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In order to evaluate the beneficiation plant environment in a more scientific and reasonable way, this paper took the workshop environment of the beneficiation plant as the research object. This paper divided the beneficiation plant into 7 evaluation units according to its functions. The evaluation indices are dust, noise, light environment, microclimate, benzene, toluene and xylene. This paper combines the G1 method and the entropy weight method to evaluate the weight of each evaluation index, the element extension model of the concentrator working environment is established by the element analysis method, and the matter element analysis method is used to establish an evaluation index system of a beneficiation plant in East China. The results show that the evaluation level of the breaking workshop and the auxiliary facilities are unqualified, the auxiliary facility is qualified, the culling workshop, culled yard and accessory building are medium, the screening workshop and grinding workshop are good. [ABSTRACT FROM AUTHOR]

Snow is a key component of the cryosphere and has significant impacts on surface energy balance, hydrology, atmospheric circulation, and etc. In addition, numerous studies have indicated that snow impurities, especially nitrate, are sensitive to sunlight and can be photolyzed to emit reactive species including NO2 and HONO, which serve as precursors of O3 and radicals and disturb the overlying atmospheric chemistry. This makes snow a reservoir of reactive species, and this reservoir is particularly important in remote and pristine regions with limited anthropogenic emissions. The magnitude of snow chemical emissions is also influenced by snow physical properties, including snow depth, density and concentrations of light-absorbing impurities (e.g., BC and dust). Exploring and elucidating the emissions and atmospheric consequences of the snow-sourced reactive species require a global or regional model with a snow module. Here, we parameterized atmospheric nitrate deposition and its distributions in snow using a regional chemical transport model, i.e., the WRF-Chem (the Weather Research and Forecasting Model coupled with Chemistry) model, and evaluated the performance of the WRF-Chem model in simulating snow cover, snow depth, and BC, dust and nitrate concentrations with field observations in northern China which is one of the regions with dense and prolong snow cover. The model reasonably reproduces the observed snow cover and depth in northeastern and northwestern China, and the observed snow dust and nitrate concentrations are also reasonably reproduced. These results illustrate the ability of WRF-Chem in simulating snow properties including concentrations of reservoir species in northern China, and in the future, we will incorporate snow nitrate photolysis in the model, exploring the emissions of snow NOx from nitrate photolysis and the impacts on local to regional atmospheric chemistry and air pollutant transformations. [ABSTRACT FROM AUTHOR]

Despite the long-term implementation of air pollution control policies in northeast China, severe haze pollution continues to occur frequently. With the adoption of a megacity (Changchun) in northeast China, we analysed the vertical characteristics of aerosols and the causes of aerosol pollution throughout the year using multisource data for providing recommendations for controlling pollution events (i.e., straw burning and fireworks). Based on a ground-based LiDAR, it was found that the extinction coefficient (EC) of aerosols at a height of 300 m in Changchun was highest in winter (0.44 km−1), followed by summer (0.28 km−1), with significant differences from those in warmer regions, such as the Yangtze River Delta. Therefore, it is recommended that air pollution control policies be differentiated between winter and summer. On Chinese New Year's Eve in Changchun, the ignition of firecrackers during the day and night caused increases in the EC at a height of 500 m to 0.37 and 0.88 km−1, respectively. It is suggested that the regulation of firecracker ignition should be reduced during the day and strengthened at night. Based on the CALIPSO and backward trajectory analysis results, two events of dust–biomass-burning composite pollution were observed in March and April. In March, the primary aerosol component was dust from western Changchun, whereas in April, the main aerosol component was biomass-burning aerosols originating from northern and eastern Changchun. Hence, reducing the intensity of spring biomass burning can mitigate the occurrence of dust–biomass-burning composite pollution. These findings can provide emission policy suggestions for areas facing similar issues regarding biomass-burning transmission pollution and firework emissions. [ABSTRACT FROM AUTHOR]

Atmospheric mineral dust is a poorly constrained yet extremely important component of the climate system. Provenance studies from geologic dust archives are crucial to understand the drivers of the dust cycle over long time scales. Our multi‐technique provenance analysis of a rare Paleogene (35–27 Ma) eolian dust sequence from Ulantatal, ∼400 km northwest of the Chinese Loess Plateau (CLP), shows that Paleogene dust transporting winds generally varied between northwesterly and westerly, the same as those in the late Neogene‐Quaternary bipolar icehouse. We propose that, as today, westerly wind circulation patterns would have been modulated by an Arctic Oscillation (AO)‐like situation, and that the warm Eocene favored a long‐term negative phase of AO, leading to meridional westerly circulation and the dominance of a northwesterly dust transport pathway. After the Eocene‐Oligocene transition (EOT), long‐term positive phase of AO‐like conditions initiated, leading to stronger and more zonal westerlies. The Siberian High (SH) also formed or strengthened at the EOT and started to control dust storm activity along the northwesterly transport pathway. We argue that increased Paleogene Northern Hemisphere (NH) ice volume was the ultimate driver of this modern‐type dust transport regime in the Ulantatal region, possibly also controlling initial Ulantatal dust sequence formation via the development of the SH and modern‐type eolian regime. The similarity between the Ulantatal and late Neogene northern CLP dust provenance signals suggests that the increased NH ice volume, via its control on the northwesterly dust transport, could have promoted increased loess formation also in the late Miocene. Plain Language Summary: Understanding the effects and responses of atmospheric mineral dust to climate changes in the geologic past is crucial for predicting future scenarios. Analysis of the source of dust deposited 35–27 million years ago in Ulantatal, Inner Mongolia, China reveals that the Central‐East Asian atmospheric circulation during this time interval was similar to that of today. Specifically, dust transport was dominated by northwesterly and westerly winds despite a significantly warmer global climate. We also propose that Arctic Oscillation (AO)‐type conditions, stemming from the temperature difference between the high and low latitudes, modulated planetary westerly winds during this period. Our results suggest that during warmer phases, a negative AO type dominated and resulted in wave‐like westerly wind patterns and a northwesterly dust transport pathway to Ulantatal. During cooler phases, the westerly circulation became stronger and more zonal. The Siberian High pressure system was possibly strengthened during increased Northern Hemisphere (NH) ice volume and further affected northwesterly dust transport. Our findings suggest that NH ice volume increase was possibly also responsible for the formation of the Ulantatal dust sequence itself. Our results imply that even under significantly warmer conditions than today, polar ice affects the long‐term dustiness in this highly populated region. Key Points: The provenance of a Paleogene (35–27 Ma) eolian dust sequence in Ulantatal, Inner Mongolia, China, reveals a modern‐type eolian regimeGlobal cooling and possibly expansion of Northern Hemisphere ice volume modulated the dust provenance by strengthening the Siberian HighLong‐term negative (positive) phase of Arctic Oscillation‐like conditions were favored in the warmhouse Eocene (coolhouse Oligocene) [ABSTRACT FROM AUTHOR]

Aerosols play a crucial role in the surface radiative budget by absorbing and scattering both shortwave and longwave radiation. While most aerosol types exhibit a relatively minor longwave radiative forcing when compared to their shortwave counterparts, dust aerosols stand out for their substantial longwave radiative forcing. In this study, radiometers, a sun photometer, a microwave radiometer and the parameterization scheme for clear-sky radiation estimation were integrated to investigate the radiative properties of aerosols. During an event in Xianghe, North China Plain, from 25 April to 27 April 2018, both the composition (anthropogenic aerosol and dust) and the aerosol optical depth (AOD, ranging from 0.3 to 1.5) changed considerably. A notable shortwave aerosol radiative effect (SARE) was revealed by the integrated system (reaching its peak at −131.27 W·m−2 on 26 April 2018), which was primarily attributed to a reduction in direct irradiance caused by anthropogenic aerosols. The SARE became relatively consistent over the three days as the AODs approached similar levels. Conversely, the longwave aerosol radiative effect (LARE) on the dust days ranged from 8.94 to 32.93 W·m−2, significantly surpassing the values measured during the days of anthropogenic aerosol pollution, which ranged from 0.35 to 28.67 W·m−2, despite lower AOD values. The LARE increased with a higher AOD and a lower Ångström exponent (AE), with a lower AE having a more pronounced impact on the LARE than a higher AOD. It was estimated that, on a daily basis, the LARE will offset approximately 25% of the SARE during dust events and during periods of heavy anthropogenic pollution. [ABSTRACT FROM AUTHOR]

Dust plays a very important role in the Earth's climate system by its direct and indirect effects. Deserts in northwestern China contribute a large amount of dust particles, both inland and outside, while the vertical distribution and transport mechanism of dust still have many uncertainties. Using Level 3 cloud-free monthly aerosol products of the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) system from 2007 to 2020, we analyzed the spatial and temporal variations and transport features for dust and polluted dust aerosols over China and the surrounding areas. The results show that the Taklimakan Desert (TD) and the Thar Desert (TRD) always act as the high-value centers of dust optical depth (DOD), while the centers of polluted dust optical depth (PDOD) are located in eastern China, the Sichuan Basin and the Indian subcontinent. The DOD shows an increasing trend in most areas, while the PDOD presents a significant decrease and increase in eastern China and central India, respectively. The largest DOD appears in spring over the TD and the Gobi Desert (GD), while the largest DOD in summer is over the TRD. Although most dusts in the TD and TRD are concentrated below 4 km, they may be higher over the TD. Most of the polluted dusts are confined to under 2 km. The dust input to the Tibetan Plateau (TP) could come from both the TD and TRD and occurs mostly in spring and summer, respectively. The polluted dusts of South Asia and the Indian subcontinent are mostly contained in the boundary layer in winter, but they could extend much higher in spring and summer, which favors their transport into southwestern China. The dust layer shows apparent seasonality. Its top reaches a higher level in spring and summer, while the base stays at a similar height in all seasons. The dust layer appears to be the thickest in spring over most areas, while the thickest layer in summer is over the TD and TRD. The polluted dust layer is thickest in the Indian subcontinent in spring. The overlapping of dust and polluted dust layers present different patterns in different regions, which suggests diverse mixture processes of dusts and pollutants. Finally, we compared and found different influences of meteorological factors, such as wind field, boundary layer height and precipitation, on the variations in DOD and PDOD over dust sources and other areas. [ABSTRACT FROM AUTHOR]

