RH Levels Research Articles

Bismuth-doping Induced Enhanced Humidity Sensing Properties of Spinel NiFe2O4 Nanoparticles

Bi-doped NiFe2O4 nanoparticles were tested for humidity detection at various RH levels at room temperature. The findings indicated that sensors with higher Bi concentrations, particularly the ones with 20 % Bi doping, showed significantly enhanced sensing response—up to 97 %, a sixfold increase compared to undoped sensors. This significant improvement suggests that Bi contributes to synergistic effects that boost sensor performance. Density Functional Theory (DFT) calculations support this by showing that Bi introduces acceptor electronic states, heightening electrical responsiveness to moisture. These Bi-doped sensors exhibit quick response times, high accuracy, negligible hysteresis, and impressive stability, making them promising candidates for reliable humidity detection.

Humidity sensors based on octaphenylcyclotetrasiloxane hypercrosslinked porous polymers for non-contact sensing and respiratory monitoring

Polyhedral oligomeric silsesquioxane (POSS) is renowned for its facile modification and excellent stability, rendering it a promising candidate for humidity-sensitive materials. Achieving humidity sensors based on POSS with broad response ranges and fast response times remains a considerable hurdle. In this investigation, four organic-inorganic hybrid porous polymers, denoted as HCP-X, were synthesized through Friedel-Crafts reaction utilizing octaphenylcyclotetrasiloxane (OPCTS). The incorporation of hydrophilic functional groups onto HCP-X polymers increases their specific surface area and enhances their adsorption capacity for water molecules, thereby accelerating the humidity sensor's response to humidity. The resulting humidity sensors derived from HCP-X demonstrated rapid response times ranging from 0.6 s to 7 s. Notably, the HCP-B-SO3 humidity sensor exhibited outstanding performance due to the synergistic effects of -OH and -SO3- groups, with a 6 orders of magnitude impedance change across the entire measured humidity range (11 % - 97 % RH), a rapid response time of 0.2 s, and excellent repeatability. It also showcased consistent long-term stability over a 30-day duration, maintaining its performance integrity at both 11 % and 97 % RH levels. The resulting humidity sensor was further utilized into non-contact switches and integrated into masks for health monitoring applications, underscoring its substantial potential in non-contact sensing and healthcare domains.

Seasonal simulation and source apportionment of SO42− with integration of major highlighted chemical pathways in WRF-Chem model in the NCP

Particulate sulfate (SO42−) is the major component of fine particles in the North China Plain (NCP). It plays an essential role in the entire atmosphere and climate system. Accurately reproducing the SO42− levels is challenging for chemical transport model. Here, the major highlighted multiple phase SO42− formation pathways are integrated into the WRF-Chem model and seasonal model performance of SO42− are assessed by observed SO42− at multiple sampling sites located in the NCP. The results show that the integration of these SO42− formation pathways obviously narrow the gap between simulation and observation in autumn, winter, and summer at three sampling sites in the NCP, for high RH conditions facilitate the hygroscopic growth of PM2.5 and promote the multiple phase reaction to form SO42−. The underestimation in autumn, winter, and summer may ascribe to the missed SO42− source from photo-induced chemical route and missed hygroscopicity of organic aerosols. The obviously discrepancy between simulation and observation in spring may ascribe to the large underestimation of SO2 levels and lack consideration of dust scheme. Source apportionment results show that the gas phase reaction played a vital role in the formation of SO42− in each season. The contribution of aqueous phase SO2 oxidation by H2O2 is higher in autumn and summer due to simultaneously high RH levels and stronger photochemical reaction activity. The Mn(II) catalytic SO2 oxidation pathway at the particle interface is important in autumn and make greater contribution to SO42− formation during winter severe haze events under extremely high RH levels.

