Decrease In Relative Humidity Research Articles

Enhanced ozone pollution in the summer of 2022 in China: The roles of meteorology and emission variations

The variation of surface ozone (O3) is linked to changes in meteorology and emission. A record-breaking high temperature struck China in the summer of 2022, resulting in positive anomalies of daily maximum temperature of 0.86 ± 1.02 °C. Consequently, the mean daily maximum 8 h average (MDA8) ozone (O3) increased by 6.46 ± 13.0 μg m−3 compared to the mean summertime MDA8 O3 from 2014 to 2021 in China. This research aimed to understand the impact of meteorology and emission changes on O3 variations in different regions in the summer of 2022 by an explainable machine learning method. Results showed that the changes in emissions dominated the O3 enhancement in the Pearl River Delta (PRD), Beijing-Tianjin-Hebei (BTH), and Twain-Hu Basin (THB) with contributions of 89%, 86%, and 53% respectively. Satellite observations suggested that the increased O3 due to emission changes in BTH and PRD were related to the decreases in NO2 emissions and increases in volatile organic compound (VOC) emissions. On the contrary, variations in meteorology contributed 63%, 63%, and 51% respectively to the increases of O3 in the Sichuan Basin (SCB), Yangtze River Delta (YRD), and Fen-Wei Plain (FWP). The increase in O3 levels due to meteorological changes was associated with an anomalous westward extension of the Western Pacific Subtropical High during the summer of 2022. Specifically, the decrease in relative humidity, increases in temperature and boundary layer height were the dominant factors contributing to the increase of meteorology related O3 in SCB, THB, and YRD, with contributions over 99%. This study recommends a continuous reduction in O3 precursor emissions to mitigate O3 pollution under the global warming background.

Zmiany wilgotności powietrza w Łodzi w latach 1966–2020 w świetle wybranych wskaźników

The aim of the study is to present changes in air humidity in central Poland in the years 1966–2000 in Łódź as an example. The values of air temperature, relative humidity and atmospheric pressure from four observation terms, 00, 06, 12 and 18 UTC, were used. On this basis, the saturated vapour pressure, the current vapour pressure, and the saturation deficit were calculated. Then, the variability of these three indicators and relative humidity was examined. The variability of monthly and seasonal average values of humidity indices in four observation periods was presented, the trends in seasonal variability of humidity indices were calculated and the distribution functions of their distributions were compared in the midday period in three 15-year periods: 1966–1980, 1986–2000 and 2006–2020. It has been shown that the pressure of saturated water vapour is the highest in summer, the lowest in winter, and slightly higher in spring than in autumn at all times, except for the night. It increased significantly in the studied period as a result of the increase in air temperature. A comparison of the distributions in three 15-year periods shows a significant increase in the probability of occurrence of high values of saturation vapour pressure, even above 30hPa. The water vapour pressure in the air is highest in summer and lowest in winter, but in spring it is lower than in autumn. All trend coefficients are positive, but only less than half are statistically significant. A comparison of the distributions over three 15-year periods show a slight increase in the probability of higher values of the actual vapour pressure. The saturation deficit, as the difference between the previous two indicators, increases significantly. Its value in spring is significantly higher than in autumn. The trend is positive, especially in spring and summer, and the comparison of distributions shows that in the last 15 years the probability of high values of saturation deficit increased significantly. The course of relative humidity is the opposite of saturation deficit. In autumn, the relative humidity is definitely higher than in spring. The trend is down. To sum up, warming brings an increase in the capacity of the atmosphere for water vapour, a slight increase in the amount of water vapour in the air, but also a significant increase in saturation deficit and a decrease in relative humidity, which is particularly strong in spring in the first half of the growing season.

Analysis of Kendal Industrial Estate (KIK) impact on the Surrounding Air Quality

The Kendal Industrial Area (KIK) is developed to accelerate economic development in the Kendal district area and to support the acceleration and expansion of economic development. Industrialization will lead to a process of air pollution which is marked by 16 companies that are already operating in the KIK area. This research was aimed to analyze the impact of the Kendal Industrial Estate on air quality. The approach of this research used descriptive method, with an analysis of changes in air quality that occurred before the existence of KIK and after the development of industrial areas. The factors that affect the air quality conditions reviewed in this study were air temperature, surface pressure, wind speed, and relative humidity. Data collection techniques used were secondary data NASA satellite imagery. The results showed that there is a change in air conditions after the presence of KIK as indicated by the increase in air pressure and air temperature and the decrease in relative humidity and wind speed. The results indicates that the existence of the Kendal Industrial Area (KIK) causes changes in environmental conditions, but these changes are not significant so they are still within the comfort limits for industrial areas.

