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BACKGROUND: Because noninvasive ventilation (NIV) delivers medical gas at high flow, inadequate humidification may cause oral dryness and patient discomfort. Heated humidification can be used during NIV, but little has been reported about the effects on the hygrometric conditions inside an oronasal mask and oral dryness during 24 hours on NIV. METHODS: We measured absolute humidity (AH) inside oronasal masks on subjects with acute respiratory failure during 24 hours on NIV. A single-limb turbine ventilator and oronasal mask with an exhalation port were used for NIV. Oral moistness was evaluated using an oral moisture-checking device, and 3 times during the 24 hours the subjects subjectively scored the feeling of dryness on a 0-10 scale in which 10 was the most severe dryness. RESULTS: Sixteen subjects were enrolled. The mean ± SD AH inside the mask was 30.0 ± 2.6 mg H2O/L (range 23.1-33.3 mg H2O/L). The median oral moistness was 19.2% (IQR 4.4 -24.0%), and the median oral dryness score was 5.5 (IQR 4-7). AH and inspired gas leak correlated inversely, both within the subjects (r = =0.56, P < .001) and between the subjects (r==0.58, P = .02). AH and oral moistness correlated within the subjects (r = 0.39, P = .04). Oral breathing was associated with reduced oral moistness (P = .001) and increased oral dryness score (P = .002). CONCLUSIONS: AH varied among the subjects, and some complained of oral dryness even with heated humidifier. Oral breathing decreased oral moistness and worsened the feeling of dryness. [ABSTRACT FROM AUTHOR]

We modelled the impact of selected meteorological factors on the daily number of new cases of the coronavirus disease 2019 (COVID-19) at the Hospital District of Helsinki and Uusimaa in southern Finland from August 2020 until May 2021. We applied a DLNM (distributed lag non-linear model) with and without various environmental and non-environmental confounding factors. The relationship between the daily mean temperature or absolute humidity and COVID-19 morbidity shows a non-linear dependency, with increased incidence of COVID-19 at low temperatures between 0 to -10 °C or at low absolute humidity (AH) values below 6 g/m 3 . However, the outcomes need to be interpreted with caution, because the associations found may be valid only for the study period in 2020-2021. Longer study periods are needed to investigate whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a seasonal pattern similar such as influenza and other viral respiratory infections. The influence of other non-environmental factors such as various mitigation measures are important to consider in future studies. Knowledge about associations between meteorological factors and COVID-19 can be useful information for policy makers and the education and health sector to predict and prepare for epidemic waves in the coming winters.

BACKGROUND: Heat and moisture exchangers (HMEs) are commonly used in chronically tracheostomized spontaneously breathing patients, to condition inhaled air, maintain lower airway function, and minimize the viscosity of secretions. Supplemental oxygen (O2) can be added to most HMEs designed for spontaneously breathing tracheostomized patients. We tested the efficiency of 7 HMEs designed for spontaneously breathing tracheostomized patients, in a normothermic model, at different minute ventilations (VE) and supplemental O2 flows. METHODS: HME efficiency was evaluated using an in vitro lung model at 2 VE (5 and 15 L/min) and 4 supplemental O2 flows (0, 3, 6, and 12 L/min). Wet and dry temperatures of the inspiratory flow were measured, and absolute humidity was calculated. In addition, HME efficiency at 0, 12, and 24 h use was evaluated, as well as resistance to flow at 0 and 24 h. RESULTS: The progressive increase in O22flow from 0 to12 L/min was associated with a reduction in temperature and absolute humidity. Under the same conditions, this effect was greater at lower VE. The HME with the best performance provided an absolute humidity of 26 mg H2O/L and a temperature of 27.8°C. No significant changes in efficiency or resistance were detected during the 24 h evaluation. CONCLUSIONS: The efficiency of HMEs in terms of temperature and absolute humidity is significantly affected by O2 supplementation and VE. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model for drying agricultural produce using a solar dryer capable of oscillating its bed while kept at an inclined position with respect to vertical. A model of the solar dryer with double-pass flat plate collector and an oscillating-bed has been fabricated and tested for drying agricultural produce (sunflower seeds). The model can predict the change in the absolute humidity of air across the bed, the temperature of the air, the moisture content, and the dryer thermal efficiency. Sunflower seeds were dried on a physical model of the solar dryer with its bed tilted at different angles and oscillated at different frequencies. The predicted and the experimental results are in good agreement. The average error and standard deviation for the absolute humidity of air across the bed is 1.74 and 1.55%, the exit temperature of air leaving the bed is 1.1 land 1.21%, and the dryer thermal efficiency is 0.78 and 1.33%, respectively. [ABSTRACT FROM AUTHOR]