Different aerosol types exhibit distinct radiative effects in different regions, attributed to their unique optical characteristics and regional distributions. This study focuses on North China, which is impacted by both natural and anthropogenic aerosols with high concentrations and a variety of aerosol types. While many studies on aerosol direct radiative effects have been conducted in this region, the majority have focused on a specific type of aerosol or overall aerosol, leaving limited research on the direct radiative effects and contributions of different aerosol types. In this study, we use CALIPSO satellite data from 2011 to 2020 to investigate concentrations and distributions of different aerosol types. The results reveal that dust, polluted dust, polluted continental/smoke, and elevated smoke are the dominant aerosol types in North China. Based on the radiative closure experiment, we systematically calculate the radiative effects of different aerosol types and their corresponding contributions to the energy budget by combining satellite data with the Fu–Liou radiative transfer model. The annual average net aerosol direct radiative effect (ADRE) of North China is −6.1 and −13.43 W m−2 at the TOA and surface, respectively, causing a net warming effect of 7.33 W m−2 in the atmosphere. For each main aerosol type, dust contributes 93% to the shortwave ADRE in the western dust source region, while polluted dust mainly contributes 31% and 45% of the total ADRE, in Northwest China and North China Plain, respectively. Anthropogenic pollutant aerosols account for 58% of the total ADRE in Northeast China. This study holds great significance in elucidating the dominant aerosol types and their concentrations in North China, comprehending the impacts of different aerosol types on the local energy balance. [ABSTRACT FROM AUTHOR]

• Characteristics of PM 2.5 components, VOCs during the haze and dust period were investigated. • SOC were estimated by EC tracer method. • SOA formation were enhanced during dust episode. • Photochemical reactions were responsible for the enhanced SOA formation. To investigate the effect of frequently occurring mineral dust on the formation of secondary organic aerosol (SOA), 106 volatile organic compounds (VOCs), trace gas pollutants and chemical components of PM 2.5 were measured continuously in January 2021 in Wuhan, Central China. The observation period was divided into two stages that included a haze period and a following dust period, based on the ratio of PM 2.5 and PM 10 concentrations. The average ratio of secondary organic carbon (SOC) to elemental carbon (EC) was 1.98 during the dust period, which was higher than that during the haze period (0.69). The contribution of SOA to PM 2.5 also increased from 2.75% to 8.64%. The analysis of the relationships between the SOA and relative humidity (RH) and the odd oxygen (e.g., O X = O 3 + NO 2) levels suggested that photochemical reactions played a more important role in the enhancement of SOA production during the dust period than the aqueous-phase reactions. The heterogeneous photochemical production of OH radicals in the presence of metal oxides during the dust period was believed to be enhanced. Meanwhile, the ratios of trans-2-butene to cis-2-butene and m-/p-xylene to ethylbenzene (X/E) dropped significantly, confirming that stronger photochemical reactions occurred and SOA precursors formed efficiently. These results verified the laboratory findings that metal oxides in mineral dust could catalyse the oxidation of VOCs and induce higher SOA production. [Display omitted] [ABSTRACT FROM AUTHOR]

Open-pit mining activities inevitably affect the surrounding ecological environment. Therefore, it is crucial to clarify the disturbance characteristics of open-pit mining activities on the surrounding vegetation and scientifically implement ecological restoration projects. This study investigates the impact of open-pit coal mining in arid and semi-arid regions on surrounding vegetation from a vegetation phenology perspective. Initially, we construct a high-frequency time series of vegetation indices by Harmonized Landsat 8 and Sentinel-2 surface reflectance dataset (HLS). These time series are then fitted using the Double Logistic and Asymmetric Gaussian methods. Subsequently, we quantify three pivotal phenological phases: Start of Season (SOS), End of Season (EOS), and Length of Season (LOS) from the fitted time series. Finally, utilizing mine boundaries as spatial units, we create a buffer zone of 100 m increments to statistically analyze changes in phenological phases. The results reveal an exponential variation in vegetation phenological metrics with increasing distance from the mining areas of Heidaigou-Haerwusu (HDG-HEWS), Mengxiang (MX), and Xingda (XD) in northwest China. Then, we propose a method to identify the disturbance range. HDG-HEWS, MX, and XD mining areas exhibit disturbance ranges of 1485.39 m, 1571.47 m, and 671.92 m for SOS, and 816.72 m, 824.73 m, and 468.92 m for EOS, respectively. Mineral dust is one of the primary factors for the difference in the disturbance range. The HDG-HEWS mining area exhibits the most significant disruption to vegetation phenological metrics, resulting in a delay of 6.4 ± 3.4 days in SOS, an advancement of 4.3 ± 3.9 days in the EOS, and a shortening of 6.7 ± 3.5 days in the LOS. Furthermore, the overlapping disturbance zones of the two mining areas exacerbate the impact on phenological metrics, with disturbance intensities for SOS, EOS, and LOS being 1.38, 1.20, and 1.33 times those caused by a single mining area. These research results are expected to provide a reference for the formulation of dust suppression measures and ecological restoration plans for open-pit mining areas. [ABSTRACT FROM AUTHOR]

To further promote dust control efforts in Chinese open-pit coal mines, this study focuses on the research of coal dust and rock dust produced by different explosions in the Haerwusu open-pit coal mine in China. By investigating the relationship between the physical and chemical characteristics of dust particles from explosions in open-pit mines and the wetting properties of dust, the main factors influencing the wetting properties of explosive dust are identified. This provides a theoretical basis for subsequent dust control work in open-pit coal mines. Simultaneously, to formulate more effective dust suppressants and reduce explosive dust pollution, this study conducts experiments on the surface tension, contact angles, and complex solution compatibility to select suitable surfactants. Ultimately, the effectiveness of the dust suppressants is evaluated through permeability experiments and indoor dust suppression experiments. The research findings are as follows: (1) The significant factors affecting the wetting properties of coal dust are the fixed carbon content and D50, while the significant factor affecting the wetting properties of rock dust is D50. (2) The formulated dust suppressants can increase the permeation height of coal dust by at least 10 times, increase moisture absorption by at least 4 times, and reduce the TSP concentration by at least 81.4%. [ABSTRACT FROM AUTHOR]

Breathing clean air is a human right still not accessible to everyone. In most of the world, the air is polluted, which affects both the environment and human health. To investigate the air pollution situation in a semi‐rural part of northern China, particles with a diameter below 2.5 μm (PM2.5) were collected in Changping, 40 km northwest of Beijing in May and June 2016. The particles were analyzed for mass, trace elements, and black carbon (BC). The mean PM2.5 mass was 49 μg/m3, ranging from 3.1 to 266 μg/m3. S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, As, and Pb were determined by Energy Dispersive X‐Ray Fluorescence (EDXRF). They constituted 4% of the PM2.5 mass, with BC adding another 3%. Enrichment factor evaluation identified S, Ni, Cu, Zn, As, and Pb as the main anthropogenic contributors to environmental impact. A pollution load index (PLI) of 0.03 showed that the site could not be considered as polluted by the trace elements in PM2.5. Positive matrix factorization (PMF) was used for source apportionment of the PM2.5 content. The PMF analysis reveals that a mixture of mineral dust, fossil fuel combustion, industries, and salts were the main sources of air pollution. The non‐carcinogenic and carcinogenic health risks were assessed, and both show a small health risk in the short study period. Following the development of PM2.5 concentrations over time in this part of China shows a decreasing trend of PM2.5 pollution, which is promising for the future. [ABSTRACT FROM AUTHOR]

Ice-nucleating particles (INPs) are crucial for cloud freezing processes in the atmosphere. Given the limited knowledge about the vertical distribution of INPs and its relation to aerosols in China, we present two aircraft observations of INPs over the North China Plain on 23 October 2019 and 25 October 2019, before and after a cold front passage. We used a well-established method to identify the INPs on a silicon wafer and then performed single-particle chemical composition analysis using an environmental scanning electron microscope-energy dispersive spectrometer (ESEM-EDS). The INP concentrations range from 0.1 to 9.2 L−1 within activation temperatures from −20 to −29 °C. INPs are mostly concentrated within the boundary layer, and their concentration shows a decreasing trend with height (0.5~6 km) before the cold front passage. However, the highest INP concentration always appears at higher altitudes (4~5 km) after the cold front passage. The cold front passage also significantly weakens the correlations between the concentrations of INPs and aerosol particles at different sizes. The activated fraction (AF) of total aerosols increases from 10−6 to 10−4 with height from near ground to 6 km, reflecting a better nucleating capacity of the aerosols at higher altitudes. There is no obvious variation in AF after the cold front passage. Chemical analysis reveals that the INPs containing mineral dust components comprise the majority of total INPs during both flights. The proportion of pure mineral dust declines from 52.2% to 43.5% after the cold front passage while the proportion of mixed mineral dust increases from 23.9% to 45.7%, suggesting that an increased probability of aging or coating of INPs is introduced by the cold front during their long-distance transport. In addition, 88% of INPs have a diameter larger than 1 μm. This indicates that larger aerosols (>1 μm) are the major contributors to INPs at high altitudes despite their relatively low abundance. Our results demonstrate a significant impact of transport events on the sources and vertical distribution of INPs in the atmosphere. [ABSTRACT FROM AUTHOR]

Dust is a major source of atmospheric aerosols. Its chemical composition is often assumed to be similar to the parent soil. However, this assumption has not been rigorously verified. Here, we generated dust aerosols from soils to determine if there is particle-size-dependent selectivity of heavy metals in the dust generation. Mn, Cd, Pb and other heavy metals were found to be highly enriched in fine-dust (PM 2.5) aerosols, which can be up to ∼ 6.5-fold. To calculate the contributions of dust to atmospheric heavy metals, regional air quality models usually use the dust chemical profiles from the U.S. Environmental Protection Agency's (EPA) SPECIATE database, which does not capture the correct size-dependent selectivity of heavy metals in dust aerosols. Our air quality modeling for China demonstrates that the calculated contribution of fine-dust aerosols to atmospheric heavy metals, as well as their cancer risks, could have significant errors without using proper dust profiles. [ABSTRACT FROM AUTHOR]