Long‐term variability of the low‐level cloud base height in Poland

AbstractThe aim of the study is to characterize the long‐term variability of the low‐level cloud base heights (CBH) in Poland in the years 1971–2020. Data were used from six weather stations belonging to the Institute of Meteorology and Water Management – the National Research Institute (IMWM‐NRI), where CBH was first measured using the IWO device and, since the 1990s, using a ceilometer. The analysis allowed for data from eight observation periods (0000, 0300, 0600, 0900, 1200, 1500, 1800, 2100 UTC), which referred to several height ranges (between the ground surface and 2500 m a.s.l.). In the analysed multiyear period, in the cool half of the year, the height of the Cumulonimbus cloud bases increased significantly, that is, the number of cases increased at a height of >1000 m and, in the warm half of the year, at >1500 m. In recent years, the number of cases of the Cumulus cloud with a base at a height between 300 and 999 m has clearly decreased, while it has increased at a height of 1000–1499 m (in October–March) and 1500–1999 m (April–September). A similar increase in CBH was found in the case of the Stratocumulus cloud (their greater share between 1500 and 2499 m). It was only in the case of the Stratus cloud that a lowering of the cloud base was noticed, possibly owing to the imperfect measurement of the fractus species. The positive upward trend in the base height of most low‐level clouds can be explained by a statistically significant increase in temperature and a decrease in relative air humidity in the lower troposphere.

Hygrothermal behaviour of a room with different occupancy scenarios

The thermal and moisture properties of building partitions and the related possibility of moisture buffering affect the water vapour exchange between the superficial layers of the hygroscopic materials and the indoor environment, which results in energy consumption for different purposes. The paper describes an analysis of the hygrothermal behaviour of a roomunder different occupancy scenarios for four wall finishing variants (variable parameters of thermal conductivity index and diffusion resistance of the applied material). The application of gypsum board and cement-lime plaster was analysed with and without a paint coat. Computer simulations using WUFI Plus were used for the analysis. The application of cement-lime plaster without a top paint coat was shown to reduce fluctuations in the amplitude of indoor relative humidity more than the other solutions. Applying a paint coat to the interior surface of a building partition limits the material's buffering properties, and consequently, the indoor relative humidity amplitude increases. Upon improving thermal efficiency, the decrease in indoor relative humidity was higher for a nursery than for an office space. For the air conditioning dynamic operation mode, it was demonstrated that gypsum board walls with no paint coat could reduce energy demand for dehumidifying systems and increase it for humidifying systems. The painted variants are characterised by a higher total energy consumption for humidification and dehumidification purposes.

Effect of Rain Cover on Tree Physiology and Fruit Condition and Quality of ‘Rainier’, ‘Bing’ and ‘Sweetheart’ Sweet Cherry Trees

A study was conducted in a commercial sweet cherry orchard in central Chile. The objective was to evaluate the rain cover effect on changes in the microclimate, vegetative growth, plant physiology and fruit quality of ‘Rainier’, ‘Bing’ and ‘Sweetheart’ sweet cherry trees. The data were compared to a control without a rain cover. The results showed that, under the rain cover, there was a 50–60% reduction in total solar radiation, as well as an increase in air temperature (+0.6 °C) and a decrease in relative humidity (−4.7 percentage points) in the upper canopy zone. Regarding the trees under rain cover, a greater shoot length (28–58%) and leaf area (24–54%) were observed among cultivars compared to the control; the trunk cross-sectional area was only significant in ‘Rainier’, it being 1.2 times greater under rain cover. CO2 assimilation showed no differences, but an increase in the leaf transpiration rate was observed. The fruit firmness and sugar content in fruits were negatively affected by the rain cover, those characteristics being of major relevance for the cherry growers. Additionally, the contents of anthocyanins and carotenoids and the antioxidant capacity were significantly lower only in ‘Rainier’ under rain cover, while the total phenol content decreased in all three cultivars. The rain cover did not negatively affect the tree physiology, but it can be detrimental in bicolor cultivars with a yellow flesh due to a lower color and phenolic compounds development.

