جستجوی مقالات مرتبط با کلیدواژه "relative humidity" در نشریات گروه "پزشکی"

Studies have demonstrated that teaching carries a substantial burden of health risks. Prevalent health issues among teachers include asthma, respiratory diseases, musculoskeletal problems, and mental disorders. These problems can be attributed to the specific attributes of their work environment. Consequently, this study aims to investigate the correlation between air quality within educational establishments and the overall health of teachers.

This systematic review aims to examine the impact of temperature, humidity, and ventilation rates within educational environments on teachers’ health status and thermal comfort. Relevant studies were searched for using the PubMed and Web of Science databases, employing keywords such as teacher, temperature, humidity, ventilation, school, classroom, health symptoms, and thermal comfort (2000-2022). The inclusion criterion was that articles examined teachers’ health and comfort with temperature, relative humidity, and ventilation of the educational place.

Out of the 103 articles found in the initial search, 13 articles were finally reviewed. Six studies investigated the voice abnormalities of teachers due to various factors (including temperature, relative humidity, and the ventilation rate of the educational place) and found that these abnormalities were affected by these factors. Two studies explored the relationship between the prevalence and exacerbation of respiratory symptoms and quality parameters of the indoor environment of educational places. Additionally, five studies investigated the relationship of air quality parameters of educational places with common non-specific symptoms among teachers.

Teachers frequently experience symptoms such as voice disorders, respiratory difficulties, allergies, and other nonspecific ailments, which may be associated with the quality parameters of the indoor environment in educational settings. These parameters include temperature, humidity, and ventilation rate. Consequently, controlling and regulating these parameters within the recommended values can help prevent the onset or exacerbation of these symptoms.

Objective (s): Thermal comfort consists of three parameters: temperature, humidity and airflow. It is one of the important factors on maintaining health and optimizing the performance of students in the classrooms. According to the climatic conditions of Qom province and the importance of thermal comfort in schools, this study aimed to assess classroom thermal conditions in primary schools. This cross-sectional study was conducted in primary schools in Qom province in 2013. Relative humidity was measured using a CASELLA hygrometer and temperature was measured using a mercury thermometer at five points in each classroom at one meter height from ground level. The measurements were performed between 9 AM to 15 PM in the spring. Thermal discomfort was measured using the thermal discomfort index (DI). All statistical analysis performed using SPSS software version 16. Overall 115 classrooms were assessed. In this study, mean temperature was equals to 27.42±2.84°C. The mean of relative humidity was 30.4±7/43% and mean of the DI was 22.46±1.72°C. In 17.4% of classrooms the DI was less than 21°C, in 60% of classrooms was 21-24°C and in 22.6% of classrooms was 24-27 °C. As a result only in 17.4% of classrooms thermal comfort conditions was favorable for students. In order to increase thermal comfort level in primary schools and educational environments, especially in tropical areas such as Qom province, appropriate actions are recommended.

Students in the elementary school they are a vulnerable group. Creating healthy environment has a very important effect on their health، and improves their performance. Physical factors in the classroom are one of the major factors contributing to the protection and promotion of children''s health. This study aimed to evaluate the physical factors including lighting، temperature and humidity as important environmental factors in primary schools. This cross-sectional study was done in 2013 in 115 classrooms in Qom province. Illumination was measured at the central stations with dimensions of 2×2 meters in 24 inches height an above ground level. Relative humidity and temperature measured in five points of each class in one meter height a above ground level. All measurements were done between 9 am to 15 pm in spring. The results were analyzed using SPSS software. The results showed that the minimum national standard was not supplied in 13% of the classes. The average of illumination was between the minimum and recommended standard in 68. 7% of classes. The temperature in 15. 7% of the classes was in the recommended range temperature. The average of relative humidity was 30. 43%. Both temperature and relative humidity were in the standard range only in 7% of studied classrooms. In a large number of classes in elementary schools، some of the physical factors affecting the health and performance of students were not favorable. So، it required proper appropriate planning to improve the conditions.

