Air Dryness Research Articles

More than three-fold increase in compound soil and air dryness across Europe by the end of 21st century

Increases in air temperature lead to increased dryness of the air and potentially develops increased dryness in the soil. Extreme dryness (in the soil and/or in the atmosphere) affects the capacity of ecosystems for functioning and for modulating the climate. Here, we used long-term high temporal resolution (daily) soil moisture (SM) and vapor pressure deficit (VPD) data of high spatial resolution (∼0.1° × 0.1°) to show that compared to the reference period (1950–1990), the overall frequency of extreme soil dryness, extreme air dryness, and extreme compound dryness (i.e., co-occurrence of extreme soil dryness and air dryness) has increased by 1.2-fold [0.8,1.6] (median [10th,90th percentile], 1.6-fold [1,2.3], and 1.7-fold [0.9,2.5], respectively, over the last 31 years (1991–2021) across Europe. Our results also indicate that this increase in frequency of extreme compound dryness (between reference and 1991–2021 period) is largely due to increased SM-VPD coupling across Northern Europe, and due to decreasing SM and/or increasing VPD trend across Central and Mediterranean Europe. Furthermore, under the RCP8.5 (Representative Concentration Pathways 8.5) emission scenario, this increase in frequency of extreme compound dryness would be 3.3-fold [2.0,5.8], and 4.6-fold [2.3,11.9] by mid-21st century (2031–2065) and late-21st century (2066–2100), respectively. Additionally, we segregated the changes in frequency of extreme dryness across the most recent (year 2021) land cover types in Europe to show that croplands, broadleaved forest, and urban areas have experienced more than twice as much extreme dryness during 1990–2021 compared to the reference period of 1990–2021, which based on the future projection data will increase to more than three-fold by mid 21st century. Such future climate-change induced increase in extreme dryness could have negative implications for functioning of ecosystems and compromise their capacity to adapt to rapidly rising dryness levels.

Contrasting impact of extreme soil and atmospheric dryness on the functioning of trees and forests

Recent studies indicate an increase in the frequency of extreme compound dryness days (days with both extreme soil AND air dryness) across central Europe in the future, with little information on their impact on the functioning of trees and forests. This study aims to quantify and assess the impact of extreme soil dryness, extreme air dryness, and extreme compound dryness on the functioning of trees and forests. For this, >15 years of ecosystem-level (carbon dioxide and water vapor fluxes) and 6–10 years of tree-level measurements (transpiration and growth) each from a montane mixed deciduous forest (CH-Lae) and a subalpine evergreen coniferous forest (CH-Dav) in Switzerland, is used. The results showed extreme air dryness limitation on CO2 fluxes and extreme soil dryness limitations on water vapor fluxes. Additionally, CH-Dav was mainly affected by extreme air dryness whereas CH-Lae was affected by both extreme soil dryness and extreme air dryness. The impact of extreme compound dryness on net CO2 uptake (about 75 % decrease) was more due to higher increased ecosystem respiration (40 % and 70 % increase at CH-Dav and CH-Lae, respectively) than decreased gross primary productivity (10 % and 40 % decrease at CH-Dav and CH-Lae, respectively). A significant negative impact on evapotranspiration and transpiration was only observed at CH-Lae during extreme soil and compound dryness (about 25 % decrease). Furthermore, with some differences, the tree-level impact on tree water deficit, transpiration, and growth were consistent with the ecosystem-level impact on carbon uptake and evapotranspiration. Finally, the impact of extreme dryness showed no significant relationship with tree allometry (diameter and height) but across different tree species. The projected future is likely to expose these forest areas to more extreme and frequent dryness conditions, thus compromising the functioning of trees and forests, thereby calling for management interventions to increase the adaptive capacity and resistance of these forests.