Application of hierarchical cluster analysis in age segmentation for thermal comfort differentiation of elderly people in summer

Thermophysiological functions should be considered in the age segmentation of elderly people for thermal comfort differentiation. This paper aims to establish a scientific age segmentation criterion for elderly people based on thermal physiological demands. Firstly, field measurements and questionnaires are conducted in two pensioners’ buildings, and hierarchical cluster analysis is adopted to segment the age of elderly people based on thermophysiological functions in summer. Secondly, the effects of the basal metabolic rate (BMR), body fat percentage (BF%) and cardiac output (CO) on the physiological indexes are analyzed, then the thermal sensation deviation degree and the environmental sensitivity of the elderly people at different ages are analyzed. Finally, subjective perception and physiological parameter are combined to explore summer indoor environmental comfort zones for elderly people at different ages. The results show that the age of elderly people is segmented into [60, 69], [70, 89] and [90, 99]. With the increase of age, BMR and CO decrease, and BF% increases; the sensitivity of subjective perception to temperature, relative humidity and air speed decreases, and the sensitivity of MST to temperature and relative humidity also decreases. For the three age groups, the air temperature comfort zones are 23.25–27.41°C, 19.50–28.67°C and 20.72–30.73°C, respectively; the humidity comfort zones are 42.50–60.83%, 40.50–68.00% and 35.00–71.67%, respectively; and the air speed comfort zones are 0.02–0.31 m/s, 0–0.27 m/s and 0–0.29 m/s, respectively. This study can provide theoretical support for thermophysiological age segmentation criteria and differentiated environment design for elderly people in summer.

Perceived Effects of Climate Change on Poultry Egg Production in Rivers State Nigeria

The study assessed the effects of climate change on poultry egg production in Rivers State, Nigeria. A total of 120 poultry egg farmers were randomly selected through questionnaire and interview schedule. Descriptive statistics and inferential statistical tools were used for data analysis. Result of the socio-economic characteristics revealed that majorities (60.8%) of the poultry farmers were males, 80.8% were married, and 61.6% had tertiary education. Also from findings, the majority (67.5%) of the poultry farmers were aware that high temperature, increase in rainfall (86.7%), erratic rainfall pattern (71.7%), decrease in relative humidity (55.8%) and flooding of poultry farms (71.7%) has harmful effects on poultry egg production. More so, the perceived effects of climate on egg production include high rate of diseases and parasites incidence, soft egg shell formation, low quantity and quality of egg production, high costs of poultry production activities, reduction in feed and water intake, and increase in poultry bird mortality. Results also revealed that television, radio, social media and fellow poultry farmers were their main sources of information on climate change. The result of Chi-square also revealed that education attainment and marital status of poultry farmers were significant at 5% used in controlling the effects of climate change, because married farmers have family labour capacity to build adaptive strategies. It is therefore commended that poultry farmers should be adequately informed on the best operating systems to minimize the harmful effect of climate change on poultry egg production as well as ensure optimum level of poultry egg production.

Factors influencing the airborne sporangia concentration of Phytophthora infestans and its relationship with potato disease severity

Forecasting systems are widely used to predict the application of fungicides for managing late blight. However, airborne inoculum has rarely been included in these forecasting systems. Monitoring the sporangia in crop environments may offer an opportunity to improve late blight forecast systems by integrating pathogen pressure. Hence, this experiment aiming to analyze relationships between weather based risk systems and sporangia levels in the atmosphere of potato crops. The experiments were conducted during two growing seasons in a potato field. During the study, the concentration of Phytophthora infestans in the air, the weather conditions, the phenology of cultivars and r-AUPDC during the crop cycle were recorded. The weather-based risk of late blight was estimated using infection pressure (IP) and the daily risk value (DRV) based on hourly relative humidity (RH) and temperature (T). The effect of weather parameters on sporangia levels was analyzed. IP and DRV showed a strong positive correlation with sporangia concentration, standing out the pronounced effect of RH on the sporangia levels. Analysis of the hourly sporangia concentration within a day showed an increase in the sporangia concentration from 9 h to 18 h. This increase in sporangia was linked to an increase in T, spore release, and a decrease in RH. Our results identified a T of 10 °C and RH of 80% as the minimum threshold for significant sporangia concentration in the air. However, maximum sporangia level was found in the air at 88% (average relative humidity) and 17 °C (average temperature). Finally, the effect of weekly P. infestans sporangia was observed on cultivars with different susceptibility to late blight.

