High Air Humidity Research Articles

Effect of lithium on the atmospheric corrosion characteristics of TZM as the first-wall material in EAST

The effect of Lithium (Li) coating on the corrosion behavior of molybdenum-titanium-zirconium (TZM) alloy was investigated in low- and high-humidity air at room temperature (RT). Additionally, the corrosion mechanism was also studied through immersion tests in deionized water and LiOH solution. The test results confirm that the corrosion of the TZM alloy depends on the presence of H2O and O2, particularly H2O. In environments with high humidity, the TZM surface without Li coating easily undergoes oxidation, resulting in the formation of dark-green MoO3·xH2O. The Li coating significantly accelerates the surface oxidation of the TZM alloy because of its high absorptive properties for H2O, O2, and CO2, thereby generating Li2O, LiOH, and Li2CO3. These processes lead to a high content of O2 and H2O near the TZM surface, facilitating the formation of MoO3·xH2O. The immersion of TZM in water also leads to oxidative corrosion, which is more severe than that in high humidity air because of the dissolution of MoO3, causing the water to become dark-green. The oxidation of TZM in LiOH solution exhibits a behavior similar to that of water immersion. However, the corrosion in the LiOH solution is more severe because of the reaction between the surface oxide MoO3 and LiOH, which forms a colorless Li2MoO4, accelerating the corrosion process. This study offers valuable insights into the effective anti-corrosion strategies for the cleaning and storage of the TZM wall material in the EAST tokamak.

Salmonella control for dried apple cubes

Pathogen contamination in low-moisture foods prepared by drying is a food safety concern. Two thermal treatments were explored in this research as pathogen control measures for apple drying operations: high humidity air heating (HHAH) and ascorbic acid (AA) treatments. Their effectivenesses on Salmonella inactivation were assessed. Apple cubes (6.4 mm) inoculated with a three-strain Salmonella cocktail (S. Enteritidis PT 30, S. Montevideo, and S. Agona 447967) were subjected to HHAH and AA treatments, and then enumerated for the survival of Salmonella. In parallel, uninoculated apple cubes treated with HHAH or AA were dried by hot air at 90 °C for 70 min. The moisture content and color values of the dried apple cubes were measured. The results revealed that HHAH treatment at 70 °C for 16 min, at 90 °C for 9 min, and AA treatment using 3.4% ascorbic solutions at 65 °C for 90 s achieved 6.9 ± 0.4, 6.2 ± 0.2, and 7.9 ± 0.6 log CFU/g reduction, respectively. The moisture content of dried apple cubes was not significantly different, highlighting the potential of these methods for enhancing microbial safety of dried apples. The HHAH treatment resulted in an increased browning effect on dried apple cubes, while the AA treatment reduced the browning of dried apple cubes. This study offers valuable insight into preventive controls for pathogen management in food drying operations.

Analisis Spasial Faktor-Faktor yang Mempengaruhi Kejadian Tuberkulosis di Malang Raya Tahun 2020-2021

Background: Indonesia is the second country with the highest TB burden in the world. The government continues to strive for TB prevention and control to reduce TB rates. One of the efforts that can help in the TB program is by utilizing a Geographic Information System (GIS)Methods: The study is an ecological study; GIS as an approach. Data was obtained from the Health Service in Malang Raya and the Central Bureau of Statistics’ websiteResult: Study results are the pattern of distribution of TB incidence that tends to be high occurs in areas that have low coverage of healthy houses, low coverage of houses with healthy lifestyle, high population density, low air temperature, high air humidity, and high rainfall.Conclusion : The pattern of distribution of TB incidence that tends to be high occurs in areas that have low coverage of healthy houses, low coverage of houses with PHBS, high population density, high air temperature, high air humidity, and high rainfall.

Forest communities of the relict Balkan endemicAesculus hippocastanum

Aesculus hippocastanumL. (European Horse-chestnut) constitutes a biogeographical relict species of the Balkan Peninsula, occurring in isolated and topographically distinct localities in Albania, Bulgaria, Greece and North Macedonia. Despite its great botanical, ornamental and pharmaceutical value, a thorough investigation ofAe. hippocastanumhabitat diversity in its native distribution range has not been conducted yet. The present study aims at the syntaxonomic classification and ecological features of plant communities dominated by this species across its overall native distribution range. On the basis of 55 phytosociological relevés, five ecologically, floristically, and spatially well differentiated clusters were identified, with the main revealed gradients of differentiation being geographic location (longitude, latitude), altitude, annual precipitation and precipitation seasonality. The distinct microhabitats with a special refugial character where these plant communities occur meet the species’ requirement for relatively high air and soil humidity. They have allowed the preservation ofAe. hippocastanumthrough time highlighting their great conservational value. The last one could be useful for the implementation of some appropriate measures for effective conservation of these communities.