Bioclimatic Conditions of the Classic Tourist Route Tashkent-Samarkand-Bukhara-Khiva in Uzbekistan

This article is devoted to assessing the bioclimatic conditions of the most popular route among foreign tourists in Uzbekistan – Tashkent-Samarkand-Bukhara-Khiva based on statistical processing of meteorological observation data for the period 2011-2020 and the use of the thermohygrometric coefficient of air dryness (THC) and Missenard’s Effective Temperature (ET). Climatic descriptions of the cities of Tashkent, Samarkand, Bukhara, and Khiva include information on the regime of air temperature, precipitation, air humidity, and cloudiness, which were used to compile the Climate-Tourism-Information-Scheme (CTIS). The results obtained show that in the cities under study, there are two seasons with the most favorable thermal comfort conditions throughout the year. In Tashkent, these are the periods April-May and September-first ten days of November, in Samarkand – March-June and September-October, in Bukhara – April-May and September-October, and Khiva – from the second ten days of April to June and from the third ten days of August to the second ten days of October.

Smoke-weather interaction affects extreme wildfires in diverse coastal regions.

Extreme wildfires threaten human lives, air quality, and ecosystems. Meteorology plays a vital role in wildfire behaviors, and the links between wildfires and climate have been widely studied. However, it is not fully clear how fire-weather feedback affects short-term wildfire variability, which undermines our ability to mitigate fire disasters. Here, we show the primacy of synoptic-scale feedback in driving extreme fires in Mediterranean and monsoon climate regimes in the West Coast of the United States and Southeastern Asia. We found that radiative effects of smoke aerosols can modify near-surface wind, air dryness, and rainfall and thus worsen air pollution by enhancing fire emissions and weakening dispersion. The intricate interactions among wildfires, smoke, and weather form a positive feedback loop that substantially increases air pollution exposure.

Lichenoindication of Urban Ecosystems of the Western Part of Azerbaijan

The lichenoindication method has been used for several decades to assess the level of environmental pollution. As a result of numerous field and laboratory studies, it has been proved that the main factor in the destruction of lichens in cities is air pollution in industrial centers. There is no doubt that the microclimate conditions (an increase in air dryness, a change in temperature, a decrease and increase in dew, a weakening of solar radiation) have a negative impact on the spread of lichens. One of the most important problems of environmental assessment of the environment is the selection of bioindicators and the assessment of tolerance. It is important to study the species composition of lichens in natural and anthropogenic ecosystems. As symbiotic organisms, lichens are of particular importance for lichenological research. Under favorable conditions, their annual growth is 1-8 mm. Lichens are deciduous, bushy grow faster than scale. The average age of deciduous and shrubby lichens is 30-80 years, some of them live up to 600 years. Lichens play an important role as a bioindicator of environmental pollution. In comparison with chemicophysical methods, the bioindication method has a number of advantages. It does not require expensive equipment and fixtures. The results are obtained by continuous observations without interfering with the processes of vital activity of the organism. The differentiating factor of species composition in urban conditions is environmental pollution.

The Growth and Physiological Characteristics of the Endangered CAM Plant, Nadopungnan (Sedirea japonica), under Drought and Climate Change Scenarios

No natural habitat of Sedirea japonica has been found in Korea for the past 20 years. This study was conducted to provide basic physiological data for the conservation strategy of this endangered plant in response to climate change. Soil fruit daylight system (SFDS) chambers were used and four treatment groups (2.6LVPD, 2.6HVPD, 8.5LVPD, and 8.5HVPD) were designed based on the RCP scenario (RCP 2.6, and 8.5) and VPD conditions (low VPD; LVPD, and high VPD; HVPD). Air dryness was induced in the HVPD groups during the daytime by increasing the atmospheric vapor pressure deficit (VPD). There was no significant difference based on the RCP scenario. However, the difference between LVPD and HVPD was considerable. Total CO2 uptake and transpiration were lower than those of LVPD due to the duration decrease of Phase I in 2.6HVPD and 8.5HVPD. There was a reduction in total biomass, leaf thickness, length, and the number of leaves. ABS/RC, DI0/RC, φD0, VK, VJ, and other chlorophyll fluorescence markers increased. φP0, RE0/RC, φE0, ψE0, φR0, RC/CS0, Sm, N, PIabs, DFabs, SFIabs, and PIabs,Total declined. Daily drought stresses impact the physiological mechanisms occurring at nighttime. The defense mechanisms against drought stress occur by conserving water by controlling the stomata, inactivating the reaction center, and increasing the dissipated energy through heat. In summary, S. japonica is flexible against drought stress.

