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학교 실내공기질 및 휘발성유기화합물의 노출평가

Title
학교 실내공기질 및 휘발성유기화합물의 노출평가
Other Titles
Indoor Air Quality and Exposure Assessment of VOCs in School
Author
이종대
Alternative Author(s)
Lee, Jong Dae
Advisor(s)
김윤신
Issue Date
2008-08
Publisher
한양대학교
Degree
Doctor
Abstract
본 연구는 학교 실내오염으로 인해 건강의 위해가 우려되는 물질의 실태를 파악하고, 이를 지속적, 체계적으로 관리 및 평가 할 수 있는 기반을 구축함과 동시에 학생의 건강영향에 중점을 둔 관리대책 수립에 필요한 자료를 제공하는 목적으로 2006년 2월 6일부터 2007년 6월 30일까지 충청남도 13개 시.군에 위치하고 있는 초?중?고등학교 132개교를 대상으로 일반교실과 특별교실의 실내공기의 농도수준과 유해물질에 의한 건강위해영향을 조사하였다. 본 연구조사 결과를 요약하면 다음과 같다. 첫째, 조사 대상학교의 교실 내 휘발성유기화합물의 평균농도는 일반교실(251.67 ㎍/㎥)이 특별교실(181.59 ㎍/㎥)보다 높게 나타났고, 포름알데히드 평균농도는 특별교실(34.22 ㎍/㎥)이 일반교실(24.61 ㎍/㎥)보다 통계적으로 유의하게 높게 나타났다. 초 ? 중 ? 고별 각각의 오염물질 평균농도는 휘발성유기화합물은 초등학교(210.79 ㎍/㎥), 중학교(207.79 ㎍/㎥), 고등학교(195.96 ㎍/㎥) 순으로 나타났고, 포름알데히드는 고등학교(36.03 ㎍/㎥), 초등학교(29.84 ㎍/㎥), 중학교(29.16 ㎍/㎥) 순으로 나타났다. 건축년도 별 교실내 오염물질 평균농도를 비교한 결과 휘발성유기화합물은 1년 미만 교실(410.93 ㎍/㎥), 2~3년 교실(156.52 ㎍/㎥), 1~2 교실(120.18 ㎍/㎥) 순으로 농도분포가 조사되었으며, 특히 1년 미만 교실의 평균농도는 학교보건법의 기준치 400 ㎍/㎥를 초과하는 것으로 나타났다. 교실 내 포름알데히드의 평균농도도 1년 미만 교실(41.37 ㎍/㎥)이 1~2, 2~3년 미만교실(31.50 ㎍/㎥ , 22.21 ㎍/㎥ )보다 평균적으로 유의하게 높게 나타났다. 둘째, 학생들은 하루 평균 실내에서 약 23.2시간 (96.6 %)의 시간을 보내는 것으로 조사되었다. 개인노출 및 국소환경에서 휘발성유기화합물 중 Benzene의 농도는 주택과 학교별로 실내에서 각각 (2.271 ㎍/㎥)과 (1.479 ㎍/㎥), 실외는 (2.852 ㎍/㎥)과(0.475 ㎍/㎥), 개인노출은 2.460 ㎍/㎥로 조사되었다. Toluene의 농도 결과는 주택실외(77.898 ㎍/㎥), 개인노출(76.716 ㎍/㎥), 주택실내(75.259 ㎍/㎥)가 비슷한 수준으로 조사되었고 학교실내(59.627 ㎍/㎥), 학교실외(19.442 ㎍/㎥) 순으로 나타났다. Toluene의 경우 실내 ? 외 농도와 상관성을 가지는 것으로 나타났다. Ethylbenzene의 농도는 주택의 실외(18.803 ㎍/㎥)와 주택의 실내(17.471 ㎍/㎥)가 비슷한 수준으로 조사되었으며 개인노출(15.946 ㎍/㎥)과 학교실내(15.698 ㎍/㎥)가 비슷한 분포를 나타냈다. 세째, Benzene의 개인노출 기여도는 학교 실내에서 18.37 %, 집의 실내에서 60.15 %, 실외에서 4.76 %를 기여하고 있는 것으로 나타났다. Toluenene의 개인노출 기여도는 학교 실내에서 25.12 %, 집의 실내에서 62.23 %, 실외에서 3.87 %를 기여하고 있는 것으로 조사되었다. Ethylbenzene의 개인노출 기여도는 학교 실내에서 25.48 %, 집의 실내 52.77 %, 실외에서 3.83 %를 기여하고 있는 것으로 조사되었다. 네째, 실내환경 인식도 조사 결과 교실 내 공기문제에 관한 관심도는 고등학생에 반해 초등학생과 중학생이 상대적으로 낮은 관심도를 나타냈다. 교실의 실내공기 수준은 학년이 올라갈수록 부정적인 판단을 하는 것으로 조사되었다. 자각증상에 따른 호소율의 결과, 전체적으로 졸리움(51.3%), 기침(42.2%), 불쾌감(40.0%)이 높은 반면, 상대적으로 피부 가려움이나 두더러기, 무기력, 천식 등은 낮은 호소율을 나타냈다. 특히 두통, 불쾌감, 무기력, 잦은 감기, 기침, 인후통 등의 증상 호소율은 평균적으로 초등학생이 높아, 고학년이 될 수록 통계적으로 유의하게 감소하는 경향을 보였다. 다섯째, 위해성 평가 결과 발암성 물질인 Benzene의 경우 개인노출, 학교실내, 집 실내에서 모두 US EPA에서 제시하고 있는 발암 허용기준치인 10-6은 초과하지 않는 것으로 나타났다. 여섯째, 비발암 물질인 Ethylbenzene과 Toluene을 대상으로 위해성평가를 실시한 결과 비발암위해도가 남?녀에서 개인노출, 학교실내, 집 실내 모두 percentile에서 1을 초과는 경우가 없었다. 따라서 비발암물질로 분류되어있는 Ethylbenzene과 Toluene의 경우 개인노출, 학교실내, 집의 실내 모두 비발암 인체 위해영향의 가능성이 없음을 시사하고 있다. 이상의 연구결과는 현재 학교보건법에서 규정하고 있는 단시간 측정법을 보완한 확산법을 이용하여 실내공간의 미세환경 별 휘발성유기화합물의 분포특성, 일일 활동시간별 개인노출, 각 실내 장소별 개인노출 기여도를 정량적으로 추정한 것으로, 향후 학교 내 실내공기오염의 예방 관리 및 학생의 건강증진 향상을 위한 기초 자료를 제시한 것으로 시사된다.; Recently, with respect to indoor air pollution, pollutant management focusing on accepters in addition to pollutant distribution characteristics is becoming an important issue. Especially, as the interest in vulnerable social groups continues to grow, the proper management policies for various indoor environments are being required. As for the national management on various indoor environments, specific management for each indoor is undertaken by Ministry of Environment, Ministry for Health, Welfare and Family Affairs, and Ministry of Education, Science and Technology but the management for school indoor environment was lastly started due to the revision of School Sanitation Act in 2006 and the current actual state of the management is insufficient. Therefore, in this study, we investigated the indoor air concentrations and the harmful effects on health by hazardous pollutants in the normal classrooms and special classrooms of 132 elementary, middle, and high schools located in 13 Cities and Guns in Chungnam from February 2006 to June 2007. The results obtained from this investigation are as follows. First, as for the results of the survey on the indoor air quality, volatile organic