Formaldehyde is a colorless, pungent gas commonly found in homes and is a respiratory irritant, sensitizer, carcinogen, and asthma trigger. Typical household sources include plywood and particleboard, cleaners, cosmetics, pesticides, and others. Development of a fast and simple measurement technique could facilitate continued research on this important chemical. The goal of this research is to apply an inexpensive short-term measurement method to find correlations between formaldehyde sources and concentration, and formaldehyde concentration and asthma control. Formaldehyde was measured using 30-min grab samples in length-of-stain detector tubes in homes ( n = 70) of asthmatics in the Boston, MA area. Clinical status and potential formaldehyde sources were determined. The geometric mean formaldehyde level was 35.1 ppb and ranged from 5 to 132 ppb. Based on one-way ANOVA, t-tests, and linear regression, predictors of log-transformed formaldehyde concentration included absolute humidity, season, and the presence of decorative laminates, fiberglass, or permanent press fabrics ( P < 0.05), as well as temperature and household cleaner use ( P < 0.10). The geometric mean formaldehyde concentration was 57% higher in homes of children with very poorly controlled asthma compared to homes of other asthmatic children ( P = 0.078). This study provides a simple method for measuring household formaldehyde and suggests that exposure is related to poorly controlled asthma. [ABSTRACT FROM AUTHOR]

Biological experiments and epidemiological evidence indicate that variations in environment have important effect on the occurrence and transmission of epidemic influenza. It is therefore important to understand the characteristic patterns of transmission for prevention of disease and reduction of disease burden. Based on case records, we analyzed the environmental characteristics including climate variables in Changsha, and then constructed a meteorological anomaly susceptive-infective-removal (SIR) model on the basis of the results of influenza A (H1N1) transmission. The results showed that the outbreak of influenza A (H1N1) in Changsha showed significant correlation with meteorological conditions; the spread of influenza was sensitive to meteorological anomalies, and that the outbreak of influenza A (H1N1) in Changsha was influenced by a combination of absolute humidity anomalous weather conditions, contact rates of the influenza patients and changes in population movements. These findings will provide helpful information regarding prevention strategies under different conditions, a fresh understanding of the emergence and re-emergence of influenza outbreaks, and a new perspective on the transmission dynamics of influenza. [ABSTRACT FROM AUTHOR]

Abstract: Satellite-based remote sensing provides a unique opportunity to monitor air quality from space at global, continental, national and regional scales. Most current research focused on developing empirical models using ground measurements of the ambient particulate. However, the application of satellite-based exposure assessment in environmental health is still limited, especially for acute effects, because the development of satellite PM2.5 model depends on the availability of ground measurements. We tested the hypothesis that MODIS AOD (aerosol optical depth) exposure estimates, obtained from NASA satellites, are directly associated with daily health outcomes. Three independent healthcare databases were used: unscheduled outpatient visits, hospital admissions, and mortality collected in Beijing metropolitan area, China during 2006. We use generalized linear models to compare the short-term effects of air pollution assessed by ground monitoring (PM10) with adjustment of absolute humidity (AH) and AH-calibrated AOD. Across all databases we found that both AH-calibrated AOD and PM10 (adjusted by AH) were consistently associated with elevated daily events on the current day and/or lag days for cardiovascular diseases, ischemic heart diseases, and COPD. The relative risks estimated by AH-calibrated AOD and PM10 (adjusted by AH) were similar. Additionally, compared to ground PM10, we found that AH-calibrated AOD had narrower confidence intervals for all models and was more robust in estimating the current day and lag day effects. Our preliminary findings suggested that, with proper adjustment of meteorological factors, satellite AOD can be used directly to estimate the acute health impacts of ambient particles without prior calibrating to the sparse ground monitoring networks. [Copyright &y& Elsevier]

Influenza recurs seasonally in temperate regions of the world; however, our ability to predict the timing, duration, and magnitude of local seasonal outbreaks of influenza remains limited. Here we develop a framework for initializing real-time forecasts of seasonal influenza outbreaks, using a data assimilation technique commonly applied in numerical weather prediction. The availability of real- time, web-based estimates of local influenza infection rates makes this type of quantitative forecasting possible. Retrospective ensemble forecasts are generated on a weekly basis following assimilation of these web-based estimates for the 2003-2008 influenza seasons in New York City. The findings indicate that real-time skillful predictions of peak timing can be made more than 7 wk in advance of the actual peak. In addition, confidence in those predictions can be inferred from the spread of the forecast ensemble. This work represent an initial step in the development of a statistically rigorous system for real-time forecast of seasonal influenza. [ABSTRACT FROM AUTHOR]