Global Increases in Lethal Compound Heat Stress: Hydrological Drought Hazards Under Climate Change

AbstractPrevious studies seldom consider humidity when examining heat‐related extremes, and none have explored the effects of humidity on concurrent extremes of high heat stress and low river streamflow. Here, we present the first global picture of projected changes in compound lethal heat stress (Th)‐drought hazards (CHD) across 11,637 catchments. Our observational datasets show that atmospheric conditions (e.g., energy and vapor flux) play an important role in constraining the heat extremes, and that Th (32% ± 11%) yields a higher coincidence rate of global CHD than wet‐bulb temperature (28% ± 11%), driven by lower relative humidity (RH) and thus air dryness in Th extremes. Our large model ensemble projects a 10‐fold intensification of bivariate CHD risks by 2071–2100, mainly driven by increases in heat extremes. Future declines in RH, wind, snow, and precipitation in many regions are likely to exacerbate such water and weather‐related hazards (e.g., drought and CHD).

Determining transpiration coefficients of ‘Rojo Brillante’ persimmon trees under Mediterranean climatic conditions

There is scarce knowledge on what are the actual water requirements of persimmon trees (Diospyros kaki). Research on this topic is required to better adjust irrigation water supplies to the actual crop water needs. This study aimed to determine the transpiration coefficients (Kp) of persimmon ‘Rojo Brillante’ trees and assess how transpiration and Kp are influenced by environmental factors and the atmospheric demand under Mediterranean climatic conditions. This was done over the course of three growing seasons by means of sap flow measurements calibrated with whole canopy gas exchange chambers. Irrigation was applied aiming to avoid water limiting conditions for trees. This was verified by monitoring the trees’ water status across the growing seasons. Sap flow measurements were linearly and highly correlated (p < 0.001) with canopy transpiration (Ep) obtained with the whole canopy chambers, but either overestimated or underestimated it. Ep increased from April until June-July in response to canopy development and increased midday canopy light interception. There was a positive linear relationship between daily Ep, reference evapotranspiration (ETo) and solar radiation. However, a non-linear relationship was obtained between Ep and vapor pressure deficit (VPD). A positive non-linear relationship (p < 0.01) was observed between Kp (Ep / ETo in non-limited water conditions) and VPD, illustrating the low stomatal regulation that persimmon trees exhibit in response to air dryness. Kp varied over the growing seasons following the ETo pattern although showing comparatively a slighter decrease during the last part of the growing season. From June to September, Kp of persimmon ‘Rojo Brillante’ trees with a midday photosynthetically active radiation (PAR) intercepted of ~30 % ranged from 0.45 to 0.56. A strong relationship was obtained between Kp and percentage of midday intercepted PAR that can be used to estimate Kp of persimmon ‘Rojo Brillante’ trees with a range of ground canopy covers. This information is useful for deriving specific water use models for persimmon trees to be implemented in decision support systems. The monthly transpiration coefficients here provided will be useful for optimizing irrigation scheduling decisions in persimmon orchards and therefore irrigation water management.

A compound event-oriented framework to tropical fire risk assessment in a changing climate

Tropical fire activity closely follows the co-occurrence of multiple climate stressors. Yet, it remains challenging to quantify how changes in climate alter the likelihood of fire risks associated with compound events. Recent abrupt changes in fire regimes in iconic landscapes in Brazil (namely the Pantanal and Xingu) provide a key opportunity to evaluate how extremely dry and hot conditions, both together and individually, have influenced the probability of large fires. Here we quantify the relationships between climate and fire across these regions and provide evidence on the extent to which fire risk and the associated impacts could be constrained if anthropogenic global warming is limited. We investigate the burned area, differentiating between fire types according to land use (forest fires, savanna fires, farming fires and grassland and wetland fires), and derive present and future fire risks linked to multiple climate variables. We show that concurrent air dryness (high vapour-pressure deficit (VPD)) and low precipitation have driven fire occurrence in both Xingu and the Pantanal, with VPD playing a dominant role. Historical climatic change has already increased compound event-related (CE-related) fire risks of all fire types (5%–10%), and these risks are likely to increase in the future due to global warming. The likelihood of CE-related increase in fire risk may be reduced by up to 14.4% if global warming is constrained to +1.5 °C instead of +3 °C. Nevertheless, substantially increased CE-related fire risks are still expected even if restricting global mean warming to 1.5 °C, particularly in the Pantanal. We thus conclude that climate action should be coordinated with environmental protection to reduce ignition sources and promote effective conservation measures to preserve these biomes.