compounds were higher in normal classrooms(251.67 ㎍/㎥) than special classrooms (181.59 ㎍/㎥), and formaldehyde was significantly higher in special classrooms (34.22 ㎍/㎥) than normal classrooms (24.61 ㎍/㎥). With regards to the differences of pollutant distribution among elementary, middle, and high schools, volatile organic compounds were highest in elementary schools (210.79 ㎍/㎥) followed by middle schools (207.79 ㎍/㎥) and high schools (195.96 ㎍/㎥), and formaldehyde was highest in high schools (36.03 ㎍/㎥) followed by elementary schools (29.84 ㎍/㎥) and middle schools (29.16 ㎍/㎥), but there were no statistically significant differences in both pollutants among three groups. With regards to the mean concentration of pollutants in connection with school building age, volatile organic compounds were highest in less than 1 year old classrooms (410.93 ㎍/㎥), followed by less than 3 year old classrooms (156.52 ㎍/㎥) and less than 2 year old classrooms (120.18 ㎍/㎥), and especially in less than 1 year old classrooms, the mean concentration of volatile organic compounds was significantly higher than 400㎍/㎥, the maximum safe level set by School Sanitation Act. Besides, Formaldehyde was also investigated to be significantly higher in less than 1 year old classrooms (41.37 ㎍/㎥) than 2 or 3 year old classrooms (31.50 ㎍/㎥, 22.21 ㎍/㎥, respectively). Second, as for the results of the survey on the daily activities of students, students were found to stay indoors almost all day long, for an average of 23.2 hours (96.63%). With respect to personal exposure to volatile organic compounds in local environments, the mean concentration of benzene indoors was 2.271㎍/㎥ in houses and 1.479㎍/㎥ in schools, and the concentration outdoors was 2.852㎍/㎥ in houses and 0.475 ㎍/㎥ in schools, the mean personal exposure was 2.460㎍/㎥. The mean concentration of toluene was found to be similarly high in outdoors of houses (77.898 ㎍/㎥), personal exposure (76.716 ㎍/㎥), indoors of houses (75.259 ㎍/㎥) followed by indoors of schools (59.627 ㎍/㎥) and then outdoors of schools (19.442 ㎍/㎥). The concentration of toluene showed to have relativity to the concentration of indoors or outdoors. The concentration of ethylbenzene was investigated to be slightly higher in outdoors of houses(18.803 ㎍/㎥) and indoors of houses (17.471 ㎍/㎥) and similar in personal exposure(15.946 ㎍/㎥) and indoors of schools (15.698 ㎍/㎥). Third, the contribution to the personal exposure to benzene was 18.37% in indoors of schools, 60.15% in indoors of houses, and 4.76% in outdoors. The contribution to the personal exposure to toluene was 25.12% in indoors of schools, 62.23% in indoors of houses, and 3.87% in outdoors. The contribution to the personal exposure to ethylbenzene was 25.48% in indoors of schools, 52.77% in indoors of houses, and 3.83% outdoors. Fourth, as for the results of the survey on the awareness about indoor environments, high school students were found to have relatively higher interest in indoor air environments than element and middle school students. With respect to the opinion of students about indoor air quality of classroom, higher grade students tend to think the air quality to be lower. With respect to the symptoms reported by students, sleepiness, cough, dysphoria were most common symptom and urticaria, inertia, asthma were relatively rare events. Especially, the incidences of headache, dysphoria, inertia, frequent cold, cough, and sore throat tended to be significantly lower in higher school students. Fifth, as for the results from the risk assessment of the pollutants, the cancer risk by benzene, a cancer-causing substance, was found to be 3.83×10-7 in females and 2.60×10-7 in males, which didn't exceed 10-6, the maximum allowable level recommended by US EPA. The cancer risk by benzene exposed in indoors of schools was found to be 4.97×10-8 in females and 3.17×10-8 in males through single value analysis. And through the Monte Carlo analysis, the