scholarly journals The effect of air velocity on moisture buffering

2019 ◽  
Vol 282 ◽  
pp. 02007 ◽  
Author(s):  
Valeria Cascione ◽  
Eugenio Cavone ◽  
Daniel Maskell ◽  
Andy Shea ◽  
Pete Walker
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Buffering Capacity ◽  
Climatic Chamber ◽  
Air Velocity ◽  
Speed Distribution ◽  
Velocity Correction ◽  
Air Speed ◽  
The Relationship ◽  
Moisture Buffering

Hygoscopic finishing materials improve the indoor hygrothermal comfort and air quality, as they reduce the extremes of variation in relative humidity. This property, known as moisture buffering, is related to the capacity of hygroscopic materials to adsorb and desorb moisture from the air. Air velocity plays an important role on the sorption performances of materials: increasing the air speed leads to increased moisture buffering capacity. In order to obtain comparable results, several moisture buffering protocols require the air speed to be constant and around 0.1 m/s during tests. However, those tests are usually performed in climatic chambers, where air speed cannot be controlled and the flow may not be homogenous. The aim of this study is to demonstrate, that positioning test specimens in different locations within the same chamber gives different moisture buffering value results, due to the non-homogenous air speed distribution. For this reason, air velocity has been monitored, measuring the differential pressure and air speed in different locations in a climatic chamber. Moisture buffering tests have been performed in six locations of the chamber and a correlation between the two analyses has been evaluated. The significance of this paper is to understand the relationship between air speed and moisture buffering performances, in order to determine an air velocity correction factor, which enables the moisture buffering value to be evaluated when existing protocols cannot be adhered.

scholarly journals Performance of Calcium Chloride and Silica Gel as Solid Desiccant Dehumidifiers for Indoor Air Quality

2021 ◽  
Vol 88 (3) ◽  
pp. 57-70
Author(s):  
Nur Kamila Ramli ◽  
Yusri Yusup ◽  
Christabel Lam Pei Lin ◽  
Baharin Azahari ◽  
Mardiana Idayu Ahmad
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Indoor Air Quality ◽  
Calcium Chloride ◽  
Silica Gel ◽  
Indoor Air ◽  
Airborne Bacteria ◽  
Air Velocity ◽  
Ability Test ◽  
Test Room

Desiccant materials are recently discovered as a viable alternative in dehumidification technology due to their naturally hygroscopic qualities and minimal energy requirement. This paper discusses the performance of four brand samples of selected desiccants used for dehumidification. In this study, dehumidification ability and indoor air quality (IAQ) tests were carried out. The dehumidification ability test was conducted in a controlled environmental chamber at a temperature of 25°C, relative humidity of 70%, and air velocity of 2 m/s for 45-minute session. Meanwhile, the IAQ test was carried out in a naturally ventilated test room, and six IAQ parameters (relative humidity, air velocity, air temperature, particulate matter (PM10), airborne bacteria and carbon dioxide (CO2) were studied. The IAQ test was performed for five different conditions: control, application of brand samples A, B, C and D in the test room. From this study, it was found, brand A (0.6823 g/kg) and brand B (0.6849 g/kg) had a relatively good dehumidification ability during the 45-minute dehumidification ability test compared to brand C (0.3108 g/kg) and brand D (0.3982 g/kg). The IAQ test revealed that brand A had the biggest variation in indoor-outdoor relative humidity of 13.12%, while brand D had the smallest difference of 11.83%. Brand B had the highest average PM10 concentration of 0.037 μg/m3. The airborne bacterial count for all conditions had no statistical significance, indicating the application of desiccants were not effective in reducing airborne bacteria. From this study, it can be concluded that calcium chloride (brand A and B) samples performed better than silica gel (brand C and D) samples in terms of dehumidification ability and IAQ profile.

scholarly journals Impacts of meteorological conditions on PM2.5 and PM10 pollution in Zhengzhou, China

2021 ◽  
Vol 257 ◽  
pp. 03025
Author(s):  
Rui Gao ◽  
Bairong Wang ◽  
Shunxiang Huang
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Meteorological Parameters ◽  
Meteorological Conditions ◽  
Backward Trajectory ◽  
Aerosol Pollution ◽  
Reduce Emissions ◽  
Pm2.5 And Pm10 ◽  
The Relationship ◽  
Local Emissions

Meteorological conditions play an important role in aerosol pollution. In this study, the relationships between wind, temperature, relative humidity, and aerosol concentrations (PM2.5 and PM10) in Zhengzhou from January 2016 to December 2017 were analysed. Backward trajectory model was also used to investigate the relationship between meteorological parameters and regional transport of pollutants. Significant seasonal variations can be observed in the time series of pollutants and wind, temperature and relative humidity. The simulation of backward trajectories indicated that pollutants from southeast is critical to the air quality in Zhengzhou, in addition to local emissions of pollutants. To improve the air quality in Zhengzhou, joint efforts to reduce emissions in both Zhengzhou and its southeast adjacent regions should be considered.