Identifikasi Tumbuhan sebagai Repellent terhadap Nyamuk : Review

Indonesia as one of the tropical countries in the world with high air humidity triggers the breeding of mosquitoes such as Aedes aegypti which is one of the vectors of Dengue Hemorrhagic Fever (DHF). This type of research is a literature study using the literature review method. This method is carried out by evaluating, interpreting and explaining the ideas discussed in several studies by searching for sources from the Google Scholar database. The selection of the type of article is based on the year of publication, the article can be accessed in its entirety, and discusses plants as repellents against mosquitoes. Based on research results from several sources, there is a biological prospect as an anti-mosquito agent for anti-mosquito and repellent/repelling power because it contains bioactive compounds, such as alkaloids, saponins, flavonoids, phenols, tannins, steroids and terpenoids. These compounds enter through respiratory contact and digestive/gastric toxins so that mosquitoes experience mortality/death. This compound also blocks chemical receptors (chemoreceptors) found on the palpus and antennae of mosquitoes, so that mosquitoes escape without sucking blood again. It is hoped that this review article can provide information regarding repellent plants as anti-mosquitoes. It can be concluded from the results of the review that there are plants that have repellent power against Aedes aegypti with increased protective power according to the increase in concentration of the plant used, as well as the length of exposure of the extract from each plant to the skin.

N-Type PVP/SWCNT Composite Films with Improved Stability for Thermoelectric Power Generation.

Single-walled carbon nanotubes (SWCNTs) are one of the promising thermoelectric materials in applications of powering wearable electronics. However, the electrical performance of n-type SWCNTs quickly decreases in air, showing a low stability, and low-cost and effective solutions to improving its stability are also lacking, all of which limit practical applications. In this study, we studied the stability of PVP/SWCNT composite films, where oxygen and moisture from air should be responsible for the decreased stability due to oxidation and hydration. In this case, we found that coating with a 0.20 g mL-1 PVP/0.002 g mL-1 PVDF layer on the surface of PVP/SWCNTs can prevent the penetration of oxygen and moisture from air, improving film stability, where there is almost no reduction in thermoelectric performance after they are exposed to air for 60 days. Based on the stable n-type PVP/SWCNT films, a thermoelectric generator was fabricated, where poly(dimethylsiloxane) (PDMS) was used to coat the surface of the thermoelectric leg to further improve its stability. This generator showed high output performance, which achieved an open-circuit voltage of 10.6 mV and a power density of 312.2 μW cm-2 at a temperature difference of 50 K. Particularly, it exhibited high stability, where the output performance kept almost unchanged after exposure to high-humidity air for 30 days. This coating technology is also applicable to other air-sensitive materials and promotes the development and application of thermoelectric materials and devices.

Effect of temperature and Humidity on the Thermal Conductivity λ of Insulation Materials

The aim of this article is to address the influence of air humidity and testing temperature on the thermal conductivity coefficient (λ) of various thermal insulation materials. This group includes wood-based materials, rock wools, heat-insulating renders, climate boards, and lightweight cellular concretes. These materials are used both indoors and outdoors in buildings. Over the course of several years, data were collected from laboratory tests to determine the thermal conductivity coefficient (λ) in relation to increases in temperature and humidity. The obtained results were compared with values provided by the manufacturers of the insulation materials. The aforementioned research was carried out due to the rather high sorption of most materials and thus the possibility of them becoming humid at high air humidity. Because of the very large difference in the thermal conductivity coefficient of water and air, a relatively small increase in the mass moisture content of the materials results in a loss of insulation.

Polymer Donor with a Simple Skeleton and Minor Siloxane Decoration Enables 19% Efficiency of Organic Solar Cells.