mean cancer risk was found to be 3.15×10-8 in females and 3.21×10-8 in males, which also didn't exceed 10-6, the maximum allowable level recommended by US EPA. The cancer risk by benzene exposed in indoors of houses was found to be 1.96×10-7 in females and 1.57×10-7 in males through single value analysis and through the Monte Carlo analysis, the mean cancer risk was found to be 1.82×10-8in females and 6.64×10-8 in males, which also didn't exceed the maximum allowable level. Sixth, as for the results from the risk assessment of ethylbenzene and toluene, non-cancer-causing substances, the non-cancer harmful effect risk by personal exposure to ethylbenzene was found to be 1.90×10-2 in females and 2.7×10-1 in males and the risk by toluene was found to be 2.7×10-1 in females and 2.1×10-1 in males through single value analysis, which didn't exceed 1. And through the Monte Carlo analysis, the mean non-cancer harmful effect risk by ethylbenzene was found to be 1.9×10-2 in females and 1.8×10-2, in males and the risk by toluene was found to be 2.7×10-1 in females and 2.1×10-1 in males, which didn't exceed 1. Besides, all the percentiles never exceeded 1. As the result of the assessment of the risk caused by them exposed in indoors of schools, the non-cancer harmful effect risk by ethylbenzene was found to be 2.1×10-3 in females and 2.3×10-3 in males and the risk by toluene was found to be 1.6×10-2 in females and 1.8×10-2 in males through single value analysis, which didn't exceed 1. And through the Monte Carlo analysis, the mean non-cancer harmful effect risk by ethylbenzene was found to be 2.0×10-3 in females and 2.3×10-3 in males and the risk by toluene was found to be 1.6×10-2in females and 1.7×10-2 in males, which didn't exceed 1. As the result of the assessment of the risk caused by them exposed in indoors of houses, the non-cancer harmful effect risk by ethylbenzene was found to be 5.5×10-3 in females and 5.0×10-3 in males and the risk by toluene was found to be 1.6×10-1 in females and 1.3×10-1 in males through single value analysis, which didn't exceed 1. And through the Monte Carlo analysis, the mean non-cancer harmful effect risk by ethylbenzene was found to be 5.7×10-3 in females and 5.4×10-3 in males and the risk by toluene was found to be 17×10-1in females and 1.3×10-1 in males, which didn't exceed 1. Besides, all the percentiles never exceeded 1. Therefore, those results suggested that ethylbenzene and toluene, classified as non-cancer-causing substances, had no risk of non-cancer harmful effects in the cases of personal exposure, indoors of schools, and indoors of houses. This study may also be significant in that it measured individual exposure and concentration in terms of micro-environment and quantitatively estimated contributions to individual exposure in each indoor environment in an attempt to estimate effects which could actually be exerted on health of the receptor. With the recently increased role of local self-governing bodies, this study assessed harmful pollutants at 132 large-sized schools in the South Chungcheong province, the results of which can be used meaningfully as important basic data by the central government as well as by local self-governing bodies to establish policies for indoor air from the hygienic perspective and set a direction for mid- or long-term management in the future. They also suggest that for indoor environment at schools, it is necessary to develop long-term concentration assessment tools, including diffusion, and conduct efficient health effects evaluation at schools all over the country, with preventive hygiene for students health considered as an important purpose.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/146405http://hanyang.dcollection.net/common/orgView/200000410260
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GRADUATE SCHOOL[S](대학원) > HEALTH SCIENCES(보건학과) > Theses (Ph.D.)
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