Role Of Humidity Research Articles

Urea modified Cu-doped LaFeO3 nano-particles for humidity sensing with contactless moisture detection for medical and agricultural application

Nowadays, the role of humidity is a major factor in numerous applications such as medical purposes and soil moisture detection. In this work, we synthesized pristine LaFeO3 (LFO1, LFO2) nanoparticles via hydrothermal method with and without urea. Furthermore, the synthesis of LFO doped with Cr, Cu and Mn was also done in the presence of urea using hydrothermal technique and studied for humidity sensing. The XRD confirms the crystalline size of the developed nanoparticles ranges in 19–25 nm. The sensing properties of pristine and doped LFO sensors for humidity sensing have been investigated in the 11 % – 90 % relative humidity (RH) range. As compared with others, the Cu-doped LFO sensor exhibits better response and recovery time of 5.4 s and 3.8 s respectively. Additionally, the nanoparticles of Cu-doped LFO show a highly porous nature having nano-perforated dumbbell structure as identified from the FESEM images. Moreover, to check the functionality of the developed sensor, the device is fabricated, resulting in the linear increase in output current with increase in relative humidity at a bias voltage of 1 V. With rapid response and recovery time, superior sensitivity and long-time stability, the developed Cu-doped LFO sensor can be used for medical detection of asthma, apnea and cough, as well as for non-contact skin monitoring that indicates its potential use to identify the moisturizing products for skin care. Finally, the efficacy of the fabricated sensor to monitor real-time humidity is also observed via IoT on a laptop/smartphone to display its potential to detect soil moisture for agriculture application.

Depletion of iodide in ageing aerosols and the role of humidity: A case study of mixed sodium iodide-malonic acid aerosol

Global sea to air iodine emissions, along with organic emissions and their oxidation products, have increased tremendously. This work presents a comprehensive analysis of the humidity mediated changes in ageing aerosols comprising iodide and water soluble dicarboxylic acid using aerosol micro-Raman spectroscopy. The studies in the model system, sodium iodide-malonic acid mixed aerosols, unveiled the depletion in iodide. Mechanistic insights gleaned through comparative studies conducted under inert (nitrogen) and oxidative (air) atmospheres reveal the iodide depletion occurs possibly via oxidation to molecular iodine. The reaction involves gaseous components, diffusion of which across the particles will be impacted by the physical state of the particles, such as viscosity, which in turn is intricately linked to ambient humidity levels. To this end, studies on the temporal evolution of the reaction at three distinct RHs covering 30–80% revealed the enhanced progression of the reaction with increasing humidity. Given that geographical locations serving as major sources for atmospheric iodine typically experience high humidity, these reactions could emerge as an additional process controlling iodine speciation in ageing aerosols.

Regional variation in the role of humidity on city-level heat-related mortality.

The rising humid heat is regarded as a severe threat to human survivability, but the proper integration of humid heat into heat-health alerts is still being explored. Using state-of-the-art epidemiological and climatological datasets, we examined the association between multiple heat stress indicators (HSIs) and daily human mortality in 739 cities worldwide. Notable differences were observed in the long-term trends and timing of heat events detected by HSIs. Air temperature (Tair) predicts heat-related mortality well in cities with a robust negative Tair-relative humidity correlation (CT-RH). However, in cities with near-zero or weak positive CT-RH, HSIs considering humidity provide enhanced predictive power compared to Tair. Furthermore, the magnitude and timing of heat-related mortality measured by HSIs could differ largely from those associated with Tair in many cities. Our findings provide important insights into specific regions where humans are vulnerable to humid heat and can facilitate the further enhancement of heat-health alert systems.

