This study aims to analyze the effects of 4 directions of wind, wind speed, year of construction of slate roofs, installation area and other factors on the concentration and size distribution of airborne fiber particles in farmhouses with a slate roof containing asbestos. Airborne fiber particle samples were collected from the air in six houses with a slate roof containing asbestos using a high flow rate pump (10 L/min) for 2 hours, three times a day with a different condition, 72 times in total. The airborne fiber particle concentrations were measured using a phase contrast microscope, and the size of fiber particles of 72 samples in total was estimated using the mean value of those in each sample measured at 100 with a field of view. The total average concentration of fiber particles collected from in the air in four directions of the targeted farmhouses was 2.83 fiber/L, and its maximum concentration was 5.75 fiber/L, which means that among all samples there was no place that exceeded 10 fiber/L, a recommended indoor air quality standard. The average size of the fiber particles was 11.55 μm, and the maximum size was 40 μm. A multiple regression analysis of factors affecting the concentration and size of fiber particles in the air collected from the farmhouses with a slate roof containing asbestos found that the closer to the main wind direction (p<0.001) and the faster the average wind speed (p<0.05), the fiber particles concentration became significantly higher. In this case, the coefficient of determination was 52.8%. It was also found that the wider the total area of the slate roof (p<0.001) and the slower the average wind speed (p<0.05), the longer the fiber particles; the coefficient of determination for this finding was 19.6%. The concentration of fiber particles in the air of farmhouses with a slate roof appeared to be the highest under the main wind direction, and became significantly higher as the wind speed became faster. This proved that fiber particles were leaked from the slate roof. The size of the fiber particles became significantly longer as the area of the slate roof became wider and the wind speed became slower.
In this study, the distribution of each facility group, the pollution level of local municipalities and the status of self-measurement were investigated and analyzed using data provided by the Ministry of Environment. It was found that most of the workplaces to be managed are facilities of sensitive class, indoor parking lots and largescale stores. The results of the survey on the total pollution level by facility group showed that the rate of contamination was the highest in the facilities where there are many sensitive users, including the subway station and the underground shopping malls. Through self-measurement, in the case of fine particle matter, it was found that it was present in amounts of 51.71 μg/m3, 50.72 μg/m3, 44.47 μg/m3 and 54.44 μg/m3 in medical institutions, day care centers, elderly care facilities and postnatal care centers, respectively. Also, there were facilities exceeding the standard in the medical institutions. However, most of the pollutants in the facilities surveyed by the municipality are higher than the self-measured concentrations, so it is necessary to examine the cause of such pollution.
In this study, we analyzed the factors affecting the concentration of airborne asbestos fiber in the indoor and outdoor environment of a slate roofing house, and performed a health risk assessment of residents living in houses with slate roofs. Sampling was conducted at ten houses with slate roofs on 3 different days under different weather conditions. A high flow rate pump was used for sampling. The specimen was assessed using a phase-contrast microscope. The degree of risk of exposure to asbestos was assessed using EPA’s carcinogen risk assessment method. Asbestos fiber concentrations for slate roofing houses were 2.43 fiber/L inside and 2.46 fiber/L outside, respectively. The correlation between the indoor and outdoor asbestos fiber concentration was 0.486. But on both sides, the asbestos fiber concentrations did not exceed the standard (10 fiber/L) for ambient air in Korea. The factors affecting the concentration of asbestos fiber were year of construction (p<0.05), total roof area (p<0.05) and average wind velocity (p<0.01). According to EPA’s ELCR (Excess Lifetime Cancer Risk) on air pollution substances, a level of 1.0E-04~1.0E-06 should be maintained. However, the ELCR level of 6 out of 10 houses was over 1.0E-04. Therefore, a risk management plan for residents of slate roofing houses must be prepared immediately.
