Increase In Relative Humidity Research Articles

Relationship between meteorological variables and pneumonia in children in the Metropolitan Region of Porto Alegre, Brazil

This work aims to analyze the relationship between meteorological conditions and the occurrence of hospital admissions for pneumonia in children under 5years of age in the Metropolitan Region of Porto Alegre, Brazil, from 1998 to 2017. To this end, data from hospital admissions obtained from the Unified Health System database (DATASUS) were used and classified into two groups: acute respiratory infections (ARI) and asthma, according to the international classification of diseases, tenth edition (ICD-10). Data regarding meteorological variables were also used: temperature, relative humidity, atmospheric pressure and wind speed, at 12Z and 18Z, as well as the Thermal Comfort Index (TCI), Effective Temperature as a function of the wind (ETw) and Windchill (W). From the data obtained, a descriptive analysis of the diseases and a statistical analysis with the analysis of correlation and main components were performed. Results showed that pneumonia (catalogued in the ICD-10 as J12 to J18) was the main cause of hospitalizations in children. The annual, monthly and daily hospitalization frequency distributions showed higher rates of admissions occurring in the months of May to September. The peaks of admissions and high admissions (HA) occurred mainly in the winter months (June, July and August), and in 1998. Meanwhile, the correlation and principal component analysis showed an increase in hospital admissions due to pneumonia related to a decrease in temperature and ETw and W indices (negative anomalies) and an increase in atmospheric pressure and relative humidity (positive anomalies).

Using acoustics and artificial intelligence to monitor pollination by insects and tree use by woodpeckers.

The collection and interpretation of field data is a prerequisite for informed conservation in protected environments. Although several techniques, including camera trapping and passive acoustic monitoring, have been developed to estimate the presence of animal species, very few attempts have been made to monitor ecological functions. Pollination by insects and wood use, including tree related foraging and intraspecific communication, by woodpeckers are key functions that need to be assessed in order to better understand and preserve forest ecosystems within the context of climate change. Here, we developed and applied for the first time an acoustic survey to monitor pollination by insects and wood use by woodpeckers in a protected Alpine forest in France. We deployed four autonomous recorders over a year, resulting in 2285 h of recordings. We trained a convolutional neural network (CNN) on spectrographic images to automatically detect the sounds of flying insects' buzzing and woodpeckers' drumming as they forage and call. We used the output of the CNN to estimate the seasonality, diel pattern, climatic breadth and distribution of both functions and their relationships with weather parameters. Our method showed that insects were flying (therefore potentially pollinating flowers) in bright, warm and dry conditions, after dawn and before dusk during spring and summer. Woodpeckers were mainly drumming around March at the time of pair formation in cool and wet conditions. Having considered the role of weather parameters, climate change might have contrasting effects on insect buzzing and woodpecker drumming, with an increase in temperature being favorable to pollination by insects but not to wood use by woodpeckers, and a concomitant increase in relative humidity being favorable to wood use but not to pollination. This study reveals that a systemic facet of biodiversity can be tracked using sound, and that acoustics provide valuable information for the environment description.

Optimizing the postharvest supply chain of imported fresh produce with physics-based digital twins

In the postharvest chain of fresh horticultural produce, it is often challenging to quantify how much potential measures improve the supply chain. This study compares and quantifies the impact of the different measures in preserving the quality of fresh produce in the cold chain. We employed physics-based digital twins of fresh produce. This digital twin is the virtual representation of fresh produce that can calculate the temperature distribution within the fruit and link these to quality decay based on the measured air temperature data. In this study, 95 shipments were monitored in the cold chain for four fruits (cucumber, eggplant, strawberry, and raspberry) imported from Spain to Switzerland. Using these temperature data as inputs for the digital twins, their hygrothermal response and physiological evolution to evaluate different optimization strategies were simulated. We showed that shortening the time length of shipment by one day at the distribution center resulted in 18% higher fruit quality index for cucumber and eggplant and 60% higher for berries. Lowering the shipment temperature by 5 °C extended the shelf life of strawberry on average by 36% and raspberry by 73%. Lowering the shelf temperature in retail stores by 5 °C prolonged the shelf life of the four fruits, on average, by about 40%, but the reduction is very fruit-dependent. For every 10% increase in relative humidity in the surroundings of unpacked fruit from during transport and at the distribution center by adjusting hygrothermal climate control, mass loss was reduced by 20% for all the studied fruits. Finally, evaporative cooling at the retail stores, which could be done by dry misting, extended the shelf life by more than 60%, due to the induced temperature reduction. Taking advantage of this digital twin's capability to evaluate the different scenarios, we can quantify the impact of cold chain optimizations more efficiently and cost-effectively in the design phase.