Role of humidity and surface roughness on direct wafer bonding

Bodies made from elastically stiff material usually bind very weakly unless the surfaces are flat and extremely smooth. In direct wafer bonding flat surfaces bind by capillary bridges and by the van der Waals interaction, which act between all solid objects. Here we study the dependency of the work of adhesion on the humidity and surface roughness in hydrophilic direct wafer bonding. We show that the long-wavelength roughness (usually denoted waviness) has a negligible influence on the strength of wafer bonding (the work of adhesion) from the menisci that form from capillary condensation of water vapor.Graphic abstractAFM surface topography for Si(100) wafer

Humidity's Role in Heat-Related Health Outcomes: A Heated Debate.

As atmospheric greenhouse gas concentrations continue to rise, temperature and humidity will increase further, causing potentially dire increases in human heat stress. On physiological and biophysical grounds, exposure to higher levels of humidity should worsen heat stress by decreasing sweat evaporation. However, population-scale epidemiological studies of heat exposure and response often do not detect associations between high levels of humidity and heat-related mortality or morbidity. These divergent, disciplinary views regarding the role of humidity in heat-related health risks limit confidence in selecting which interventions are effective in reducing health impacts and in projecting future heat-related health risks. Via our multidisciplinary perspective we seek to a) reconcile the competing realities concerning the role of humidity in heat-related health impacts and b) help ensure robust projections of heat-related health risks with climate change. These objectives are critical pathways to identify and communicate effective approaches to cope with present and future heat challenges. We hypothesize six key reasons epidemiological studies have found little impact of humidity on heat-health outcomes: a) At high temperatures, there may be limited influence of humidity on the health conditions that cause most heat-related deaths (i.e., cardiovascular collapse); b) epidemiological data sets have limited spatial extent, a bias toward extratropical (i.e., cooler and less humid), high-income nations, and tend to exist in places where temporal variations in temperature and humidity are positively correlated; c) analyses focus on older, vulnerable populations with sweating, and thus evaporative, impairments that may be further aggravated by dehydration; d) extremely high levels of temperature and humidity (seldom seen in the historical record) are necessary for humidity to substantially impact heat strain of sedentary individuals; e) relationships between temperature and humidity are improperly considered when interpreting epidemiological model results; and f) sub-daily meteorological phenomena, such as rain, occur at high temperatures and humidity, and may bias epidemiological studies based on daily data. Future research must robustly test these hypotheses to advance methods for more accurate incorporation of humidity in estimating heat-related health outcomes under present and projected future climates. https://doi.org/10.1289/EHP11807.

The Role of Humidity in India’s Covid-19 Seasonality and Effectiveness of Policy Controls During the Second and Third Waves of 2021 and Early 2022

Background: The first wave of COVID-19 in India began to decline suddenly in September 2020 and appeared to be nearly over by the end of January 2021. At the time, no models or papers predicted or explained this decline. The authors hypothesized in their previous study that the cases decreased due to increased Relative Humidity during Monsoon and forecasted that another wave would begin with the dry season in February 2021 and would be contained by monsoon humidity. The current study was carried out to put the seasonality hypothesis to the test in 2021-22. The study also included findings about the effectiveness of policy control measures on case decline.Methods: Humidity cycles in India were studied to determine the most humid periods, which corresponded to changes in daily cases across the country, on a zone-by-zone basis, and in smaller regions. The enforcement date and subsequent case decline (if any) were observed for the effectiveness of policy control measures.Results: In low humidity periods, there was a clear relationship between relative humidity and case decline and case increase. Policy controls have been found to be effective in reducing and halting case increase, resulting in a subsequent decline.Conclusion: In India, COVID-19 increases during the dry season around February and decreases during the monsoon season. Policy controls (lockdowns) are an effective way to halt the virus's exponential spread. The findings may be useful in planning local control and prevention activities.

