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This study introduces an innovative outdoor nephelometer system designed to monitor the dynamic hygroscopic behavior of aerosols in ambient air. Field measurements conducted in the Pearl River Delta region of China unveil significant roles of relative humidity (RH) swings on aerosol phase states. Highlighting the occurrence of aerosol crystallization in the afternoon followed by gradual deliquescence as RH increases, particularly when minimum afternoon RH drops below 35%, with no such behavior observed when it exceeds 40%. Emphasizing that aerosol phase states are shaped not only by RH and chemical composition but also by their RH history, illustrating that RH levels of 70% in the morning or evening may correspond to fully dissolved metastable or partially dissolved metastable states of ambient aerosols. These findings underscore the need to account for RH history when predicting aerosol phase states and have broader implications for comprehending aerosol behavior and its atmospheric impacts. Plain Language Summary: This research introduces a new device to study how tiny particles called atmospheric aerosols in the air behave when they encounter moisture. We tested it in a region of China and discovered that relative humidity fluctuations from morning to evening impact significantly on phase state of atmospheric aerosols. In the afternoon, some of the particles might become solid, like tiny crystals, and later turn into liquid gradually as humidity increases. This phenomenon occurs when the afternoon minimum relative humidity is low, below 35%, but does not take place when it exceeds 40%. Suggesting that relative humidity history matters for aerosol phase. For example, relative humidity of 70% in the morning or evening, particles may be in a liquid or semi‐liquid state. This study helps us understand phase changes of atmospheric particles and their effects on our environment. Key Points: Innovative outdoor nephelometer system was developed to monitor aerosol hygroscopic behavior in ambient airAerosol crystallization in the afternoon followed by gradual deliquescence observedRelative humidity history plays significant roles in determining aerosol phase state [ABSTRACT FROM AUTHOR]

Waterfront park is an important composition of current urban ecological tourism in China, which sufficiently reveals the economic development situation of the city and the leisure culture life of the masses, and embodies rich regional cultural characteristics. Taking Xianghu Lake Park of Nanchang City as the example, design features of its water landscape and building are analyzed and explored The design follows the principle of utilization function combining with artistry, pays attention to plane layout and spatial organization, and retains classical architectural style of the building. [ABSTRACT FROM AUTHOR]

Submicron aerosol (PM1) species measured by aerosol mass spectrometers have been widely used to validate chemical transport models; however, the uncertainties due to chemical differences between PM1 and PM2.5 are poorly constrained. Here we characterized such differences in a highly polluted environment in north China in winter. Our results showed that the changes in PM1/PM2.5 ratios as a function of relative humidity (RH) were largely different for primary and secondary species. Secondary organic and inorganic aerosol (SOA and SIA) presented clear decreases in PM1/PM2.5 ratios at RH > 60% during periods with high SIA contributions (>50%), likely driven by the changes in aerosol hygroscopicity and phase states, while the traffic and coal combustion OA had limited dependence on RH. Thermodynamic modeling showed negligible impacts of PM differences on predictions of particle acidity, yet these impacts can cause a difference in aerosol water content by up to 50–70%. Plain Language Summary: Current air pollution studies rely largely upon aerosol mass spectrometers that provide real‐time measurements of submicron aerosol (PM1) species, and in many studies, PM1 aerosol species are used to validate those of PM2.5 in chemical transport models and estimate particle acidity and aerosol water content which are key parameters in studying heterogeneous reactions. However, the uncertainties in air pollution studies due to the chemical differences of PM1 and PM2.5 are poorly constrained, particularly in highly polluted environment, for example, China and India. We found that the changes in PM1/PM2.5 ratios as a function of relative humidity were largely different for primary and secondary aerosol species in highly polluted environment, which was likely driven by the changes in aerosol hygroscopicity and phase states. The chemical differences of PM1/PM2.5 ratios were also found to have negligible impacts on predictions of particle acidity, yet these impacts can cause a difference in aerosol water content by up to 50–70%. Considering the rapid increases in the deployments of aerosol mass spectrometers worldwide, the results in this study are of great importance for a better understanding of the uncertainties in both modelling and observations. Key Points: We observed large chemical differences between PM1 and PM2.5 under high relative humidity periods in highly polluted environmentThe RH dependence of PM1/PM2.5 ratios of primary and secondary species was largely different due to different hygroscopicityThe chemical differences between PM1 and PM2.5 have negligible influences on particle acidity prediction, yet have a large impact on AWC [ABSTRACT FROM AUTHOR]