Development of polymer donors with simple chemical structure and low cost is of great importance for commercial application of organic solar cells (OSCs). Here, side-chain random copolymer PMQ-Si605 with a simply 6,7-difluoro-3-methylquinoxaline-thiophene backbone and 5% siloxane decoration of side chain is synthesized in comparison with its alternating copolymer PTQ11. Relative to molecular weight (Mn) of 28.3kg mol-1 for PTQ11, the random copolymer PMQ-Si605 with minor siloxane decoration is beneficial for achieving higher Mn up to 51.1kg mol-1. In addition, PMQ-Si605 can show stronger aggregation ability and faster charge mobility as well as more efficient exciton dissociation in active layer as revealed by femtosecond transient absorption spectroscopy. With L8-BO-F as acceptor, its PMQ-Si605 based OSCs display power conversion efficiency (PCE) of 18.08%, much higher than 16.21% for PTQ11 based devices. With another acceptor BTP-H2 to optimize the photovoltaic performance of PMQ-Si605, further elevated PCEs of 18.50% and 19.15% can be achieved with the binary and ternary OSCs, respectively. Furthermore, PMQ-Si605 based active layers are suitable for processing in high humidity air, an important factor for massive production of OSCs. Therefore, the siloxane decoration on polymer donors is promising, affording PMQ-Si605 as a high-performing and low cost candidate.

Degradation of Graphene in High- and Low-Humidity Air, and Vacuum Conditions at 300-500 K.

Graphene is a fundamental unit of carbon materials and, thus, primary sp2-bonded carbon material. Graphene is, however, easily broken macroscopically despite high mechanical strength, although its natural degradation has rarely been considered. In this work, we evaluate the natural degradation of two-layer graphene in vacuo, in low-humidity air, and in high-humidity air at 300, 400, 450, and 500 K. Over 1000 days of degradation at 300 K, the graphene structure was highly maintained in vacuo, whereas the layer number of graphene tended to decrease in high- and low-humidity air. Water was slightly reacted/chemisorbed on graphene to form surface oxygen groups at 300 K. At 450 and 500 K, graphene was moderately volatilized in vacuo and was obviously oxidized in high- and low-humidity air. Surprisingly, the oxidation of graphene was more suppressed in the high-humidity air than in the low-humidity air, indicating that water worked as an anti-oxidizer of graphene by preventing the chemisorption of oxygen on the graphene surface.

Experimental investigation of mold growth risk among typical residential indoor materials: Case study in coastal city, China

Mold growth poses significant threats to building structures and occupant health, particularly in regions with high air humidity. Existing mold prediction models involve fewer categories of building materials and are less reliable in predicting complex real environments. This research investigated mold growth risk of ten typical residential indoor materials. Firstly, this work carried out meticulous sampling in a residential building, followed by incubation tests in a controlled mold incubator, and evaluated by the mold growth index. The results revealed varying degrees of mold growth risk among different materials at different relative humidity (RH) levels. Paints exhibited a generally low susceptibility to mold contamination, while panels and wallcovering displayed a higher risk of mold growth. Under high humidity, mold growth was observed in the panels on the first day of inoculation. Conversely, 25 % of the latex paints did not reach index 1 at the end of the experiment. The results showed that below 75 % RH at 25 °C was a safe area for all experimental materials. Moreover, experimental results indicated that a lag approximately one-week in the appearance of mold was observed when the RH was reduced by 10 %. However, the final mold growth index did not differ by more than one grade after the test cycle.

Bazi Sofralık Ve Şaraplık Üzümlerin Fenolojik ve İklim Endeksleri ile Samsun-Bafra Ovasında Yetiştirilme Durumunun İncelenmesi

The aim of this study was to determine the viticultural potential of Bafra plain based on viticulture climate indices. Bafra district was classified as warm-temperate according to Winkler and Huglin indices. The Winkler index (WI) 1969.0, Huglin index (HI) 2184.4 °C units, Branas Heliothermic Index (BHI) 4.5, and Branas Hydrothermal Index (HYI) 3423.6 were obtained for the Bafra region. Annual sunshine duration was calculated as 2295.5 hours, while sunshine duration during the growing period was 1715.0 hours. Considering the HYI value being somewhat high, this combined with the high air humidity in the summer months shows an increased risk of fungal diseases. The bud burst occurred in the second week of April and flowering occurred in the first week of June in all cultivars. The earliest veraison initiated with early ripening ‘Early Sweet’ and ‘Trakya İlkeren’ cultivars and the latest veraison was in ‘Ugni Blanc’ and ‘Red Globe’. The earliest ripening was determined in ‘Early Sweet’ with 937.7 GDD, and the latest ripening was determined in the ‘Ugni Blanc’ cultivar as 1729.2 GDD. The period from bud burst to maturity was 110 days in ‘Early Sweet’ and 170 days in the ‘Ugni Blanc’. Sites selected with high altitude, areas that slope slightly to the south sides, low humidity, and far from sea areas are suitable for early and mid-season ripening grape cultivars. The high humidity in the summer and heavy rain in the fall season increase fungal disease risks in the Bafra region.