Light harvesting hexamolybdenum cluster integrated with the 3D ordered semiconductor inverse opals for optoelectronic property

Solar energy-harvesting materials have significantly contributed to the development of energy-saving applications for several decades. We have mainly used a new concept composed of the electrophoretic deposition technique and photonic crystal structural engineering to understand the tunable light-absorption and electronic conduction properties. A hexamolybdenum cluster compound (denoted as the Mo6 cluster) was successfully functionalized on a tin pyrophosphate semiconductor integrated within an inverse opal photonic crystal. The size of the periodical pores, surface modification, and chemical composition of the infiltration material of the inverse opal film have been investigated to control the photonic bandgap in the visible range and the efficiency of the deposited Mo6 cluster. The photoactive Mo6 clusters act as a visible light harvester and generate an efficient photo-induced current upon light absorption that is enhanced by a slow photon effect occurring at the photonic stopband edges. The electron and proton are transferred in the inorganic-organic network via hydrogen bonds by a hopping mechanism to generate a rapid photoconductivity response during light irradiation. Specific attention focused on the role of humidity and temperature regarding the reproducibility of the experiments and the photosensitivity of the nanocomposite. The suitable tunable photo-induced conduction property in organic-inorganic materials opens a new opportunity for the applicability of cluster-based compounds in visible optoelectronic devices.

Comparison of Urban Heat Island Diurnal Cycles under Various Atmospheric Conditions Using WRF-UCM

The rapid growth of urbanization significantly influences local atmospheric conditions and life quality of residents living in urban areas by creating a localized phenomenon known as an urban heat island. Urban heat island characteristics are strongly formed by prevailing atmospheric conditions influencing their magnitude and intensity. In this study, we used the Weather Research and Forecasting model to investigate the effects of different airmass and windspeed characteristics on the diurnal cycle of the urban heat island phenomenon during four real weather situations presenting typical scenarios with clear sky conditions. The scenarios consisted of warm dynamic and non-dynamic situations and cold dynamic and non-dynamic situations identified with respect to temperature profiles, humidity and wind speed. The comparison of urban heat island intensity between all four scenarios showed a significant effect of wind speed on urban heat island characteristics and intensity as well as the role of humidity and airmass temperature in diurnal changes. The results showed that urban heat island is best defined by conditions with strong radiative heating and weak wind speed regardless of temperature. Air humidity appears to have significant influence on UHII with cold non-dynamic situations in dry air showing a very high UHII amplitude during the daylight period and high intensity during the night. The comparison of warm and cold dynamics situations showed the influence of vertical heat exchange with strong mixing of air between near-surface levels and lower levels of the troposphere with a mild effect on UHII during the warm situation and strong influence on decreasing UHII during the cold scenario.

The Shearing Behavior of Nanowire Contact Pairs in Air and the Role of Humidity

A new technique based on optical microscope nanomanipulation is developed to permit optical observation of the shearing process between cantilevered nanowires (NWs). Real‐time observation of the deflection shape of NWs during shearing under controlled environmental conditions enables their shear stress evolution to be evaluated with respect to relative humidity (RH). The average static and kinetic shear strengths, and MPa, are found to be insensitive to the RH within the range of 40–60%. When the RH increased to 74%, the shear strength values increase to and MPa. When the RH decreases to 20%, a dramatic increase in the static and kinetic shear strengths is observed: and MPa. Water films absorbed on the surface of NWs within the RH range of 40–60% can lubricate their frictional interface and thus dramatically decrease the shear strength. At high RH of above , the viscous effects of a water meniscus condensed around the contact point between two NWs can significantly enhance the shear strength and dampen stick‐slip behavior. The detachment of two NWs is then controlled by the rupture of a meniscus bridge, leading to high ultimate shear strength value of several tens of MPa.

A review on factors influencing fog formation, classification, forecasting, detection and impacts.