Surface temperatures reveal the patterns of vegetation water stress and their environmental drivers across the tropical Americas.

Vegetation is a key component in the global carbon cycle as it stores ~450 GtC as biomass, and removes about a third of anthropogenic CO2 emissions. However, in some regions, the rate of plant carbon uptake is beginning to slow, largely because of water stress. Here, we develop a new observation-based methodology to diagnose vegetation water stress and link it to environmental drivers. We used the ratio of remotely sensed land surface to near surface atmospheric temperatures (LST/Tair ) to represent vegetation water stress, and built regression tree models (random forests) to assess the relationship between LST/Tair and the main environmental drivers of surface energy fluxes in the tropical Americas. We further determined ecosystem traits associated with water stress and surface energy partitioning, pinpointed critical thresholds for water stress, and quantified changes in ecosystem carbon uptake associated with crossing these critical thresholds. We found that the top drivers of LST/Tair , explaining over a quarter of its local variability in the study region, are (1) radiation, in 58% of the study region; (2) water supply from precipitation, in 30% of the study region; and (3) atmospheric water demand from vapor pressure deficits (VPD), in 22% of the study region. Regions in which LST/Tair variation is driven by radiation are located in regions of high aboveground biomass or at high elevations, while regions in which LST/Tair is driven by water supply from precipitation or atmospheric demand tend to have low species richness. Carbon uptake by photosynthesis can be reduced by up to 80% in water-limited regions when critical thresholds for precipitation and air dryness are exceeded simultaneously, that is, as compound events. Our results demonstrate that vegetation structure and diversity can be important for regulating surface energy and carbon fluxes over tropical regions.

Retrospective survey for clinical course and aggravating factors of adolescent atopic dermatitis in two years' cohort study on first‐year university students

AbstractBackgroundRecent epidemiological studies have revealed increased numbers of adolescent subjects with atopic dermatitis, most of who experienced chronic symptoms since childhood. However, the complete clinical nature of atopic dermatitis in Japanese adolescents is poorly understood. We conducted this study to accumulate knowledge of factors contributing to protracted atopic dermatitis symptoms in adolescent subjects to avoid an unfavorable clinical outcome in these patients.MethodsOn 2013 and 2014, first‐year students at our university answered a retrospective self‐questionnaire about their demographic characteristics and past history of allergies. Answers from 6105 respondents were analyzed. Subjects with atopic dermatitis were divided into four groups according to their clinical courses, and factors potentially influencing their clinical courses were identified.ResultsNearly 16% of the students had a history of diagnosed atopic dermatitis, many of who had experienced symptoms since childhood (protracted course). Other respondents had experienced remission (32%), adolescent onset (14%), or recurrence (6%). Logistic regression analysis found that psychological stress and air dryness were apparent exacerbating factors that increased the risk of the protracted, recurrent, and adolescence courses. Furthermore, sleep loss, house dust, pollen, high temperature, and sweat were the aggravating factors associated with the protracted course alone.ConclusionsWe found that a high proportion of Japanese adolescent subjects with atopic dermatitis had experienced protracted symptoms and further identified factors that may have led to this unfavorable course. We expect that limiting these factors in this population might alleviate the subjects' chronic symptoms.

Portable ultrasonic humidifier exacerbates indoor bioaerosol risks by raising bacterial concentrations and fueling pathogenic genera.