The concentration of VOCs, NO2 was measured both inside and outside residential homes surrounding an industrial complex. Measurements were performed in the area of the industrial complexes and around 10 km away from the industrial complex area. Benzene did not exceed the air quality standard value. Toluene exhibited a high value of concentration in outdoor Yeosu investigated group. The concentration of NO2 is higher than outside concentrations of houses in both inside housing research group compared with the group of Gwangyang and Yeosu. Benzene and toluene showed high correlation (p<0.001) in the housing interior in Gwangyang, It showed a high correlation (p<0.01) in the housing interior in the comparison group. In Yeosu there was a high correlation (p<0.001) between the inside and outside of the housing in the survey group. In the control group there was only high correlation (p<0.05) in the inside of the housing.
The objectives of this study were to characterize the factors affecting exposure to the VOCs and NO2 in the vicinity of Gwangyang industrial complex. The VOCs and NO2 levels were measured for residents of an exposure group (industrial area within 5 km) and a control group (15 km farther), respectively using the VOCs and NO2 filter badge as a passive sampler from August to September 2006. The means of indoor, outdoor, workplace and personal exposure levels of benzene were 1.10 ppb, 0.94 ppb, 1.85 ppb and 2.35 ppb respectively in the exposure group. The means regarding toluene for the exposure group were 9.29 ppb indoor, 8.09 ppb outdoor, 14.5 ppb workplace, 14.2 ppb personal exposure. The means regarding ethylbenzene were 4.96 ppb(indoor), 4.45 ppb(outdoor), 6.84 ppb (workplace), 6.10 ppb(personal exposure), and the means regarding xylene were 0.10 ppb(indoor, outdoor), 0.18 ppb(workplace) 0.17 ppb(personal exposure). The means for the indoor, outdoor, workplace and personal exposure level of NO2 were 18.40 ppb, 18.51 ppb, 18.59 ppb, 18.80 ppb respectively in the exposure group. Correlations between personal exposures and workplace concentrations of individual VOCs and NO2 exposures, and each of the microenvironment was statistically significant.
Indoor pollutants seem to have a negative affect on people from vulnerable households who are considered to be weak by the department of environmental health, such as the elderly, infants, children, patients, and pregnant women. In this study, the concentrations of pollutants were measured, especially those pollutants that endanger vulnerable households such as PM10, HCHO, TVOCs, TBC and fungi. The measurements were taken from September to October of 2013 in the Chungnam area. The results were as follows: PM10 33.2 μg/m3, HCHO 20.35 μg/m3, VOCs 132.30 μg/m3, TBC 562.71 CFU/m3 and fungi 362.04 CFU/m3. In the case of TBC and fungi, there were excessive concentrations at 30.9% and 49.3% compared to the standards set by WHO. In the case of fungi, buildings built before the 1980s showed a concentration of 446.23 CFU/m3, those built in the 1980s and 1990s had a concentration of 320.21 CFU/m3 and those built in the 2000s had a concentration of 313.43 CFU/ m3 indicating that fungi concentration was higher when the building was older. The correlation analysis between indoor air pollutants and factors affecting indoor concentrations indicate that HCHO (r = 0.423), TVOCs (r = 0.329), and humidity (r = 0.359) showed a significant difference (p < 0.01). The current study focused on vulnerable households that were unable to protect themselves from indoor pollutants and where poor living circumstances prevailed such as households that do not receive much sunlight; thus, more attention and focus needs to be given to these particular households
목적 : 발달지연 아동들에게 Capute와 Bayley 발달검사를 실시하여 뇌성마비 감별에 이들 지수들의 유용성을 평가하고, 이들 검사 중에 뇌성마비를 가장 잘 감별할 수 있는 발달검사 척도를 찾아 뇌성마비 아동을 조기에 진단하고 재활중재와 개입전략을 세우는데 도움이 되고자 한다.
연구방법 : 2002년 8월부터 2005년 12월까지 천안시 소재 모대학교 재활의학과에 발달지연으로 내원한 아동 중 검사시 연령이 48개월까지의 아동 250명을 대상으로 Capute 발달검사인 언어지수(CLAMS), 인지적응검사(CAT), 혼합발달지수(CAT/CLAMS)와 Bayley 발달검사인 정신발달지수(MDI), 운동발달지수(PDI), 행동평가척도(BRS)를 검사하였고, 정신발달지수와 운동발달지수의 차이(MDI-PDI)를 계산하였다.