With the changing climate and environment, the nature of fog has also changed and because of its impact on humans and other systems, study of fog becomes essential. Hence, the study of its controlling factors such as the characteristics of condensation nuclei, microphysics, air–surface interaction, moisture, heat fluxes and synoptic conditions also become crucial, along with research in the field of prediction and detection. The current review expands for the period between 1976 to 2021, however, especially focused on the research articles published in the last two decades. It considers 250 research papers/research letters, 24 review papers, four book chapters/manuals, five news articles, 15 reports, six conference papers and five other online readings. This review is a compilation of the pros and cons of the techniques used to determine the factors influencing fog formation, its classification, tools and techniques available for its detection and forecast. Some recent advanced are also discussed in this review: role of soil properties on fogs, application of microwave communication links in the detection of fog, new class of smog, and how the cognitive abilities of humans are affected by fog. Recently India and China are facing an emergence and repetitions of fog haze/smog and thus their policies initiatives are also briefly discussed. It is concluded that the complexity in fog forecasting is high due to multiple factors playing a role at multiple levels. Most of the researchers have worked upon the role of humidity, temperature, wind, and boundary layer to predict fogs. However, the role of global wind circulations, soil properties, and anthropogenic heat requires further investigations. Literature shows that fog is being harnessed to address water insecurity in various countries, however, coastal areas of Angola, Namibia and South Africa, Kenya, Eastern Yemen, Oman, China, India, Sri Lanka, Mexico, along with the mountainous regions of Peru, Chile, and Ecuador, are some of the potential sites that can benefit from the installation of fog water harvesting systems.

Influence of temperature on mortality in the French overseas regions: a pledge for adaptation to heat in tropical marine climates

Tropical areas and small islands are identified as highly vulnerable to climate change, and already experiencing shifts in their temperature distribution. However, the knowledge on the health impacts of temperatures under tropical marine climate is limited. We explored the influence of temperature on mortality in four French overseas regions located in French Guiana, French West Indies, and in the Indian Ocean, between 2000 and 2015. Distributed lag non-linear generalized models linking temperature and mortality were developed in each area, and relative risks were combined through a meta-analysis. Models were used to estimate the fraction of mortality attributable to non-optimal temperatures. The role of humidity was also investigated. An increased risk of mortality was observed when the temperature deviated from median. Results were not modified when introducing humidity. Between 2000 and 2015, 979 deaths [confidence interval (CI) 95% 531:1359] were attributable to temperatures higher than the 90th percentile of the temperature distribution, and 442 [CI 95% 178:667] to temperature lower than the 10th percentile. Heat already has a large impact on mortality in the French overseas regions. Results suggest that adaptation to heat is relevant under tropical marine climate.

The efficiency and mechanism of humidity in alleviating CO2 inhibition on H2S adsorption to straw biochars

Adsorption tests were conducted to clarify the impact of carbon dioxide (CO2) on hydrogen sulfide (H2S) removal to straw biochars and the role of humidity in affecting the CO2 impact. When straw biochars were dry, CO2 proved significantly detrimental to their H2S adsorption, regardless of the CO2 contents. In contrast, when adjusting the humidity of the biochars to 20%, the presence of CO2 promoted the conversion of H2S into sulfites, though still inhibited the generation of elemental sulfur, through which the original negative CO2 impact was nearly compensated. The presence of low to medium contents of CO2 even slightly improved the adsorption capacity and extended the breakthrough time. This phenomenon was ascribed to a favorable carbon surface environment for H2S dissociation and oxidation, created from the reactions of the major minerals (Ca and Mg) with CO2 and water. To sum up, the CO2 inhibition on the H2S adsorption to biochars was ascribed to the competition of CO2 for the active sites; however, humidity induced a series of CO2-participated chemical reactions between H2S and the minerals, sufficiently alleviating the CO2 inhibition. The results also highlight the necessity to recognize the most critical biochar properties or an efficient balance of crucial biochar properties in achieving an optimal H2S removal when CO2 is present in the syngas.