In order to understand the mechanism of dust aerosol influence on regional climate change, it is crucial to quantify the radiative forcing effect of dust aerosols. However, studies on the direct radiative forcing of dust aerosols over long time series in China are still lacking. The direct radiative forcing effect of dust aerosols in China over the past 20 years was simulated and evaluated based on the WRF-Chem (Weather Research and Forecasting model coupled to Chemistry) model in conjunction with remote sensing satellites and ground-based observations. The results showed that dust aerosols exhibited an obvious inter-annual positive radiative forcing effect (about 0.38 W m−2) on net radiation at the top of the atmosphere, mainly in northwest China and the North China Plain, while at the atmosphere dust aerosols presented negative radiative forcing effects on shortwave radiation and positive effects on longwave radiation, with a value of 1.54 W m−2 of net radiative forcing, showing a warming effect. Dust aerosols have a net radiative forcing value of −1.16 W m−2 at the surface, indicating a cooling effect, with a positive forcing effect on longwave radiation and a negative forcing effect on shortwave radiation, both of which coincide with the geographical distribution of dust aerosol concentrations. In terms of inter-monthly variations, at both the atmosphere and top of the atmosphere, the dust aerosols net radiative forcing values showed an increasing trend, with March (−0.20 W m−2 and 0.68 W m−2) < April (0.48 W m−2 and 1.44 W m−2) < May (0.94 W m−2 and 2.42 W m−2). Meanwhile, at the surface, the dust aerosols net radiative forcing values displayed a decreasing trend, with March (−0.88 W m−2) > April (−0.96 W m−2) > May (−1.48 W m−2). [ABSTRACT FROM AUTHOR]

Dust storms are one of the most frequent meteorological disasters in China, endangering agricultural production, transportation, air quality, and the safety of people's lives and property. Against the backdrop of climate change, Mongolia's contribution to China's dust cannot be ignored in recent years. In this study, we used the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), along with dynamic dust sources and the HYSPLIT model, to analyze the contributions of different dust sources to dust concentrations in northern China in March and April 2023. The results show that the frequency of dust storms in 2023 was the highest observed in the past decade. Mongolia and the Taklimakan Desert were identified as two main dust sources contributing to northern China. Specifically, Mongolia contributed more than 42% of dust, while the Taklimakan Desert accounted for 26%. A cold high-pressure center, a cold front, and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China, where they affected most parts of the region. Moreover, two machine learning methods [the XGBoost algorithm and the Synthetic Minority Oversampling Technique (SMOTE)] were used to forecast the dust storms in March 2023, based on ground observations and WRF-Chem simulations over East Asia. XGBoost-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023, with a mean absolute error of 33.8 µg m−3 and RMSE of 54.2 µg m−3. [ABSTRACT FROM AUTHOR]

Long‐range transport and vertical distribution of aerosols are important factors for assessing the uncertainty in aerosol radiative forcing. This paper reveals the vertical distribution and trends of aerosol optical properties in China using 15 years of Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) data. The Hybrid Single‐Particle Lagrangian integrated trajectory model was used to analyze the transport and trends of aerosols in the layer with the highest occurrence frequencies of dust, polluted dust, polluted continental and elevated smoke aerosols. The results indicated that (a) there were significant regional and seasonal differences in the vertical distribution of aerosols. The aerosol optical depth (AOD) trend in a given region depends on the changes in the aerosol type with the highest frequency and the layer corresponding to the largest AOD in the vertical profile. The frequency of polluted dust aerosols was the highest in Beijing‐Tianjin‐Hebei (BTH) and Central China. The considerable decrease in the 0–2 km AOD led to a significant trend of the column AOD. (b) The changes of AOD and main aerosol types in a region are also affected by the changes of aerosol sources and long‐range transport pathways. In the BTH, dust aerosols originated from the Mongolian Plateau, accounting for 57.88% of the total trajectories. The Pearl River Delta was dominated by elevated smoke aerosols, with trajectories mainly originating from the Myanmar and Vietnam, accounting for 27.38% and 29.59%, respectively. The trend of 15‐year backward trajectories of dust aerosols on the Tibetan Plateau indicated that the trajectory from India is increasing. Plain Language Summary: Aerosols are one of the main factors affecting global climate change, influencing global radiation through direct and indirect effects. Long‐range transport aerosols and their vertical distribution are important factors for assessing the uncertainty in aerosol radiative forcing. At present, there is limited research on the vertical distribution and transport pathways of different types of aerosols in multiple regions over China. Considering that aerosols in different regions of China exhibit large vertical distribution and transport differences, we revealed the vertical distribution and trends of aerosol optical properties in China using 15 years of Cloud‐Aerosol Lidar with Orthogonal Polarization data. The Hybrid Single‐Particle Lagrangian Integrated Trajectory model was used to analyze the transport and trends of different aerosols. We found significant regional and seasonal differences in the vertical distributions of aerosols. The changes in the aerosol optical depth and main aerosol types in a given region were also significantly affected by the changes in aerosol transport sources and transport pathways. This study provides comprehensive insight into the vertical distribution and transport characteristics of different types of atmospheric aerosols in the Chinese region over the last 15 years, which is very important to further evaluation of the impact of different aerosol types on the radiative effects and the environment. Key Points: The vertical distribution of aerosol optical properties exhibits notable seasonal and regional differences using 15 years of Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) dataThe trend of total aerosol optical depth (AOD) mainly depends on the joint changes of the highest frequency aerosol and the maximum AOD layer in a vertical profileThe changes of AOD and main aerosol types in a region are also affected by the changes of aerosol transport sources and transport pathways [ABSTRACT FROM AUTHOR]

Despite intensive research exploring how aerosols respond to emission control over Northern China, efforts mostly focus on the environmental benefit, especially in winter. Here we found that unlike the most substantial PM2.5 concentration reduction in winter, aerosol optical depth (AOD) declines more than 2 times faster in summer, causing an increase in aerosol radiative effects of 1.2 (5.7)Wm−2 on all‐sky (clear‐sky) conditions over 2013–2019 and largely shaping the climate impact. Low‐level aerosols are shown to be the prime contributor under the synergetic effects of aerosol composition and ambient relative humidity (RH). The dominance of the highly hygroscopic sulfate combined with high RH enables a strong extinction efficiency of the reduced summertime aerosols, while the insignificant AOD decline in wintertime result from the dominance of organic aerosols with weak hygroscopicity, and is further offset by the increased frequencies of extremely high RH. We show the environmental and climatic responses of aerosols to emission control exhibit distinctively different seasonality. Plain Language Summary: Although many efforts have been devoted to assessing the aerosol responses to emission reductions in Northern China, these efforts mostly focus on the environmental benefit, especially in winter. Here we examined the seasonal features of aerosol changes over 2013–2019 and found a distinct seasonality for trends of aerosol concentrations and optical properties. Unlike the most substantial PM2.5 concentration reduction in winter, aerosol optical depth (AOD) declines much faster in summer by a factor of 2–2.9 and causes an increase in aerosol radiative effects of 5.7 and 1.2 m−2 on clear and all‐sky conditions. Low‐level aerosols are shown to play the prime role. The highly hygroscopic sulfate, combined with the high ambient relative humidity (RH) leads to a strong extinction efficiency of the reduced summertime aerosols, which explains the remarkable AOD decline. Contrarily, changes in winter are dominated by organic aerosols (OA). Though the sharp reduction of primary OA emissions leads to a more prominent decline of PM2.5 concentrations in winter, the corresponding AOD decrease remains insignificant due to its weak hygroscopicity and is offset by the increasing frequency of extremely high RH conditions. Our work demonstrates the synergetic effects of aerosol composition and ambient RH on the distinctively different environmental and climatic responses of aerosols. Key Points: Trends of aerosol concentrations and optical properties show different seasonality, with a larger decline in winter and summer separatelyChanges in low‐level aerosols below 1 km play a prime role under the synergetic effects of aerosol composition and relative humiditySummertime aerosol changes cause an increase in aerosol radiative effects of 1.2 Wm−2 over 2013–2019, largely shaping the climate impact [ABSTRACT FROM AUTHOR]

The snow physical parameters are closely related to the sizes, shapes, and chemical composition of light‐absorbing particles (LAPs). By utilizing a computer‐controlled scanning electron microscope software called IntelliSEM‐EPASTM, we first report the measured size‐resolved concentration of soot, dust, and fly ash particles in fresh (wet) and aged (dry deposition) snow samples collected at an industrial city in China during and after a snowfall at intervals of 6–8 days. Due to wet scavenging by seasonal snow, soot and dust particles in snow are absorbed by 69.7% and 30.3% at wavelengths of 550 nm, lowering snow albedo by 0.0089 and 0.0039, respectively. Soot particle size increases slightly during dry deposition, whereas size‐resolved mineral dust does not undergo a significant shift in particle size. These results indicate the essentiality to involve the effects of accurate size and composition of in‐snow LAPs for a better assessment of snow light absorption and reflectance. Plain Language Summary: A field survey was undertaken to collect freshly fallen (1) and aged surface (15) snow samples at 1‐day intervals in the center of Changchun city, China, which is surrounded by heavy industrial emission sources. We used an advanced computer‐controlled scanning electron microscope to determine particle size and number distributions of three major light‐absorbing particle types with diameters of 0.2–10 μm in seasonal snow, namely soot, dust, and fly ash. Soot and dust particles deposited in various ice‐grain sizes via wet and dry deposition were also examined in terms of their contributions to light absorption and snow albedo reduction. We report here a first attempt to detect a combination of log‐normal soot, dust, and fly ash in seasonal snow, as well as their potential effects on the reduction of snow albedo. Key Points: Computer‐controlled scanning electron microscopy was used to identify size‐resolved light‐absorbing particles in surface snowSoot particle size increases slightly during dry deposition, whereas size‐resolved dust doesn't undergo a significant shift in particle sizeSize‐resolved soot and dust are critical factors in the determination of snow light absorption and albedo [ABSTRACT FROM AUTHOR]