결과 : 1. 발달지연아 총 250명중에서 뇌성마비군이 86명(34.4%)으로 감별되었고 전반적 발달지연군은 164명(65.6%)이었다.2. 재태기간이 37주 미만군에서 뇌성마비아가 41.7%로 37주 이상군의 26.8%보다 유의하게 높았다(p<0.05).3. 뇌성마비군과 전반적 발달지연군에서의 Capute 및 Bayley 발달검사의 평균 점수의 차이는 Capute 발달검사인 인지적응검사지수와 혼합발달지수에서는 뇌성마비군에서 유의하게 낮은 점수를 보였으며(각각, p<0.001, p<0.01), Bayley 발달검사 중 운동발달지수와 행동평가척도도 뇌성마비군이 유의하게 낮은 점수였고(각각, p<0.001, p<0.01), 정신발달지수와 운동발달지수의 차이는 뇌성마비군이 유의하게 높은 점수를 나타냈다(p<0.001).4. Capute 발달검사의 각 지수별 뇌성마비 감별기준 점수로 80미만으로 하였을 때 인지적응검사지수, 혼합발달지수에서 뇌성마비군의 비율이 유의하게 높은 분포를 보였다(각각, p<0.001, p<0.01). Bayley 발달검사인 운동발달지수, 행동발달척도, 정신발달지수와 운동발달지수와의 차이의 감별기준 점수를 각각 85미만, 25미만, 13이상으로 하였을 때 뇌성마비군의 비율이 통계학적으로 유의하게 높은 분포를 나타내었다(각각, p<0.001, p<0.05, p<0.001).5. Capute 및 Bayley 발달검사의 각 지수 간에는 모두 유의한 상관관계를 나타내었다(각각, p<0.001).6. 뇌성마비 감별에 영향을 주는 예측 모형을 로지스틱 다중회귀분석 모형으로 분석한 결과 운동발달지수(Odds Ratio; OR=14.559, p<0.001)의 예측력이 가장 높았고, 다음으로 재태기간(OR=3.080, p<0.001), 정신발달지수와 운동발달지수의 차이(OR=2.678, p<0.01) 순으로 분석되었으며 이 모형의 설명력은 25.1%였다.
결론 : 발달지연 아동 중 뇌성마비아를 조기에 감별할 때에 Bayley 발달검사의 운동발달지수가 가장 유용한 것으로 나타났으며, 정신발달지수와 운동발달지수의 차이도 고려하는 것이 뇌성마비아 감별에 도움이 되는 것으로 나타났다.
This study performed and re-analysed the articles of exposure assessment for the indoor environment of houses in many environment-related journals published. in Korea since 1990. Based on this comparative study, we estimated the unit health risk on indoor environment. The objective of this study was to offer scientific data for decision-making policy for improvement and management of indoor air quality on Korean house in. The pooled concentrations for the critical air pollutants in the house were 13.93±13.91㎍/m3 (PM10), 680±226 ppm for (CO2), 1.9±1.6 ppm (CO), 419±158 CFU/m3 (bacteria), 0.036 ± 0.002 ppm (NO2), and 104.935 ± 16.424 Bq/m3 (Rn), The pooled concentrations for the volatile organic compounds were 6.9±6.7㎍ /m3 (benzene), 39.3±55.1㎍/m3 (toluene), 4.2±4.0㎍/m3 (ethylbenzene), 11.4±8.3㎍/m3 (m, p-xylene), 4.2 ±1.5㎍/m3 (styrene) and 6.3±4.5㎍/m3 (o-xylene). The unit cancer risk for men and women by inhalation of benzene was 3.7 × 10-5 and 4.8 × 10-6, respectively. In additio
This study was performed to investigate the concentration levels of CO2 and the associated parameters in the subway from lines 1 to 8 in Seoul metropolitan area, during 1 to 30 Sept. 2005. CO2 concentration was measured at the entrance and center in subway passenger cabin by non-dispersive infrared analyser. The associated parameters for CO2 were estimated based on the number of passenger, open and closed doors etc. The mean CO2 concentrations were measured to be 1,646±712 ppm in subway passenger cabins. The CO2 concentrations showed the highest values between 7 and 9 AM in rush hour(p〈0.01). The correlation coefficient between CO2 and the number of passenger was highly significant(r=0.824). The general linear model indicated that subway line, subway location (ground and underground tract), and measurement point (enterance and center of cabins) and running time (morning and afternoon) significantly influenced the concentrations of CO2. An extended study is needed to examine the sources of CO2 in subway cabins and to compare pollutants concentration among subway lines.