Spatio-Temporal Evolution of the Thermo-Hygrometric Index (THI) during Cold Seasons: A Trend Analysis Study in Iran

Global warming can cause deep and extensive changes in the Earth’s climate and changes in the time and place of climatic phenomena. The present trend analysis study assesses cold stress using the thermo-hygrometric index (THI) in the two seasons of autumn and winter in outdoor environments in Iran. The data related to the average of the two variables of daily air temperature and relative humidity from 60 synoptic meteorological stations for a statistical period of 30 years were obtained from the Iranian Meteorological Organization. The THI index was calculated for autumn and winter, and the level of thermal discomfort was determined for each station. The Mann–Kendall statistical test with the help of Minitab ver17.1.0 software was also used to investigate the changes in air temperature, relative humidity and THI index. The THI for autumn increased in 68% of the stations, and this increasing trend is statistically significant in 51% of these stations. The THI for winter increased in 83% of the stations, and this increasing trend is statistically significant in 51% of these stations. In autumn, 53% of the stations were in the range of thermal discomfort, and in winter only 5% were in the range of thermal comfort. The decreasing trend in THI in some climatic types, along with the increasing trend in air temperature, can indicate the decrease in relative humidity in the monitored stations during the studied years. It is recommended to know the temporal and spatial distribution and the probability of occurrence of cold stress through the use of THI in order to adopt preventive measures and policies in the outdoors in Iran.

Long-term ion hydration process and lithosphere-atmosphere coupling following the 2021 Fagradalsfjall volcanic eruption using remotely sensed data

After a series of earthquakes, the Reykjanes peninsula in Iceland faced a volcanic eruption for the first time in 800 years. This volcanism of the 2021 Fagradalsfjall started on March 19, 2021, and lasted until September 18, 2021. In this study, the vestiges of the mutual interplay of Earth’s different geophysical shells due to the local lithospheric changes around the Fagradalsfjall were extensively investigated with the help of satellite-based remotely sensed datasets. Firstly, the regional surface deformations caused by the pre-eruption seismic activity are determined using interferometric image pairs, and horizontal and vertical displacement rates are analyzed. Secondly, the satellite observations revealed that the land surface temperature of the entire area increased to a maximum of 40 °C during the maximum phase of lava discharge by the end of May 2021. Moreover, we observed that the surface mass concentrations of SO2 and CO trace gases started to ascend in parallel with the lava discharge after the initial eruption, where their concentrations were doubled in April before reaching their maximum phases (three to four times more than the initial eruption) in May 2021. The cumulative concentrations of the trace gases in the atmosphere emitted from the Fagradalsfjall volcano pushed the regional atmospheric balance into a non-equilibrium state by creating air ionization through various chemical reactions with other atmospheric gases. These ion clusters underwent an ion hydration process that changed the electric conductivity of the atmospheric boundary layer, which covers the first two kilometers of the atmosphere. Finally, our observations showed a sharp decrease in the atmospheric relative humidity that led to an increase in the atmospheric air temperature due to this ion hydration process. The large ion clusters in the atmospheric boundary layer produced a vertical electric field that penetrated over the affected region and brought long-term changes in the ionosphere layer. This unique phenomenon of the simultaneous interaction of different geophysical layers was specifically observed during the maximum phase of the lava discharge and increased ion concentrations in the atmosphere. The used data sets cover the first three months of the volcanism, and this interval seemed to be sufficient to reveal the atmospheric traces. Our comprehensive study provides an important contribution to the theory of the coupling of volcanism and the Earth's atmospheric dynamics.