Feasibility of low-cost particulate matter sensors for long-term environmental monitoring: Field evaluation and calibration

Low-cost sensor networks offer the potential to reduce monitoring costs while providing high-resolution spatiotemporal data on pollutant levels. However, these sensors come with limitations, and many aspects of their field performance remain underexplored. During October to December 2023, this study deployed two identical low-cost sensor systems near an urban standard monitoring station to record PM2.5 and PM10 concentrations, along with environmental temperature and humidity. Our evaluation of the monitoring performance of these sensors revealed a broad data distribution with a systematic overestimation; this overestimation was more pronounced in PM10 readings. The sensors showed good consistency (R2 > 0.9, NRMSE<5 %), and normalization residuals were tracked to assess stability, which, despite occasional environmental influences, remained generally stable. A lateral comparison of four calibration models (MLR, SVR, RF, XGBoost) demonstrated superior performance of RF and XGBoost over others, particularly with RF showing enhanced effectiveness on the test set. SHAP analysis identified sensor readings as the most critical variable, underscoring their pivotal role in predictive modeling. Relative humidity consistently proved more significant than dew point and temperature, with higher RH levels typically having a positive impact on model outputs. The study indicates that, with appropriate calibration, sensors can supplement the sparse networks of regulatory-grade instruments, enabling dense neighborhood-scale monitoring and a better understanding of temporal air quality trends.

Element composition of several marine macrophytes (Crimea, Black Sea) and correlations with the element abundances in sediments and seawater

The study of the element accumulation in marine plants against the backdrop of permanently increasing environmental pollution is of particular importance due to the participation of these plants in biogeochemical cycles. The element abundances are highly variable and depend on both the macrophyte species and environment. The purpose of this study was to analyze the elemental composition of widespread marine plants of different taxonomic affiliations collected in the same area of the Black Sea coast. The contents of 74 elements in three species of lower (red, brown, green algae) and one species of higher plants (seagrass) were analyzed using inductively coupled plasma mass spectrometry. High contents of most elements were found in the red alga Ceramium ciliatum and in rhizomes of the seagrass Zostera noltei. In C. ciliatum, high metal bioaccumulation factors were found, which are dependent also on their concentration in the environment. Compared to the higher plant, all the macroalgae accumulated increased amounts of As and I. The seagrass proved to be a good concentrator of Mo and Sb, and relatively high contents of Mn, Co, Ni, Zn, Cd and Ir were registered in its leaves. High contents of Mg, S, Ge, Se and Ta were found in the green alga Ulva rigida, and elevated levels of Al, As, Sr, Zr, Ru, Rh, Pd, Ag, Ba and Re were noted in the brown alga Gongolaria barbata. The enrichment factors for most elements in the sediments were well above 1 with respect to both the local Late Pleistocene sediments and the upper continental crust. The strength of correlations between the element contents in the plants and sediments was found to decrease with the specific surface area growth and appeared to have a lower asymptotic limit of the sediments–seawater correlation strength.

N-doped TiO2/rGO: synthesis, structure, optical characteristics, and humidity sensing applications

In the current study, the effect of rGO ratio on the N-dopped TiO2 has been synthesized through sol–gel method. The prepared N-doped TiO2/rGO composites were examined for humidity sensing applications. The relationship between optical properties and the humidity sensing properties was studied. The structure, morphology, and bonding interaction have been examined using XRD, FT-IR, PL and HRTEM respectively. The average particle size as estimated from XRD and HRTEM was found to be about 9 nm. The optical properties have been studied using UV/ Vis. Spectroscopy. Further, optical parameters including refractive index and optical band gap energy have been estimated. The humidity sensing behavior of the resultant composites were evaluated in a wide range of humidity (7%–97% RH) at different testing frequencies. The optical band gap was found to be decreased as the amount of rGO increase. Among all prepared samples, both the optical parameters and humidity sensing experiments confirmed that the 0.5% rGO@N-dopped TiO2 sample is the best candidate for the humidity sensing applications. The best optimum testing frequency was demonstrated to be 50 Hz. The sensor demonstrates a fast response and recovery times of 13 s and 33 s with low hysteresis and large sensitivity. The humidity sensing mechanism was studied using complex impedance spectroscopy at different RH levels under testing frequency range from 50 Hz to 5 MHz and testing voltage of 1 VAC. The produced structure demonstrated a promising material for humidity measuring devices.