The direct ingestion of indoor dust particles at historical heritage sites is a primary exposure pathway for employees to heavy metals. Water-soluble ions (WSIs) and heavy metal levels, sources, bioaccessibility, and health risks associated with indoor dust in the Mogao Grottoes were analyzed using comprehensive methods to determine the differences in the concentrations and distribution characteristics of WSIs and heavy metals between statue dust and floor dust. The concentrations of WSIs and heavy metals and the magnetic values of χ lf and SIRM in indoor dust were higher than those in street dust and topsoil. The mean χ lf and SIRM of statue dust particles were 100.3 × 10 − 8 m 3 k g − 1 and 1686.9 × 1 0 − 5 Am 2 k g − 1 . Specifically, the concentration of Pb was 277 mg k g − 1 , 15-fold higher than the background value, indicating the continual receipt of heavy metals with high magnetic minerals during dust deposition. WSIs mainly originate from the weathering of surrounding rocks and earthen plaster; Pb originates from the shedding of paint of murals and sculptures; and Zn, Cu, and magnetic minerals originate from traffic sources. The bioaccessibility of heavy metals is high in the gastrointestinal phases of indoor dust. Overall, the health risks posed by heavy metals in indoor dust were low, with moderate to high risks in individual caves. Ingestion presents the highest noncarcinogenic and carcinogenic risk to employees. These results provide essential knowledge on indoor dust characteristics in the Mogao Grottoes, facilitating strategies for dust pollution mitigation and employee health risk control. [ABSTRACT FROM AUTHOR]

With the abrupt and significant drop of PM2.5 concentrations during the lockdown in 2020, hourly direct radiation (Rdir) at surface substantially increased in East China, such as Zhengzhou, Wuhan and Baoshan, with the maximum enhancement of 86% at Wuhan. Most of these stations had decreased diffuse radiation (Rdif) except Zhengzhou. Zhengzhou had both enhanced Rdir and Rdif, as well as reduced but still high PM2.5 concentrations, indicating atmospheric particles were more scattering in this region. At Beijing and Harbin in North and Northeast China, intensification of aerosol pollution led to hourly Rdir (Rdif) falling (rising) up to −28% (59%) and −23% (40%), respectively. By contrast, surface solar radiation (SSR) in West China was also greatly influenced by the elevated dust/smoke layers, revealed by aerosol layer vertical distribution and the reduction of SSR and PM2.5 concentrations. This study highlighted the importance of aerosol optical properties and vertical structures in aerosol–radiation interactions. Plain Language Summary: Atmospheric particulate matters block sunlight and reduce the amount of solar radiation reaching the ground. The emission reduction during the COVID‐19 Atmospheric particulate matters block sunlight and reduce the amount of solar radiation reaching the ground. The emission reduction during the COVID‐19 lockdown reduced fine particles (PM2.5) concentrations and resulted in substantial rise of direct radiation and drop of diffuse radiation at most stations in East China, with Wuhan having the maximum enhancement in direct radiation of 86%. The unusual increase of PM2.5 concentrations during the control period in North and Northeast China also correspondingly declined (enhanced) the observed direct (diffuse) radiation at surface. Actually, surface solar radiation is affected not only by particles near the ground, but also by aerosols at high levels. For example, the elevated layer of smoke/dust weakened the direct radiation at Urumqi, Yuzhong, Lhasa and Kunming in West China. In addition, the absorbing/scattering property of ambient aerosols also played a role in the aerosol‐radiation interactions, suggested by the unique increase in both direct and diffuse radiation, as well as reduced but still high PM2.5 concentrations at Zhengzhou. This study provided observational evidences and quantitative ranges of aerosol‐radiation interactions in the COVID‐19 lockdown across China. Key Points: Variations of surface solar radiation in East China during the COVID‐19 lockdown were highly linked to changes of PM2.5 concentrationsThe increase of both Rdir and Rdif and the reduced but still high PM2.5 concentration indicated aerosols at Zhengzhou became more scatteringRdir in West China could be weaken by the elevated aerosol layers despite the drop of ground PM2.5 concentrations [ABSTRACT FROM AUTHOR]

This work investigated seasonal variation of aerosol iron (Fe) solubility for coarse (>1 µ m) and fine (<1 µ m) particles at Xi'an, a megacity in northwestern China impacted by anthropogenic emission and desert dust. Total Fe concentrations were lowest in summer and were similar in other seasons for coarse particles but lowest in summer and highest in spring for fine particles; for comparison, dissolved Fe concentrations were higher in fall and winter than spring and summer for coarse particles but highest in winter and lowest in spring and summer for fine particles. Desert-dust aerosol was always the major source of total Fe for both coarse and fine particles in all four seasons, but it may not be the dominant source of dissolved Fe. Fe solubility was lowest in spring for both coarse and fine particles and highest in winter for coarse particles and in fall for fine particles. In general, aerosol Fe solubility was found to be higher in air masses originating from local and nearby regions than those arriving from desert regions after long-distance transport. Compared to coarse particles, Fe solubility was similar for fine particles in spring but significantly higher in the other three seasons, and at a given aerosol pH range, Fe solubility was always higher in fine particles. Aerosol Fe solubility was well correlated with relative abundance of aerosol acidic species, implying aerosol Fe solubility enhancement by acid processing; moreover, such correlations were better for coarse particles than fine particles in all four seasons. Fe solubility was found to increase with relative humidity and acid acidity for both coarse and fine particles at Xi'an, underscoring the importance of aerosol liquid water and aerosol acidity in regulating Fe solubility via chemical processing. [ABSTRACT FROM AUTHOR]

The potential impacts of dust aerosols and atmospheric convective available potential energy (CAPE) on the vertical development of precipitating clouds in southeastern China (20–30 ∘ N, 110–125 ∘ E) in June, July, and August from 2000 to 2013 were studied using multisource observations. In southeastern China, heavy-dust conditions are coupled with strong northerly winds that transport air masses containing high concentrations of mineral dust particles, with cold temperatures, and with strong wind shear. This leads to weaker CAPE on dusty days compared with that on pristine days. Based on satellite observations, precipitating drops under dusty conditions grow faster in the middle atmospheric layers (with a temperature of between -5 and + 2 ∘ C) but slower in the upper and lower layers compared with their pristine counterparts. For a given precipitation top height (PTH), the precipitation rate under dusty conditions is lower in the upper layer but higher in the middle and lower layers. Moreover, the associated latent heating rate released by precipitation in the middle layer is higher. The precipitation top temperature (PTT) shows a fairly good linear relationship with the near-surface rain rate (NSRR): the linear regression slope between the PTT and NSRR is stable under dusty and pristine conditions. However, the PTT 0 (the PTT related to rain onset) at the onset of precipitation is highly affected by both the CAPE and aerosol conditions. On pristine days, a stronger CAPE facilitates the vertical development of precipitation and leads to a decrease in PTT 0 , at a rate of -0.65 ∘ C per 100 J kg -1 of CAPE for deep convective precipitation (with a variation of 15 %) and at a rate of -0.41 ∘ C per 100 J kg -1 of CAPE for stratiform precipitation (with variation of 12 %). After removing the impacts of CAPE on PTT, dust aerosols led to an increase in PTT 0 , at a rate of + 4.19 ∘ C per unit aerosol optical depth (AOD) for deep convective precipitation and at a rate of + 0.35 ∘ C per unit AOD for stratiform precipitation. This study showed clear evidence that meteorological conditions and aerosol conditions combine to impact the vertical development of precipitation clouds. A quantitative estimation of the sensitivity of PTT to CAPE and dust was also provided. [ABSTRACT FROM AUTHOR]

The enrichment levels, sources, and potential hazards of heavy metals (HMs) and magnetic minerals in street dust and sand-dust storm from an extremely arid city (Dunhuang) in the northwest of China were analyzed. The assessment was performed using pollution indices, magnetic parameters, positive matrix factorization (PMF), and risk assessment models. Average enrichment levels of HM (including Cd, Zn, Pb, Cu, Cr, Co, and Ni) in street dust were higher than those in urban topsoil and the background values. The enrichment factor, pollution load index (PLI), and geoaccumulation index showed that the HMs came from both natural and anthropogenic sources, with Cu, Zn, Pb, and Cd being strongly influenced by anthropogenic sources. The means mass-specific susceptibility (χlf) and saturation isothermal remanent magnetization (SIRM) of street dust were 135.65 × 10−8 m3/kg and 1792 × 10−5Am2/kg, respectively, indicating that the street dust continuously receives pollutants containing high levels of coarse pseudo single-domain and multidomain ferromagnetic minerals. Ni, Zn, Cd, Cr, Fe, and ferromagnetic particles were principally associated with the industrial source and accounted for about 30.4% of these HM contents. Pb and Co were mainly produced from coal mining and coal combustion sources. Cu was principally associated with traffic emissions. Al, Mn, and Co were mainly generated by natural sources, contributing 38.9%. The ecological risk of HMs in street dust was moderate with considerable risk in individual sites, driven by Cd. The non-carcinogenic risks of HMs were within safety limits, and the carcinogenic risks were below the receivable values. [ABSTRACT FROM AUTHOR]

Dust storms are of great importance to climate change, air quality, and human health. In this study, a complete application frame of integrating hybrid methods based on multi-source data is proposed for remote sensing monitoring and process analysis of dust storms. In the frame, horizontal spatial distribution of dust intensity can be mapped by optical remote sensing products such as aerosol optical depth (AOD) from MODIS; the vertical spatial distribution of dust intensity by LIDAR satellite remote sensing products such as AOD profile from CALIPSO; geostationary satellite remote sensing products such as Chinese Fengyun or Japanese Himawari can achieve high-frequency temporal distribution information of dust storms. More detailed process analysis of dust storms includes air quality analysis supported by particulate matter (PM) data from ground stations and the dust emission trace and transport pathways from HYSPLIT back trajectory driven by meteorological data from the Global Data Assimilation System (GDAS). The dust storm outbreak condition of the source location can be proved by precipitation data from the WMO and soil moisture data from remote sensing products, which can be used to verify the deduced emission trace from HYSPLIT. The proposed application frame of integrating hybrid methods was applied to monitor and analyze a very heavy dust storm that occurred in northern China from 14–18 March 2021, which was one of the most severe dust storms in recent decades. Results showed that the dust storm event could be well monitored and analyzed dynamically. It was found that the dust originated in western Mongolia and northwestern China and was then transmitted along the northwest–southeast direction, consequently affected the air quality of most cities of northern China. The results are consistent with the prior research and showed the excellent potential of the integration of the hybrid methods in monitoring dust storms. [ABSTRACT FROM AUTHOR]