제주 지역별 기후변화 특성과 건축물 에너지 요구량에 관한 연구

The purpose of this study is to investigate the climate change of the past 30 years in Jeju Island and to analyze the change in energy demand accordingly. As a research method, data from the four regions (Jeju-si, Gosan, Seongsan, Seogwipo) of the Korea Meteorological Administration (ASOS) were used as climate data, and the amount of cooling and heating energy required was calculated through Energy # v2.5, an energy analysis program. The resulting values were derived. As for climate change by region, the average temperature in the middle and summer continued to rise compared to the winter, and the average relative humidity also increased in the summer. As a result of analyzing the change in energy demand by region (1991 ~ 2020), it was found that cooling energy demand increased due to the increase in average temperature and relative humidity in all four regions. In addition, due to the increase in average temperature, the heating energy demand in winter is showing a tendency to decrease slightly. In particular, Jeju, Gosan, and Seongsan regions show a higher change than Seogwipo regions. Through the analysis of climate information and energy demand for the four regions of Jeju, it will be possible to predict the change in the building energy performance of Jeju Island by estimating the trend of climate change over the past 30 years, the change in energy consumption, and future climate information.

Effects of temperature and relative humidity on resonant frequency of mems cantilever resonators under atmospheric pressure

In this study, the effects of temperature and relative humidity on the resonant frequency of a micro-electro-mechanical system (MEMS) cantilever resonator under atmospheric pressure (p=101325 Pa) are discussed. The squeeze film damping (SFD) problem of MEMS cantilever resonators is modeled by solving the modified molecular gas lubrication (MMGL) equation, the equation of motion of micro-cantilever, and their appropriate boundary conditions, simultaneously in the eigen-value problem. The effective viscosity (µeff(RH, T)) of moist air is utilized to modify the MMGL equation to consider the effects of temperature and relative humidity under atmospheric pressure. Thus, the effects of temperature (T) and relative humidity (RH) on the resonant frequency of MEMS cantilever resonators over a wide range of gap thicknesses and under atmospheric pressure are discussed. The results showed that the frequency shift increases as the relative humidity and temperature increase. The influence of relative humidity on the resonant frequency becomes more significant under conditions of higher temperature and smaller gap thickness.

Experimental investigation on the impact of different thermodynamic parameters on the depletion behavior of nuclear aerosols in the IN-EX facility