Aflatoxin contamination might occur due to the improper storage conditions of harvested pistachios. Different environmental factors affect the fungal growth and mycotoxin production as the harmful secondary metabolites. Improved storage conditions can be effective to prevent the contamination of pistachios. Environmental factors consisting of kernel moisture content, relative humidity, temperature, water activity and fungi and pests might affect the contamination of pistachio. These were studied in 47 stores and warehouses in the cities of Kerman, Sirjan, Zarand and Rafsanjan regions at three month intervals for the storage period of 12 months. The levels of water activity and kernel moisture content in this study ranged from 0.12 to 0.46 and 3.1 to 5.3 (%), respectively. In most stores, the average of relative humidity ranged from 24 to 26 % with minimum and maximum values of 13.7 and 36.5 respectively and average temperature of 23.3 to 26.1 ZC. On the other hand, observed low levels of kernel moisture content and water activity remained at a constant level for most sampling times. These results indicated that equilibrium moisture content was not in favor of Aspergillus flavus growth and aflatoxin production. The observation also showed that the frequency of storage pest contamination was less than 1% and Aspergillus contamination varied from undetectable to 1 %. The stores or warehouses conditions concerned with pistachio in Kerman province are not in situations to create and promote fungal growth and aflatoxin production.

One of the main problems of bread industry is waste of these products. But today the availability of packaging film with a wide range of physical and chemical properties could reduce the amount of waste. It seems that by choosing an appropriate packaging and management environment of packed samples, it is also the shelf life and quality of gluten-free bread would be increased. In this study, the effect of temperature (10 and 25°C), relative humidity of storage (50 and 75%), and type of wrapper packaging (modified polypropylene (OPP), polyethylene terephthalate, aluminum, low density polyethylene (PAP), polyethylene terephthalate, polyethylene terephthalate, and low density polyethylene (PPP)) in order to maintain the quantity and quality of gluten-free sorghum bread was evaluated. In order to measure the crust color, Image J software was used. With increasing temperature and decreasing relative humidity, the moisture content, water activity, L* value, b* value, and overall acceptability were decreased and the firmness and a* value was increased. However, PAP, PPP and OPP packaging had, respectively, the best performance to maintain the quality characteristics of sorghum gluten free bread specially postpone the staling rate. Using the appropriate packaging film and storage in optimal conditions, in addition to maintaining the qualitative and quantitative characteristics of the final product, platitude/staling is one of the most problems in getting a fresh product to the celiac disease is reduced.

Benzene is one of the most widely used volatile organic compounds showing severely adverse effects on human health. Removing benzene from the airflow or controlling its amounts، is one of the issues put to discussion in the field of environmental engineering. The objective of this study was to examine the efficacy of the Ultraviolet-C (UV-C) radiations on removing benzene from the airflow under conditions of varying humidity and reaction time in the UV/O3 process.

This was an experimental study which was performed on a laboratory scale. The testing and measurement system included an air pump، an injection pump، a mixing chamber، a rotameter، an ozone generator، a heater، an impinger، and a steel reactor with 45 cm long، and with a net volume of 1. 35 L in which a 15-watt UV-C lamp with a wavelength of 254 nm was placed. Different concentrations of benzene were continuously exposed to the UV/O3 process under varying conditions of reaction time and humidity. The concentrations of benzene before and after exposure to the treatment process were measured taking aforementioned factors into account. The data were analyzed using descriptive and inferential statistics and three-way ANOVA test.

The results demonstrated that increasing the humidity levels up to 60% led to an increase in the efficacy of UV-C in the removal of benzene، while this efficacy decreased at humidity levels above 60%. Additionally، the findings indicated that increasing the reaction time can lead to the highest benzene removal rates in the presence of humidity (13. 2%، P < 0. 001).

Given the improvement in the efficacy of benzene removal as a result of the simultaneous use of UV and humidity، and the effects of increased reaction times in a process involving the simultaneous use of the UV rays and relative humidity، it can be concluded that the use of UV-C rays in an airflow containing humidity levels of 50% to 60% can have a positive potentiating effect on the efficacy.

Personal protective equipments (PPE) are common equipments for control of workers exposure to harmful agents in work environment. Regarding to the critical role of the filter collection efficiency under hazardous conditions such as exposure to carcinogen materials, this study was performed to determine the effect of different factors on efficiency of respirator filters in removing hexavalent chromium mist. In this quasi-experimental study, homogenous chromium mist at different conditions (concentration 1.25 and 2.5 mg/m3, relative humidity 50 and 80%, and temperature 0-5 and 35-40 oC) passed through two types of respirator filters (MSA and Spasciani). All samples (n= 384) were collected, using NIOSH 7600 test method at upstream and downstream of respiratory filters, simultaneously and analyzed, using an atomic absorption spectrometer and inductively coupled plasma (ICP), respectively. Although type of filter had significant effect on hexavalent chromium mist removal, the ANOVA test results indicated that the increase of chromium mist concentration and relative humidity resulted a significant decrease in removal efficacy 0.53% and 0.42%, respectively (p<0.001). The temperature had not significant effect on filter efficiency. Increase of hexavalent chromium mist concentrations and relative humidity has significant negative effect on collection efficiency of respirator filters.