Portable ultrasonic humidifiers are frequently used in heating rooms to ease air dryness. However, it has also posed serious health concerns such as "humidifier fever" because the bioaerosol concentration and community in the humidified space may alter quickly before the occupants could even notice. We compared the microbial proliferation rates in the humidifiers' reservoirs filled with three commonly used water types and investigated the impacts of the ultrasonic humidifiers on the temporal concentration, size distribution, and community variations of indoor bacterial and fungal aerosols during two-week humidification. The concentration of indoor bacterial aerosols increased exponentially, concentrating in the respiratory size ranges (≤1.1µm), and was proportional to the humidification level, which soon exceeded 1000CFU/m3 in one week (at RH=70%), while the fungal concentration always remained low (≤177CFU/m3 ). The indoor bioaerosol community, significantly associated with the humidifier water, was substantially distorted after humidification and dominated by the pathogenic Pseudomonas spp. (40.50%), Brevundimonas spp. (3.02%), Acinetobacter spp. (0.98%) and Legionella spp. (0.69%). Our results show that ultrasonic humidification contaminates indoor air by raising bacterial concentrations and fueling the pathogenic genera. To minimize the exposure risks, occupants should avoid long-term and excessive humidification (RH≥70%) and clean the ultrasonic humidifier weekly.

Tensile Bond Strength of Self-adhesive Flowable Composite as Pit and Fissure Sealant Bonded to the Enamel Surface in Comparison with Fissure Sealants (in vitro study)

Aims: The objectives of this study to compare the tensile bond strength (TBS) of self-adhesive Flowable composite with conventional fissure sealants. Materials and Methods : an experimental study was carried out using forty non-carious upper first premolars that were collected of orthodontic extracted teeth. The crowns separated from the roots and the buccal surface were cleaned and polished to obtain a clean enamel surface. The samples were randomly divided into 4 main groups according to the types of resin material (n:10 for each group). Group I: testing TBS for Vertise Flow, Group II: testing TBS for Prevent, Group III: testing TBS for Angie, Group IV: testing TBS for Conseal. A translucent plastic tube was fixed after acid etching application on enamel surface for 15 seconds followed by water rinsed and air dryness, the tube filled incrementally with flowable resin and fissure sealant then ready small post screws with twisted orthodontic wire gauge 0.012 inch which placed inside the tube until the serrations of the screws were embedded in the last increment and light-cured. The Samples were stored in the distilled water at room temperature for 24 hours. Tensile bond strength was measured using a universal testing machine (Electronic Elastic Strength Tester GT-C04-2, GESTER, CHINA).The values were statistically analyzed using one way ANOVA and Duncan tests. Results : A significant difference in the tensile bond strength were observed among all groups (p<0.05). Vertise Flow showed higher tensile bond strength value than fissure sealants followed by Prevent , Angie and Conseal. Conclusions: The tensile bond strength of Vertise Flow better than the fissure sealant due to the presence bond (Optibond) with etchant properties.

Indirect Economic Effects of Vertical Indoor Green in the Context of Reduced Sick Leave in Offices

Low indoor humidity has been shown to influence the transmission of respiratory diseases via air. A certain proportion of sick leave in offices is therefore attributable to dryness of air. An improvement in these conditions thus means a reduction in sick leave, which is accompanied by cost savings for companies. Vertical indoor greening has a verifiable positive effect on air humidity, especially in winter months. In this article, the correlation between improved air humidity in greened rooms and reduction of sick leave due to improved air humidity was described. The resulting indirect economic effect was determined by comparing the costs for construction, green care, and technical maintenance of indoor greenery with savings due to lower sick leave. Based on long-term measurement data on air humidity and temperature, and actual cost values for three buildings, located in Vienna, Austria, with 6 greened and 3 reference rooms without greenery, the correlation of the method was derived and finally formulated in a generalized way using dimensioning factors. Only considering the influence on air humidity, profitability of 6.6 m2 vertical greening installed in an example office with six workplaces equipped with technical ventilation and saving of two sick days already results after about 4.5 years.

Past Variance and Future Projections of the Environmental Conditions Driving Western U.S. Summertime Wildfire Burn Area.