Fission products (FPs) released in the process of a severe loss of coolant accident can reach the containment – the last barrier against the leakage of radioactive isotopes to the surrounding environment – as airborne particles. Consequently, reliable assessment of a potential radiological source term requires in-depth knowledge of the aerosol behavior. The IN-EX facility at Forschungszentrum Jülich (FZJ, Germany) is built to study nuclear aerosol depletion behavior under accident scenarios by varying thermodynamic parameters (relative humidity, temperature and pressure). We performed a series of experiments using both, pure and mixed particles. The objective is to improve the understanding of aerosol depletion mechanisms and provide the latest data for optimization and validation of computational models for aerosol behavior.In the IN-EX experiments, SnO2 and CsI represent the insoluble and soluble particles released from the damaged core, respectively. In the case of mixed particles, in order to figure out the effect of varying mass composition on the aerosol behavior, we used the mass compositions of CsI and SnO2 in the ratio of 3:7 and 6:4 in this paper. In this work, we measured the mass concentration and size distribution, and derived the corresponding aerosol removal rate to analyze the data. During the experiments on CsI aerosols, we observed that the aerosol removal rate is accelerated by an increase in relative humidity, while relative humidity seems to have no effect on the depletion of SnO2 aerosol. Furthermore, pressure or temperature appears to have no significant effect on the depletion behavior both of SnO2 and CsI aerosols. Combining with the results of pure substances, we investigated the regularity of the depletion behavior of mixed aerosols. In general, SnO2 has the highest aerosol removal rate, while CsI has the lowest one. The removal rate of the mixture is between SnO2 and CsI. The components in the mixture with a high mass fraction determine the depletion behavior of this mixture. Particularly in the condensed state, we found almost no difference in the aerosol removal rate of either pure substances or mixtures.

Spatial analysis to evaluate risk of malaria in Northern Sumatera, Indonesia

BackgroundAs Indonesia aims for malaria elimination by 2030, provisional malaria epidemiology and risk factors evaluation are important in pursue of this national goal. Therefore, this study aimed to understand the risk factor of malaria in Northern Sumatera.MethodsMalaria cases from 2019 to 2020 were obtained from the Indonesian Ministry of Health Electronic Database. Climatic variables were provided by the Center for Meteorology and Geophysics Medan branch office. Multivariable logistic regression was undertaken to understand the risk factors of imported malaria. A zero-inflated Poisson multivariable regression model was used to study the climatic drivers of indigenous malaria.ResultsA total of 2208 (indigenous: 76.0% [1679] and imported: 17.8% [392]) were reported during the study period. Risk factors of imported malaria were: ages 19–30 (adjusted odds ratio [AOR] = 3.31; 95% confidence interval [CI] 1.67, 2.56), 31–45 (AOR = 5.69; 95% CI 2.65, 12.20), and > 45 years (AOR = 5.11; 95% CI 2.41, 10.84). Military personnel and forest workers and miners were 1,154 times (AOR = 197.03; 95% CI 145.93, 9,131.56) and 44 times (AOR = 44.16; 95% CI 4.08, 477,93) more likely to be imported cases as compared to those working as employees and traders. Indigenous Plasmodium falciparum increased by 12.1% (95% CrI 5.1%, 20.1%) for 1% increase in relative humidity and by 21.0% (95% CrI 9.0%, 36.2%) for 1 °C increase in maximum temperature. Plasmodium vivax decreased by 0.8% (95% CrI 0.2%, 1.3%) and 16.7% (95% CrI 13.7%, 19.9%) for one meter and 1 °C increase of altitude and minimum temperature. Indigenous hotspot was reported by Kota Tanjung Balai city and Asahan regency, respectively. Imported malaria hotspots were reported in Batu Bara, Kota Tebing Tinggi, Serdang Bedagai and Simalungun.ConclusionBoth indigenous and imported malaria is limited to a few regencies and cities in Northern Sumatera. The control measures should focus on these risk factors to achieve elimination in Indonesia.

The combined effect of water management and environmental control on the planting of two varieties of garden egg in a partially shaded greenhouse: an energy and yield indicator analysis