The National Institute of Environmental Research (3rd KONEHs) conducted a survey of 280 residents in Ulsan, Suwon and Asan, and the concentration of heavy metals in the blood and urine were also analyzed. In case of blood lead concentration, Ulsan 2.27 ㎍/㎗, Suwon 2.08 ㎍/㎗, and Asan 1.75 ㎍/㎗, the high peak in Ulsan, and the low peak in Asan. In case of cotinine concentration, Ulsan smoking(609.16 ㎍/g_ct) is higher than nonsmoking(74.07 ㎍/g_ct), as Suwon and Asan smoking(416.72 ㎍/g_ct, 903.21 ㎍/g_ct) is higher than nonsmoking(72.72 ㎍/g_ct, 18.06 ㎍/g_ct), smoking group is higher than nonsmoking group in all areas revealed statistically significant correlation(p<0.01). In considering results synthetically, these study results are an aid to constructing environmental health science-side heavy metal management measure education programs for normal residents.
The purpose of this study is to assess the effects of heavy metal concentrations in the blood and urine of the general population. This research had been conducted from April to December 2008, studying 545 residents of Daejeon and Chungcheong Province. Through the concentrations of heavy metals(Pb, Cd, Hg, As, Mn) in the biota samples and questionnaires, the residents heavy metal exposure level and the influential factors according to personal characteristics or lifestyle were evaluated. As to the heavy metal concentration in the blood and urine of the comparing region, were As and Mn statistically significant(p<0.01, p<0.05). Blood lead and urinary mercury concentrations were higher in males than females. The heavy metal concentration for each age group increased blood mercury. The concentration of all heavy metals were higher in the drinkers than in the non-drinkers. Blood lead and mercury concentrations were higher in the smokers than in the non-smokers, but the urinary cadmium, arsenic and blood manganese was higher in the non-smokers than in the smokers. As to the blood lead and urinary cadmium concentration according to the food preference fish showed high concentration. To clarify the factors affecting the heavy metal concentration in biota among subjects multiple regression analysis was conducted. As a results, it turned out that as to lead content in blood, sex, age and smoking have influence on the subjects with explanatory adequacy of 14.0 %. These results demonstrated that the factors affected the concentrations of heavy metals in blood and urine. The results of this study could be used as the foundational data for setting the health risk assessment.
지그비 모듈용 소형 PCB안테나를 30mm×8mm의 좁은 영역으로 제한된 공간에서 구현함과 동시에 안테나의 반사손실을 개선시키기 위하여, 기생소자로 접지면과 이격되는 도체를 가지는 미앤더 슬롯 안테나가 제안된다. 본 논문을 통해 설계되어 제작된 안테나의 공진주파수는 대략 2.44GHz이고, 대역폭은 113MHz(VSWR≤2)이다. 방사패턴은 동작주파수영역에서 다이폴 안테나의 방사특성과 거의 유사하고, 안테나의 효율 및 이득은 각각 60% 및 2.7dBi이상의 값을 가진다. 이러한 안테나의 모든 특성들은 지그비에 응용되기 위해 요구되어지는 규격을 모두 만족함을 알 수 있다. 본 논문이 제안하는 안테나의 타당성을 보여주기 위해 모의실험 결과 및 측정결과를 비교하여 제시하였다.