Evaluation of Adsorption-Photocatalysis Duality of Cu-Btc and Zif-8: The Role of Humidity

Evaluation of Adsorption-Photocatalysis Duality of Cu-Btc and Zif-8: The Role of Humidity

The role of humidity in determining future electricity demand in the southeastern United States

Co-occurrence of high relative humidity levels and high temperatures can increase human discomfort, thereby affecting electricity requirements for space cooling. While relative humidity is generally projected to decrease over land in a warming climate, the combined impact of warming and changes in humidity on heat stress, and thus electricity demand, are less clear. To evaluate the role of relative humidity in determining future electricity demand, we first develop predictive models based, separately, on temperature (T) and a heat stress index (apparent temperature (AT)) at an hourly scale using meteorological reanalysis data and electricity load from the United States Energy Information Administration over the four electricity regions in the southeastern United States. The AT model performs better than the T model in the historical period. We then apply the predictive models to a set of high-resolution climate projections to understand the role of relative humidity in determining the electricity demand in a warmer climate. Due to the nonlinear behavior of heat stress with warming, future electricity demand is substantially larger when estimated from AT than from T. The increase in demand projected by AT ranges between 16%–29%, 20%–33%, 14%–32% and 13%–26% and that by T model ranges between 12%–19%, 15%–19%, 14%–22% and 12%–20% over Southeast, Florida, Carolina, and Tennessee respectively. This amplification of electricity demand by humidity is strongest for the highest temperature quantiles, but also occurs at moderate future temperatures that coincide with elevated relative humidity episodes, emphasizing the importance of considering humidity in future heat stress and electricity demand assessments.

Delaying effect of humidity on leaf unfolding in Europe

Understanding the drivers of plant phenology is critical to predict the impact of future warming on terrestrial ecosystem carbon cycling and feedbacks to climate. Using indoor growth chambers, air humidity is reported to influence spring phenology in temperate trees. However, previous studies have not investigated the effect of air humidity on the spring phenology using long-term and large-scale ground observations. Therefore, the role of humidity in spring phenology in temperate trees still remains poorly understood.Here, we synthesized 229,588 records of leaf unfolding dates in eight temperate tree species, including four early-successional and four late-successional species, at 1716 observation sites during 1951–2015 in Europe, and comprehensively analyzed the effect of humidity on the spring phenology.We found that rising humidity significantly delayed spring leaf unfolding for all eight temperate tree species. Leaf unfolding was more sensitive to humidity in early-successional species compared to late-successional species. In addition, the delaying effect of humidity on leaf unfolding increased as temperature warmed over the past 65 years.Our results provide evidence that spring leaf unfolding of temperate trees was significantly delayed by rising humidity. The delaying effect of humidity may restrict earlier spring phenology induced by warming, especially for early-successional species, under future climate warming scenarios in temperate forests.

The Role of Humidity in the Management of Premature Neonates in a Rural Incubator.

BackgroundWhile growing inside the uterus, the human fetus floats in amniotic fluid, and the mother maintains a stable temperature of 37 °C and a humidity of 100%. In most neonatal incubators, a stable temperature is maintained but not the humidity. We hypothesised that maintaining a humidity of 70% and a temperature of 32 °C in incubator rooms might improve the outcomes related to low birth weight (LBW) neonates.MethodsIn this interventional study, 30 preterm LBW neonates delivered at different gestational ages were studied. Instead of an incubator box, we converted one entire room (14’/9’/10’) into an incubator. Three 200-watt bulbs were fixed to the wall at a height of 1 meter from babies. The room thermometer was mounted on the wall close to babies. The room temperature was maintained at 32 °C by turning the lights on or off as required. Wet cotton sheets (4’ × 6’) were spread on the opposite wall with the support of a stand. A hygrometer was fixed to the wall near to babies, and the humidity of the room was maintained at 70-80%.The hydration and nutrition needs of the babies were met with IV fluids/nasogastric (NG) tube feeding. Antenatal steroids were given to all mothers before the completion of 38 weeks. Babies were discharged when they were stable, and further care was given at home with similar arrangements of maintaining temperature and humidity. Birth weights, the number of babies that developed neonatal respiratory distress syndrome (NRDS), hypothermia, septicaemia, neonatal intensive care unit (NICU) admission days, home incubator days, and neonatal deaths were recorded and compared with the findings in the existing literature.ResultsAmong the 30 neonates studied, birth weights ranged from 1.00 to 1.95 kg. Twenty-three babies developed NRDS, and four babies developed septicaemia; NICU days ranged from five to 28 days, and at-home incubator days ranged from 15 to 60 days. One baby succumbed to the illness.ConclusionOpen nursing care of functionally premature neonates at room temperature of 32 °C and humidity of 70% is a cost-effective method that can lead to excellent outcomes.