Environmental fatigue crack growth of PV glass/EVA laminates in the melting range

AbstractThe delamination of encapsulants in photovoltaic (PV) modules is a common issue that leads to power loss due to optical losses. Encapsulant debonding is usually examined under monotonic loading conditions subsequent to environmental exposure such as damp heat. Service‐relevant, superimposed environmental‐mechanical fatigue loads are not considered adequately. Hence, the environmental fatigue delamination resistance of thermally toughened double glass laminates with an ethylene vinyl acetate copolymer (EVA) adhesive layer was investigated in this study. Focus was given to the melting range of EVA, in which the non‐crosslinked crystalline phase fraction is already in the partly molten state. Double cantilever beam specimens were tested on an electrodynamic test machine at temperatures of 60, 70, 80, and 90°C and relative humidity (rh) levels of 2%, 30%, 50%, and 80%. The fractured surfaces were characterized by digital microscopy, Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The cyclic fatigue tests revealed a decay in delamination resistance at elevated temperature and humidity levels. At 70°C, the delamination resistance was low, regardless of the relative humidity. Most of the laminates failed by debonding. XPS analysis showed a reduction of the C=O and C–O content, along with an increase in Si–O content with increasing relative humidity. For laminates tested at 60 and 70°C, an EVA recrystallization peak was observed in DSC experiments. This peak was shifted to significantly higher temperatures at 80% rh. XPS and DSC indicated local hydrolysis within the porous fracture process zone ahead of the crack tip. Consequently, acetic acid formation led to a decrease in delamination resistance, resulting in lower fatigue threshold values. The investigations confirmed the significant impact of environmental conditions on the fatigue delamination resistance within glass/encapsulant laminates. Notably, acetic acid formation and a significant reduction in delamination properties were observed after around 100 h of environmental fatigue exposure.

Uncharacteristic Adsorption Breakthrough Behavior of a Core–Shell Copper Hydroxysulfate Metal–Organic Framework Against Gaseous Formaldehyde

AbstractCore–Shell structured microspheres with a packed nano‐platelet copper hydroxysulfate (CHS) core and an octahedral crystalized metal–organic framework‐199 (CHS@M199) shell are synthesized and tested as adsorbent for gaseous formaldehyde (FA). CHS@M199 outperforms reference materials (e.g., activated carbon (AC), CHS, and M199) with adsorption capacity (Q) of 8.13 mg g−1 and partition coefficient (PC) of 0.263 mol kg−1 Pa−1 against 10 Pa FA at 10% breakthrough (BT) level with the aid of large surface area and copper sites for coordinating with carbonyl group. Contrary to general expectations, CHS@M199 exhibits a unique adsorption behavior in that BT volume increases systematically with the rise in FA inlet partial pressure (e.g., 5–10 Pa). The 10% BT capacity of CHS@M199 decreases noticeably (8.13 to 2.08 mg g−1) with increasing relative humidity (0.016 to 10%), reflecting water‐FA competition for hydrophilic adsorption sites. Although FA adsorption on CHS@M199 diminishes with elevated RH levels, such reduction intensifies when simulating ambient conditions (through stepwise addition of competing components: O2, CO2, and H2O). The FA adsorption on CHS@M199 is well described by both pseudo‐first‐order (PFO) and pseudo‐second‐order (PSO) kinetics. Polymerization may play a pivotal role in the adsorption of FA on CHS@M199, as Qi‐LeVan isotherm best fits the experimental data.

Cesium Cyclopropane Acid‐Aided Crystal Growth Enables Efficient Inorganic Perovskite Solar Cells with a High Moisture Tolerance

AbstractWhile all‐inorganic halide perovskites (iHPs) are promising photovoltaic materials, the associated water sensitivity of iHPs calls for stringent humidity control to reach satisfactory photovoltaic efficiencies. Herein, we report a moisture‐insensitive perovskite formation route under ambient air for CsPbI2Br‐based iHPs via cesium cyclopropane acids (C3) as a compound introducer. With this approach, appreciably enhanced crystallization quality and moisture tolerance of CsPbI2Br are attained. The improvements are attributed to the modified evaporation enthalpy of the volatile side product of DMA‐acid initiated by Cs‐acids. As such, the water‐involving reaction is directed toward the DMA‐acids, leaving the target CsPbI2Br perovskites insensitive to ambient humidity. We highlight that by controlling the C3 concentration, the dependence of power conversion efficiency (PCE) in CsPbI2Br devices on the humidity level during perovskite film formation becomes favorably weakened, with the PCEs remaining relatively high (&gt;15 %) associated with improved device stability for RH levels changed from 25 % to 65 %. The champion solar cells yield an impressive PCE exceeding 17 %, showing small degradations (&lt;10 %) for 2000 hours of shell storage and 300 hours of 85/85 (temperature/humidity) tests. The demonstrated C3‐based strategy provides an enabler for improving the long‐sought moisture‐stability of iHPs toward high photovoltaic device performance.