The objective of this study is to investigate the performance of partially shaded solar greenhouse and water management on the growth and bioactive yield of garden eggs under micro climate management. For this reason, two local varieties of garden egg (Solanum aethiopicum and Solanum gilo) were planted in a partially shaded natural convention greenhouse at Umudike South Eastern Nigeria and nurtured for four months from June to September before harvest. The plants were supplied water at 50, 70 and 100% field capacity with the internal condition of the greenhouse naturally controlled by the ambient condition. The evaluation parameters were the average monthly heat load flux, ventilation flux, transpiration rate, plant growth parameters, and phytochemicals and anti-oxidants characteristics of the fruits from the garden egg in comparison with the open field plantation. Thermal analysis showed that an increase in temperature and lower relative humidity increases the evapotranspiration rate in the greenhouse. The average sensible and latent heat load ranged from 10.9 to 121.3 W/m2 and 21.94 to 63.56 W/m2 respectively. In contrast, the average monthly ventilation flux which was deduced as a function of heat load ranged from 5.307 × 10−3 to 8.053 × 10−3 m3/m2.s. While water management and greenhouse had negative effects on most of the growth parameters of the garden egg, they significantly increased the antioxidant contents in the garden egg, particularly total phenolic contents (TPC) and total flavonoid contents of fruits which is a quality needed for a healthy body. This shows that climatic control and water management influence garden egg quality more than the growth parameters. The data from this study will enhance understanding of the influence of water stress on garden egg yield under controlled environmental conditions, which might be important in providing the needed nutrient for healthy body.

Quantifying effects of meteorological parameters on air pollution in Kathmandu valley through regression models.

Most studies on air pollution have focused on source apportionment aspect but very few have considered meteorological factors responsible for variation in air pollution levels including studies in Nepal. Consequently, the effects of meteorological parameters including effects of seasonality and lag effects are investigated and quantified for Kathmandu valley, Nepal. Daily temporal data of air pollution for 2017-early 2020 monitored by the Department of Environment and US Embassy, Kathmandu, Nepal, and meteorological data monitored by the Department of Hydrology and Meteorology, Kathmandu, Nepal, are used. Regression models namely exponential, Box-Cox transformed and Gamma generalized linear models are used to quantify the effects supported by regression diagnostics. Results depict high proportions of observed air pollution variations (79-85%) explained by the fitted models with varied effects of meteorological parameters. Around 5% reduction in PM10 (96% CI: 0.034-0.069) and PM1 (95% CI: .0.029-0.063) levels per 1°C increase in average temperature and significant increase in surface O3 level (0.177, 95% CI: 0.126-0.228 Box-Cox transformed value) per 1°C increase in average temperature are detected. Similarly, around 0.7% (95% CI: 0.1-1.3) and 2% (96% CI:1.3-2.5) decrease in PM1 and PM10, respectively per 1% increase in relative humidity, 0.032 (95% CI: 0.024-0.040) decrease in transformed value of PM2.5 per 1mm increase in rainfall, and 7.3% (95% CI: 1.3-15.9) decrease in PM10 per 1m/s increase in wind speed are also detected. In conclusion, meteorological conditions are found significant contributing factors in determining air pollution levels in Kathmandu valley. On the long run, atmospheric conditions can play vital roles in air pollution situation shifts mainly due to climate change characterized by changes in meteorological values.

Fog-Haze Transition and Drivers in the Coastal Region of the Yangtze River Delta.

Low-visibility events (LVEs) are severe weather phenomena that are closely linked with anthropogenic pollution, which negatively affects traffic, air quality, human health, and the environment. This study conducted a two-month (from October to December 2019) continuous measurement campaign on Chongming Island in Shanghai to characterize the LVEs transition and its drivers. The LVEs accounted for 38% of the time during the campaign, of which mist accounted for 14%, fog–haze for 13%, haze for 6%, and fog for 5%. The fog and mist mainly occurred from midnight to early morning, while haze mostly occurred during the daytime. Different LVEs were interdependent and transitioned from one to another. Fog generally turned into haze after sunrise, while haze turned into fog after sunset. Their formation and evolution were caused by the combined impacts of meteorological conditions and aerosol particles. It was found that temperature difference was the dominant meteorological factor driving the evolution of LVEs. Within the short term, cooling led to a greater increase in relative humidity than humidification. Radiative cooling during the night promoted the formation of fog and mist. During fog and mist events, cloud condensation nuclei (CCN) were mainly internally mixed due to the impact of fog droplet removal and aqueous/heterogeneous aerosol reactions occurring under high humidity. Increased CCN concentration appeared to increase the fog droplet number and liquid water content in fog events. Overall, conditions of high humidity and high particle loading were conducive to LVEs, whereas conditions of sufficient water vapor at a low particle level and sufficient particles at a low humidity level also caused LVEs. This study provided insights into LVEs classification, evolution scheme, and aerosol roles from a micro point of view. The findings could be useful for improving forecasts of local radiative fog and other LVEs.