Assessment of the radiative forcing of aerosols in models still lacks sufficient input data for aerosol hygroscopicity. The light scattering enhancement factor [f(RH, λ)] is a crucial parameter for describing aerosol hygroscopic growth properties. In this paper, we provide a survey of f(RH, λ) studies in China for the past seven years, including instrument developments of humidified nephelometers, ambient f(RH, λ) measurements in China, f(RH, λ) parameterization schemes, and f(RH, λ) applications in aerosol measurements. Comparisons of different f(RH, λ) parameterizations are carried out to check their performance in China using field measurement datasets. We also summary the parameterization schemes for predicting f(RH, λ) with aerosol chemical compositions. The recently developed methods to observe other aerosol properties using f(RH, λ) measurements, such as calculating the aerosol hygroscopicity parameter, cloud condensation nuclei number concentration, aerosol liquid water content, and aerosol asymmetry factor, are introduced. Suggestions for further research on f(RH, λ)in China are given. [ABSTRACT FROM AUTHOR]

Daytime HONO photolysis is an important source of atmospheric hydroxyl radicals (OH). Knowledge of HONO formation chemistry under typical haze conditions, however, is still limited. In the Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain in 2018, we investigated the wintertime HONO formation and its atmospheric implications at a rural site Gucheng. Three different episodes based on atmospheric aerosol loading levels were classified: clean periods (CPs), moderately polluted periods (MPPs) and severely polluted periods (SPPs). Correlation analysis revealed that HONO formation via heterogeneous conversion of N O 2 was more efficient on aerosol surfaces than on ground, highlighting the important role of aerosols in promoting HONO formation. Daytime HONO budget analysis indicated a large missing source (with an average production rate of 0.66 ± 0.26, 0.97 ± 0.47 and 1.45 ± 0.55 ppbV/hr for CPs, MPPs and SPPs, respectively), which strongly correlated with photo-enhanced reactions (N O 2 heterogeneous reaction and particulate nitrate photolysis). Average OH formation derived from HONO photolysis reached up to (0.92 ± 0.71), (1.75 ± 1.26) and (1.82 ± 1.47) ppbV/hr in CPs, MPPs and SPPs respectively, much higher than that from O 3 photolysis (i.e., (0.004 ± 0.004), (0.006 ± 0.007) and (0.0035 ± 0.0034) ppbV/hr). Such high OH production rates could markedly regulate the atmospheric oxidation capacity and hence promote the formation of secondary aerosols and pollutants. [ABSTRACT FROM AUTHOR]

Although numerous studies on hydrogeochemistry in karst catchments have been performed, some challenges in understanding their hydrogeochemical behavior remain due to the unique architecture of karst groundwater systems and the high heterogeneity of the karst medium. Here we used a multicriteria approach combining hydrodynamic, hydrochemical, and stable isotopic tools to investigate the impact of heterogeneity on karst hydrogeochemistry in a mountainous area of Hubei Province, Central China. Our results showed that groundwater was dominated by Ca2+, Mg2+, HCO 3 −, and SO 4 2−, and typically characterized by HCO 3 –Ca·Mg type in the shallow aquifer and by SO 4 –Ca·Mg type in the deep aquifer. With increasing circulation depth, water-rock interactions and the heterogeneity of the karst medium produced water with increased Ca2+, Mg2+, Sr2+, and SO 4 2− concentrations, and also increased the dissolved total solids. Calcite, dolomite, and gypsum dissolution in local and intermediate flows were important geochemical processes in groundwater evolution, and calcite precipitation occurred in the regional flow due to dedolomitization, supported by PHREEQC modeling of minerals. The decreased major ions and increased nitrate with increasing δ18O due to the dilution of shallow groundwater by high δ18O recharge and nitrogen fertilizer required during the summer rainy season were found relying on Plots of δ18O vs major ions, which offer an alternative approach to learn seasonal effects of hydrogeochemistry. All advances presented were integrated into a hydrogeochemical conceptual model, including local, intermediate, and regional flows, hydrogeochemical evolution, horizontal and vertical karst zones, hydrochemistry, and stable isotopes of groundwater, providing a typical model for multiple karst groundwater systems in Central China. [Display omitted] • Impact of heterogeneity on karst hydrogeochemistry was studied based on hydrodynamic, hydrochemical, and stable isotopic tools. •Time series analysis and circulation depths of groundwater highlighted the existence of the Sixi multiple karst groundwater systems. •Calcite, dolomite, and gypsum dissolution were important geochemical processes in local and intermediate flows, and dedolomitization occurred in the regional flow. •A hydrogeochemical conceptual model representing multiple karst groundwater systems in Central China was proposed. [ABSTRACT FROM AUTHOR]