Impacts of urban landscape pattern changes on land surface temperature in Southeast Brazil

Urban sprawl is a global concern, considering the current climate change scenario. The conversion of natural habitats or other land uses to urban areas increases the Land Surface Temperature (LST), impacting people mainly in tropical regions, such as Brazil, where the temperature is aggravated by high air humidity. In this context, we assessed the seasonal variation of LST in response to the land-use/land-cover (LULC) changes over a large city in southwest Brazil during the last 36 years (1985–2020). We used Mapbiomas LULC data and LST retrieved from the Landsat series with the Google Earth Engine platform. The methodology involved the change detection analysis from 1985 to 2020 for all LULC types, a non-parametric Dwass-Steel-Critchlow-Fligner test to estimate the LST spatio-temporal variability over different LULC types, and a non-parametric Sperman's rho test and scatter plots to relate LST changes to the LULC patterns. The results presented areas exchanging under an intense urbanization process, wherein nearly 13% of the transitions were from agricultural to urban areas. These transitions occurred jointly with an increase in temperature for all LULC types. Forest formation registered the lowest LST and a moderate to strong negative correlation with LST in both seasons. On the other hand, urban areas showed the highest temperatures and a moderate to strong positive correlation with LST in summer. From 1985 to 2020, the mean temperature in urban (built-up) areas during the summer increased by 7 °C. In 2020, the mean temperature in urban areas was 32.5 °C and 27.8 °C in forested areas during the summer. The main contribution of this study is to provide evidence-based support for establishing LULC governance at the city scale. It offers essential scientific information about the detrimental impact of urban sprawl against the climate benefits of green infrastructure on the city scale, even in tropical regions with high forest fragmentation, temperatures, and long periods with high air humidity.

Analyzing the role of climatic factors in the driver—vehicle—road—environment system

Climate peculiarities affect road performance and, consequently, vehicle operating conditions. The autumn-winterspring period is characterized by sharp air temperature fluctuations within 0...± 4 °C, large amounts of precipitation, high air humidity, thaws, icing, which are a concomitant factor of accidents on the roads. The analysis of road accident statistics showed that in the transitional periods of fall-winter and winter-spring there are localized spikes in the number of accidents. During the analysis it was revealed that the increase in the number of accidents in the transition period falls on the so-called "critical" month, characterized by air temperature spikes in the range of 0...±4 °C and heavy precipitation. Keywords WADS system; climatic zones of the Russian Federation; factors of the subsystem "environment"; accident statistics; winter road maintenance

Sodium Potassium Niobate-Based Piezoelectrics Sintered in Humid Air.

While the consequences of humidity during solid-state processing of sodium potassium niobate-based lead-free piezoelectric powders are well established, the effect of humidity at later fabrication steps is less known. This study assesses the effect of humidity on the sintering and functional properties of 0.06LiNbO3-0.94(K0.5Na0.5)NbO3 (LKNN). Samples sintered in high-humidity air display a higher density, lower dielectric losses, and an increased mechanical quality factor. The observed properties persisted even after five months of storage with marginal reduction in the measured piezoelectric parameters. While the improvements shown with the high-humidity sintering method might be too small to justify investments in special atmosphere sintering, it more importantly indicates that no special equipment or atmosphere control is required to avoid adverse effects of humidity during sintering of sodium potassium niobate-based piezoceramics.

Latent Infestation of Potato Tubers with Soft Rot and Ring Rot Pathogens under Changing Weather Conditions in Ukraine