scholarly journals A multi-model comparison of meteorological drivers of surface ozone over Europe

2018 ◽  
Author(s):  
Noelia Otero ◽  
Jana Sillmann ◽  
Kathleen A. Mar ◽  
Henning W. Rust ◽  
Sverre Solberg ◽  
...  
Keyword(s):  
Time Series ◽  
Air Quality ◽  
Relative Humidity ◽  
Surface Ozone ◽  
Meteorological Variables ◽  
Maximum Temperature ◽  
Quality Models ◽  
The Balkans ◽  
Ozone Concentrations ◽  
The Relationship

Abstract. The implementation of European emission abatement strategies has led to significant reduction in the emission of ozone precursors during the last decade. Ground level ozone is also influenced by meteorological factors such as temperature, which exhibit interannual variability, and are expected to change in the future. The impacts of climate change on air quality are usually investigated through air quality models that simulate interactions between emissions, meteorology and chemistry. Within a multi-model assessment, this study aims to better understand how air quality models represent the relationship between meteorological variables and surface ozone concentrations over Europe. A multiple linear regression (MLR) approach is applied to observed and modelled time series across ten European regions in springtime and summertime for the period of 2000–2010 for both models and observations. Overall, the air quality models are in better agreement with observations in summertime than in springtime, and particularly in certain regions, such as France, Mid-Europe or East-Europe, where local meteorological variables show a strong influence on surface ozone concentrations. Larger discrepancies are found for the southern regions, such as the Balkans, the Iberian Peninsula and the Mediterranean basin, especially in springtime. We show that the air quality models do not properly reproduce the sensitivity of surface ozone to some of the main meteorological drivers, such as maximum temperature, relative humidity and surface solar radiation. Specifically, all air quality models show more limitations to capture the strength of the relationship ozone-relative humidity detected in the observed time series in most of the regions, in both seasons. Here, we speculate that dry deposition schemes in the air quality models might play an essential role to capture this relationship. We further quantify the relationship between ozone and maximum temperature (mo3-T, climate penalty) in observations and air quality models. In summertime, most of the air quality models are able to reproduce reasonably well the observed climate penalty in certain regions such as France, Mid-Europe and North Italy. However, larger discrepancies are found in springtime, where air quality models tend to overestimate the magnitude of observed climate penalty.

scholarly journals A multi-model comparison of meteorological drivers of surface ozone over Europe

2018 ◽  
Vol 18 (16) ◽  
pp. 12269-12288 ◽  
Author(s):  
Noelia Otero ◽  
Jana Sillmann ◽  
Kathleen A. Mar ◽  
Henning W. Rust ◽  
Sverre Solberg ◽  
...  
Keyword(s):  
Time Series ◽  
Air Quality ◽  
Relative Humidity ◽  
Central Europe ◽  
Surface Ozone ◽  
Meteorological Variables ◽  
Maximum Temperature ◽  
Quality Models ◽  
Ozone Concentrations ◽  
The Relationship

Abstract. The implementation of European emission abatement strategies has led to a significant reduction in the emissions of ozone precursors during the last decade. Ground-level ozone is also influenced by meteorological factors such as temperature, which exhibit interannual variability and are expected to change in the future. The impacts of climate change on air quality are usually investigated through air-quality models that simulate interactions between emissions, meteorology and chemistry. Within a multi-model assessment, this study aims to better understand how air-quality models represent the relationship between meteorological variables and surface ozone concentrations over Europe. A multiple linear regression (MLR) approach is applied to observed and modelled time series across 10 European regions in springtime and summertime for the period of 2000–2010 for both models and observations. Overall, the air-quality models are in better agreement with observations in summertime than in springtime and particularly in certain regions, such as France, central Europe or eastern Europe, where local meteorological variables show a strong influence on surface ozone concentrations. Larger discrepancies are found for the southern regions, such as the Balkans, the Iberian Peninsula and the Mediterranean basin, especially in springtime. We show that the air-quality models do not properly reproduce the sensitivity of surface ozone to some of the main meteorological drivers, such as maximum temperature, relative humidity and surface solar radiation. Specifically, all air-quality models show more limitations in capturing the strength of the ozone–relative-humidity relationship detected in the observed time series in most of the regions, for both seasons. Here, we speculate that dry-deposition schemes in the air-quality models might play an essential role in capturing this relationship. We further quantify the relationship between ozone and maximum temperature (mo3−T, climate penalty) in observations and air-quality models. In summertime, most of the air-quality models are able to reproduce the observed climate penalty reasonably well in certain regions such as France, central Europe and northern Italy. However, larger discrepancies are found in springtime, where air-quality models tend to overestimate the magnitude of the observed climate penalty.