Epidemiological Dynamics of Xanthomonas xonopodis pv. phaseoli in French bean (Phaseolus vulgaris): Unraveling the Factors Governing Bacterial Blight Pathogenesis

The study was conducted during May, 2020 to June, 2021 in the Department of Plant Pathology Laboratory of Dr. Y.S Parmar University of Horticulture and Forestry, Nauni, located in Solan district of Himachal Pradesh, India to study the role of various epidemiological parameters on the development of common bacterial blight of French bean. The diseased samples were collected and the pathogen was isolated and purified on Luria Bertani (LB) agar plates. The pathogenicity test was performed on the potted plants as well as on the detached leaves using carborundum abrasion and pin prick method of inoculation. The incubation period on potted plants using carborundum abrasion and pin prick method revealed the initial symptoms after 117.60 h and 120.30 h, respectively, while on detached leaves they were visible after 72.30 h and 84.50 h of inoculation, respectively. Further to study the effect of different epidemiological factors on disease development, the leaves inoculated using carborundum abrasion were subjected to four temperature levels, five relative humidity levels and five different durations of leaf wetness under controlled conditions in relative humidity cum temperature control cabinet. The observations were recorded at different intervals and the data revealed that the pathogen caused severe symptoms on the leaves with high apparent rate of infection under 30°C temperature, 100% RH and a maximum of 24 h of leaf wetness. It was observed that the severity of disease decreased as the temperature raised from 30°C and increased with the rise in RH levels and leaf wetness duration.

Effects of simulated secondary organic aerosol water on PM1 levels and composition over the US

Abstract. Water is a key component of atmospheric aerosol, affecting many aerosol processes including gas-to-particle partitioning of semi-volatile compounds. Water related to secondary organic aerosol (SOAW) is often neglected in atmospheric chemical transport models and is not considered in gas-to-particle partitioning calculations for inorganic species. We use a new inorganic aerosol thermodynamics model, ISORROPIA-lite, which considers the effects of SOAW, to perform chemical transport model simulations for 1 year over the continental United States to quantify its effects on aerosol mass concentration and composition. SOAW can increase average fine aerosol water levels by up to a factor of 2 when secondary organic aerosol (SOA) is a major PM1 component. This is often the case in the south-eastern US, where SOA concentrations are higher. Although the annual average impact of this added water on total dry PM1 concentrations due to increased partitioning of nitrate and ammonium is small (up to 0.1 µg m−3), total dry PM1 increases of up to 2 µg m−3 (with nitrate levels increases of up to 200 %) can occur when RH levels and PM1 concentrations are high.

Chemical composition-dependent hygroscopic behavior of individual ambient aerosol particles collected at a coastal site

Abstract. This study investigated the hygroscopic behavior of individual ambient aerosol particles collected at a coastal site of Jeju Island, South Korea. The size of the particles changes along with the phase transitions during humidification and dehydration processes, and the chemical compositions of the particles were determined by optical microscopy and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX), respectively. Of the 39 particles analyzed, 24 were aged sea spray aerosols (SSAs), with diverse mixing ratios of Cl− and NO3-. The ambient SSAs exhibited multiple deliquescence and efflorescence transitions that were dominantly influenced by NaCl, NaNO3, MgCl2, Mg(NO3)2, and organic species covering the surface of the aged SSAs. For Cl-rich SSAs with X(Na,Mg)Cl&gt;0.4, although some particles showed very slow water uptake at low relative humidity levels (RH ≃30 %), two major transitions were observed during the humidification process. The first was at RH ≃63.8 %, regardless of their chemical compositions, which is the mutual deliquescence relative humidity (MDRH) level; and the second was at RH 67.5 % to 73.5 %, depending on their chemical compositions, which are the final deliquescence relative humidity (DRH) levels. During the dehydration process, the Cl-rich SSAs showed single-stage efflorescence at RH 33.0 % to 50.5 %, due to simultaneous heterogeneous crystallization of inorganic salts. For Cl-depleted SSAs with X(Na,Mg)Cl&lt;0.4, two prompt deliquescence transitions were observed during the humidification process. The first was at MDRH 63.8 %, and the second was at RH 65.4 % to 72.9 %. The mutual deliquescence transition was more distinguishable for Cl-depleted SSAs. During the dehydration process, step-wise transitions were observed at efflorescence RH levels (ERH 24.6 % to 46.0 % and 17.9 % to 30.5 %), depending on their chemical compositions. Additionally, aged mineral particles showed partial or complete phase changes with varying RH due to the presence of SSAs and/or NO3- species. In contrast, non-reacted mineral and Fe-rich particles maintained their size during the entire hygroscopic process. The mixture particles of organic and ammonium sulfate (AS) exhibited lower deliquescence and efflorescence RH levels compared to pure AS salt, highlighting the impact of organic species on the hygroscopic behavior of AS. These findings emphasize the complexity of atmospheric aerosols and the importance of considering their composition and mixing state when modeling their hygroscopic behavior and subsequent atmospheric impacts.