Dust aerosols pose non‐negligible impacts on regional and global climate, particularly over northwest China (NWC), where dust events frequently occur. Here, six dust events with different intensities occurred from 2014 to 2019 in NWC were simulated by the Weather Research and Forecasting model coupled to Chemistry (WRF‐Chem) to quantitatively evaluate the contributions of dust aerosols to radiation fluxes, surface energy, and meteorology, with specific consideration to the distinctions between daytime and nighttime. The results show that the contributions of dust aerosols to surface energy and meteorology were significantly affected by dust concentrations and dust layer heights and exhibited diurnal variation. In the case with high dust concentration and low dust layer height, dust aerosols increased the surface energy during the nighttime but decreased in the daytime, and the increase was much greater than the decrease. As a result, dust aerosols increase surface energy (0.06 W/m2 in the dust source region; 0.13 W/m2 in the dust affected region (DAR)) and surface temperature (0.0088°C in the DSR; 0.0781°C in the DAR) and decrease surface relative humidity (−0.053% in the DSR; −0.205% in the DAR) throughout the whole day. In contrast, dust causes opposite impacts on surface meteorology throughout the whole day due to the nighttime warming effect from the dust events with low dust concentration and high dust layer height is lesser than the daytime cooling effect. The study provides scientific insights for improving our understanding of dust aerosols‐regional meteorology interaction. Plain Language Summary: Dust aerosols pose non‐negligible impacts on regional and global climate, particularly over northwest China, where dust events frequently occur. However, the differences in the impacts of dust aerosols on surface energy and meteorological fields during daytime and nighttime are still not fully understood and warrant in‐depth investigations. Six dust events simulated by the WRF‐Chem model show that the contributions of dust aerosols to surface energy and meteorology are significantly affected by dust concentrations and dust layer heights and exhibit diurnal variation. The underlying mechanisms of the impacts of two kinds of typical dust events on surface energy and meteorology are revealed. The study provides scientific insights for improving our understanding of dust aerosols‐regional meteorology interaction. Key Points: The dust direct radiative forcing over different regions of northwest China exhibits significant differences during daytime and nighttimeThe underlying mechanisms of the impacts of two kinds of typical dust events on surface energy and meteorology are revealedThe dust concentration and dust layer height are the key factors resulting in opposite changes in surface atmospheric variables [ABSTRACT FROM AUTHOR]

Dust emitted from arid and semi-arid areas of China is a main contributor to the global atmospheric aerosols. However, the long-term spatial and temporal variations in dust concentrations in China is still unknown. Here, we simulated the spatial and temporal variations in spring dust concentrations in China from 2000 to 2020 using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). The results showed that the configured WRF-Chem model in this study reproduced the spatial patterns and temporal variations of dust aerosols. The annual mean spring dust concentration at the country level was 26.95 g kg−1-dry air and showed a slightly increasing trend in China during 2000–2020. There were clear spatial differences and inter-annual variations in dust concentrations. The dust concentration generally decreased from the dust source regions of the northwest to the southeast regions of China. Obvious increasing and decreasing trends in spring dust concentrations were identified in the regions of northern Xinjiang and Gansu and in the regions of southern Xinjiang and western Inner Mongolia, respectively. In May, the dust concentration showed an increasing trend in most regions of northwestern China. This provided the basic information for insight into the long-term spatial and temporal variations in spring dust concentrations in China. [ABSTRACT FROM AUTHOR]

The Taklamakan Desert and the Gobi Desert in East Asia constitute the second-largest sources of dust in the world. In particular, dust originating from the Gobi Desert is more susceptible to long-range transport, with consequent impacts in downwind Asian countries and the Northwest Pacific region. Two intensive dust events (the 3·15 dust event and the 3·28 dust event) were experienced in North China in March 2021. The 3·15 dust process was rated as the most intensive dust process in China in the past 10 years. In this study, by using a combination of spaceborne remote sensing datasets from geostationary and polar-orbiting satellites, ground-based columnar observations of aerosol optical parameters, meteorological reanalysis data, and backward trajectory simulations of air masses, the transport pathways and the three-dimensional structure characteristics of dust aerosols during the transport of the two dust events in March 2021 were cross-validated. The results of the study indicated that the two dust events were induced by the Mongolian cyclone. Due to the different configurations of the ground meteorological system conditions, a backflow process occurred during the 3·15 dust event transmission process. After passing over North China and the Bohai Sea, the direction of transport of the dust plume was reversed. The wind deflected from northwest to northeast, and the dust reached the eastern coastal areas of China and was finally deposited on land. The 3·28 dust event exhibited aerosol stratification in the transport path, the higher pure dust layer reached up to 9 km height, and the lower layer underwent aerosol mixing and became a polluted dust aerosol. This study implies that the investigation of dust aerosol transport and the deposition processes, the impact on the ocean, and the impact of marine aerosols on land also needs to be taken into consideration; the integration of advanced satellites and ground-based remote sensing data, the meteorological reanalysis data and the backward trajectories simulation, which complemented and verified each other, can enhance the ability to delineate the transport pathways and the three-dimensional structural characteristics of dust events. [ABSTRACT FROM AUTHOR]

The patterns and forcing mechanism of dust storms in arid Northwest China remain unclear and debated due to lack of reliable long‐term geological records. Here we present a ∼1,600‐year dust storm history in Northwest China based on the sedimentary coarse fraction (>63 μm) retrieved from Lake Hurleg and Lake Qinghai on the northeastern Tibetan Plateau (NETP). The NETP dust storm history, which agrees well with those from North China, shows two prolonged intervals of high dust storm occurrences during the Medieval Warm Period and the past century, and two prolonged weakened dust storm intervals from ∼400 to 700 CE and during the Little Ice Age. The temporal variation in NETP dust storm activities is out‐of‐phase with moisture records over central Asia, with enhanced dust storms corresponding to warm‐dry intervals, and vice versa. The prolonged centennial warm‐dry climates over arid Northwest China to arid central Asia could have led to decreased soil moisture, deteriorated vegetation cover, and increased dust particle supply and dust storm activities; while the prolonged centennial cold‐wet climates could have increased soil moisture, vegetation cover, and decreased dust storm activities. We contend that whilst human impact could be responsible for the obviously increased eolian dust flux in the most recent century, it is most likely that the prolonged natural hydroclimatic conditions regulate the global dust storm activity before the Anthropocene. Key Points: A ∼1,600‐year dust storm history over Northwest China was reconstructed based on sedimentary grainsize from Lake Hurleg and Lake QinghaiProlonged drought dominates dust storm occurrence by decreasing vegetation cover and increasing dust‐particle supply on centennial timescaleNatural climate variability rather than human activity could have shaped the Northwest China dust storm activities before the Anthropocene [ABSTRACT FROM AUTHOR]

Salt lakes considerably affect the regional climate, environment, and ecology of semiarid regions characterized by low rainfall and high evaporation. However, under the stresses of global change and human disturbance, anthropogenic pollution is the primary factor threatening the lake's ecological environment. Surface sediment samples collected from four salt lakes in the Ordos Plateau were used to investigate the salinity, concentration, pollution status, potential sources of heavy metals, and influencing factors. The surface sediments of Beida Pond and Gouchi Pond were weakly alkaline (pH < 9) due to the presence of Na2SO4, whereas those of Chaigannaoer and Hongjiannao were strongly alkaline (pH > 9) due to the presence of Na2CO3. The concentration range of Cr, Ni, Cu, Zn, As, Cd, and Pb in the sediment samples collected from the salt lakes in the Ordos Plateau followed the order of Cr > Zn > Ni > Pb > Cu > As > Cd. The Cr concentration values were higher in Chagannaoer and Hongjiannao; however, the Ni, Cu, and Zn values were higher in Beida Pond and Gouchi Pond. The geoaccumulation index (Igeo) and enrichment factor (EF) consistently indicated that Cr posed the greatest potential ecological risk and that Ni, Cu, and Zn pollution was more severe in Beida Pond and Gouchi Pond than in Chagannaoer or Hongjiannao. However, the ecological risk index and potential ecological risk value indicated that these heavy metals posed low risks to the environment. The risk assessment code (RAC) revealed that Pb and Cr exhibited no mobility and had low potential bioavailability risk. Meanwhile, Zn, Ni, and As were categorized as medium risk. Cu had the highest mobility and was categorized as high risk. Principal component analysis for the four salt lakes revealed that the source of Ni, Cu, Zn, and Cd might be associated with water-soluble elements associated with aqueous migration, while the source of Cr, Pb, and As might be the lithospheric minerals carried by dust storms. Pearson's correlation analysis indicated that clay minerals were the primary adsorbers of Ni, Cu, Zn, and Cd. Moreover, pH was identified as the main environmental factor controlling the distribution of heavy metals in the salt lakes. [ABSTRACT FROM AUTHOR]

A knowledge gap exists concerning how chemical composition and sources respond to implemented policy control measures for aerosols, particularly in a semi-arid region. To address this, a single year's offline measurement was conducted in Hohhot, a semi-arid city in northern China, to reveal the driving factors of severe air pollution in a semi-arid region and assess the impact of the COVID-19 lockdown measures on chemical characteristics and sources of PM 2.5. Organic matter, mineral dust, sulfate and nitrate accounted for 31.5 %, 14.2 %, 13.4 % and 12.3 % of the total PM 2.5 mass, respectively. Coal combustion, vehicular emission, crustal source and secondary inorganic aerosols were the main sources of PM 2.5 in Hohhot, at 38.3 %, 35.0 %, 13.5 %, and 11.4 %, respectively. Due to the coupling effect of emission reduction and improved atmospheric conditions, the concentration of secondary inorganic components, organic matter and elemental carbon declined substantially from the pre-lockdown (pre-LD) period to the lockdown (LD) and post-lockdown (post-LD) periods. The source contribution of secondary inorganic aerosols increased (from 21.1 % to 37.8 %), whereas the contribution of vehicular emission reduced (from 35.5 % to 4.4 %) due to lockdown measures. The rapid generation of secondary inorganic components caused by unfavorable meteorological conditions during lockdown led to serious pollution. This study elucidates the complex relationship between air quality and environmental policy. [ABSTRACT FROM AUTHOR]