Evaluation of evaporative cooler models using cotton-based fabric pads for tropical housing units

Direct evaporative cooling (DEC) is a passive cooling strategy adopted in predominantly hot regions to restore building thermal comfort with less energy consumption and minimum impact on the environment. The implementation and studies of DEC in tropical housing are limited. Although DEC can reduce air temperature, an increase in relative humidity can still be seen as a disadvantage. Many materials were introduced for the cooling pads, but none was explicitly proposed for use in the housing unit. The present study explores different cotton-based fabrics to be used in the proposed evaporative cooler of the public housing unit in Surabaya. It analyses its ability to reduce air temperature and identify the increase in air humidity that may occur. A small-scale model of the housing unit that incorporates an evaporative cooling system is set, and internal air temperature and humidity are recorded. Results of the analysis show that different fabric specifications can lead to various thermal performances. A cotton-based blanket is found to be suitable for the proposed strategy.

Influence of Weather Conditions on COVID-19 Case in Several Regions of Indonesia

This study investigates the relationship between COVID-19 and weather conditions in six regions in Indonesia, namely South Jakarta, East Jakarta, North Jakarta, Jember Regency, Semarang City, and West Pasaman Regency. The study uses the daily number of positive cases of COVID-19 and weather data. Weather parameters used in this study are the average, maximum, and minimum temperature, rainfall, and relative humidity. Weather data were obtained from surface observation of Agency for Meteorology, Climatology and Geophysics (BMKG) and reanalysis product (ERA-5) from European Centre for Medium-Range Weather Forecasts (ECMWF). The effect of weather conditions on the number of COVID-19 cases was evaluated using the Spearman and Kendall correlation. It was found that the number of positive cases of COVID-19 had a relationship with weather parameters. A negative correlation was found between the temperature and the number of positive COVID-19 cases. Thus, the number of positive COVID-19 cases increases when the temperature decreases. On the other hand, rainfall and relative humidity positively correlate to the number of positive cases of COVID-19, which means that when the rainfall and relative humidity increase, the number of positive cases of COVID-19 increases. The relationship between weather conditions and the number of COVID-19 cases is more apparent in areas with a higher population density, such as Jakarta. The results of this study can be valuable information in handling COVID-19 cases.

Tracing the biomass burning emissions over the Arabian Sea in winter season: Implications from the molecular distributions and relative abundances of sugar compounds

The widespread haze pollution over South Asia typically occurs in winter, affecting the abundance of organic aerosols (OA) over the Arabian Sea due to prevailing meteorology. We determined the concentrations of biomass burning (BB) derived anhydrosugars (levoglucosan: Lev, galactosan: Gal, and mannosan: Man), sugars (glucose, fructose, sucrose, and trehalose) and sugar alcohols (arabitol, mannitol, erythritol, and inositol) over the Arabian Sea during a winter cruise (6–24 December 2018). Molecular distributions revealed predominance of levoglucosan or sucrose. Besides, levoglucosan strongly correlated with mannosan, galactosan, sugar alcohols and elemental carbon, emphasizing their BB-origin. Backward air mass trajectories intercepted by the satellite-based fire counts over the Indo-Gangetic Plain together with relationship between stable carbon isotopic composition of TC (δ13CTC) and levoglucosan-C to organic carbon (%), confirmed the impact of BB-derived OA. A comparison of Lev/Man (av. 16.2) and Lev/K+ (av. 0.27) ratios over the Arabian Sea with the source-emissions revealed their origin from crop-residue burning. Rather high concentrations of Lev over the Arabian Sea compared to those documented over the Bay of Bengal, East China Sea, Sea of Japan and the western North Pacific further suggests a stronger impact of BB in the continental outflow over this marine basin. Besides, Lev/K+ ratios in marine aerosols exponentially decreased with an apparent increase in ambient relative humidity and temperature over the Arabian Sea during the South Asian outflow, implying a photochemical oxidation of BBOA. Such field-based relationship of Lev with the meteorological parameters can be useful for modelling the impact of BBOA on the surface Ocean. Besides, the aeolian input of sugar-C and water-soluble organic carbon (WSOC) accounted for 83 % and 92 % of that riverine supply to the Arabian Sea, respectively. This means atmospheric dry-deposition of sugars is an important external source of dissolved organic compounds to the surface water.