The role of humidity and UV-C emission in the inactivation of B. subtilis spores during atmospheric-pressure dielectric barrier discharge treatment

Experiments are performed to assess the inactivation of Bacillus subtilis spores using a non-thermal atmospheric-pressure dielectric barrier discharge. The plasma source used in this study is mounted inside a vacuum vessel and operated in controlled gas mixtures. In this context, spore inactivation is measured under varying nitrogen/oxygen and humidity content and compared to spore inactivation using ambient air. Operating the dielectric barrier discharge in a sealed vessel offers the ability to distinguish between possible spore inactivation mechanisms since different process gas mixtures lead to the formation of distinct reactive species. The UV irradiance and the ozone density within the plasma volume are determined applying spectroscopic diagnostics with neither found to fully correlate with spore inactivation. It is found that spore inactivation is most strongly correlated with the humidity content in the feed gas, implying that reactive species formed, either directly or indirectly, from water molecules are strong mediators of spore inactivation.

Initial stages of metal soaps` formation in model paints: The role of humidity

The presence of metal soaps is well documented in paintings originating from the 15th century onward, and in numerous cases, the soaps`formation is attributed to environmental factors, like relative humidity, light exposure and/or high temperature. Understanding the formation mechanism, involving effects of these particular factors during artwork`s realization, is crucial for the search of suitable conservation and preservation strategies.In the present study, the role of humidity on the formation of metal carboxylates and other secondary products in mixtures of lead-based pigments (i.e., minium, lead-tin yellow and lead white) with linseed oil was described within the experimental drying of model paints. Samples were exposed to various relative humidity conditions and the processes were monitored by Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD) involving both the hourly measurements for the monitoring of immediate processes and long-term (up to two months) monitoring to evaluate secondary changes.The acquired data clearly demonstrated the influence that the different levels of humidity may have on the formation of lead carboxylates during the painting's drying. The selected methods were efficient in the reaction monitoring and provided new insights leading to a better understanding of factors affecting the metal soaps' formation in paints.

Heat wave trends in Southeast Asia during 1979–2018: The impact of humidity

In tropics, especially Southeast Asia (SEA), heat wave (HW) research is seriously scarce although several global studies have projected this region to be greatly susceptible to increasing HW events under climate change scenarios. Using the recently released ERA5 reanalysis data, we find that in most parts of SEA, HWs are becoming more frequent, longer-lasting and stronger, no matter using dry-bulb or wet-bulb temperatures to define HW. The increasing trends of HW characteristics based on minimum temperatures are larger than those based on maximum temperatures, suggesting an alarming situation of anomalously warm night. HW characteristics based on wet-bulb temperatures show higher increasing rates in the IndoChina Peninsula and Malay Peninsula than those based on dry-bulb temperatures. Nearly all HW characteristics are significantly correlated with El Niño index, but Indian Ocean Dipole only significantly impacts HW characteristics based on wet-bulb temperature in Java. Results derived from other reanalysis products exhibit general agreement with those from ERA5, lending support to the findings reported herein. This study highlights the different role of humidity in changing HW trends in different regions of SEA, and calls for attention to the associated risk of increasing nighttime temperatures during HWs.

Erratum: "The Role of Humidity in Associations of High Temperature with Mortality: A Multicountry, Multicity Study".

Background: There is strong experimental evidence that physiologic stress from high temperatures is greater if humidity is higher. However, heat indices developed to allow for this have not consist ...