• Particle and aerosol research
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• v.20 no.2
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• pp.25-33
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• 2024

Suspension of particulate matter (PM) in indoor spaces, which increases risk of negative impact on occupants' health from exposure to PM, is influenced by humidity level in the indoor environment. The goal of this study is to investigate the property of size-resolved PM suspension in accordance with the relative humidity through simulation chamber experiments which reflect the indoor environmental characteristics. The relative humidity of simulation chamber is adjusted to 35%, 55% and 75% by placing it inside a real-size environmental chamber which allows artificial control of climatic conditions (e.g., temperature, humidity). At the respective humidity conditions, PM suspension concentration caused by occupant walking is analyzed by particle size (0.5-0.8, 0.8-1.0, 1.0-2.5, 2.5-3.5, 3.5-4.5, 4.5-5.5, 5.5-8.0, and 8.0-10 ㎛). Irrespective of the particle size, the suspension concentration reveals a decreasing tendency as the relative humidity increases. Furthermore, a one-way analysis of variance (one-way ANOVA) test statistically verifies that the suspension concentration has a significant difference depending on the indoor relative humidity level. In addition, as the relative humidity increases, a proportion of the suspended particles with 0.5-2.5 ㎛ diameter decreases, while that with 2.5-3.5 ㎛ diameter increases. The reason is considered that the humidity has an effect on adhesion and coagulation forces of the particles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.39-40
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• 2017

This study aims to evaluate the humidity control performance of low-priced generic ceramic panels that are used to control humidity. Temperature and humidity are monitored by using 'Living Lab' and the change of indoor relative humidity is measured and analyzed. According to the results of the study, the indoor relative humidity of rooms installed with ceramic panels was found to be low compared to that of living rooms by 2.2%RH (test period) and 3.2%RH (daily). In the case of maximum relative humidity, rooms installed with ceramic panels were found to be low by 6.9%RH. The results are attributable to the humidity absorption of ceramic panels. Accordingly, future ceramic panels need the improvement of performance and an appropriate construction area should be derived depending on indoor space.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.33 no.12
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• pp.81-90
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• 2017

This study was conducted to investigate the thermal environment status of nursery rooms in workplace daycare centers in Jeju and propose measures to improve their indoor physical thermal environment. For this purpose, measurements were performed in the winter indoor physical environment of 51 nursery rooms in 11 workplace daycare centers and a psychological evaluation survey on the thermal environment of nursery rooms was conducted for 70 nursery teachers. The investigation was carried out over 11 days in January 2017. The results are as follow. The average indoor temperature of the nursery rooms was $21.3^{\circ}C$($18.7-23.8^{\circ}C$) and the indoor temperatures of 47 nursery rooms (92.9%) were higher than the environmental hygiene management standard for domestic school facilities ($18-20^{\circ}C$). The average relative humidity was 33.9% (16.4-56.0%), and 37 nursery rooms (86.3%) showed a lower average relative humidity than the standard (40-70%). The average absolute humidity was $9.1g/m^3$ ($4.7-13.6g/m^3$), which was lower than the standard for preventing influenza ($10g/m^3$). When the indoor temperature and humidity of the nursery rooms were compared with international standards, it was found that 85% or more of the 51 nursery rooms maintained appropriate indoor temperatures, but 40-50% of the nursery rooms maintained a low humidity condition. Therefore, they need to pay attention to maintaining the appropriate humidity of the nursery room to keep the children healthy. The average indoor temperature of the nursery rooms showed a weak negative correlation with the average relative humidity. The indoor temperature had a significant effect on the relative humidity: a higher indoor temperature resulted in lower relative humidity. Regarding the fluctuations in the average indoor temperature of the nursery rooms during the day, in daycare centers that used floor heating, the indoor temperature gradually increased form the morning to the afternoon and tended to decrease during lunch time and the morning and afternoon snack times, due to ventilation. The daycare centers that used both floor heating and ceiling-type air conditioners showed a higher indoor temperature and greater fluctuations in temperature compared to the daycare centers that used floor heating only. In the survey results, the average value of the whole body thermal sensation was 3.0 (neutral): 32 respondents (62.7%) answered, "Neutral", Which was the largest number, followed by 21 respondents (30%) who answered, "Slightly hot" and 17 respondents (24.2%) who answered, "Slightly cold." Twenty-nine respondents answered, "Slightly dry," which was the largest number, followed by 28 respondents (54.9%) who answered, "Neutral" and 10 respondents (19.6%) who answered, "Dry." The total number of respondents who answered, "Slightly dry" or "Dry" was large at 39 (56.4%), which suggests the need for indoor environment management to prevent a low-humidity environment. To summarize the above results about the thermal environment of nursery rooms, as the indoor temperature increased, the relative humidity decreased. This suggests the effect of room temperature on the indoor relative humidity; however, frequent ventilations also greatly decrease the relative humidity. Therefore, the ventilation method and the usage of air conditioning systems need to be re-examined.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.642-646
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• 1999

