2 %, and the results can effectively predict the multi-dimensional distribution of the PM2.5 mass concentration in the residential environment, which could provide an effective reference and analytical tool for the creation of a healthy environment in residential areas.

Heterogeneity in the health effects of PM2.5 sources across the major metropolitan cities, South Korea: Significance of region-specific management

Ambient PM2.5, well-known for its adverse impacts on human health, is a very heterogeneous pollutant. Its chemical composition and attributable sources vary by region, influenced by meteorological and geographical conditions as well as emission sources. However, administrative policies are currently focused on mass concentrations. However, not all PM2.5 sources provide equally toxic particles. Thus, those sources that should be the focus of controls has not been the priority. In the present study, we conducted source apportionment utilizing positive matrix factorization (PMF) and investigated the association of PM2.5 source contributions with emergency department visits (EDVs) in major megacities in South Korea. Overall, an interquartile range (IQR) increment in source contribution increased the number of emergency room visits. Industry and coal combustion sources, marked by heavy metals, were principally associated with the adverse health impacts. However, the sources showing significant associations with EDVs differed across the study area. In addition, we found that region-specific relationships between PM2.5 sources and morbidity were plausible, considering the existence of relevant sources such as industrial complexes and coal-fired power plants. The analysis of source contributions according to wind conditions also supported the source-morbidity relationships. These findings suggest that administrative policies for PM2.5 control should be established and implemented considering region-specific characteristics of the links between PM2.5 sources and health impacts to maximize the control’s public health effects. Furthermore, the results of the present study indicate that PMF was an effective method for linking acute exposure to PM2.5 source types with health outcomes to prioritize its sources.

Deep learning-aided temporal downscaling of GRACE-derived terrestrial water storage anomalies across the Contiguous United States

The Gravity Recovery And Climate Experiment (GRACE) and GRACE-FollowOn (GRACE(−FO)) satellites have been monitoring Earth’s changes in terrestrial water storage (TWS) or surficial mass changes at monthly sampling and a spatial scale longer than ∼330 km (half wavelength) over the past two decades. At monthly sampling or revisit time, the use of satellite gravimetry is difficult to effectively monitor abrupt extreme weather events which are high-frequency, including the climate-induced hurricanes/cyclones, flash floods and droughts. The majority of the contemporary studies have focused on satellite gravimetry spatial downscaling, and not on reducing the temporal resolution of Earth’s mass change. Here, we developed a Deep Learning (DL) algorithm to downscale monthly GRACE/ GRACE(−FO) Mass Concentration (Mascon) TWS anomaly (TWSA) solutions to daily sampling over the Contiguous United States (CONUS), with the aim of monitoring rapidly evolving natural hazard episodes. The simulative performance of the DL algorithm is validated by comparing the modeling to an independent observation and the land hydrology model (LHM) predicted TWSA. To confirm that our daily and monthly simulations captured the climatic variations, we first compared our simulations with El Niño/La Niña Southern Oscillation (ENSO) circulation system index, which has a dominant climatological and socioeconomic impact across CONUS, and results reveal high correlations which are statistically significant. Next, we assessed the feasibilities to detect long- and short-term variations in the TWSA signals triggered by hydrological extremes, including the 2011 and 2019 Missouri River Floods, the August 2017 Atlantic Hurricane Harvey landfalls in Texas, the 2012–2017 drought in California, and the flash drought in the Northern Great Plains in 2017. Additional validation results using independent in situ observations reveal that our DL-aided gravimetry downscaled daily simulations are capable of elucidating hazards and water cycle evolutions at high temporal resolution.