Insights into the different mixing states and formation processes of amine-containing single particles in Guangzhou, China

The formation processes of particulate amines are closely related to their emission sources and secondary reactions, which can be revealed through the investigation of their real-time mixing states in individual particles. The mixing states of methylamine (MA)-, trimethylamine (TMA)-, and diethylamine (DEA)-containing particles were studied using a high-performance single particle aerosol mass spectrometer (HP-SPAMS) in Guangzhou, China, in January 2020. The sharp increase in TMA particles was found to be closely associated with the increase in the ambient relative humidity (RH), while the MA- and DEA-containing particles were not similarly influenced by the changes in the RH. The prominent enrichment of secondary oxygenated organics in DEA particles during the daytime was consistent with the active period of photochemistry, implying that the sharp decrease in DEA particles in the afternoon was likely due to photo-oxidation of the DEA. The number fraction (Nf) of DEA particles, the Nf of the nitrate in the DEA particles, and the abundance of nitrate increased as the NOx content all increased during the nighttime, suggesting that the formation of DEA·HNO3 salt was the dominant pathway of particulate DEA production. These results are consistent with our previous measurements in Nanjing, confirming the general and distinct mixing states of TMA and DEA particles. Positive matrix factorization analysis revealed that the total fraction of the more oxidized organics factor and the less oxidized organics factor were much higher in the DEA particles (26.9 %) than in the TMA particles (9 %), confirming the significant enrichment of oxygenated species in the DEA particles. The different mixing states of the amines revealed the unique response of each type of amine to the same atmospheric environment, and the prominent mixing states of the DEA with secondary oxygenated species suggest the potential role of DEA in tracing the evolution of organic aerosols.

Integrated simple design wind tower and enhanced solar still for hot and arid climate

ABSTRACT The present work deals with a novel system in which a wind tower having evaporative cooling channel made of flat cotton ropes is integrated with solar still to fulfill the need of thermal comfort and potable water both. In proposed system, cooled water obtained in wind tower has been utilized for increasing the yield of solar still. Additionally, floating pieces of flat cotton rope are provided in still to enhance evaporation rate. The performance of proposed integrated unit has been analyzed mathematically for hot and dry climate of Jaisalmer, Rajasthan (India). The proposed wind tower has resulted average drop in air temperature of 12.5°C and increase in relative humidity of 45.5%, whereas air velocity is found to be in range of 1.2 m/s–1.8 m/s. The maximum reduction in temperature of water in basin of integrated solar still is about 21°C, whereas the same for glass temperature is about 34°C in summer. In winter season these reductions are about 20°C and 15°C, respectively. About 44%–49% additional yield has been found by proposed solar still compared to conventional when mass flow rate of water varies from 0.01 kg/s–0.08 kg/s. The proposed system resulted 45.5% more yield in summer and 40.1% in winter for constant 0.07 kg/s flow rate of water. The cost of potable water and payback period for the proposed system is US $ 0.036 /liter and 0.61 years, respectively.