The HAMSTRAD (HO Antarctica Microwave Stratospheric and Tropospheric Radiometers) microwave radiometer operating at 60 GHz (oxygen line, thus temperature) and 183 GHz (water vapour line) has been permanently deployed at the Dome C station, Concordia, Antarctica [75°06′S, 123°21′E, 3,233 m above mean sea level] in January 2010 to study long-term trends in tropospheric absolute humidity and temperature. The great sensitivity of the instrument in the lowermost troposphere helped to characterize the diurnal cycle of temperature and HO from the austral summer (January 2010) to the winter (June 2010) seasons from heights of 10 to 200 m in the planetary boundary layer (PBL). The study has characterized the vertical resolution of the HAMSTRAD measurements: 10-20 m for temperature and 25-50 m for HO. A strong diurnal cycle in temperature and HO (although noisier) has been measured in summertime at 10 m, decreasing in amplitude with height, and phase-shifted by about 4 h above 50 m with a strong HO-temperature correlation (>0.8) throughout the entire PBL. In autumn, whilst the diurnal cycle in temperature and HO is less intense, a 12-h phase shift is observed above 30 m. In wintertime, a weak diurnal signal measured between 10 to 200 m is attributed to the methodology employed, which consists of monthly averaged data, and that combines air masses from different origins (sampling effect) and not to the imprint of the null solar irradiation. In situ sensors scanning the entire 24-h period, radiosondes launched at 2000 local solar time (LST) and European Centre for Medium-Range Weather Forecasts (ECMWF) analyses at 0200, 0800, 1400 and 2000 LST agree very well with the HAMSTRAD diurnal cycles for temperature and relatively well for absolute humidity. For temperature, HAMSTRAD tends to be consistent with all the other datasets but shows a smoother vertical profile from 10 to 100 m compared to radiosondes and in-situ data, with ECMWF profiles even smoother than HAMSTRAD profiles, and particularly obvious when moving from summer to winter. For HO, HAMSTRAD measures a much moister atmosphere compared to all the other datasets with a much weaker diurnal cycle at 10 m. Our study has helped characterize the time variation of the PBL at Dome C with a top around 200 m in summertime decreasing to 30 m in wintertime. In summer, from 2000 to 0600 LST a stable layer is observed, followed by a well-mixed layer the remaining time, while only a nocturnal stable layer remains in winter. In autumn, a daytime convective layer shallower than the nocturnal stable layer develops. [ABSTRACT FROM AUTHOR]

We have investigated by the methods of a given stationary heat flow and calorimetry the heat conductivity and the heat capacity of the typical soil cover materials of a coniferous forest such as fallen-off pine needles, moss, and lichen. Samples of the investigated materials differed in the bulk density and moisture content that were varied over the ranges characteristic of the natural conditions of the geographic latitudes of Belarus. The elucidated laws of the change in the thermal characteristics of the above materials were investigated with the use of the generalized models of the heat transfer in heterophase media and self-consistent calculation of a layered medium with percolation in the direction parallel to the thermal energy transfer. [ABSTRACT FROM AUTHOR]

Influenza epidemics occur periodically during the winter season in temperate areas. Characteristic features of winter include low temperature and low humidity. Humidity is expressed in two different ways: absolute humidity (AH) defined as absolute amount of water in the air, and relative humidity (RH) defined as the relative proportion of water in the air in comparison to the maximum water vapor. There have been many arguments for RH as a determinant factor for influenza epidemics. On the other hand, we have been putting emphasis on AH on the basis of our epidemiological observations. In this context, a recent experimental and theoretical study by other investigators has shown that AH correlates with influenza survival, transmission, and seasonality. Accordingly, we collected meteorological and influenza epidemiological data from 46 prefectures in temperate Japan for 1991-1995 and 1999-2009, and analyzed 2,392 sets of weekly compiled data for each season year by using multiple linear regression analysis, in which the numbers of influenza cases were regarded as a function of AH and RH. We found that the standardized partial regression coefficient for AH was consistently stronger than that for RH with statistical significance. In addition, AH increased and decreased significantly at the time of the epidemic onset and subsidence in seven and twelve out of fourteen influenza seasons, respectively, whereas RH did so in none and two out of fourteen influenza seasons. Thus, we have substantiated our quarter-century-old assertion that AH strongly correlates with the onset and subsidence of influenza epidemics. [ABSTRACT FROM AUTHOR]