Factors governing the rate of heat exchange comprise the air temperature, the speed of air movement, relative humidity, and relation indoors. Recently, there are many researches on the transient analysis of indoor environmental factors such as the dry bulb temperature, relative humidity and air velocity in miniature models. The purpose of this study is to measure the environmental factors and to analyze and evaluate the characteristics of indoor environment with the different envelope structures using a granite dome model. According to the variation of humidity, the state of interior relative humidity for clay model has an equal tendency, although a little range of variation is shown in comparison to the cement model.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.2
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• pp.34-38
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• 2002

This studies were performed to determine the effects of indoor relative humidity conditions on the growth of Arachniodes aristata and Pyrrosia lingua in native fern and investigate an applicable possibility of indoor plants. The response of Arachniodes aristata and Pyrrosia lingua was evaluated in growth chamber (KG-8407-87) to 3 relative humidity and 3 soils. Relative humidity was applied to 25%, 50%, 90%; soils were prepared based on soil mixture(SM), top field soil(TF), masa soil(MS). Results of experiments are as follows ; 1. Under a low humidity condition, such as 25%, Water contents, chlorophyll content, ornamental value of Arachniodes aristata and Pyrrosia lingua decreased much more a 50-90%. 2. The growth of Arachniodes aristata were best in pots under a soil mixture(SM) but Pyrrosia lingua were field top soil(FT) under 25%. It seemed that Pyrrosia lingua due to tolerance of desiccation more than Arachniodes aristata. Though these studies, coefficient of relative humidity and soil was plays an important role in Arachniodes aristata and Pyrrosia lingua growth in indoor environments.

• Journal of Animal Environmental Science
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• v.3 no.2
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• pp.77-85
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• 1997

Recently, local swine producers are rapidly adopting the indoor production system which developed in foreign countries. However, this imported system is reported as not functioning properly because of different climate conditions. The objective of this project was to investigate the environment characteristics of a windowless delivery swine building. The parameters studied were the heating and cooling loads, the daily changes of indoor temperature and relative humidity, the horizontal and the vertical distributions of indoor temperature, and the effect of mist cooling on indoor temperature. From this study, the following are founded : 1. The maximum cooling and heating loads were - 317.0kcal/㎡$.$h and 336.5kal/㎡$.$h in summer and in winter. The large loads seems to be on account of inappropriate operations of ventilating fans. 2. The daily variations of relative humidity in indoor were smaller than those in outside. Those values both in summer and in winter as relative humidities in door was lower than optimum for growing pigs, the additional humidifier might be helpful to increase the relative humidity in indoor. 3. The horizontal distribution of the indoor temperature was found to be uniform in the variation range of 1$^{\circ}C$. 4. The vertical distribution of the indoor temperature was not found to be uniform; the temperature of upper part was higher than that of slot part. 5. Average values of indoor temperature became lower by 3$^{\circ}C$ by mist cooling. But the variation of temperature was found to be larger; The middle part of the room was cooled down, but the corner part of the room was not affected by misting due to uneven nozzle configuration.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.89-98
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• 2002