Proton-conductive aromatic membranes reinforced with poly(vinylidene fluoride) nanofibers for high-performance durable fuel cells.

Durability and ion conductivity are counteracting properties of proton-conductive membranes that are challenging to achieve simultaneously and determine the lifetime and performance of proton exchange membrane fuel cells. Here, we developed aromatic ionomers reinforced with nonwoven poly(vinylidene fluoride) (PVDF) nanofibers. Because of the right combination of an isotropic nonwoven PVDF with high porosity (78%) and partially fluorinated aromatic ionomers (SPP-TFP-4.0), the resulting composite membrane (SPP-TFP-4.0-PVDF) outperformed state-of-the-art chemically stabilized and physically reinforced perfluorinated Nafion XL membrane, in terms of fuel cell operation and in situ chemical stability at a high temperature (120°C) and low relative humidity (30%). The SPP-TFP-4.0-PVDF membrane exhibited excellent chemical stability and stable rupture energy at high and low RH levels, allowing it to be an alternative proton-conductive membrane to meet the U.S. Department of Energy target to be used in automobile fuel cells in 2025.

Atmospheric corrosion behaviors of 6000-series aluminum alloy under tropical climate influences of Thailand

Abstract The current research was aimed to investigate atmospheric corrosion behaviors of 6005A and 6082 aluminum alloys for a certain application in high-speed railway employed for service in Thailand. Actual exposure atmospheric test with the maximum period of 18 months was conducted at urban and marine–coastal environments. After completion of actual exposure test, corrosion behaviors of the uncoated alloys were determined based on corrosion mass loss and pitting corrosion aspects. It turned out that remarkable corrosion severity found at marine–coastal environment with respect to urban environment was attributed to higher deposition rates of cumulative chloride (around 1331 mg m−2 day−1) and sulfur dioxide (around 200 mg m−2 day−1) together with higher levels of RH (&gt;80%) for the entire year of exposure. The alloys exposed at marine–coastal environment for 18 months long revealed the corrosion mass loss of approximately 2 g m−2, average pit depth of greater than 80 μm, and density of around 3 pits⋅cm−2.

Indoor air quality in a training centre used for sports practice.

One of the measures for controlling the coronavirus disease 2019 (COVID-19) pandemic was the mass closure of gyms. This measure leads us to determine the differences between indoor and outdoor air quality. That is why the objective of this study was to analyse the indoor air quality of a sports centre catering to small groups and rehabilitation. The study was conducted in a single training centre, where 26 measurements were taken in two spaces (indoors and outdoors). The air quality index, temperature, relative humidity, total volatile compounds, carbon monoxide, ozone, formaldehyde, carbon dioxide, and particulate matter were measured indoors and outdoors using the same protocol and equipment. These measurements were taken twice, once in the morning and once in the afternoon, with all measurements made at the same time, 10 am and 6 pm, respectively. Additionally, four determinations of each variable were collected during each shift, and the number of people who had trained in the room and the number of trainers were counted. In the different variables analysed, the results show that CO2 and RH levels are higher indoors than outdoors in both measurement shifts. Temperatures are higher outside than inside and, in the evening, than in the morning. TVOC, AQI and PM show less variation, although they are higher outdoors in the morning. CO is highest indoors. HCHO levels are almost negligible and do not vary significantly, except for a slight increase in the afternoon outside. Ozone levels are not significant. All the variables showed practically perfect reliability in all the measurements, except for ozone measured outside in the morning. On the other hand, the variables exhibit variations between indoors and outdoors during the morning and afternoon, except for the three types of PM. Also, the data show that all the main variables measured inside the sports training centre are similar between morning and afternoon. However, outside, temperature, relative humidity and HCHO levels show significant differences between morning and afternoon while no differences are observed for the other variables. The indoor air quality of the training centre assessed was good and met current regulations; some of its components even exhibited better levels than fresh air. This article is the first to measure indoor air quality in a sports training centre catering to rehabilitation and small groups.