Mixed cellulose ester (MCE) filters, used routinely to collect dust samples from air for fiber analysis, are the only filter type that can be prepared for both phased contrast microscopy and transmission electron microscopy analyses. However, whenever fiber counts require collecting dust masses <100 μg on a single filter under variable relative humidity (RH) conditions, historically noted effects of humidity on MCE filter mass can hinder accurate estimates of dust mass, measured as loaded minus unloaded filter mass (M). In this study, a baseline set of hundreds of paired measures of change in RH versus M over different time intervals were obtained over a 5-day period for replicate series of 40 unloaded 37-mm MCE filters under varying RH conditions at a nearly constant temperature. Similar baseline data were obtained for 25-mm MCE filters. Linear regressions fit to these data allow improved estimates of dust mass loaded onto MCE filters from measures of M and RH made before and after loading occurs. Using established theory, these relationships were generalized to address temperature variation as well, and examples of numerical applications are provided. [ABSTRACT FROM PUBLISHER]

Abstract: Following the emergence of a novel strain of influenza A(H1N1) in Mexico and the United States in April 2009, its epidemiology in Europe during the summer was limited to sporadic and localised outbreaks. Only the United Kingdom experienced widespread transmission declining with school holidays in late July. Using statistical modelling where applicable we explored the following causes that could explain this surprising difference in transmission dynamics: extinction by chance, differences in the susceptibility profile, age distribution of the imported cases, differences in contact patterns, mitigation strategies, school holidays and weather patterns. No single factor was able to explain the differences sufficiently. Hence an additive mixed model was used to model the country-specific weekly estimates of the effective reproductive number using the extinction probability, school holidays and weather patterns as explanatory variables. The average extinction probability, its trend and the trend in absolute humidity were found to be significantly negatively correlated with the effective reproduction number — although they could only explain about 3% of the variability in the model. By comparing the initial epidemiology of influenza A (H1N1) across different European countries, our analysis was able to uncover a possible role for the timing of importations (extinction probability), mixing patterns and the absolute humidity as underlying factors. However, much uncertainty remains. With better information on the role of these epidemiological factors, the control of influenza could be improved. [Copyright &y& Elsevier]

Abstract: A high or low humidity environment is related closely to not only many health problems, but also has great influence on the construction durability and energy consumption. It is very important to control humidity level, in order to achieve a healthy and comfortable indoor environment. However, various problems of the air humidity in inhabited dwellings are not yet taken serious consideration in China. Moreover, there is hardly any information available regarding the actual humidity environment in Chinese residential houses. For this reason, it is difficult to select appropriate moderate moisture strategies to maintain a harmonious indoor humidity level. The current authors carried out a field measurement survey on indoor thermal environment in nine Chinese cities. Based on this investigation, the purpose of this present study is to develop a database of actual indoor humidity conditions for moisture moderate design, through which the characteristics of indoor humidity environment in Chinese residential houses can be identified and clarified. The results demonstrated that the indoor humidity level is too low with the relative humidity falls below 20% in some cities where residences equipped with central heating system in winter. On the other hand, indoor humidity is very high with the relative humidity beyond 80% in some cities where residences have inadequate heating and high outside humidity ratio in winter. The severe indoor humidity environment indicated that the moisture level in the residential houses of China should be mitigated and controlled in order to achieve a sustainable and healthy indoor environment. [Copyright &y& Elsevier]

Abstract: Sweating measurement is a very useful tool for the physiological health state of the human body. A sweating measuring system developed in this study was composed of several sensors. All sensors were calibrated to ensure the accuracy. Three pretreatment physiological states for test subjects before sweating measurement included sit and rest for 5min, walking for 5min, and running for 5min. The whole sweating value was measured and calculated over 5-min periods. The results of sweating measurement indicated the usefulness of this device. The sweating quantity of three states did not have a significant relationship with the height, weight and body mass index (BMI) values of subjects. The first sweating index is the difference between active treatment and sitting state. The second sweating index is the ratio between active state and sitting. The relationship between two sweating index and BMI values could be found. This device could serve as a detecting tool to establish the sweating database for normal conditions and to be used for diagnosis. [Copyright &y& Elsevier]

The paper reports about the role of humidity on the breakdown of air in non-uniform fields at 30 kHz - a frequency within the VLF/LF bands used for long distance communication. Experiments were conducted using rod/rod and rod/plane configurations with gap lengths ranging from 8 to 1000 mm. The results indicate that the breakdown voltage at 30 kHz is affected by humidity with varying impact based on gap length. Short (8-45 mm) gaps show a reduction in the breakdown voltage with humidity, while no significant variation is observed for long gaps (125-1000 mm). Breakdown voltages are observed to be markedly lower for 30 kHz when compared to the same gap at 60 Hz. Breakdown mechanisms for explaining this phenomenon are proposed. A correction factor to calculate breakdown voltage as a function of humidity for VLF is presented. [ABSTRACT FROM AUTHOR]