This study was taken in general hospital, hotel, shopping center, underground cafe, school, house, for the purpose of investigating the distribution of indoor radon concentration in urban area, by E-PERM which approved U.S. EPA, between August and November 1999. There are two sampling Places were exceed 148 ㏃/㎥(4 pCi/L; U.S EPA remedial level), difference mean is 24.0㏃/㎥ when compared with underground vs. aboveground indoor radon concentration in the same building and ratio is 1.6, so underground area is higher than aboveground (p<0.05). Influencing factors were examined. They related to the location of sampler(detector) open or near the door is lower radon concentration than inside portion, which explains probably open area has better ventilated air and dilutes indoor radon concentration. Temperature has a negative relationship (p<0.05) with indoor radon concentration and relative humidity has a positive (p<0.05) Simultaneously to investigate water radon concentration, collected piped-water and the results were very low, which is the same in piped-water concentration other countries. In conclusion, underground indoor radon concentration is higher than aboveground. Concentration was related to sampling spot, open portion is lower than inside. Higher the temperature, lower the indoor radon concentrations. On the other hand higher the relative humidity, higher the indoor radon concentrations. Indoor radon concentration is influenced by sampling point, temperature, relative humidity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.6
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• pp.599-607
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• 2004

The purpose of this study is to reevaluate the performance of Hanji as an architectural material. Hanji has good things in controlling indoor space comfortably. Particularly, ability of controlling humidity of Hanji affects indoor space comfort and human health. The major focuses of this experimental research are (1) how much of water vapor passes through Hanji, (2) how much of water vapor is absorbed into Hanji. In the first case, indoor humidity is higher than outdoor humidity. In this case, approximately 38 g of water vapor passes through Hanji 1, genarally utilized in window paper (Changhoji), per square meter in one hour. And approximately 4 g of water vapor is absorbed into Hanji 2, genarally utilized in wallpaper, per square meter. In the second case, outdoor humidity is higher than indoor humidity. In this case, Hanji passes water vapor to inner space at first, but when indoor relative humidity reach approximately 66%, although outdoor humidity is higher than indoor humidity, water vapor doesn't pass through Hanji. If Hanji is utilized in window material and wallpaper, indoor space is maintained comfortably without mechanical devices in humidity control.

• Land and Housing Review
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• v.5 no.4
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• pp.291-296
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• 2014

The apartment buildings were hard to emission of water vapor by reduced infiltration. The purpose of this study was to investigate the generation of indoor temperature and humidity in the recent construction of small size apartment buildings. The temperature and humidity were measured in 3 apartments in Seongnam and Daejeon city. During the winter indoor temperature and relative humidity were measured ranged from 20 to $24^{\circ}C$ and 40 to 60%. Generated humidity caused by various characteristics of the residents, rather than external influences. Compare daytime (6:00 to 22:00) and nighttime (22:00 to 6:00), the temperature is low and absolute humidity is high at nighttime. Condensation is likely to occur at nighttime. Using the cumulative relative frequency and absolute humidity, small apartments design criteria (temperature, relative humidity) can be set.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.1
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• pp.71-76
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• 2001

Factors governing the rate of heat exchange comprise temperature, air velocity, relative humidity, and relation indoors. Recently, there are many researches on the transient analysis of indoor environmental factors such as dry bulb temperature, relative humidity and air velocity in miniature models. The purpose of this study is to measure the environmental factors and to analyze and evaluate the characteristics of indoor environment in different envelop structures using granite dome models. The interior relative humidity is constant regardless of exterior humidity although a little range of variation is shown in comparison to the cement model.