The Evaluation on Thermal Performance of Rumah Negeri Sembilan Berserambi Dua dan Beranjung

Traditional Malay house, a passive design architecture, is believed to have more effective thermal performance than modern residential houses through climatic design strategies. Unfortunately, the Malay house has experienced numerous changes and is confronted with constant dangers due to present-day science and innovation. Thus, this study aimed at evaluating the thermal performance of rumah Negeri Sembilan berserambi dua dan beranjung for sustainable practice in the tropical environment. The method used was fieldwork: observation and thermal measurement. Comparing the suggested comfort level by ASHRAE 55 and ICOP, 20% percent of the total data is falls within the thermal comfort range suggested. However, the house is considered in comfort environment between 25-27ºC, which is only in the early morning. As for the wind flow, each house division recorded different readings. However, it was still within the comfort level range, i.e., between 0.12-1.25m/s, while the RH level was 50-60%. Therefore, the primary findings elaborate that the Malay house construction has five factors that directly influence the house's thermal performance. These include floor areas, openings, floor and roof heights, materials, open compound areas, and building setting. This study aspires to provide useful insights regarding the effectiveness of practices in the climatic design strategies of a traditional Malay house. Thus, its contribute to the scientific discussions on sustainable practices in modern residential design which aligned with the Twelfth Malaysia Plan (RMK12) Theme 3.

Size–resolved mixing state of ambient refractory black carbon aerosols in Beijing during the XXIV Olympic winter games

Atmospheric loading of black carbon aerosols influences air quality and visibility, and their mixing state and aerosol chemistry were sensitive to both emission scenarios and regional transport. In this study, the aerodynamic size-resolved mixing state of refractory black carbon aerosols (rBC) was investigated using a novel tandem system consisting of an aerodynamic aerosol classifier (AAC), a single particle soot photometer (SP2), and single-particle-aerosol mass spectrometry (SPA-MS) during the XXIV Olympic Winter Games (OWG) at an urban site in Beijing. Particles with aerodynamic diameter (Dae) of 200 nm and 300 nm were selected by AAC to focus on the effect of relative differences in morphology on the coating thickness, coating compositions, and optical properties of rBC particles. We found that rBC-containing particles with Dae of 300 nm were characterized by a rBC core with a count median diameter (CMD) of 108 ± 4 nm that typically have regular morphology (χ:mean∼1), higher relative coating thickness (RCT: mean ∼1.9), and strong light absorption enhancement (Eabs: mean ∼1.5). The rBC-containing particles with Dae = 200 nm normally had irregular shapes (χ:mean∼1.4) and weak Eabs (Eabs: mean ∼1.37). Classification based on air mass clustering and air pollution level revealed that the coating thickness of rBC particles only exhibited unimodal patterns under clean air conditions and distinct bimodal distributions under heavy pollution conditions, implying multiple origins of rBC particles, even during OWG periods. The coating thickness and Eabs of rBC particles were greater when influenced by the higher RH air from east. Furthermore, the chemical compositions of the rBC coating quantitatively determined by SPA-MS were used to estimate the possible origins of the Dae = 300 nm, featured by a thicker coating thickness and stronger light absorption enhancement. Our results showed that rBC particles were primarily mixed with organics, nitrate, and sulfate during the XXIV OWG period. The organic components have a limited role in increasing rBC coatings under polluted conditions, while the alkali metal ions (K and Na) associated with traffic emissions and the secondary inorganic species favor the formation of thick coatings. Higher RH makes limited contributions to rBC mixed with sulfate and organics only (BCOC*_S) and pure BC. The relatively fresh BC could directly mix with organics and sulfate at low RH levels while evolving to mix with nitrate at high RH conditions. In addition to high concentrations of locally emitted precursors and high RH that tend to form thick coatings of nitrate-related rBC aerosols, secondary transport from the west and southwest also contributes to rBC aerosols mixed with nitrate with relatively thick coatings.