Aerosol vertical distribution generally determines their health impacts and climate effects. By using long‐term (2007–2019) CALIPSO lidar measurements, we present a large‐scale insight into the climatology of aerosol types and their vertical structure over East Asia. Despite the low sampling frequency, comparison with MODIS aerosol optical depth (AOD) shows that the integrated CAIPSO vertical extinction can reasonably reproduce spatial patterns of the aerosol loading. With the unique advantage of active detection, CALIPSO reveals an obvious enhancement of the night‐time AOD due to worse diffusion conditions. Moreover, long‐range transport of different aerosols including dust, polluted dust, and smoke has substantial contribution to the aerosol loading over East Asia. Pure dust particles are mainly concentrated over the deserts with notable dust transport belts (dust AOD > 0.2 at 532 nm) along downwind regions during winter and spring. By contrast, polluted dust is prevalent over the downstream eastern China with much higher AODs throughout the year. In particular, AOD of polluted dust (~0.5) is higher in winter rather than in spring, which is consistent with their seasonal occurrences. Smoke aerosols usually appear in the night‐time over southern China. The top heights of aerosols are around 4–6 km, with dust and smoke having higher extinction at upstream regions. The climatology of these aerosol types and vertical distribution can provide a significant constraint for associated studies of air quality and climate effects. [ABSTRACT FROM AUTHOR]

In recent years, climate change and the intervention of anthropogenic activities have altered the seasonal features of Asian dust storms. This may also cause seasonal variations (including dust occurrence frequency and optical/microphysical properties) in dust aerosols transported to downstream regions. The Jianghan Plain is dramatically influenced by multiple dust sources due to its geographical location in central China. In this study, we focused on the climatology of dust aerosols over the Jianghan Plain based on the 15-year (2006–2021) continuous space-borne observations of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) as well as Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) reanalysis data. A typical dust event that intrudes the Jianghan Plain was studied in detail. According to the statistical results, dust aerosols frequently intrude into the Jianghan Plain in spring and winter, with occurrence frequencies (under cloud free condition hereafter) exceeding 0.70 and higher altitudes of 4–6 km. The dust occurrence frequency declined to approximately 0.40 in autumn and nearly zero in summer, while the dust plumes were generally located at lower altitudes of 1–3 km. The dust plumes observed in the Jianghan Plain were simultaneously linked to the Taklimakan Desert and Gobi Desert in spring and mainly originated from the Taklimakan Desert in winter and autumn. The dust particles were mainly distributed below 4-km altitude, with the largest dust extinction coefficients and dust mass concentrations in spring. In all seasons, the particle depolarization ratios are 0.1–0.2 below 4-km altitude, suggesting a possible mix with local anthropogenic aerosols. The mean dust column mass concentrations in spring showed an evident declining trend from 210 µg m−2 in 2006 to 100 µg m−2 in 2021 in the Jianghan Plain, attributed to the reduced dust activity in the source regions of Asian dust. [ABSTRACT FROM AUTHOR]

To avoid adverse drug reactions associated with injection, off-label nebulization of Tanreqing (TRQ) injection is often used in China to treat respiratory diseases. However, the aerodynamic properties and lung availability of TRQ aerosols remain largely uninvestigated. This study aimed to investigate the size distribution of TRQ aerosols and to compare the pharmacokinetics and tissue distribution of two compounds from TRQ (baicalin and oroxyloside) after transnasal aerosol inhalation and intravenous administration. Furthermore, this study aimed to evaluate the efficacy of TRQ against lipopolysaccharide-induced lung inflammation. The Dv(50) and transmission of TRQ aerosols were 2.512 μm and 74.867%, respectively. The Cmax of baicalin and oroxyloside in rat plasma after inhalation was lower than that after intravenous injection. After inhalation, the area under the curve (AUC) of baicalin and oroxyloside in tissues (lung, bronchoalveolar lavage fluid, and trachea) was 7.9–115.3 and 9.5–16.0 times that observed after intravenous administration, respectively. Baicalin and oroxyloside maintained high concentrations 4 h after inhalation, but only 1 h after intravenous injection. The mean lung-to-plasma concentration ratios of baicalin and oroxyloside were 287.6 and 49.9 times higher than with intravenous administration. Inhaled TRQ achieved the same effect against lipopolysaccharide-induced lung inflammation in mice at doses of only 1/16–1/8 of those administered intravenously. The results indicate that TRQ inhalation is a promising alternative to intravenous injections for the treatment of respiratory infection. [ABSTRACT FROM AUTHOR]

Haze is the phenomenon of visibility degradation caused by extinction effects related to the physicochemical properties of atmospheric particulate matter (APM). Atmosphere heterogeneous reactions can alter the physicochemical properties of APM. Therefore, it is important to understand the atmospheric heterogeneous reactions of APM in order to reveal the cause of haze. Herein, the current situation, developmental trend, source, and composition of APM pollution in China are reviewed. Additionally, we introduce the reaction characteristics and key chemical processes of common inorganic, organic, and mixed pollutant gases on the surface of mineral particles. The effects of mineral particulate matter on aggregation, regulation, and catalysis in the formation of atmospheric aerosols and the synergistic reaction mechanism of SO2, NO2, O3, and VOCs on the surfaces of different mineral particles are summarized. The problems existing in the current research on heterogeneous reactions on the surfaces of mineral particles are also evaluated. This paper aims to gain a deep understanding of the mechanism of mineral particulate matter promoting the formation of secondary aerosols and attempts to provide theoretical support for effective haze control. [ABSTRACT FROM AUTHOR]

Glaciers, known as solid reservoirs, are important water supply sources in northwest China. In this paper, mineral dust collected from a Chinese alpine mining area (Beizhan iron mine) and an ice cube (with a 225 cm2 section and a volume of 1000 mL) were employed via a delicate physical experiment to study the ablation of glaciers covered by mineral dust in alpine regions. After that, the ablation mechanism was revealed using the energy conservation theory. The main findings are as follows: (1) When the solar radiation intensity is 993 W/m2, the glacier ablation rate increases by 13.9% (from 282 to 321.2 mL/h) as the mineral dust coverage rate increases from 0% to 42.7%. (2) When the mineral dust coverage rate remains at 30%, the glacier ablation rate increases by 11.6% (from 291.8 to 325.78 mL/h) as the solar radiation intensity increases from 1007 to 1153 W/m2. (3) When the solar radiation intensity and mineral dust coverage rate remain unchanged, the ablation rate of the glacier covered by the mineral dust inversely increases with the dust particle size. The ablation rates of the particle size gradings C, B, and A (the dust particle sizes of gradings A, B, and C in 0.0375–0.075 mm, 0.075–0.125 mm, and 0.125–0.25 mm accounted for 5%:50%:45%, 30%:40%:30%, and 70%:30%:0%, respectively) were 293.4, 301.2, and 305.6 mL /h, respectively, and the corresponding ablation rates increased by 2.7% and 1.5%. (4) The smaller the average particle size of the mineral dust, the greater the contribution to the ablation rate; a 1 °C temperature increase to the glacier ablation rate is equivalent to 29.1%, 33.6%, and 40.6% increases in dust coverage for particle size classes C, B, and A. (5) The mineral dust covering the glacier surface could not only reduce the reflectivity of the glacier surface to solar radiation but could also continuously transfer the absorbed radiant energy and its own chemical energy to the glacier body, accelerating the glacier's meltwater speed. The findings of this paper can provide the necessary theoretical basis for mineral dust control and glacier water conservation in alpine mining areas. [ABSTRACT FROM AUTHOR]

Due to the complexity of emission sources, a better understanding of aerosol optical properties is required to mitigate climate change in China. Here, an intensive real-time measurement campaign was conducted in an urban area of China before and during the COVID-19 lockdown in order to explore the impacts of anthropogenic activities on aerosol light extinction and the direct radiative effect (DRE). The mean light extinction coefficient (bext) decreased from 774.7 ± 298.1 Mm -1 during the normal period to 544.3 ± 179.4 Mm -1 during the lockdown period. A generalised additive model analysis indicated that the large decline in bext (29.7 %) was due to sharp reductions in anthropogenic emissions. Chemical calculation of bext based on a ridge regression analysis showed that organic aerosol (OA) was the largest contributor to bext in both periods (45.1 %–61.4 %), and the contributions of two oxygenated OAs to bext increased by 3.0 %–14.6 % during the lockdown. A hybrid environmental receptor model combined with chemical and optical variables identified six sources of bext. It was found that bext from traffic-related emissions, coal combustion, fugitive dust, the nitrate and secondary OA (SOA) source, and the sulfate and SOA source decreased by 21.4 %–97.9 % in the lockdown, whereas bext from biomass burning increased by 27.1 %, mainly driven by the undiminished need for residential cooking and heating. An atmospheric radiative transfer model was further used to illustrate that biomass burning, rather than traffic-related emissions, became the largest positive effect (10.0 ± 10.9 W m -2) on aerosol DRE in the atmosphere during the lockdown. Our study provides insights into aerosol bext and DRE from anthropogenic sources, and the results imply the importance of controlling biomass burning for tackling climate change in China in the future. [ABSTRACT FROM AUTHOR]

Dust aerosols persistently affect nearly all landscapes worldwide, and the saltation activity caused by dusty weather (e.g., dust days) releases considerable amounts of aerosol into the atmosphere. Nevertheless, dust-induced saltation activity may also occur on non-dust days. To date, few studies have investigated the saltation activity characteristics on non-dust days. Moreover, the contribution of non-dust days to the total saltation activity remains ambiguous. This study comprehensively investigates the characteristics of saltation activity on non-dust days. Specifically, we analyze the influence of the saltation activity of non-dust days on dust aerosols by utilizing saltation, atmospheric, soil, dust aerosol (i.e., PM10 and aerosol optical depth), and weather record data obtained from the Taklimakan Desert, China, between 2008 and 2010. Our results show that lower temperature, vapor pressure, and soil moisture on non-dust days reduces the saltation threshold velocity (5.9 m/s) more compared to on dust days (6.5 m/s). Furthermore, regarding wind speed, relatively strong monthly saltation activity occurs from March to August, and daily saltation activity occurs from 9:00 to 16:00. Although non-dust days only contribute 18.5% and 7.7% to saltation time and saltation count, respectively, both significantly influence the dust aerosols. Therefore, the effect of saltation activity on non-dust days cannot be undervalued, particularly while performing dust aerosol studies. [ABSTRACT FROM AUTHOR]