Quantifying and characterizing the impacts of PM2.5 and humidity on atmospheric visibility in 182 Chinese cities: A nationwide time-series study

Ambient particulate matter less than 2.5 μm (PM2.5) and humidity have been considered as two leading determinants of atmospheric visibility. However, quantitative evidence of their independent and interactive effects on visibility is rare at multi-city level. Based on the data of 190 monitoring stations from 182 Chinese cities, the generalized linear model combined with nonlinear smoother was constructed to estimate the station-specific effects of PM2.5 and relative humidity on visibility. Then, multivariate meta-analysis was used to pool the station-specific estimates. Finally, attributable visibility loss respectively due to PM2.5 and humidity were calculated. In general, both PM2.5 and relative humidity were detected to have a significant non-linear negative influence on visibility. Per 1 μg/m3 increase in PM2.5 was associated with a visibility reduction of 0.232 km and 0.030 km under the level of PM2.5 below or above 68 μg/m3, respectively. The visibility declined by 0.105 km, 0.254 km, and 0.569 km per 1% increase in relative humidity under low (<58%), middle (58%–85%), and high (>85%) humidity, respectively. Significant interactive effects of PM2.5 and humidity were observed. The impacts of PM2.5 on visibility were significantly amplified in days with moderate humidity. However, extremely high humidity could largely attenuate the PM2.5-visibility association. The influence of extremely high humidity (like 99%) also consistently declined as the PM2.5 concentration elevated. From the national perspective, PM2.5 accounted for a higher proportion of average daily visibility loss than humidity [9.75 km (95%CI: 7.94, 11.57) vs. 7.23 km (95%CI: 5.02, 9.45)]. The relatively mild polluted southern China suffered from similar PM2.5-attributable visibility loss with northern China. The findings could provide important information for the prediction and improvement of atmospheric visibility.

Impacts on Meteorological Parameters and Pollutants by Aerosol Direct Radiative Effect Over Tianjin, China

The direct radiative effect (DRE) of anthropogenic aerosols on meteorological elements and pollutants over Tianjin, China, was investigated using a fully coupled meteorology-chemistry model [Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem)] for the entire year of 2021. The results showed that the ground solar radiation decreased from 208.84 W m−2 to 194.52 W m−2 due to DRE in Tianjin, and the percentage of the reduction was 6.86%. The reduction of ground solar radiation resulted in a 0.90% decrease in temperature, 1.13% decrease in boundary layer height, and 6.01% decrease in visibility, respectively, and a 0.80% increase in relative humidity. Changes in meteorological parameters changed the diffuse conditions of pollutants, leading to an increase of PM2.5. Higher concentration of pollutants leads to stronger DRE, and the percentages of changes caused by DRE on polluted days are higher than those on clean days. The DRE influence on pollutants can be summarized as a weather → aerosol → weather → air quality circulation mechanism. The DRE had more severe influence on meteorological elements and pollutants on foggy days. With the emission reduction of pollutants, the influence of the DRE has declined.

Identifying socio-ecological drivers of common cold in Bhutan: a national surveillance data analysis

The common cold is a leading cause of morbidity and contributes significantly to the health costs in Bhutan. The study utilized multivariate Zero-inflated Poisson regression in a Bayesian framework to identify climatic variability and spatial and temporal patterns of the common cold in Bhutan. There were 2,480,509 notifications of common cold between 2010 and 2018. Children aged < 15 years were twice (95% credible interval [CrI] 2.2, 2.5) as likely to get common cold than adults, and males were 12.4% (95 CrI 5.5%, 18.7%) less likely to get common cold than females. A 10 mm increase in rainfall lagged one month, and each 1 °C increase of maximum temperature was associated with a 5.1% (95% CrI 4.2%, 6.1%) and 2.6% (95% CrI 2.3%, 2.8%) increase in the risk of cold respectively. An increase in elevation of 100 m and 1% increase in relative humidity lagged three months were associated with a decrease in risk of common cold by 0.1% (95% CrI 0.1%, 0.2%) and 0.3% (95% CrI 0.2%, 0.3%) respectively. Seasonality and spatial heterogeneity can partly be explained by the association of common cold to climatic variables. There was statistically significant residual clustering after accounting for covariates. The finding highlights the influence of climatic variables on common cold and suggests that prioritizing control strategies for acute respiratory infection program to subdistricts and times of the year when climatic variables are associated with common cold may be an effective strategy.