Physical and Chemical Characteristics of Dew and Rain in North-West Africa with Focus on Morocco: Mapping Past and Future Evolution (2005–2100)

In the context of global warming and a reduction in fresh water availability, this study presents the evolution of dew, rain and evapotranspiration in the North-West (NW) of Africa. This study is followed by a chemical analysis of dew and rain data in a representative site. The time periods are concerned with the years 2005–2020 using existing data, and years 2020–2100 using the low and high emissions representative concentration pathway scenarios RCP 2.6/8.5 from the coordinated regional climate downscaling experiment database. A continuous decrease in rain precipitation is observed, on the order of −14 mm·decade−1 for the more credible scenario RCP 8.5. The amplitude is maximum on the coast and on the foothills of Atlas. A clear decrease in dew yields (up to 7%) is also observed along a NW/SE axis. It is strongly correlated with a corresponding decrease in relative humidity. Chemical dew and rain data in the representative site of Mirleft correspond to the major cations of Na+ > Ca2+ > Mg2+ > K+, similar to local spring water. The concentrations in rain are about two times less than in dew water. Ionic concentrations are compatible with the World Health Organization standards. The seasonal variations of the ionic concentrations in dew and rain follow a volume dilution dependence. In the future, the expected diminution in dew and rain volumes according to the RCPs 2.6 and 8.5 should increase the dew and rain ionic concentrations.

The influence of different bacteria consortium and irrigation levels on yield and physiological attributes of durum wheat (Triticum durum Desf.) grown under organic farming conditions

BackgroundInorganic fertilizers help to prevent yield and quality losses in agricultural production; however, adversely affect soil quality and human health. The rising public awareness is switching the production focus from conventional to organic farming. Therefore, obtaining higher yields under organic farming conditions is inevitable. Different bacterial consortia have been found helpful in improving crop yields under stressful and benign environments. Therefore, current study tested the impact of two bacterial consortia on yield and physiological attributes of durum wheat (Triticum durum Desf.) grown under organic farming conditions with two different irrigation levels. MethodsTwo bacteria consortiums [(consortium 1 = Bacillus megaterium RCK-869 + Pantoea agglomerans RK-120 + Paenibacillus polymyxa RCK-540 + Bacillus subtilis RCK-561), (consortium 2 = Azospirillum, Rhizobium, Azotobacter and Acetobacter) and two irrigation levels, i.e., 50 and 100% of the required moisture were included in the study. Data on chlorophyll index, flag leaf area, soluble sugar content, plant height, protein ratio, and grain yield were drecorded. ResultsThe GY in bacteria-free treatment was 3512.0 kg ha−1, which increased to 4868.3 kg ha−1 with the application of bacteria consortium 1. The application of 50% irrigation significantly reduced the yield and related traits, whereas the application of bacteria consortium 1 significantly improved these traits under normal and 50% irrigation. Overall, higher values of the studied traits were recorded during 1st year than 2nd year. The decrease in total precipitation and relative humidity, and the increase in temperature in the second year caused a decrease in grain yield, agronomic and physiological parameters. ConclusionBacteria consortium consisting of Bacillus bacteria significantly improved the yield and related traits of durum wheat under deficit and normal irrigation. Therefore, bacterial consortium consisting of B. megaterium + P. agglomerans + P. polymyxa + B. subtilis could be used to improve durum wheat production under organic farming conditions and deficit irrigation.

Evaluation Strategies on the Thermal Environmental Effectiveness of Street Canyon Clusters: A Case Study of Harbin, China

Urban overheating significantly affects people’s physical and mental health. The addition of street trees is an essential, economical, and effective means by which to mitigate urban heat and optimize the overall thermal environment. Focusing on typical street canyon clusters in Harbin, China, landscape morphology was quantified by streetscape interface measurements (sky view factor, tree view factor, and building view factor). Through ENVI-met simulations, the correlation mechanism between streetscape interface measurements and thermal environment was evaluated, and optimization methods for assessing the thermal environment of urban streets were proposed. The results revealed: (1) The thermal environment optimization efficiency of general street canyon types was greatest when street tree spacing was 12 m. At present, the smaller spacing has not been simulated and may yield better thermal environment results. The average decrease in temperature (Ta), relative humidity (RH) and mean radiant temperature (MRT) was 0.78%, 2.23%, and 30.20%, respectively. (2) Specific street canyon types should adopt precise control strategies of streetscape interface according to their types to achieve the optimal balance between thermal environment optimization and cost. (3) Streetscape interface measurements and thermal environment indexes show quadratic correlation characteristics, and are critical points for further investigation. The conclusions are more specific than previous research findings, which are of great significance for decreasing the urban heat island effect at the block scale, improving residents’ physical and mental health, and improving the urban environment quality.