scholarly journals Kontribusi Faktor Klimat di Luar Kandang terhadap Perubahan Mikroklimat Closed House dengan Panjang Berbeda pada Periode Brooder di Musim Kemarau

2019 ◽  
Vol 19 (1) ◽  
pp. 59-67
Author(s):  
Arliana Endraswati ◽  
Luthfi Djauhari Mahfudz ◽  
Teysar Adi Sarjana
Keyword(s):  
Relative Humidity ◽  
Correlation Analysis ◽  
Dry Season ◽  
Climatic Factor ◽  
Regression Equations ◽  
Air Velocity ◽  
Brooding Period ◽  
R Value ◽  
The Relationship ◽  
Microclimate Variation

ABSTRAK. Penelitian ini bertujuan untuk menguji kontribusi faktor klimat di musim kemarau terhadap kondisi mikroklimat closed house periode brooder dengan panjang kandang berbeda. Unit kandang digunakan yaitu kandang ukuran panjang 60 m dan 120 m. Pengamatan dilakukan pagi hari (05.00 WIB), siang hari (13.00 WIB) dan malam hari (21.00 WIB). Parameter makroklimat yang diamati meliputi suhu, kelembaban udara, kecepatan angin dan radiasi matahari serta kondisi mikroklimat meliputi suhu, kelembaban udara, kecepatan angin dan THI. Besaran kontribusi diukur berdasarkan keeratan hubungan dengan analisis korelasi. Koefisien korelasi yang menunjukkan hubungan cukup kuat dengan nilai r0,3, digunakan untuk membentuk persamaan regresi. Hasil penelitian menunjukkan besaran kontribusi komponen makroklimat pada pagi hari, siang hari maupun malam hari terhadap kondisi mikroklimat berupa suhu, kecepatan angin dan THI lebih besar di kandang panjang 60 m, sedangkan kontribusi makroklimat terhadap kelembaban udara mikroklimat lebih besar di kandang 120 m (p0,05). Rentang nilai r pada korelasi yaitu cukup kuat hingga sangat kuat. Hasil persamaan regresi yang terbentuk memiliki nilai determinasi R2 sangat kuat, sehingga layak digunakan sebagai prediktor. Prediktor kelembaban udara di kandang 60 m berupa kecepatan angin, kelembaban udara dan radiasi matahari makroklimat, sementara prediktor kelembaban udara di kandang panjang 120 m berupa suhu, kelembaban udara dan radiasi matahari. Simpulan penelitian yaitu kontribusi faktor makroklimat terhadap variasi kondisi mikroklimat berupa suhu, kecepatan angin dan THI pada periode brooder lebih besar di kandang 60 m daripada 120 m, sedangkan kontribusi komponen makroklimat terhadap kelembaban udara di kandang 120 m lebih besar dari kandang 60 m. (Contribution of climatic factor outside the lengths to the change of microclimate closed house with different lengths in brooder period in the dry season) ABSTRACT. This study conducted to calculate macroclimate contribution during brooding period house to different closed house length in dry season. Two broiler closed house 60 m and 120 m length here used in this research. Observed data were daily at 05.00 a.m, 1.00 p.m. and 9.00 p.m to represented microclimate condition in the morning, afternoon and night. Macroclimate parameters observed included temperature, relative humidity, air velocity, sun radiation and microclimate parameters included temperature, relative humidity, air velocity, THI. Macroclimate contribution on the microclimate was calculates based on the strength of the relationship using correlation analysis. Subsequently, regression equation formed on parameters which has r value more than 0.3. Results showed that macroclimate contributes on variation of microclimate condition such as temperature, air velocity and THI which is larger in the 60 m length than 120 m length closed house(p0.05). Macroclimate factors contributes on microclimate humidity which is larger in the 120 m than 60 m closed house length. The range of correlation r value are strong enough to very strong. Regression equations confirmed to having strong determination R value, thus can be used as a predictor of microclimate variation. Predictor parameter of microclimate humidity in 60 m closed house consist of air velocity, relative humidity and sun radiation, whereas microclimate humidity in 120 m closed house predictors consist of temperature, relative humidity and sun radiation. In conclusion macroclimate that contributes to the microclimate variation consist of temperature, air velocity and THI, which is larger in 60 m than 120 m closed house. Meanwhile, macroclimate that contributes to the microclimate humidity is larger in 120 m than 60 m closed house.

