• 한국환경보건학회지
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• 제40권1호
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• pp.10-16
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• 2014

Objectives: This pilot study assessed secondhand smoke (SHS) exposure in smoking and non-smoking nightclubs in Seoul, Korea by measuring the concentration of particulate matter smaller than $2.5{\mu}m$ ($PM_{2.5}$). Methods: This comparative study was conducted in three nightclubs in Seoul. While one non-smoking nightclub was measured on weekdays and weekends, different smoking nightclubs were measured on weekdays and weekends. The concentration of $PM_{2.5}$ was observed using a real-time monitor over an average of three hours. The number of people in the clubs was also estimated. Settled dust was collected in a smoking and a non-smoking nightclub and analyzed for NNK concentration. Results: The $PM_{2.5}$ concentration in the smoking nightclubs was higher than those found in the non-smoking nightclub by 26 times on weekdays and three times on weekends. Indoor $PM_{2.5}$ concentration was correlated with the number of people in the smoking nightclubs. Relatively high $PM_{2.5}$ concentration was observed in the non-smoking nightclub on weekends. NNK concentration in the smoking nightclub was 7 times higer than in the non-smoking nightclub. Conclusion: Smoking in nightclubs caused high $PM_{2.5}$ concentration. Although the non-smoking nightclub had a lower $PM_{2.5}$ concentration, $PM_{2.5}$ concentration on weekends was higher due to the smoking room. Complete prohibition of smoking in nightclubs can protect patrons from secondhand smoke exposure.

• 대한방사선기술학회지:방사선기술과학
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• 제40권1호
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• pp.127-134
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• 2017

본 연구는 실내 라돈 가스의 농도를 낮추기 위한 방법을 찾기 위해 건물의 준공연도, 건물의 용적, 환기 세 가지 변수에 따른 실내 라돈 농도를 비교, 측정하여 그 영향을 알아보고자 한다. 측정은 1973년에 건축이 되었고, 2011년에 증축이 된 건물의 6층을 대상으로 용적이 서로 다르고 준공연도가 1973년과 2011년인 6개의 강의실을 측정하였다. 준공연도에 따른 라돈농도를 비교하기 위해 4개의 강의실을 선정하였고, 용적에 따른 라돈농도를 비교하기 위해 준공연도가 같고 용적이 다른 강의실을 선정하였고, 환기에 따른 라돈농도를 비교하기 위해 6개의 강의실의 폐쇄와 환기를 시행하였다. 결과적으로 준공연도에 따른 라돈농도는 최근에 지어진 건물에서 라돈농도가 최대 4배 높게 나타났으며, 용적에 따른 라돈농도는 용적이 작을수록 높게 나타났다. 환기에 따른 라돈농도의 변화는 폐쇄 시보다 환기를 할 경우 약 80%의 감소율을 보였다. 특히, 준공연도가 최근이면서 용적이 작을수록 라돈농도가 높게 검출되었고, 세 가지 변수 중 환기가 라돈농도 감소에 가장 큰 영향을 끼쳐 라돈에 의한 피폭감소 효과를 기대할 수 있을 것으로 사료된다.

• 대한기계학회논문집B
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• 제30권1호
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• pp.57-66
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• 2006

The experimental and the numerical study was performed on the comparison of thermal comfort(TC) and indoor air quality(IAQ) in the lecture room for cooling loads when the operating conditions are changed. PMV value and $CO_2$ concentration of the lecture room were measured and compared with the numerical results. The numerical results showed a good agreement with the experimental one and then the numerical tool was used to analyze thermal comfort and IAQ for a couple of operating conditions. As a result it was found that the increment of the discharge angle of system air-conditioner makes TC uniformity worse, but rarely affects IAQ. Also TC and IAQ were hardly affected by the variation of the discharge airflow. Finally it turned out that TC is merely affected by the increment of the ventilation airflow, but the average $CO_2$ concentration can be satisfied with Japanese IAQ standards of classrooms when the ventilation airflow is more than $800m^3/h$ in this study.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.965-968
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• 2007

Two major parameters, i.e. carbon dioxide ($CO_2$) and particulate matters smaller than $10{\mu}m\;(PM_{10})$, were selected as the index pollutants in managing indoor air quality. The former pollutant, $CO_2$, is the index that shows the ventilation status and is exhaled by passengers when they breathe in train or subway. It is generally known that high $CO_2$ concentration in the vehicle may be decreased by insufficient air-tightening vehicle bodies and the air is ventilated when vehicles stop at the station and doors open. However, there is no established proof or quantitatively identified data on how much the $CO_2$ concentration is reduced when ventilation is done while doors are opened. In this study, $CO_2$ concentrations were measured in 6 lines of Korail and one line of Seoul Metro subway linesand a theoretical approach was takento predict the changing trend of $CO_2$ concentrations during the operation of vehicle by using $CO_2$ dilution factor through natural ventilation. As a result, the change could be quantified and it was found that app. 35% of indoor $CO_2$ was removed through natural ventilation.