Potato is one of the most important food crops in the world. Cultivation of potatoes is an important segment of the agriculture and economy as a whole in Ukraine. Bacterial diseases such as ring rot caused by Clavibacter sepedonicus, as well as soft rot and blackleg caused by Pectobacterium atrosepticum evoke tremendous losses of the potato crop. Stored seed tubers are the main source of accumulating pathogens in latent form. In addition, potato crop yield and quality are significantly affected by weather conditions. Along with affecting potatoes directly, meteorological factors such as air temperature and humidity can also impact tuber infestation with bacterial pathogens. The aim of the study was to monitor the prevalence of bacterial ring rot pathogen C. sepedonicus and soft rot pathogen P. atrosepticum in potato tubers on the territory of Ukraine in 2020 and 2021 years and assess its association with different weather conditions. Methods. Potato seed lots from newly harvested crops in eight regions of Ukraine (Odesa, Kyiv, Donetsk, Kherson, Cherkasy, Mykolaiv, Dnipropetrovsk, and Zhytomyr regions) without visual symptoms of diseases were used for the experiments. The detection of C. sepedonicus and P. atrosepticum was conducted by the immunochemical method DAS ELISA. Basal meteorological data (the sum of precipitation (mm/month) and average air temperature (°C) were obtained from the local meteorological stations. The amplitude of air temperature and the sum of precipitation during potato planting, growing, and harvesting seasons, as well as Sielianinov’s hydrothermal coefficient (K) were additionally calculated. The Spearman correlation coefficient was used for the analysis of the correlation between pathogen prevalence and weather parameters. Results. Both ring rot pathogen C. sepedonicus and soft rot pathogen P. atrosepticum were detected in potato lots from all surveyed regions, but the prevalence of latent infestation varied between 2020 and 2021. In 2020, the highest soft rot pathogen prevalence values were registered for Mykolaiv, Kyiv, and Cherkasy regions (21.7, 10.5, and 10% respectively), where high rainfall levels in May and June were observed. In 2021, potato planting, growing, and harvesting seasons were marked by significantly higher precipitation levels, as compared to 2020, in all regions. Average occurrence values for P. atrosepticum in potato lots were 1.7 times higher than that in 2020. The highest prevalence (40%) was observed in the Donetsk region with extremely high air humidity during the potato growing period. Strong positive correlation (r = 0.721) was found between soft rot pathogen prevalence and K coefficients during the potato growing season, as well as between P. atrosepticum prevalence and the sum of precipitation during planting and early growing seasons. Prevalence of ring rot pathogen didn’t differ significantly in 2020 and 2021. The highest C. sepedonicus prevalence was observed in 2020 in the Kyiv region (18.9%), and in 2021 — in the Donetsk region (20%). A moderate positive correlation (r = 0.591) was found between pathogen prevalence and air temperature during planting and early growing season. Conclusions. Weather factors such as air temperature and humidity over the planting and early growing potato season can influence progeny tuber infestation with P. atrosepticum and C. sepedonicus. Knowledge of the effect of the changing weather conditions on the susceptibility of potato varieties with different genetic features to infestation with soft rot and ring rot pathogens warrants future investigation since it is crucially important for developing measures for disease control by potato producers.

Deterioration of single-use biodegradable plastics in high-humidity air and freshwaters over one year: Significant disparities in surface physicochemical characteristics and degradation rates

More single-use plastics are accumulating in the environment, and likewise biodegradable plastics (BPs), which are being vigorously promoted, cannot escape the fate. Currently, studies on the actual degradation of BPs in open-air and freshwaters are underrepresented despite they are potentially headmost leakage and contamination sites for disposable BPs. Herein, we compared the degradation behavior of six BP materials and non-degradable polypropylene (PP) plastics over a 1-year in situ suspension in the high-humidity air, a eutrophic river, and an oligotrophic lake. Moreover, a 3-months laboratory incubation was performed to detect the release of dissolved organic carbon (DOC) from BPs. In both air and freshwaters, poly(p-dioxanone) (PPDO) degraded significantly while PP and polylactic acid (PLA) showed no signs of degradation. The average degradation rates of three poly(butylene adipate-co-terephthalate) (PBAT)-based films varied: 100% in river, 55% in lake, and 10% in air. In addition to PLA, surface chemical groups, hydrophilicity, and thermal stability of BPs changed, and microplastics were found on their surfaces. Correspondingly, BPs with faster degradation rates released relatively higher amounts of DOC. Environmental microbial and chemical characteristics may contribute to differences in BP degradation besides polymer specificity. Altogether, our results indicate the need for appropriate monitoring of BPs.

Enhanced charge extraction enabled by amide-functionalized carbon quantum dots modifier for efficient carbon-based perovskite solar cells

The effective improvement of interfacial charge extraction and inhibition of charge recombination are crucial for promoting the performance of perovskite (PVK) solar cells (PSCs). Here, the N,N’-methylenebisacrylamide-functionalized carbon quantum dots (MBA/CQDs) with defects passivation effect and appropriate energy levels are proposed as a back interface modifier for carbon-based CsPbBr3 PSCs. The functionalization of MBA molecules not only increases the content of sp2 hybrid carbon in CQDs, but also expands the passivation effect of CQDs on surface defects of PVK films by introducing carbonyl and amino groups, which improves the carrier transport and reduces the carrier nonradiative recombination. Additionally, the modification of MBA/CQDs provides an intermediate energy level at the PVK/carbon back interface, which boosts hole extraction and lowers energy loss. Finally, a leading-edge power conversion efficiency of 10.40 % is derived for the MBA/CQDs modified champion device, which is significantly improved compared to the 7.02 % efficiency for the original CsPbBr3 PSCs. Furthermore, the unpackaged CsPbBr3 PSCs with MBA/CQDs have an excellent stability, maintaining an initial efficiency of 92 % after 30 days of storage at high humidity (85 % relative humidity) and temperature (85 °C) in air.