EL NINO RELATED CLIMATE AND DENGUE FEVER CASES IN JEDDAH, SAUDI ARABIA

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
MASROOR ALI KHAN ◽  
KHALID AL GHAMDI ◽  
JAZEM A. MEHYOUB ◽  
RAKHSHAN KHAN
Keyword(s):  
Relative Humidity ◽  
Dengue Fever ◽  
El Niño ◽  
Significant Relationship ◽  
El Nino ◽  
Climate Data ◽  
Light Traps ◽  
Mosquito Abundance ◽  
Dengue Transmission ◽  
The Relationship

The focus of this study is to find the relationship between El Nino and dengue fever cases in the study area.Mosquito density was recorded with the help of light traps and through aspirators collection. Climate data were obtained from National Meteorology and Environment centre. (Year wise El Nino and La Nina data are according to NOAA & Golden Gate Weather Services). Statistical methods were used to establish the correlation coefficient between different factors. A high significant relationship was observed between Relative Humidity and Dengue fever cases, but Aedes abundance had no significant relationship with either Relative humidity and Temperature. Our conclusion is that the El Nino does not affect the dengue transmission and Aedes mosquito abundance in this region, which is supported by earlier works.

scholarly journals Managing pH of Organic Matrices and New Commercial Substrates for Ornamental Plant Production: A Methodological Approach

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 851
Author(s):  
Sonia Cacini ◽  
Sara Di Lonardo ◽  
Simone Orsenigo ◽  
Daniele Massa
Keyword(s):  
Methodological Approach ◽  
Buffering Capacity ◽  
Ornamental Plant ◽  
Plant Production ◽  
Climatic Chamber ◽  
Step Procedure ◽  
Coir Dust ◽  
Organic Matrices ◽  
Substrate Mixtures

Professional peat-free substrates for ornamental plant production are increasingly required by nursery growers. Most promising materials are green compost, coconut coir dust, and woody fibre, used alone or in mixtures. One of the major concerns is pH, usually higher than optimal. In this work, a method based on a three-step procedure was adopted to acidify three organic matrices alone or in mixtures and to individuate the most suitable product, between iron(II) sulphate 7-hydrate and elemental sulphur chips. Firstly, the determination of the buffering capacity by dilution with sulphuric acid was carried out to determine dosages. Afterwards, an incubation trial of 84 (iron(II) sulphate) or 120 days (sulphur chips) was conducted on matrices and substrate mixtures with calculated doses in a climatic chamber maintained at 21 °C. Iron(II) sulphate resulted not suitable because it caused a rapid, but not lasting, pH lowering and an excessive electrical conductivity (EC) increase. Sulphur chips could instead guarantee an adequate and lasting pH lowering. These results were then validated in the open field trial on matrices and substrates. The proposed acidification methodology could be considered in developing new substrates, but the rapidity of pH acidification and EC increase on plant and mineral nutrition should be further investigated.

scholarly journals Spatiotemporal Variation of the Burned Area and Its Relationship with Climatic Factors in Central Kazakhstan

2021 ◽  
Vol 13 (2) ◽  
pp. 313
Author(s):  
Yongfang Xu ◽  
Zhaohui Lin ◽  
Chenglai Wu
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Central Asia ◽  
Climatic Factors ◽  
Spatiotemporal Variation ◽  
Lower Atmosphere ◽  
Burned Area ◽  
Circulation Index ◽  
Precipitation Anomalies ◽  
The Relationship

Central Asia is prone to wildfires, but the relationship between wildfires and climatic factors in this area is still not clear. In this study, the spatiotemporal variation in wildfire activities across Central Asia during 1997–2016 in terms of the burned area (BA) was investigated with Global Fire Emission Database version 4s (GFED4s). The relationship between BA and climatic factors in the region was also analyzed. The results reveal that more than 90% of the BA across Central Asia is located in Kazakhstan. The peak BA occurs from June to September, and remarkable interannual variation in wildfire activities occurs in western central Kazakhstan (WCKZ). At the interannual scale, the BA is negatively correlated with precipitation (correlation coefficient r = −0.66), soil moisture (r = −0.68), and relative humidity (r = −0.65), while it is positively correlated with the frequency of hot days (r = 0.37) during the burning season (from June to September). Composite analysis suggests that the years in which the BA is higher are generally associated with positive geopotential height anomalies at 500 hPa over the WCKZ region, which lead to the strengthening of the downdraft at 500 hPa and the weakening of westerlies at 850 hPa over the region. The weakened westerlies suppress the transport of water vapor from the Atlantic Ocean to the WCKZ region, resulting in decreased precipitation, soil moisture, and relative humidity in the lower atmosphere over the WCKZ region; these conditions promote an increase in BA throughout the region. Moreover, the westerly circulation index is positively correlated (r = 0.53) with precipitation anomalies and negatively correlated (r = −0.37) with BA anomalies in the WCKZ region during the burning season, which further underscores that wildfires associated with atmospheric circulation systems are becoming an increasingly important component of the relationship between climate and wildfire.

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