The paper reports about the role of humidity and frequency on the electrical breakdown of air in uniform field gaps. Experiments were conducted on Rogowski-profile electrodes with gap lengths ranging from 5 to 53 mm at power frequency (60 Hz) and frequencies in the range of 18-50 kHz, corresponding to the VLF/LF bands used for long-range communication. The results show that breakdown voltage at VLF decreases with humidity, opposite to that observed at 60 Hz. Breakdown mechanisms for explaining this important phenomenon are proposed. A correction factor to calculate breakdown voltage as a function of humidity for VLF is presented. [ABSTRACT FROM AUTHOR]

Background: High-frequency oscillation ventilation (HFOV) is an accepted ventilatory mode for acute respiratory failure in neonates. As conventional mechanical ventilation, inspiratory gas humidification is essential. However, humidification during HFOV has not been clarified. In this bench study, we evaluated humidification during HFOV in the open circumstance of ICU. Our hypothesis is that humidification during HFOV is affected by circuit design and ventilatory settings. Methods/Materials: We connected a ventilator with HFOV mode to a neonatal lung model that was placed in an infant incubator set at 37°C. We set a heated humidifier (Fisher & Paykel) to obtain 37°C at the chamber outlet and 40°C at the distal temperature probe. We measured absolute humidity and temperature at the Y-piece using a rapid-response hygrometer. We evaluated two types of ventilator circuit: a circuit with inner heating wire and another with embedded heating element. In addition, we evaluated three lengths of the inspiratory limb, three stroke volumes, three frequencies, and three mean airway pressures. Results: The circuit with embedded heating element provided significantly higher absolute humidity and temperature than one with inner heating wire. As an extended tube lacking a heating wire was shorter, absolute humidity and temperature became higher. In the circuit with inner heating wire, absolute humidity and temperature increased as stroke volume increased. Conclusion: Humidification during HFOV is affected by circuit design and ventilatory settings. [ABSTRACT FROM AUTHOR]

To clarify effects of gravity on the water vapor exchange between plants and the ambient air, we evaluated the transpiration rate of plant leaves at 0.01, 1.0, and 2.0 g for 20 s each during parabolic airplane flights. The transpiration rates of a strawberry leaf and a replica leaf made of wet cloth were determined using a chamber method with humidity sensors. Absolute humidity at 3 and 8 mm below the lower surface of leaves was measured to evaluate the effect of gravity on humidity near leaves and estimate their transpiration rate. The transpiration rate of the replica leaf decreased by 42% with decreasing gravity levels from 1.0 to 0.01 g and increased by 31% with increasing gravity levels from 1.0 to 2.0 g. Absolute humidity near the intact strawberry leaf was 5 g m−3 at ambient absolute humidity of 2.3 g m−3 and gravity of 1.0 g. The absolute humidity increased by 2.5 g m−3 with decreasing gravity levels from 1.0 to 0.01 g. The transpiration rate of the intact leaf decreased by 46% with decreasing gravity levels from 1.0 to 0.01 g and increased by 32% with increasing gravity levels from 1.0 to 2.0 g. We confirmed that the transpiration rate of leaves was suppressed by retarding the water vapor transfer due to restricted free air convection under microgravity conditions. [ABSTRACT FROM AUTHOR]

The article presents a study to evaluate the humidification performance of a large number of adult heat and moisture exchangers (HMEs). It assesses 48 devices using a bench test apparatus that simulated real-life physiologic ventilation conditions, and performs three hygrometric measurements for each device. The research suggests that several HMEs performed poorly and should not be used as HMEs.

The decay time of residual DC charge in 500-kV transmission line was measured during five fine and dry days of winter. The results showed a large scattering not dependent on the simultaneously observed weather conditions, such as temperature or relative humidity. The authors performed an additional experiment in a laboratory to discuss the factors that affect the residual DC charge leakage in dry conditions focusing on the moisture in the air and the dust floating in the atmosphere. It is shown that absolute humidity alone decides the decay time without scattering under clean and calm condition. The floating dust blown up by the wind, however, reduces the decay time and brings a large scattering. The dust should be a charge carrier moving freely in the atmosphere. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(2): 45–52, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20417 [ABSTRACT FROM AUTHOR]