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A Regional Air Quality Model System (RAQMS) driven by WRF was applied to explore the emission, transport, deposition, and direct radiative effect of mineral dust over western China in July 2022, with focus on the Tibetan Plateau (TP). Model validation against ground and satellite observations demonstrated the model reproduced meteorological variables, PM 10 concentration, aerosol optical depth (AOD), and extinction coefficients in the vertical reasonably well. There was a dust event during 3–7 July 2022, which was originated from the Taklimakan Desert (TKD) and affected eastern and central TP under anticyclonic flows, resulting in the maximum hourly PM 10 concentration exceeding 50 μg m−3 in Lhasa. Shortwave radiation was reduced considerably by dust aerosols over eastern TP, with the maximum decrease in daytime mean shortwave radiation reaching 30 W m−2 around Nyingchi on 5 July. Anthropogenic aerosols dominated PM 10 mass in the capital cities of western China (54–67 %), while dust aerosols were dominant in the cities near the deserts. During this dust event, dust aerosols from TKD and Qaidam Desert (QDD) significantly influenced eastern TP, with dust contributions to PM 10 mass concentration of 52 %, 76 % and 69 %, respectively, in Chamdo, Lhasa and Nyingzhi, respectively. The total dust emission in western China was about 10.6 Tg in July 2022, with the largest contribution from TKD (63.5 %), followed by Gobi Desert (GB) (26 %). The total deposition of dust was estimated to be 6.2 Tg, in which TKD and GB contributed 66 % and 22 %, respectively. During the study period, about 418 Gg dust aerosols were deposited on TP, 49 % of which was from TKD and 25 % from QDD. Foreign dust sources contributed approximately 7 % and 9 % to dust concentration and total deposition over TP, respectively. Over southern TP, the source contribution to dust deposition was estimated to be 42 %, 24 % and 21 % from TKD, foreign sources and QDD, respectively, suggesting potentially important impact of long-range transboundary dust transport on deposition, surface albedo and climate over TP. [Display omitted] • A dust event from the Taklimakan desert to eastern TP on 3–7 July 2022 was explored. • This event led to evident changes in PM 10 concentration and solar radiation over eastern TP. • Foreign dust sources contributed 24 % of the total deposition amounts over southern TP. [ABSTRACT FROM AUTHOR]

Dithionite-citrate-bicarbonate (DCB) treatment is a classical method for removing iron oxides from soil. The DCB-induced dissolution effects on iron oxides are controversial. In this paper, samples from a typical loess-paleosol sequence in the Chinese Loess Plateau (CLP) and from other aeolian dust deposits in southern China were collected, and changes in the grain size composition and magnetic properties of the samples after DCB treatment were analyzed. The results show that the dissolution of iron oxides in loess-paleosol samples from the CLP is highly grain size dependent. In addition to completely dissolving nanometer-sized pedogenic iron oxides (< 0.2 μm), the standard DCB procedure can also dissolve submicron- and micron-sized aeolian iron oxides (0.2–6 μm). For these aeolian iron oxides, the submicron-sized (0.2–1 μm) iron oxides are sufficiently dissolved, and the solubility of the micron-sized (1–6 μm) iron oxides decreases with increasing particle size. The dissolution of > 6 μm aeolian iron oxides is negligible. DCB can neither separate pedogenic iron oxides from aeolian iron oxides nor selectively dissolve magnetite or maghemite. Although the total amount of dissolved iron oxides in the profiles from southern China is higher than that in the LC profile from northern China, the submicron- and micron-sized aeolian iron oxides in the latter are more easily dissolved. [ABSTRACT FROM AUTHOR]

Nitryl chloride (ClNO2), an important precursor of Cl atoms, significantly affects atmospheric oxidation capacity and O3 formation. However, sources of ClNO2 in inland China have not been fully elucidated. In this work, laboratory experiments were conducted to investigate heterogeneous reactions of N2O5 with eight saline mineral dust samples collected from different regions in China, and substantial formation of ClNO2 was observed in these reactions. ClNO2 yields, φ (ClNO2), showed large variations (ranging from <0.05 to ∼0.77) for different saline mineral dust samples, depending on mass fractions of particulate chloride. In addition, φ (ClNO2) could increase, decrease or show insignificant change for different saline mineral dust samples when relative humidity (RH) increased from 18 % to 75 %. We further found that current parameterizations significantly overestimated φ (ClNO2) for heterogeneous uptake of N2O5 onto saline mineral dust. In addition, assuming a uniform φ (ClNO2) value of 0.10 for N2O5 uptake onto mineral dust, we used a 3-D chemical transport model to assess the impact of this reaction on tropospheric ClNO2 in China and found that weekly mean nighttime maximum ClNO2 mixing ratios could have been increased by up to 85 pptv during a severe dust event in May 2017. Overall, our work showed that heterogeneous reaction of N2O5 with saline mineral dust could be an important source of tropospheric ClNO2 in inland China. [ABSTRACT FROM AUTHOR]

The magnetic measurement is an effective tool to identify the source of pollutants and diagnose the urban pollution. In this study, 132 group samples (that topsoil and street dust were sampled at the same location is regarded as a group) were collected from Xinyang, central eastern China. In addition, the background samples (19 topsoils under woodland around the outskirts) were also sampled. Herein, the aim was to investigate and compare the magnetic characteristics of both topsoil and street dust, and further to discuss the source and environmental implications using magnetic and diffuse reflection spectrum methods. The following points are highlighted: (1) the primary magnetic carrier of both materials was magnetite and that of the background sample were magnetite and maghemite. Furthermore, the ferrimagnetic mineral concentration and magnetic domain follow the order: street dust > topsoil > background sample. (2) The source of both materials was mainly from anthropogenic activities (e.g. industrial and traffic vehicles). The difference between them was the contribution related to natural sources (e.g. parent materials), which was negligible in street dust, and played a secondary role in topsoil. (3) Both materials showed that areas with a higher intensity of anthropogenic activities had higher pollution level, whereas areas with a lower anthropogenic intensity had lower pollution level. [ABSTRACT FROM AUTHOR]

Using 14 years (2007–2020) of data from passive (MODIS/Aqua) and active (CALIOP/CALIPSO) satellite measurements over China, we investigate (1) the temporal and spatial variation of aerosol properties over the Beijing–Tianjin–Hebei (BTH) region, the Yangtze River Delta (YRD), and the Pearl River Delta (PRD) and (2) the vertical distribution of aerosol types and extinction coefficients for different aerosol optical depth (AOD) and meteorological conditions. The results show the different spatial patterns and seasonal variations of the AOD over the three regions. Annual time series reveal the occurrence of AOD maxima in 2011 over the YRD and in 2012 over the BTH and PRD; thereafter the AOD decreases steadily. Using the CALIOP vertical feature mask, the relative frequency of occurrence (rFO) of each aerosol type in the atmospheric column is analyzed: rFOs of dust and polluted dust decrease from north to south; rFOs of clean ocean, polluted continental, clean continental and elevated smoke aerosol increase from north to south. In the vertical, the peak frequency of occurrence (FO) for each aerosol type depends on region and season and varies with AOD and meteorological conditions. In general, three distinct altitude ranges are observed with the peak FO at the surface (clean continental and clean marine aerosol), at ∼1 km (polluted dust and polluted continental aerosol) and at ∼3 km (elevated smoke aerosol), whereas dust aerosol may occur over the whole altitude range considered in this study (from the surface up to 8 km). The designation of the aerosol type in different height ranges may to some extent reflect the CALIOP aerosol type classification approach. Air mass trajectories indicate the different source regions for the three study areas and for the three different altitude ranges over each area. In this study nighttime CALIOP profiles are used. The comparison with daytime profiles shows substantial differences in the FO profiles with altitude, which suggest effects of boundary layer dynamics and aerosol transport on the vertical distribution of aerosol types, although differences due to day–night CALIOP performance cannot be ruled out. [ABSTRACT FROM AUTHOR]

This study examined the effect of compost fortified with rock dust on the soil properties, soil microbial activity, and yield and fruit quality in a mature apple orchard from the Jiangsu province of China. The incorporation of rock dust significantly improved the microelement contents of Ca, Mg, Fe, Mn, Zn, B, and Al, but without increasing phytotoxicity of the compost. The fortified compost had higher metabolic activity and functional diversity of microorganisms as determined by the community-level physiological profiling with Biolog EcoPlates. The two-year incorporation of the rock dust compost into a poor-quality soil led to a significant increase in the yield with the increase of 120% and 187% compared to untreated control in 2013 and 2014, respectively. Application of the rock dust compost obviously promoted superoxide dismutase (SOD) activity and concentration of vitamin C in mature apple trees. The beneficial effects coincided with higher microbial activity and shifts in the composition of the soil microbiome. Our results demonstrate that the practice of combining the rock dust-fortified compost with NPK fertilizers provides a cost-effective way of supplying crops with macro-and micronutrients ensuring better vegetative growth and higher yields. [ABSTRACT FROM AUTHOR]

• The heavy haze episodes formation in autumn was related with the increase of secondary organic aerosols and NH 4. • The contribution of POC and NH 4 + were significant during the evolution of pollution periods in wintertime. • The local and short-distance air mass transportation have significant impact. To study the pollution features and underlying mechanism of PM 2.5 in Luoyang, a typical developing urban site in the central plain of China, 303 PM 2.5 samples were collected from April 16 to December 29, 2015 to analyze the elements, water soluble inorganic ions, organic carbon and elemental carbon. The annual mean concentration of PM 2.5 was 142.3 μg/m3, and 75% of the daily PM 2.5 concentrations exceeded the 75 μg/m3. The secondary inorganic ions, organic matter and mineral dust were the most abundant species, accounting for 39.6%, 19.2% and 9.3% of the total mass concentration, respectively. But the major chemical components showed clear seasonal dependence. SO 4 2− was most abundant specie in spring and summer, which related to intensive photochemical reaction under high O 3 concentration. In contrast, the secondary organic carbon and ammonium while primary organic carbon and ammonium significantly contributed to haze formation in autumn and winter, respectively. This indicated that the collaboration effect of secondary inorganic aerosols and carbonaceous matters result in heavy haze in autumn and winter. Six main sources were identified by positive matrix factorization model: industrial emission, combustion sources, traffic emission, mineral dust, oil combustion and secondary sulfate, with the annual contribution of 24%, 20%, 24%, 4%, 5% and 23%, respectively. The potential source contribution function analysis pointed that the contribution of the local and short-range regional transportation had significant impact. This result highlighted that local primary carbonaceous and precursor of secondary carbonaceous mitigation would be key to reduce PM 2.5 and O 3 during heavy haze episodes in winter and autumn. [Display omitted] [ABSTRACT FROM AUTHOR]