Temperature, discharge, and stable isotope ratios of five karst springs in a mountainous area of Zigui County, Hubei Province, Central China, were analyzed. The purpose was to illustrate the heat exchanges linked to circulation depth in the exposed karst water systems through the development of a method for estimating heat input and heat flux during a rainstorm. Meteorological water in the study area conformed to a local meteoric water line (δD = 8.37 δ18O + 12.99) with a mean δ18O elevation gradient of −4.0‰ km−1, which was used to estimate mean circulation depths of 209–686 m. The mean spring temperatures defined a vertical gradient of −5.4 °C km−1, which resembled that of the stable atmosphere of the Earth, indicating that the thermal response patterns are mainly controlled by surface air temperature. Thermal convection after rainfall events dominated heat exchange between baseflow and recharge water, leading to a warmer and colder recharge during summer and winter, respectively, whereas thermal conduction dominated the heat exchange only between groundwater, surrounding geology, and the interface air under a condition of no rainfall, resulting in only small temperature variations of the baseflow. Successful application of the method for estimating heat exchange showed that the characteristics of shallow circulation, strong karstification, and well-developed epikarst readily allowed disruption of the thermal balance of the Yuquandong system, resulting in a poor heat regulation capacity, a larger variation of heat input, a lower mean heat flux, and lower baseflow temperatures compared to those of the Dayuquan system. [ABSTRACT FROM AUTHOR]

Psoriasis (PS; MIM#177900) is a chronic inflammatory immune-mediated skin disorder. Although the disease is believed to be caused by a combination of genetic, immunologic and environmental factors, its complete etiology has not been fully understood. Here, we focused on the BSG (MIM#109480), a member of the immunoglobulin superfamily expressed ubiquitously in circulating immune cell populations. We observed that the expression level of BSG in PBMCs was elevated in psoriasis patients. To understand the underlying mechanism for this change, we genotyped the rs8259 T>A SNP located in the 3′UTR of the BSG gene from 668 psoriasis patients and 1,143 healthy controls. The rs8259 T allele was associated with significantly decreased psoriasis susceptibility (OR = 0.758, 95% CI 0.638-0.901, p = 0.002). Interestingly, the rs8259 polymorphism was located in a seed region for miR-492 binding. The miR-492 was able to bind to the BSG 3′UTR sequence bearing the rs8259 T allele as assayed by luciferase reporter gene assay. The substitution of T with A abolished miR-492 binding. BSG protein expression in PBMCs from patients carrying the rs8259 AA genotype was significantly higher than in those from patients carrying the rs8259 TT genotype. Our study suggests that miR-492 may physiologically suppress BSG expression and the BSG rs8259 polymorphism is associated with decreased psoriasis susceptibility through affecting miR-492 binding. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is the most important light-absorbing species in the atmosphere and has a strong positive direct radiative forcing. Recent studies found that BC-containing particles may also modify the structure of planetary boundary layer and thus enhance haze pollution, especially in densely populated areas, for instance, in China. It is however difficult to quantify these effects due to their complex mixing state, hygroscopicity and the high spatial variability of concentration. During an intensive field campaign conducted in the North China Plain in a cold season, the mass size distribution and mixing state of BC was measured with a single particle soot photometer (SP2). During a severe haze event, the BC mass concentration exceeded 15 ug m-3. Stemming from the strong aging process under high relative humidity condition, freshly emitted BC particle was observed to turn into internally mixing within a short time scale. To understand the variation of the hygroscopicity of BC during its aging process, the hygroscopic growth factor of BC-containing particles was measured with a combination of a hygroscopic tandem differential mobility analyzer and a SP2. The particle hygroscopic growth factor was found to be correlated with the volume fraction of BC. During haze events, a fraction of the more-hygroscopic mode particles was observed to contain BC cores; while a minor fraction of the hydrophobic mode particles contained no BC. [ABSTRACT FROM AUTHOR]