Continuous monitoring of the concentration of atmospheric particulate matter was carried out for 7 years by both gravimetric method and β-ray attenuation method (BAM) from a building rooftop in the Tokyo metropolitan area. The two methods showed a different tendency in each season: the data observed by BAM were higher than those by the gravimetric method in summer, and this difference was reversed in winter. The volatilization of ammonium salts accounted for only 30% of the difference between the monitoring methods in summer. Thus, we considered the differences in the water content measured by each method. The concentration difference between methods increased when relative humidity exceeded the deliquescence point of ammonium sulfate in summer, and the water content was estimated to be 30%. However, differences in relative humidity did not explain why the data obtained by the gravimetric method exceeded BAM data by 20–30% in winter. We found that the gravimetric measurements generally exceeded BAM measurements in winter if the ambient absolute humidity during particle collection was higher than the absolute humidity during sample weighing. The water content of atmospheric aerosols greatly influences their mass concentrations. Care must be taken when using mass concentration data for purposes such as evaluating health effects. [Copyright &y& Elsevier]

Studies the effect of humidifying devices on the accurate measurement of tidal volume by mechanical ventilators. Information on the patient protocol; Model lung protocol used in the study; Results of the study.

Different methods to determine the height of the convective boundary layer from lidar measurements are described and compared. The differences in either aerosol backscatter or in humidity between the boundary layer and the free troposphere are used, and either the variance or the gradient profile of the parameter under study is evaluated. On average the different methods are in very good agreement. Temporal resolution of the gradient methods is very high, on the order of seconds, but often there is an ambiguity in the choice of the “relevant” minimum in the gradient that corresponds to the boundary-layer height. This is avoided by combining the variance and the gradient methods, using the result of the variance analysis as an indicator for the region where the minimum of the gradient is sought. The combined method is useful for automated determination of the boundary-layer height at least under convective conditions. Aerosol backscatter is found to be as good an indicator for boundary-layer air as humidity, so a relatively simple backscatter lidar is sufficient for determination of the boundary-layer height. [ABSTRACT FROM AUTHOR]

[Display omitted] • Temporal and spatial variation of dry/wet islands in urban areas at national scale. • Absolute humidity is increasing with rise of urban artificial water dissipation. • Cold and dry cities are prone to be wet islands, while humid ones to be dry islands. • Most of the cities are prone to be dry islands in summer, while wet in winter. • Absolute humidity of all cities increased in winter after urbanization. Evapotranspiration links land surface hydrological processes with the atmosphere and has an important influence on regional water cycles and the water balance. Research has shown that urbanization can impact the hydrological balance, leading to urban wet and dry island effects; however, the mechanisms driving these phenomena remain uncertain. In this study, the humidity levels of urban areas in China were compared with the surrounding areas prior to (1960–1969), and following (2010–2019) rapid urbanization to determine the drivers and mechanisms of urban wet and dry island effects. Monthly observational datasets of temperature, water vapor pressure, and relative humidity from 613 meteorological stations were combined with the processes of urban artificial water dissipation to analyze the temporal and spatial characteristics of urban dry/wet islands. Results showed that cold and dry urban areas tended to have wet island effects, while warm and humid urban areas had dry island effects. The dry/wet island intensity was less than 3.5% in most cities. Furthermore, urban areas tended to be dry islands during summer and wet islands during winter. Coastal cities were an exception, being dry islands throughout the year. Comparisons of humidity prior to and following rapid urbanization revealed that absolute humidity had generally increased, during winter, all regions displayed increased absolute humidity, by as much as 8%–16% in northern China. This was despite an overall trend towards increased dry island intensity, and was attributed to intensifying urban heat island effects. These results provide valuable information to help understand the causes of dry/wet island effects in urban areas. [ABSTRACT FROM AUTHOR]

• Simultaneous temperature and relative humidity measurement. • Potential to measure absolute humidity. • Highly linear temperature response in proposed range (3.97 nm/°C, R2>0.99). • Small sensing region (one fibre tip) for two parameters. • Low-cost with simple manufacturing process compared with other optical fibre sensors. Temperature and humidity are essential parameters in monitoring the health of patients in critical care. An optical fibre sensor has been developed for simultaneous measurement of relative humidity (RH) and temperature at a single optical fibre tip based on the reflected intensity. Combining these measurements enables absolute humidity values to be obtained. The fibre tip is first modified with a coating of poly(allylamine hydrochloride) (PAH) / silica nanoparticles (SiO 2 NPs) for relative humidity (RH) measurement and then coated with thermochromic liquid crystal (TLC) for temperature measurement. Experimental results demonstrate that the RH and temperature sensitivity are respectively 0.43 %/RH% (intensity at a wavelength of 650 nm) from 55 to 90% RH (R2 = 0.973) and 3.97 nm/°C from 28 to 46 °C (R2>0.99). Moreover, the proposed sensor has low crosstalk between each of the sensing parameters, with a response time of 3.1 s temperature (30–38 °C) and 13.2 s for relative humidity (20–80 %). In comparison to grating based optical fibre sensors the proposed sensor is low-cost with a simple manufacturing process which has the potential to find widespread use in healthcare applications. [ABSTRACT FROM AUTHOR]