• 설비공학논문집
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• 제25권9호
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• pp.506-515
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• 2013

The PFT (PerFluorocarbon Tracergas Technique) is of advantage to field surveys for evaluating the ventilation condition, due to its simplicity and convenience. On the other hand, it requires researchers to make some additional considerations that include uncertainties, such as the substance concentration distribution in indoor air, representativeness of a sampler, deviation of emission sources, and analysis error. In this study, the PFT and $CO_2$ tracer gas methods were applied simultaneously, to evaluate the accuracy of PFT on six ventilation conditions in the three-storied detached house. The air exchange and the outdoor air introduction a between and into zones were measured. As the results, deviations of PFT concentration distributions were observed at a sufficiently low level for an accurate determination for a house where the interior height was large, and there were relatively many partition walls. However, when a uniform airflow appeared in the indoor air, it was also validated that the indoor air would be exhausted without sufficient mixing, and consequently the measurement error of the PFT would be large.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.21-26
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• 2005

We performed the numerical analysis on the characteristics of indoor air quality and local supply index with a variation of supply · exhaust airflow rate. We analyzed the local supply index and carbon dioxide concentration at the room and breathing zone with respect to the variation of the supply · exhaust airflow rate. From the numerical results, we found that local supply index was affected but carbon dioxide concentration was hardly affected by the variation of the airflow rate in the room. And we also knew that carbon dioxide concentration was raised in despite of the increment of the supply airflow rate in the breathing zone. After this study it is necessary to analyze the local exhaust index when we evaluate the state of the ventilation in the room.

• 설비공학논문집
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• 제30권3호
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• pp.116-122
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• 2018

The purpose of this study was to confirm the effects of flush-out in the reduction of formaldehyde concentration in newly built residential buildings. The field measurements were conducted on two complexes of multi-residential buildings which are located in the suburban area of Seoul. About eight samples of residential buildings were selected to measure the changes in formaldehyde concentrations after flush-out from the two apartment complexes. The concentration of formaldehyde was measured using DNPH cartridge and HPLC. From the results of the field measurements, it was established that indoor formaldehyde concentration decreases 27.6~54.2% in the samples after flush-out. The number of days that the flush-out were conducted was noted to have no significant influence on the reduction rate of formaldehyde concentration when the flush-out continued more than 7 days. The comparison with Bake-out showed that flush-out also can reduce formaldehyde in newly built buildings as same levels of it.

• 설비공학논문집
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• 제19권2호
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• pp.142-148
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• 2007

The purpose of this study is to suggest the effective ventilation strategies and control methods that can minimize energy cost maintaining acceptable IAQ level in apartment house. The effects of the air-cleaning and heat-recovery ventilation system on IAQ under various operating conditions are investigated based on the experimental and CFD analyzed results. The results can be summarized as follows. (1) When a ventilator is not operated, the concentration of several pollutants may highly show in the house even though environment-friendly building materials are applied. Therefore, a mechanical ventilation system is required to obtain proper ventilation. (2) The pollutant concentration is noticeably deceased under air-cleaning/ventilation mode of air-clinic system, however, pollutant of kitchen is stagnant, because fresh air is not carried into the kitchen. (3) When air-clinic system is only equipped at master bedroom and living room, the system does not effectively deliver fresh air throughout the whole house, and then high pollutant concentration is obtained in each room. In contrast the average pollutant concentration meets the guideline when air-clinic system is installed at each room. (4) The air-cleaning/ventilation mode significantly affects on room ventilation in comparison with ventilation mode only.

• 한국환경보건학회지
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• 제37권3호
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• pp.193-200
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• 2011

Objective: The purpose of this study is to compare and analyze the level of exposure to volatile organic compounds for different kinds of households in apartments or houses and analyze the relation between atopy-related symptoms and concentration of volatile organic compounds in order to improve indoor air quality and start to build a process to prevent environmental diseases. Method: From July 2010 to November 2010, TVOC concentration levels were measured and analyzed in 402 general households and 236 weak households, totalling 638 households. Residents were asked to fill out a survey on environmental disease. All resources were analyzed using SPSS 12.0 program. Result: In comparing the differences in concentration levels of volatile organic compounds for different types of households, including existing apartments and houses, the type of housing did not affect the concentration level of volatile organic compounds, but the relevance with skin trouble, diagnosed atopy, and atopy systems all had statistical similarities. Moreover, above-limit volatile organic compounds showed statistical relevance with amount of ventilation, time of construction, skin trouble, diagnosed atopy and atopy symptoms. Conclusion: The study concludes that as the time of construction recedes further into the past and as the amount of ventilation is higher, the exposure level to volatile organic compounds was lower and the group that were suffering from atopy symptoms had higher exposure to volatile organic compounds.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.113-119
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• 2018

Occupancy-based heating control is effective in reducing heating energy by preventing unnecessary heating during unoccupied period. Various technologies on detecting human occupancy have been developed using complicated machine learning algorithm and stochastic methodologies. This study aims at deriving low-cost and simple algorithm of occupancy inference that can be implemented to residential buildings. The core concept of the algorithm is to combine the occupancy probabilities based on indoor CO2 concentration and PIR(passive infrared) signals. The probability was estimated by applying different levels of decrement ratio depending on CO2 concentration change rate and aggregated PIR signals. The developed algorithm was validated by comparing the inference results with the occupancy schedule in a real residential building. The results showed that the inference algorithm can achieve the accuracy of 75~99%, which would be successfully implemented to the control of residential heating systems.