InSAR observation with a wide range and high sensitivity is one of the main techniques for active landslide identification, but due to the influence of the SAR satellite side-view imaging method and observation angle, single-track images in alpine valley areas facing geometric distortion, such as shadowing, layover, and foreshortening, which leads to ineffective observation in some areas. Combining the ascending and descending observation results is expected to compensate for this deficiency to a large extent. This work constructs a pixel-level image fusion method to achieve the fusion of InSAR ascending and descending orbit deformation results, consisting of three algorithms: the DMPI (decision matrix-guided pixel-level InSAR image fusion algorithm), the DMFS (deformable median filter based on decision feedback), and the Q S D S (superpixel-based dual-space InSAR image fusion quality evaluation algorithm). To verify the effect, the Batang section of the Jinsha River with high mountain canyon terrain and frequent active landslides is selected. The results show that using the DMPI fused InSAR ascending and descending orbit images can improve spatial perception by enhancing the texture gradient value of remote sensing images by a maximum of two orders of magnitude, compared with the single-track InSAR observation images. Meanwhile, the number of landslides identified increased by 31.5%, and the total area increased by 50.9% on average, improving the accuracy of target detection and identification. In noise reduction, DMFS improves fusion image readability and feature detail by removing SPN (salt and pepper noise) while preserving target edge detail. Furthermore, the Q S D S which can evaluate the quality of InSAR fusion images from the perspective of human eye vision, provides an adequate basis for determining the interpretability of InSAR images. This fusion method can partially improve the question of incomplete ground observation due to radar line of sight occlusion in the high mountain canyon area, thus better presenting the InSAR observation results and helping to comprehensively and conveniently interpret the InSAR deformers. • A new method of the ascending and descending observation InSAR image fusion is presented • A decision matrix-guided pixel-level InSAR image fusion algorithm is developed • A deformable median filter based on decision feedback is proposed • A hyperpixel-based dual-space InSAR image fusion quality evaluation algorithm is constructed [ABSTRACT FROM AUTHOR]

During the spring of 2021, rapid surface cooling in the Arctic area expanded to most of the East Asian region, featuring surface-temperature dipole patterns of the colder west (Mongolia and northern-central China) and the warmer east (eastern-northeastern China, the Yellow Sea, and Korea). Despite the decreasing trend of dusty days within Korea, a notable rise in the occurrence of transboundary mineral dust-induced dusty days was observed in contributing to an increase in PM 10 levels in the spring of 2021. This study investigated the PM 10 source apportionment of anthropogenic dust, mineral dust, and biomass burning in the East Asian region and its transboundary impact on Korea, within the context of the surface-temperature dipole pattern observed in April of 2021. Source apportionment of PM 10 was determined through a comparative analysis between baseline and sensitivity experiments conducted by means of a WRF-Chem simulation. In these sensitivity simulations, emissions from each source were systematically excluded to assess their individual contributions. PM 10 Base refers to baseline simulations, PM 10 Anthro to anthropogenic emissions, PM 10 Dust to mineral dust, and PM 10 Biomass to biomass burning. The colder west pattern was linked to increased synoptic-scale cyclonic activity, marked by higher positive potential vorticity, causing a sudden surge in severe dust storms over Mongolia and northern China. PM 10 Base levels were most elevated in the higher terrain of Mongolia, comprising predominantly PM 10 Dust (95%). However, the dominance of atmospheric-warming-induced anticyclones, represented by enhanced negative potential vorticity, prevailed over the lower terrain in the warmer east regions, obstructing the transboundary dispersion of PM 10 Base to Korea. Nevertheless, Korea experienced a transboundary contribution of PM 10 Dust , reaching 35%. In addition, the source apportionments indicated a PM 10 Anthro ratio of 55% in eastern China and a PM 10 Biomass ratio of 35% in northeastern China, contributing 25% and 5% respectively to Korea. During April 14–30, 2021, the dipole pattern evolved further to the significantly colder west (Mongolia and China) and the moderately warmer east (the Yellow Sea and Korea). The transboundary contributions of PM 10 Anthro , PM 10 Dust , and PM 10 Biomass were intensified as a composite mixture within Korea, an outcome attributed to the intermittent cyclones and subsequent anticyclones. • Dusty days fell in Korea, but mineral dust surged, raising PM 10 in spring 2021. • Arctic spring cooling led to an East Asian cold-west, warm-east dipole pattern. • The colder west amplified cyclones, sparking dust storms in Mongolia and China. • Warming-induced anticyclones obstructed the transboundary dispersion of mineral dust. • Dust from eastern-northern China impacted Korea's PM 10 in a warm anticyclone. [ABSTRACT FROM AUTHOR]

Long-range transport of North African and Middle Eastern dust has been frequently observed in East Asia. However, understanding of their characteristics and effects in this region is insufficient. In this study, the transboundary transport of multi-source dust was captured by a polarized micro-pulse lidar from April 5 to 10, 2012, during a field campaign in Dunhuang, northwest China. Six dust plumes (DN1-DN6) were selected based on the spatiotemporal evolution of the depolarization ratio. Furthermore, the source, vertical characteristics of the coarse and fine components and their contributions were investigated by combining lidar observation with the WRF-Chem model simulation. The results indicated that DN1 was from Central Asia and it took approximately 4–5 days. DN2 originated from sources in North Africa and the Middle East and took approximately 6–7 days to reach Dunhuang. Samples DN3-DN6 originated from the Taklimakan and Gobi deserts in East Asia. A noticeable contrast was observed in the vertical distribution of the coarse and fine components between the long-range transported (DN1∼DN2) and fresh (DN3∼DN6) dust plumes. DN1 and DN2 presented comparable dust components (DD = Dc + Df, where Dc and Df are coarse- and fine-mode dust, respectively) and non-dust (ND) component contributions and a high predominance of Dc particles was present with at least 40% of total components in DN3-DN4. The contribution of ND particles was nearly negligible in DN5 and DN6. Lidar observations and model simulation both indicated that the maximum contribution of North African and Middle Eastern dust to the local aerosol loading exceeded 58%. However, the model simulation underestimated the contribution of DN1 by an average of 18% compared to lidar observations because DN1 was not reproduced well. This implies that the vertical distribution of dust should be carefully considered when dust impacts (e.g., radiation effects and air quality) are finely assessed using a model on a regional scale. [Display omitted] • POLIPHON algorithm was conducted to the P-MPL observations over northwest China. • A noticeable contrast exists in the vertical structure between the long-range transported and fresh dust plumes. • Model underestimates the contribution of long-range transported dust to local aerosol loading. [ABSTRACT FROM AUTHOR]

The POLIPHON (Polarization Lidar Photometer Networking) method is a powerful pathway to retrieve the height profiles of dust-related particle mass and ice-nucleating particles (INP) concentrations. The conversion factors fitted from the sun photometer observation data are the major part of the POLIPHON computations, which can convert the polarizationlidar- derived dust extinction coefficients into the dust-related particle mass and INP concentrations. For a central China megacity Wuhan (30.5°N, 114.4°E), located at the downstream area several thousands of kilometers far away from the source regions of Asian dust, dust particles always mix with other aerosols from local emission. Therefore, very few dust case data sets can be available when using the column-integrated Ångström exponent (for 440-870 nm) <0.3 and aerosol optical depth (at 532 nm) >0.1 recorded by sun photometer as the filtering criteria. Instead, we present another dust-case data-set screening scheme that applies the simultaneous polarization lidar observation to verify the occurrence of dust. Based on the 33 dust-intrusion days identified during 2011-2013, the extinction-to-volume (푐푣,푑) and extinction-to-large particle (with radius >250 nm) number concentration (푐250,푑) conversion factors are determined to be 0.52 × 10-12 Mm m³m-3 and 0.11 Mm cm-3, respectively. They are both smaller than those observed at Lanzhou SACOL (36.0°N, 104.1°E), a site closer to the Gobi Desert, due to the partial dust sedimentation during transport. The conversion factors are applied in a dust event in Wuhan to reveal the typical dust-related INP concentration over East Asia city. The proposed dust-case data-set screening scheme may potentially be extended to the other polluted city sites more influenced by mixed dust. [ABSTRACT FROM AUTHOR]

A variety of dust control methods are often applied in coal mines, among which the application of wet scrubbers has proven to be an efficient technology for the removal of dust in airstreams, rather than diluting or confining the dust. In this paper, a wet scrubber design was developed. Based on a self-designed experimental test platform, the total dust concentration, respirable dust concentration, air volume, and average pressure drops of wet scrubbers with 12, 16, 20, and 24 blades were measured under different water intake conditions. The results show that the different water intake levels have only minimal effects on the air volume of the wet scrubbers. However, increased water intake had improved the dust removal efficiency of the wet scrubbers with the same number of blades. The wet scrubber with 16 blades was found to have the best dust removal efficiency at a water intake level of 1.35 m3/h. Its total dust and respirable dust removal efficiency reached 96.81% and 95.59%, respectively. The air volume was 200.4 m3/min, and the average pressure drop was determined to be 169.4 Pa. In addition, when the wet scrubber with 16 blades was applied in a coal preparation plant in China's Shanxi Province, it was observed that the total dust concentration had fallen below 8.1 mg/m3, and the respirable dust concentration had fallen below 5.9 mg/m3. Therefore, the results obtained in this research investigation provide important references for the use of wet scrubbers to improve coal production environmental conditions. [ABSTRACT FROM AUTHOR]