Different interventions targeting live poultry markets (LPMs) are applied in China for controlling avian influenza A (H7N9), including LPM closure and "1110" policy (i.e., daily cleaning, weekly disinfection, monthly rest day, zero poultry stock overnight). However, the interventions' effectiveness has not been comprehensively assessed. Based on the available data (including reported cases, domestic poultry volume, and climate) collected in Guangdong Province between October 2013 and June 2017, we developed a new compartmental model that enabled us to infer H7N9 transmission dynamics. The model incorporated the intrinsic interplay among humans and poultry as well as the impacts of absolute humidity and LPM intervention, in which intervention strategies were parameterized and estimated by Markov chain Monte Carlo method. There were 258 confirmed human H7N9 cases in Guangdong during the study period. If without interventions, the number would reach 646 (95%CI, 575–718) cases. Temporal, seasonal and permanent closures of LPMs can substantially reduce transmission risk, which might respectively reduce human infections by 67.2% (95%CI, 64.3%–70.1%), 75.6% (95%CI, 73.8%–77.5%), 86.6% (95%CI, 85.7–87.6%) in total four epidemic seasons, and 81.9% (95%CI, 78.7%–85.2%), 91.5% (95%CI, 89.9%–93.1%), 99.0% (95%CI, 98.7%–99.3%) in the last two epidemic seasons. Moreover, implementing the "1110" policy from 2014 to 2017 would reduce the cases by 34.1% (95%CI, 20.1%–48.0%), suggesting its limited role in preventing H7N9 transmission. Our study quantified the effects of different interventions and execution time toward LPMs for controlling H7N9 transmission. The results highlighted the importance of closing LPMs during epidemic period, and supported permanent closure as a long-term plan. • A new compartmental model was developed for better understanding H7N9 transmission dynamics. • Effectiveness of different interventions and execution time toward live poultry markets were systematically evaluated. • Closing live poultry markets (especially permanent closure) are highly effective in preventing H7N9 infections in humans. • Only implementing the "1110" policy is unlikely to stop H7N9 transmission. [ABSTRACT FROM AUTHOR]

Over a 28-year period cerebrospinal meningitis, in sporadic as well as epidemic situations, mainly affected the Beninese territory from November to March, April or sometimes May. On the average, the acme occured in February–March. A regression analysis confirmed that 14 to 34.5% of the temporal variability of the disease was due to the northern trade wind (harmattan) and a low absolute humidity in the northern areas, which constitute the main epidemiological pole of the country. On the contrary, cerebrospinal meningitis and climate turned out to be fully independent one from the other in the southernmost areas, where the harmattan is seldom experienced although the meningitis belt is at the present time spreading southwards. But the case-fatality ratio was especially high in the coastal region and during the off season, i.e. when endemic meningitis predominantly affected small children aged under one year. In any way, the climate-meningitis relationship proved to be weaker than is sometimes assumed, perhaps because this relationship is partly overshadowed by both anthropic effects (vaccination campaigns) and latency before disease outbreak. [ABSTRACT FROM AUTHOR]

Further studies on the effect of ambient atmospheric conditions during spinning on yarn properties are described in this paper. The results obtained indicate that maximum lea strength in the spinning room is obtained when yarns are spun at the highest level of relative humidity (76%) and lowest level of temperature (70°F); maximum strength under standard laboratory conditions is shown by yarns spun at the highest levels of relative humidity (76%) and temperature (91°F). Maximum yarn elongation under standard laboratory conditions is obtained with yarns spun at the lowest level of tem perature (70°F) and humidity (34%). Yarn properties are significantly influenced by spinning factors and absolute humidity of the spinning room, the extent of change being different for different types of cotton. [ABSTRACT FROM PUBLISHER]