Evaluating Corrosion Behaviour of Copper Under Deliquescent Drying/Wetting Cycles in Humid Air Condition

Most nuclear safety agencies around the world agree that deep geological repositories (DGRs) constructed hundreds of meters below ground in stable host rock formations are viable solutions to safely isolate used nuclear fuel. In Canada, the DGR design involves storing used nuclear fuel in sealed copper coated used fuel containers (UFC) surrounded by highly compacted bentonite blocks (HCB) ~500 m underground. Shortly after emplacement, heat generated by radioactive decay of the used fuel will warm the UFC and its surroundings, desiccating the HCB and decreasing moisture on the container surface. As water vapour is driven from the UFC surface, the presence of minor amounts of dissolved salts may cause droplet formation prior to complete evaporation, during which deposits of salts may be left behind on the UFC. Later, as conditions evolve and the relative humidity increases and the temperature decreases, condensation of liquid water on the UFC surfaces will produce droplets again, due to the deliquescence of minor salt deposits. In either the wetting or the drying scenario, secondary spreading and spatial separation of anodic and cathodic reactions and consequent non-uniform corrosion could be possible, due to the droplet geometry.To investigate this scenario, the quartz crystal microbalance (QCM) technique is being used. The QCM initially consists of a quartz plate, covered by gold electrodes on both sides where a layer of copper is deposited on the crystal by using magnetron sputtering. In this technique, the change in the resonance frequency of a vibrating quartz crystal is correlated to its mass change due to the corrosion process. To investigate the effect of salts and their deliquescence behaviours, different salts (NaCl, CaCl2, and MgCl2) and CR10-E simulated groundwater were loaded on the copper surface using an inkjet printer, and then corrosion tests were performed at different temperatures and relative humidity (RH) values. In parallel, a set of long-term vapour-phase corrosion tests was performed on wrought and cold-sprayed copper coupons at 75 °C and different RH values. As part of the post-experiment analysis, the corrosion products were analyzed using a suite of surface analysis techniques, including optical microscopy, Raman spectroscopy, and scanning electron microscopy (SEM).The results from QCM experiments at RH values below salts deliquescence point showed a low mass change that could correlate with less corrosion in comparison to the experiments at RH values above salts deliquescence point. It’s worth noting that even at RH values below the deliquescence point of the salts, a trace of corrosion was observed which could be indicative of the presence of monolayers of water on the surface. The results obtained from NaCl and CR10-E exposure conditions showed higher mass change and therefore higher corrosion in comparison to CaCl2 and MgCl2 salts. As for the long-term vapour-phase corrosion tests, Raman spectroscopy confirmed the presence of CuO and Cu2O on the surface as corrosion products. Further surface characterizations and mass loss measurements are underway to determine the extent of corrosion on the copper coupons.

Fog Droplet Collection by Corona Discharge in a Needle–Cylinder Electrostatic Precipitator with a Water Cooling System

In this study, a needle–cylinder electrostatic precipitator with a water cooling system was designed to enhance the harvest of atmospheric water in wet flue gas. The effects of flow rate, temperature and particles on the collection of fog droplets were investigated. Meanwhile, the energy efficiency of water collection was analyzed at different voltages. The results show that the current decreases with the increase of air relative humidity under the same voltage, and the breakdown voltage increases obviously. Concurrently, by appropriately reducing the wet flue gas flow velocity, the residence time of fog droplets in the electric field can be increased, fully charging the droplets and improving the water collection efficiency. Moreover, experiments revealed that through decreasing the flue gas temperature, both the water collection rate and energy efficiency can be improved. In addition, the presence of particles in wet gas can improve the water collection rate by 5~8% at different discharge voltages. Finally, based on energy efficiency analysis, with the increase of voltage, although the water collection rate increased, the energy efficiency decreased.