Sustainability enhancement of calcined clay and limestone powder hybrid ultra-high-performance concrete using belite-rich Portland cement

• BRC is used to produce sustainable LC3-UHPC. • BRC can control the hydration of LC3-UHPC. • BRC concrete has lower shrinkage, hydration heat, and CO 2 emissions. • BRC can improve late age strength. • 33% BRC is the optimal substitution amount for LC3-UHPC. In this study, limestone calcined clay cement (LC3) was used to prepare ultra-high-performance concrete (UHPC), and the effects of different cement types (ordinary Portland cement (OPC) and belite-rich Portland cement (BRC)) on the performance of LC3-UHPC were investigated. The main objective was to develop UHPC with low autogenous shrinkage, low heat of hydration, low CO 2 emissions, and high compressive strength. The water–cement ratio of the specimens was 0.2, the weight ratio of cement: calcined clay: limestone was 7:2:1, and the replacement rates of BRC for OPC were 0, 33, 66, and 100%. A series of macroscopic and microscopic tests were conducted for all specimens to assess their properties and performance. The experimental results show that BRC can effectively control cement hydration, reduce the internal temperature increase, slow the decrease in internal relative humidity, and effectively reduce autogenous shrinkage. After 28 d of curing, the compressive strength and ultrasonic pulse velocity of the BRC-doped specimens significantly increased, and the Ca(OH) 2 content and resistivity decreased compared to those of the OPC specimens. In addition, the CO 2 emission calculations revealed that the incorporation of BRC reduced the total and normalized CO 2 emissions. The specimens doped with 33% BRC exhibited the lowest normalized CO 2 emissions. In general, LC3-UHPC showed a good comprehensive performance, particularly after replacing OPC with BRC. It exhibited low autogenous shrinkage, low heat of hydration, low CO 2 emissions, and high compressive strength, which promote sustainability and engineering applications of UHPC.

Causes and course of climate change and its hydrological consequences in the Greater Poland region in 1951-2020

The paper presents effects of changes in climatic elements in the Greater Poland region (Poland), their causes and consequences for shaping the water balance of this area, copying with the most severe water deficit in Poland. The study period covers 70 years (1951–2020). The research identified an abrupt and significant change in the climate of Greater Poland, which started between 1987 and 1989, concerning not only air temperature but also a wider spectrum of climatic elements. The change in the state of the climate, which covers the entire Atlantic-Eurasian circulation sector, re-sults from a sudden change in the macro-circulation conditions in the middle troposphere (500 hPa). The reason for the change in the mid-tropospheric circulation is an equally abrupt and simultaneous change in the intensity of the ocean heat transport by the North Atlantic thermohaline circulation (NA THC). Climate change observed in Greater Poland is manifested in an increase in sunshine duration (SD) and air temperature, a decrease in relative humidity, a change in the cloud structure, and an increase in the degree of sky coverage. The main, physical reason for an increase in air tempera-ture is a rapid and strong increase in SD in the warm half-years, which began after 1988, and a significant increase in the frequency of positive North Atlantic Oscillation (NAO) phases in winters. The ongoing climate change entails various effects, among which the most important is considered to be hydrological consequences. The water balance of Greater Poland is becoming increasingly unfavourable, mainly as a result of a rapid increase in field evaporation.

Drought and ozone air quality in California: Identifying susceptible regions in the preparedness of future drought