This study investigated the effects of weather conditions, air pollutants, and the air quality index (AQI) on daily cases of COVID-19 in the Bangkok Metropolitan Region (BMR). In this research, we collected data from January 1 to March 30, 2020 (90 days). This study used secondary data of meteorological and air pollutant parameters obtained from the Pollution Control Department of the Ministry of Natural Resources and Environment as well as daily confirmed COVID-19 case data in the BMR obtained from the official webpage of the Department of Disease Control, Ministry of Public Health, Thailand. We employed descriptive statistics, and Spearman and Kendall rank correlation tests were used to investigate the associations of weather variables, air pollutants, AQI with daily confirmed COVID-19 cases. Our findings indicate that CO, NO 2 , SO 2 , O 3 PM 10 , PM 2.5 , AQI have a significantly negative association with daily confirmed COVID-19 cases in the BMR, whereas meteorological parameters such as temperature, relative humidity (RH), absolute humidity (AH) and wind speed (WS) showed significant positive associations with daily confirmed COVID-19 cases in the BMR. Our study is a useful supplement to encourage regulatory bodies to promote environmental strategies, as air pollution regulation could be a sustainable policy for mitigating the harmful effects of air pollutants. Furthermore, this study provides new insights into the relationship between daily meteorological factors, AQI, and air pollutants and daily confirmed COVID-19 cases in the BMR. These data may provide useful information to the public health authorities and decision makers in Thailand, as well as to the World Health Organization (WHO), in order to set proper strategic aimed at reducing the impact of the COVID-19. Future studies concerning SARS-CoV-2 and other viruses should investigate the possibility of infectious droplet dispersion in indoor and outdoor air during and after the epidemic outbreak. • The NO levels and AQI decreased during the outbreak. • SO 2 , NO 2 , CO, PM 2.5 , PM 10 , and O 3 rose by 42.16%, 39.02%, 23.00%, 18.43%, 3.17%, and 0.02%, respectively. • The temperature, RH, AH and WS showed positive significant associations with daily confirmed COVID-19 cases. • The daily confirmed COVID-19 cases displayed negative associations with CO, NO 2 , SO 2 , O 3 , PM 10 , PM 2.5 , and AQI. [ABSTRACT FROM AUTHOR]

This study aims to analyze the correlation between environmental factors and confirmed cases of COVID-19 pandemic in Victoria, Mexico. The analysis is performed at the micro-level, filtering only confirmed cases of COVID-19 that are located near air quality monitoring stations, within an approximate coverage of 2.5 km, in order to identify a possible specific association between PM 2.5 , PM 10 , carbon monoxide (CO), relative humidity, temperature, absolute humidity, and total confirmed cases of COVID-19. The results evidenced that the cases of COVID-19 were very strongly associated with CO concentration. Our results also suggested that particulate matter pollution (PM 2.5 and PM 10) exposure have a significant correlation for confirmed cases of COVID-19. Furthermore, we studied the changes in air quality during the COVID-19 outbreak by comparing the average concentration of the four weeks before lockdown (February 16 to March 14, 2020) and the following twelve weeks during the partial lockdown (March 15 to June 06, 2020), revealing a very significant decrease of pollutants. • The first study on the effects of environmental and meteorological factors on COVID-19 cases in Mexico. • A decrease of more than 44% was found in the concentration levels of PM 2.5 , PM 10 and CO during the lockdown period. • A strong positive correlation between confirmed COVID-19 cases with carbon monoxide. • PM 2.5 and PM 10 show a positive association with confirmed cases of COVID-19. • Temperature is negatively correlated to the spread of COVID-19. [ABSTRACT FROM AUTHOR]

Environmental factors are well known to affect spatio-temporal patterns of infectious disease outbreaks, but whether the rapid spread of COVID-19 across the globe is related to local environmental conditions is highly debated. We assessed the impact of environmental factors (temperature, humidity and air pollution) on the global patterns of COVID-19 early outbreak dynamics during January–May 2020, controlling for several key socio-economic factors and airport connections. We showed that during the earliest phase of the global outbreak (January–March), COVID-19 growth rates were non-linearly related to climate, with fastest spread in regions with a mean temperature of ca. 5 °C, and in the most polluted regions. However, environmental effects faded almost completely when considering later outbreaks, in keeping with the progressive enforcement of containment actions. Accordingly, COVID-19 growth rates consistently decreased with stringent containment actions during both early and late outbreaks. Our findings indicate that environmental drivers may have played a role in explaining the early variation among regions in disease spread. With limited policy interventions, seasonal patterns of disease spread might emerge, with temperate regions of both hemispheres being most at risk of severe outbreaks during colder months. Nevertheless, containment measures play a much stronger role and overwhelm impacts of environmental variation, highlighting the key role for policy interventions in curbing COVID-19 diffusion within a given region. If the disease will become seasonal in the next years, information on environmental drivers of COVID-19 can be integrated with epidemiological models to inform forecasting of future outbreak risks and improve management plans. Unlabelled Image • The role of environmental conditions on COVID-19 transmission is controversial. • In earliest outbreaks, COVID-19 growth rate was related to climate and PM2.5. • Early growth rates were faster in cold, dry climates and in polluted regions. • Environmental effects faded almost completely when considering later outbreaks. • Containment measures overwhelm impacts of environmental variation on COVID-19. [ABSTRACT FROM AUTHOR]