Increases in vapor pressure deficit (VPD) have been hypothesized as the primary driver of future fire changes. The Coupled Model Intercomparison Project Phase 5 (CMIP5) models agree that western U.S. surface temperatures and associated dryness of air as defined by the VPD will increase in the 21st century for Representative Concentration Pathways (RCPs) 4.5 and 8.5. However, we find that averaged over seasonal and regional scales, other environmental variables demonstrated to be relevant to flammability, moisture abundances, and aridity—such as precipitation, evaporation, relative humidity, root zone soil moisture, and wind speed—can be used to explain observed variance in wildfire burn area as well or better than VPD. However, the magnitude and sign of the change of these variables in the 21st century are less certain than the predicted changes in VPD. Our work demonstrates that when objectively selecting environmental variables to maximize predictive skill of linear regressions (minimize square error on unseen data) VPD is not always selected and when it is not, the magnitude of future increases in burn area becomes less certain. Hence, this work shows that future burn area predictions are sensitive to what environmental predictors are chosen to drive burn area.

Amazon rainforest photosynthesis increases in response to atmospheric dryness.

Earth system models predict that increases in atmospheric and soil dryness will reduce photosynthesis in the Amazon rainforest, with large implications for the global carbon cycle. Using in situ observations, solar-induced fluorescence, and nonlinear machine learning techniques, we show that, in reality, this is not necessarily the case: In many of the wettest parts of this region, photosynthesis and biomass tend to increase with increased atmospheric dryness, despite the associated reductions in canopy conductance to CO2 These results can be largely explained by changes in canopy properties, specifically, new leaves flushed during the dry season have higher photosynthetic capacity than the leaves they replace, compensating for the negative stomatal response to increased dryness. As atmospheric dryness will increase with climate change, our study highlights the importance of reframing how we represent the response of ecosystem photosynthesis to atmospheric dryness in very wet regions, to accurately quantify the land carbon sink.

Water Hummer Technology for Soil Destruction on Dredgers

The present investigation aims to propose a solution of the problem which is connected with slurry processing during the dredger’s operation under difficult conditions. On dredgers, depending on the degree of air dryness or low ambient temperatures very often arises technical problem that creates difficulties for the crew. It is connected with the fact that soil surface layer is very dense. It is very difficult to dredge the soil during extraction under water surface or unloading from the hold of a vessel at low ambient temperatures. The top layer of the very soil is characterized by a high degree of compaction and can be destroyed in two ways only. The first way is to use very powerful mechanical equipment (percussion mechanisms, vibration equipment, etc.). This method is associated with high energy spending and its use on a vessel is technically difficult. The second way is to use the soil cutting process with the use of mechanical cutters. Dredger’s operation with the use of milling equipment is always characterized by the fact that during soil mechanical treatment there is always occurs breakage of the cutter teeth or rapid wear of the cutting surfaces. A similar problem occurs when sandy or clay soil is extracted under water, which is compacted by its properties. In investigation a non-trivial solution was used to solve the problem of destruction of the compacted soil layer during the operation of the dredger. It was proposed to use the hydrodynamic method based on water hammer as the main mechanism for the destruction of compacted soil. As a result of the interaction of the compacted soil layer and high pressurized directed water jets, good performance of the dredger can be achieved. The two-dimensional mechanism of destruction of the compacted soil layer can be described by the condition of dynamic equilibrium of the three main flows - the jet, which flows from the conical nozzle and two flows along the soil surface. For these streams, a reactive force evaluation has been performed. Destructive jets can be generated by standard marine pumps in combination with the use of water hammer. Based on the results of the experiments, it was found that the qualitative destruction of the surface layer of compacted soil occurs using two or three phases of hydraulic water hummer.

Association between early life indoor environment factors and prevalence and onset of asthma/allergic disease among preschool children in Taiyuan