Volatile organic compounds (VOCs) are present in essentially all natural and synthetic materials from petrol to flowers. In this study, indoor and outdoor VOCs concentrations of houses, offices and internet-cafes were measured and compared simultaneously with personal exposures of each 50 participants in Asan and Seoul, respectively. Also, factors that influence personal VOCs exposure were statistically analyzed using questionnaires in relation to house characteristics, time activities, and health effects. All VOCs concentrations were measured by OVM passive samplers (3M) and analyzed with GC/MS. Target pollutants among VOCs were Toluene, o-Xylene, m/p-Xylene, Ethylbenzene, MIBK, n-Octane, Styrene, Trichloroethylene, and 1,2-Dichlorobenzene.
Indoor and outdoor VOCs concentrations measured in Seoul were significantly higher than those in Asan except Ethylbenzene. Residential indoor/outdoor (I/O) ratios for all target compounds ranged from 0.94 to 1.51 and I/O ratios of Asan were a little higher than those of Seoul. Relationship between personal VOCs exposure, and indoor and outdoor VOCs concentrations suggested that time-activity pattern could affect the high exposure to air pollutant. Factors that influence indoor VOCs level and personal exposure with regard to house characteristics in houses were building age, inside smoking and house type. In addition insecticide and cosmetics interestingly affected the VOCs personal exposure. Higher exposure to VOCs might be caused to be exciting increase and memory reduction, considering the relationship between measured VOCs concentrations and questionnaire (p<0.05).
The personal exposures of nitrogen dioxide(NO2), microenvironmental levels and daily time activity patterns on Seoul subway station workers were measured from February 10 to March 12, 1999. Personal NO2 exposure for 24 hours were 29.40±9.75 ppb. NO2 level of occupational environment were 27.87±7.15 ppb in office, 33.60±8.64 ppb in platform and 50.13±13.04 ppb in outdoor. Personal exposure time of subway station workers was constituted as survey results with 7.94±3.00 hours in office, 2.82±1.63 hours in platform and 1 hours in outdoor. With above results, personal NO2 exposure distributions on subway station workers in Seoul were estimated with Monte Carlo simulation which uses statistical probabilistic theory on various exposure scenario testing. Some of distributions which did not have any formal patterns were assumed as custom distribution type. Estimated personal occupational NO2 exposure using time weighted average (TWA) model was 31.29±5.57 ppb, which were under Annual Ambient Standard (50 ppb) of Korea. Though arithmetic means of measured personal NO2 exposure was lower than that of occupational NO2 exposure estimated by TWA model, considering probability distribution type simulated, probability distribution of measured personal NO2 exposures for 24 hours was over ambient standard with 3.23%, which was higher than those of occupational exposure (0.02%). Further research is needed for reducing these 24 hour NO2 personal excess exposures besides occupational exposure on subway station workers in Seoul.
This study was carried out to evaluate the characteristics of dissolved organics based on their origins, which were divided into two categories. The first group consisted of river, lake and secondary sewage treatment effluent, which were chosen as representative of their origins. The second group were artificial samples which were made of AHA(Aldrich humic acids) and WHA(Wako humic acids). Physicochemical characteristics, biological degradability and THMFP(trihalomethane formation potential) of the samples were analysed based on the AMWD(apparent molecular weight distribution). Large portion of dissolved organic carbon(DOC) in the river and lake samples was comprised of LMW(low molecular weight), while that of AHA and WHA was HMW(high molecular weight). The DOC of the lake was evenly distributed in the all range of molecular weight.
The river, lake and secondary treated effluent have lower ultraviolet(UV) absorbance at 254nm, and have a higher amount of humic acids. Higher absorbance of humic acids means that aliphatic bond and benzenoid type components that absorb UV light were contained in these kind of humic acids. It was expected that lake sample was the most biodegradable in the different samples investigated, and in order of secondary sewage treatment effluent, river, WHA and AHA based on the result of determination of specific ultraviolet absorbance(SUVA).
Biodegradability showed similar result except for ABA, while dissolved organics in the range of LMW decreased during the biodegradability test, and on the contrary those of HMW increased. Production of the SMPs(soluble microbial products) was observed during humicification of dissolved organics and the SMPs were in the range of 0.7∼5.5% of DOC which was the lowest value. Sample had a higher portion of HMW showed a higher production of the SMPs. THM formation was high in the samples containing HMW and similar tendency was shown in the THMFP(trihalomethane formation potential), except for WHA.