Impedance Measurement and Demonstrator Tests of Developed Thermally Sprayed and Sealed Coating Systems for Bearing Applications

To avoid early stage failure of rolling bearings as components of train drives of electrical engines, the bearings must be protected. As state of the art, alumina coatings are applied by atmospheric plasma spraying and subsequently an organic sealer is used to enhance the service life of these bearings under harsh conditions. This includes high applied frequencies and high ambient air humidity. For further improvement, mullite coatings and a newly developed an epoxy‐ and silicon‐based sealer applied by different sealing techniques are investigated to further enhance the electrical insulation of the bearing coatings. Impedance measurements under dry and wet conditions are conducted to analyze the capacitive behavior of the coatings. X‐ray diffraction measurements are used to correlate the influence of the present crystallographic phases of the ceramic coating on the capacitive behavior. In a following step, selected coating systems are applied onto bearings and tested in demonstrator tests. For higher currents of roughly IBearing ≥ 0.6 A, all newly developed coatings exhibit a decreased number of electrical breakdowns compared to the reference. Consequently, choosing this coating system as electrical protection coating for bearings in electrical engines can reduce the damage occurring from electrical current breakdowns.

Transmission of COVID-19 in Cities with Weather Conditions of High Air Humidity: Lessons Learned from Turkish Black Sea Region to Face Next Pandemic Crisis

The goal of this study is to analyze associations between COVID-19 transmission and meteorological indicators in cities of the Black Sea region of Turkey, located specifically in the dampest area, with excess rainfall and recurring fog. In particular, the working hypothesis is that the widespread transmission of new coronavirus SARS-CoV-2 (leading to the airborne disease COVID-19) in cities can be explained by specific weather conditions, namely high levels of air humidity. Statistical evidence here does not seem, in general, to support the hypothesis that the accelerated transmission of COVID-19 in the studied cities can be explained by high levels of humidity because different meteorological, environmental, demographic, and socioeconomic factors also plays a critical role in the disease transmission dynamics of the investigated region. The main implications of our findings here are that the demographic structure of the population, climate indicators, organization of the health system, and environmental factors (e.g., air pollution, etc.) should be considered through a systemic approach when designing effective national and regional pandemic plans directed to implement health policies for facing new variants of COVID-19 and/or new airborne diseases, in order to reduce their negative effects on health, social and economic systems.

Revisiting an ecophysiological oddity: Hydathode-mediated foliar water uptake in Crassula species from southern Africa.

Hydathodes are usually associated with water exudation in plants. However, foliar water uptake (FWU) through the hydathodes has long been suspected in the leaf-succulent genus Crassula (Crassulaceae), a highly diverse group in southern Africa, and, to our knowledge, no empirical observations exist in the literature that unequivocally link FWU to hydathodes in this genus. FWU is expected to be particularly beneficial on the arid western side of southern Africa, where up to 50% of Crassula species occur and where periodically high air humidity leads to fog and/or dew formation. To investigate if hydathode-mediated FWU is operational in different Crassula species, we used the apoplastic fluorescent tracer Lucifer Yellow in combination with different imaging techniques. Our images of dye-treated leaves confirm that hydathode-mediated FWU does indeed occur in Crassula and that it might be widespread across the genus. Hydathodes in Crassula serve as moisture-harvesting structures, besides their more common purpose of guttation, an adaptation that has likely played an important role in the evolutionary history of the genus. Our observations suggest that ability for FWU is independent of geographical distribution and not restricted to arid environments under fog influence, as FWU is also operational in Crassula species from the rather humid eastern side of southern Africa. Our observations point towards no apparent link between FWU ability and overall leaf surface wettability in Crassula. Instead, the hierarchically sculptured leaf surfaces of several Crassula species may facilitate FWU due to hydrophilic leaf surface microdomains, even in seemingly hydrophobic species. Overall, these results confirm the ecophysiological relevance of hydathode-mediated FWU in Crassula and reassert the importance of atmospheric humidity for some arid-adapted plant groups.