• 대한토목학회논문집
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• 제26권6B호
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• pp.695-701
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• 2006

Toluene을 유일 탄소원으로 배양한 혼합미생물 군으로부터 순수미생물을 분리배양한 후, 염기서열을 분석하여 Pseudomonas sp. TDB4 균주를 얻었다. 이 균주의 VOC 분해능을 평가하기 위해 toluene, benzene, p-xylene, styrene을 대상기질로 하여 회분식 생분해실험을 진행하였으며, 단일 기질인 경우 toluene, benzene, styrene, p-xylene의 순으로 분해능이 좋은 것으로 나타났다. 또한 VOCs 혼합물을 주입하였을 경우에는 모든 조합조건에서 styrene, toluene, benzene, pxylene의 순서로 쉽게 분해하였다. 이러한 결과로부터 VOC가 공존할 경우 toluene과 p-xylene은 다른 VOC의 분해를 촉진시키지만 styrene은 저해물질로 작용함을 알 수 있었다. 한편 연속식 계면활성제 미생물 반응기(Bioactive Foam Reactor, BFR)에 혼합미생물 배양액과 TDB4 배양액을 접종하고 장기 운전하면서 운전특성과 미생물 동적변화를 확인하였다. VOCs 혼합물질 유입농도가 250 ppm 이상에서는 처리효율이 급격히 저하되었는데, FISH 분석 결과에 따르면 동일한 시점에서 TDB4가 차지하는 비율이 전체 미생물의 20% 미만으로 감소하여 BFR의 처리효율과 미생물상은 매우 밀접한 관련이 있음을 알 수 있었다. 본 연구 결과 FISH 분석법을 계면활성제 미생물 반응기의 미생물 군집변화 해석에 유용하게 사용할 수 있음을 확인하였으며, 미생물 반응조를 장기간 운전할 때에는 안정적인 처리효율을 유지하기 위하여 주기적인 식종을 해주는 것이 적절하다고 판단된다.

• 한국대기환경학회지
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• 제20권1호
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• pp.77-85
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• 2004

In this study, the concentrations of reduced S compounds (including hydrogen sulfide (H$_2$S); methyl mercaptan ($CH_3$SH); dimethyl sulfide (($CH_3$)$_2$S); carbon disulfide (CS$_2$); and dimethyl disulfide (($CH_3$)$_2$S$_2$) were determined from landfill gas (LFG) in three municipal landfill sites in the two cities of Gwang Ju (GJ) and Jeju (JJ), Korea. The S gas concentrations measured in these landfill sites were found to be dominated by H$_2$S with its mean concentration of 850 ppm from 10 LFG samples. Both absolute and relative dominance of H$_2$S was seen to be significant in most LFG samples, except those collected from very old and inactive landfills. Unlike the pattern of H$_2$S, other S gases were typically observed at much reduced concentration levels (a few ppm or less) as follows: DMS (3.5); $CH_3$SH (1.3); CS$_2$(1.2); and DMDS (0.02 ppm). If compared equally in mass concentration unit (mg m$^{-3}$ ), H$_2$S generally explained far above 90% of all S gas masses determined concurrently. Moreover, as its mass concentration commonly exceeds those of the major aromatic VOC components in LFG (like benzene and toluene), it appeared to be one of the most dominant gaseous components emitted as LFG in a quantitative sense.

• Journal of Korean Society for Atmospheric Environment
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• 제17권E3호
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• pp.101-107
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• 2001

Source profiles were developed for a total of 45 volatile organic compounds (VOC) that can be emitted from gasoline evaporation. The gasoline samples of five major brands (for each season) were blended on the basis of the market share in Seoul area and analyzed by a GC-MS/FID system. In addition, we calculated gasoline evaporative compositions using the Raoult's law from the liquid gasoline compositions. The measured and estimated gasoline vapor compositions agree well each other. As a group, alkanes are the most abundant in the gasoline vapors profiles (77.4% on average), followed by alkenes (19.1%), and aromatics (1.7%). As a specie in gasoline vapor, i-pentane is the most abundant, followed by n-butane, n-pentane, i-butane, trans-and cis-2-butenes, 2-methyl-2-butene, and trans-and cis-2-pentenes . It was also seen that aromatic content was much lower in the vapor phase compositions. From the comparison between experimental and calculated compositions, we identified the fact that once the gasoline vapor composition is reliably constructed entirely from the measured gasoline composition and the Raoult's law calculations, the need for doing separate chemical analyses of the gasoline vapor can be reduced.