TPS 752: Respiratory effects and allergies, Exhibition Hall, Ground floor, August 27, 2019, 3:00 PM - 4:30 PM Background: Indoor environment factors can influence asthma and allergic disease in preschool children but few studies are available on associations between early life exposure and incidence/remission of children’s disease in their early childhood. Methods: Data on children’s symptoms and home environment factors were collected from questionnaires completed by parents of children from 10 kindergartens in Taiyuan, China. Binary logistic regression models and reduced regression models were used to analyze associations between indoor environment factors and children’s symptoms (wheeze, rhinitis and eczema). Results: Visible mold [OR=1.60(1.24, 2.07)], window pane condensation [OR=1.22(1.02, 1.47)], moldy odor [OR=1.90(1.34, 2.87)], air dryness [OR=1.40(1.15, 1.71)] and stuffy odor [OR=1.53(1.24, 1.88)] were associated with prevalence of rhinitis. Visible mold [OR=1.53(1.12, 2.11)], air dryness [OR=1.42(1.11, 1.83)] and stuffy odor [OR=1.58(1.23, 2.04)] have association with prevalence of wheeze. Stuffy odor [OR=1.39(1.03, 1.88)] and pets [OR=1.73(1.20, 2.49)] have association with eczema in the first 2 years. Comparing the prevalence of children’s symptoms in the first 2 years and last year, visible mold [OR=1.51(1.08,2.91), 1.63(1.22,2.18), 1.92(1.13,3.24)], air dryness [OR=1.78(1.39,2.28), 1.46(1.18,1.81), 2.10(1.37,3.21)] and new furniture or renovation [OR=1.37(1.07,1.75), 1.31(1.07,1.61), 1.65(1.08,2.54)] have positive associations with the onset of children’s wheeze, rhinitis and eczema symptoms from first 2 years to last year of children, respectively. Conclusion: The results showed that exposure to visible mold can be a risk factor for both prevalence and incidence of children’s asthma/allergic symptoms. Indoor air quality (air dryness, moldy odor, stuffy odor and new furniture or renovation) can influence childhood asthma later in life. Early life exposure to mold and dampness should be avoided at home. Chemical emissions during early life from new furniture or renovation can also be a health problem.

Effects of air temperature, humidity and air pollution on fertility of birch pollen in urban environments

We studied effects of environmental factors on pollen fertility of Betula pendula Roth.) in 15 sites of the city of Barnaul (Russia, Altai Territory), differing in traffic intensity. We found that low temperature was more stressful for the development of birch pollen compared to high one. When the temperature drops below +8°C, the amount of sterile pollen in all locations significantly increased regardless of the anthropogenic load, on average exceeding 8%. With an increase in temperature of more than +10 °C, the proportion of sterile pollen also increased, but the jump was not as sharp as in cold weather. The optimum temperature for the formation of fertile pollen grains was in the range of 8–10 °С. The optimal humidity for the development of fertile pollen of B. pendula was 40–45%. The increase in air dryness led to a significant decrease in the quality of pollen grains, the proportion of sterile ones exceeded 8%. According to the transmission coefficient (Keff = 0.1514), the dominant factor in the development of sterile pollen grains of birch was the level of air pollution (concentration of carbon monoxide). Air temperature (Keff = 0.1427) and humidity (Keff = 0.1427) affected equally the quality of pollen. The proposed model makes it possible to predict the level of sterile birch pollen in the conditions of Barnaul depending on the weather conditions of vegetation and on the level of pollutants in the atmosphere.

Microleakage of Dyract AP compomers in class V preprations of deciduous teeth after air-dried versus not dried salivary contamination at the occlusal wall (in vitro study)

This in vitro study was conducted to asses the affect of salivary contamination incase of air dried or not dried (kept moist) before the application of the bonding agent(prime and bond NT) on the microleakage of Dyract AP compomers (advanceperformance) in primary molars at the occlusal wall of class V preparations andcompare it to the standardized technique of application.Sixty class V cavities were prepared in 30 teeth (exfoliated primary molars), thecavities were prepared in the middle third of the buccal and lingual surface of eachcrown and randomly divided into three groups (each group consists of 20 cavities)Group (I): air-dried after salivary contamination, Group (II): not dried after salivarycontamination (kept moist), Group (III): with out salivary contamination. After theteeth were filled, stored in distilled water for 24 hours, thermocycled, stained withbasic fuchsin dye, sectioned to record the extend of dye penetration understereomicroscope. Results revealed that there is no difference in the linearmicroleakage among groups at the occlusl wall. Although the differences were notstatistically significant, greater microleakage was found in group (I) indicating that ifsalivary contamination occur, it is better to leave the preparation moist rather thancomplete air dryness.