Effect of relative humidity on the efficacy of entomopathogen Beauveria bassiana-based mycopesticide against red spider mite Tetranychus macfarlanei

Tetranychus macfarlanei is a potential threat to various economically important crops. Chemical control is widely used to control this spider mite, but the exclusive reliance on chemical acaricides is now being questioned, and entomopathogens are emerging as a promising alternative. The efficacy of the entomopathogens largely depends on abiotic factors like temperature, humidity, rainfall etc. The experiments were conducted to determine the effect of relative humidity on the efficacy of the entomopathogen Beauveria bassiana (strain GHA), marketed as BotaniGard ES, against the adult female and egg stages of T. macfarlanei under laboratory conditions. Adult females and eggs of T. macfarlanei were treated with three concentrations of BotaniGard (1×106, 1×107, and 1×108 conidia/ml), and virulence was assessed on mites held at three relative humidity levels (55, 75, and 95 ± 2% RH) at 25 ± 1 °C. The results showed that the mortalities of adult females and eggs of T. macfarlanei were dose-dependent, and there is certainly a synergistic effect of relative humidity on the efficacy. When the eggs were treated under the above laboratory conditions, highest egg mortalities of 86.4 and 91% were recorded at a concentration of 1×108 conidia/mL at 75 and 95 ± 2% RH, respectively, after six days of treatment. The LT50 values on adult females were 28.7 h and 33.4 h at 95 and 75 ± 2% RH in a concentration of 1×108 conidia/ml, respectively, which was significantly lower than values for other concentrations and RH levels. This study identified 1×108 conidia/ml of B. bassiana at 75 to 95 ± 2% RH as the best possible combination than other lower RH to manage the spider mite.

Uptake and reactivity of acetic acid on Gobi dust and mineral surrogates: A source of oxygenated volatile organic compounds in the atmosphere?

The uptake of acetic acid (AcA) on natural Gobi dust is studied at room temperature and in the relative humidity range (<0.01–95% RH) using zero air as bath gas. The experiments were carried out in a U-shaped reactor coupled to a Selected-Ion Flow-Tube Mass Spectrometer (SIFT-MS) for gas-phase monitoring. The initial uptake coefficient, γ0, of AcA is found to decrease with RH according to the following expression γ0=γdry−(1.3×10−8)RH0.42, indicating a competition between AcA and water molecules for the same adsorption sites. AcA can be adsorbed both reversibly and irriversibly on Gobi dust. Interestingly, we evidenced that AcA uptake is reactive, especially at high levels of relative humidity (>30%) leading to the formation of oxygenated volatile organic compounds (OVOCs), such as methanol, acetaldehyde, and acetone. This is the first experimental study reporting the reactivity of AcA on natural mineral dust under ambient temperature and dark conditions. To unravel the kinetics, the uptake behavior, and reactivity of AcA on Gobi we also investigate the uptake of AcA on various mineral surogates SiO2, Al2O3, CaCO3, TiO2, Fe3O4. The results of the current study demonstrate the interest of studying heterogeneous processes at typical atmospheric levels of RH. Moreover we estimate that under atmospherically-relevant conditions, around 4% of the adsorbed AcA leads to OVOCs formation pointing at an unexplored but significant atmospheric process.

Elemental profiling of human semen with confirmed normozoospermia: Baseline levels for 44 elements

BackgroundAs a consequence of the progressive decline in human semen quality in recent decades, modern epidemiological investigations have identified several trace elements that could be responsible for this phenomenon. However, their levels in semen have not been clearly elucidated, particularly for elements present in ultra-trace levels. MethodsWe aimed to determine the levels of 39 (ultra)trace elements and 5 macroelements in human semen samples with confirmed normozoospermia using ICP-based techniques. The research was amplified by analyzing blood samples from the same participants. ResultsAmong the analyzed (ultra)trace elements in semen samples, Zn is the most and Tm is the least prominent. Zn levels in semen are so high that Zn should be considered as a macroelement in this matrix. The levels of Zn, Rh, Sm, Re, Ir, Tl, Na, and Ca were significantly higher in semen, while the levels of Cu, As, Rb, Gd, Sb, Tb, Tm, Lu, K, and Fe were significantly higher in blood. Correlation analysis of the levels of 44 individual elements in paired semen and blood samples revealed positive correlations between 43 of the elements, particularly for Tl and Pt. An exception was the negative correlation for Cu, which showed that its high level in semen is associated with a low level in blood and contrariwise. ConclusionThe reported data can be used as baseline levels/reference values for 44 elements in human semen. Furthermore, the findings of this study could be relevant for further consideration of male infertility.