• 한국대기환경학회지
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• 제22권6호
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• pp.779-790
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• 2006

This study examines relative contributions of volatile organic compounds (VOCs) to the formation of hydroxyl (OH) and peroxy radicals such as $HO_2$ and $RO_2$ during the intensive sampling period (Jun. $1{\sim}30$, 2004) in the air of Seoul metropolitan area. As to the contribution of VOCs to $HO_x$ levels, the impact of individual VOC concentration change on $HO_2$ concentration change was more than an order of magnitude higher than that on OH concentration change during the study period. The contribution of change in isoprene concentration to $HO_2$ concentration change was 38 times higher than OH and that in the concentration of alkene compounds to $HO_2$ concentration change was 31 times higher than OH. Moreover, the concentration changes of isoprene and aromatic compounds (AROM) played significant roles in $HO_x$ concentration changes. On the other hands, aldehydes (ALD2) and alkanes (ALKA) showed anti-correlation (negative) in $HO_x$ concentration changes with low contribution ($-4{\times}10^{-3}$ pptv/ppbv (OH) and $-58{\times}10^{-3}$ ($HO_2$) for ALD2; $-1{\times}10^{-3}$ (OH) and $-15{\times}10^{-3}$ ($HO_2$) for ALKA). Unlike other VOCs, $C_2H_6$ and $C_3H_8$ showed positive or negative contribution to peroxy radicals, depending on ambient air conditions. The contribution of VOC concentration changes to changes in $CH_3O_2$ and $RO_2$ concentration showed similar pattern to $HO_x$ contribution.

• 한국대기환경학회지
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• 제15권2호
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• pp.121-138
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• 1999

This study was carried out to evaluate the performance of a sampling and analytical methodology for the measurement of selected volatile organic compounds (VOCs) in the ambient air. VOCs were determined by the adsorbent tube sampling and automatic thermal desorption coupled with GC/FID and GC/MSD analysis. Target analytes were aromatic VOCs, including BTEX, 1,3,5-and 1,2,4,-trimethylbenzenes(TMBs), and naphthalene. The methodology was investigatedwith a wide range of performance criteria such as repeatability, linearity, lower detection limits, collection efficiency, thermal conditioning, breakthrough volume and calibration methods using internal and external standards. standards. Stability of samples collected on adsorbent tubes during storage was also investigated. In addition, the sampling and analytical method developed during this study was applied to real samples duplicately collected in various indoor and outdoor environments. Precisions for the duplicate samples and distributed volume samples appeared to be well comparable with the performance criteria recommended by USEPA TO-17. The audit accuracy was estimated by inter-lab comparison of both duplicate samples and standard materials between the two independent labs. The overall precision and accuracy of the method were estimated to be within 30% for major aromatic VOCs such as BTEX. This study demonstrated that the adsorbent sampling and thermal desorption method can be reliably applied for the measurement of BTEX in ppb levels frequently occurred in common indoor and ambient environments.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.55-58
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• 2003

The ambient concentrations of benzene, toluene, and $\alpha$-/$\beta$-pinene were measured from July, 2002 to August, 2002 at the Gumsung mountain site in Jeonnam province. The mean concentration of benzene for this study was $62.6{\pm}43.9$ pptv (Min. 20.4 ~ Max. 151.2 pptv) , and that of toluene was 619.8 ${\pm}$ 330.2pptv (264.8~1, 386pptv). It was observed that the concentrations of $\alpha$ -pinene and $\beta$ -pinene were $169.0{\pm}97.7$ pptv (72.9~396.1pptv) and $11.2{\pm}27.9$pptv (7.5 ~95.9 pptv) , respectively. The ambient concentrations of aromatic and natural VOCs were found at the pptv level. In this study, the toluenelbenzene ratios were $13.9{\pm}11.2$ , but they were a little higher than those found in the domestic study and approximately 5 times greater than the values in the foreign study. The $\beta$ -/ $\alpha$ -pinene ratios ranged between 0.05 and 0.55, and this range was found to be similar in the foreign study.