California experienced extreme and prolonged drought conditions during the early 2010s. To date, little is known regarding the influence of drought on air quality. Our study quantified site-specific associations between drought (defined by the Standardized Precipitation-Evapotranspiration Index; SPEI) and daily maximum 8-h ozone (O3) concentrations for California, USA, and then pooled these associations for the years 2009–2015. Overall, ambient O3 concentration was higher during droughts by 1.18 ppb (95% confidence interval (CI) = 1.00–1.36). The sensitivity of O3 to drought was greater during the warm season than during the cool season (1.73 ppb versus 0.79 ppb higher O3 during droughts) with substantial regional variation. In a pooled analysis with meteorological parameters as potential effect modifiers, the spatial heterogeneity of drought-O3 associations was explained strongly by average relative humidity for each season (71.9% (warm season) and 73.4% (cool season) of the drought-O3 associations explained), followed by the drought-related changes in relative humidity (47.6% (warm season)) and temperature (53.6% (cool season)). The pooled regression further identified regions susceptible for drought-related O3 increases as those with relatively low average relative humidity (10–25th percentiles or 44.3–47.3%) and larger drought-related decrease in relative humidity and increase in temperature. As the drought events are projected to occur with increased frequency and intensity in the era of climate change, the excess health burdens from O3 exposures attributed to the projected drought events need to be taken into account when allocating air quality and health resources. The impacts of O3 on health during droughts would confound the health burdens from the drought itself.

Wearable cooling and dehumidifying system for personal protective equipment (PPE)

While PPE prevents the health care personnel from exposing to the harmful surroundings, it creates a barrier to the dissipation of body heat and perspiration, leading to severe heat stress during prolonged exposure. Here, we report a lightweight wearable cooling and dehumidifying system capable of extracting 51.7 W heat and 26.3 g/hour moisture within protective coverall without compromising the protection. The system could continuously operate for 6 h without taking off the PPE. Compared with the available commercial cooling garments with different cooling methods, the system could provide about 3.2 ∼ 5.0 times mean cooling power per unit weight in a prolonged working condition. In a simulated hospital environment, the optimum cooling effect was equivalent to 3.5 °C drop in ambient temperature and 6 % decrease in ambient relative humidity. It will not only enhance user’s comfort and performance but potentially reduce the heating, ventilation and air conditioning (HVAC) energy consumption by 12 % ∼ 30 % in building environments.

Wetting trend in Northwest China reversed by warmer temperature and drier air

Northwest China has experienced a warming-wetting climate featured by increasing temperature and precipitation during the past six decades. Recent studies suggested that the climate may have shifted from wetting to drying after the 1990s if changes in energy supply were considered. However, how the change in energy supply affects the dryness remains unclear. In this study, we quantified the dryness in Northwest China based on the Standardized Precipitation Evapotranspiration Index (SPEI) which considers the impact of potential evapotranspiration estimated by the Penman-Monteith equation on dryness during 1961–2018. Then, the contributions of changes in meteorological variables (precipitation, temperature, relative humidity, wind speed, and net radiation) to the dryness changes were estimated using a detrending technique. The results indicated that Northwest China experienced a wetting period (1961–1989) and then a drying period (1989–2018). During 1961–1989, increased precipitation and slowed wind were the main drivers of the wetting trend. During 1989–2018, although the increased precipitation and decline in solar radiation favored a wetting condition, warmer temperature, drier air (decrease in relative humidity), together with rebounded wind speed offset the wetting trend and resulted in significantly increasing dryness in Northwest China. The dryness would further increase if current climate trends continue in the future, which may have important implications for water management in Northwest China.

Response of Low Flows of Polish Rivers to Climate Change in 1987–1989

The paper discusses changes in the low-flow regime of rivers in Poland, resulting from climate change that occurred between 1987 and 1989. The low-flow variability of rivers was measured with the use of the number of days with low flows (NDLF) below a threshold value, which was adopted as the 0.1 (10%) percentile (Q10) from the set of daily flows recorded in the multi-annual period 1951–2020 at 140 water gauges on 83 rivers. The analysis of the course of climate change over Poland showed that it was caused by macro-circulation conditions, controlled by changes in the intensity of thermohaline circulation in the North Atlantic (NA THC). Climate change consisted of a sharp increase in sunshine duration and air temperature, and a decrease in relative humidity after 1988. Along with the lack of changes in precipitation totals, characterized by a strong yearly variability, and an increase in field evaporation, it led to noticeable changes in the water balance. As a result, in 1989–2020, there was a significant increase in NDFL detected in about 2/3 of the area of Poland. With the change in the NA THC phase and the macro-circulation conditions, there was also a change in the spatial distribution of areas drained by rivers with increased NDFL. In 1951–1988, these included the eastern parts of Poland, while after the climate change (1989–2020), its western and south-western parts.