• 한국환경과학회지
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• 제12권4호
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• pp.487-496
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• 2003

본 연구에서 실시한 VOC의 각 배출원별 구성물질 성분비를 조사한 결과로부터 다음과 같은 결론을 얻었다. 1) 우리나라의 VOC 주요 배출원에서 배출되는 성분은 주로 toluene으로서 도로포장 배출물질과 자동차, 도장시설, 가솔린증기 구성성분이 각각 35, 18, 16, 5%로 높은 분율을 차지하고 있음을 알 수 있었다. 2) 자동차와 주유소 그리고 가솔린 저장탱크 배출 물질의 경우 주로 $C_{5}$ 이하의 성분들이 배출되었는데, 이들 성분들은 주로 휘발유를 취급하는 곳에서 상당량 배출되고 있었다. 3) 도장시설에서는 m/p-xylene과 toluene, 1,2,4-TMB, o-xylene 둥이 각각 34, 16, 10, 9%로 배출되고 있어 주로 방향족 화합물들이 많이 배출되고 있었다. 4) 세탁시설에서는 주로 석유계 연료를 사용하고 있어 nonane이 41%, 1,2,4-TMB가 22%, 1,3,5-TMB가 13%로 배출되었으며, 도로포장시 아스팔트에서는 toluene과 benzene, m/p-xylene, o-xylene, ethyl benzene 등of 각각 35, 10, 4, ,3, 2%로 배출되고 있어 BTEX가 상당량 배출되고 있었다. 5) 본 연구의 경우 시료채취시 약 20초간의 짧은 시료채취이므로 정확한 자료를 얻기 위해서는 비교적 장시간을 채취하여 분석하여야 될 것으로 사료되며, 도로포장의 경우 시료채취지점으로 부터 약 100m 전방에 편도 2차선의 도로가 있어 자동차 배출물질이 다소 포함되었을 가능성이 있음을 밝혀둔다.

• Environmental Analysis Health and Toxicology
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• 제17권3호
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• 한국대기환경학회지
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• 제14권2호
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• pp.153-160
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• 1998

The concentrations of volatile organic compounds (VOCs) in the atmosphere were measured from the Yochon Industrial Estate and compared with those from Tongkwangyang and Seoul. The first important phenomenon observed in the air of Yochon was high concentrations of alkenes and in particular, ethylene and propene. For most dominant species, their means and standard deviations were high simultaneously. Concentrations of several major aliphatic species exhibited a similar pattern of diurnal variation, however, with different species combination on each day. Concentrations of several hazardous aromatic species also exhibited a similar pattern of diurnal variation on the same day, which was different from that observed in the diurnal variation of major aliphatic species. It was interpreted that some species were intermittently released from relevant processes. It was also understood that high concentrations and variations of VOC species in Yochon were localized and not related to high average concentrations of ozone in Yochon and Tongkwangyang areas.

• 분석과학
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• 제17권6호
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• pp.496-513
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• 2004

본 연구는 환경 대기 중 독성 VOC 측정을 위하여 흡착제를 이용한 시료채취와 열탈착을 병용한 GC/MSD 분석방법론 전반을 총괄적으로 평가하고, 나아가 각종 흡착제의 VOC 시료채취 특성을 비교 평가하기 위하여 수행하였다. 측정대상물질은 BTEX와 유기염소계 화합물을 포함하는 총 33개의 VOC를 선정하였으며, 조사된 흡착제는 상용중인 10종을 대상으로 하였다. 이들 흡착제는 총 6종의 탄소계 (Carbotrap, Carbopack B, Carbotrap C, Carbosieve-SIII, Carboxene 1000 및 Activated Charcoal)와 4종의 고분자 수지계 (Tenax TA, Porapak Q, Chromosorb 102, Chromosorb 106) 로 구분되어 진다. 시료채취과정은 단일 흡착관과 다중흡착관을 대상으로 표준시료와 실제 현장시료를 대상으로 재현성과 감응계수 측면에서 평가하였으며, 측정 정확성은 Carbotrap을 기준으로 평가하였다. 실험결과, 독성 VOC에 가장 적합한 흡착제로는 Carbotrap과 Carbopack B 및 Tenax TA 인 것으로 나타났으며, 강한 흡착제는 열탈착 성능이 떨어지고, 시료 중 수분의 영향으로 감도와 재현성이 현저히 떨어지는 문제점으로 인하여 적합하지 않은 것으로 나타났다. 3 종류의 이중흡착관과 2 종류의 삼중흡착관의 시료채취특성을 평가한 결과, Carbotrap C와 Carbotarp으로 조합된 경우가 가장 우수한 것으로 나타났다. 반면, 친수성인 강한 흡착제가 같이 충전된 삼중 흡착관의 사용은 수분의 영향을 최소화하는데 매우 세심한 주의가 필요한 것으로 나타났다. 결과적으로 흡착시료채취법을 이용하여 실내외 환경에서의 독성 VOC 농도에 대한 신뢰성 있는 자료를 얻기 위해서는 적절한 흡착제의 선정 (혹은 조합) 및 그에 따른 최적 분석 조건의 설정에 무엇보다도 세심한 주의가 요망된다.