Historically, the control of stored-product insects has mostly relied on the use of fumigants such as methyl bromide (MB) and phosphine. However, methyl bromide is no longer used for structural fumigations, and phosphine insecticide resistance is rising globally. Methyl benzoate (MBe) is a new green pesticide that occurs naturally as a metabolite in plants. In this study, we evaluated the the potential use of MBe as a fumigant against a variety of stored-product insects. According to our laboratory findings, MBe showed strong fumigation toxicity against the Indian meal moth and flat grain beetle with an LC50 value of 0.1 μL/L and 0.76 μL/1.5 L air, respectively, compared to the other tested insects. Furthermore, no significant differences were observed in susceptibility levels between the lab strain and the phosphine-resistant lesser grain borer and rice weevil. However, the red flour beetle had the highest LC50 value of 8.26 μL/1.5 L air. Overall, MBe seems to be a highly promising candidate for the development of environmentally-friendly alternative fumigants.

Sensing of volatile organic compounds (VOCs) is a growing research topic because of the concern about their hazard for the environment and health. Furan is a VOC produced during food processing, and it has been classified as a risk molecule for human health and a possible biomarker of prostate cancer. The use of carbon nanotubes for VOCs sensing systems design could be a good alternative. In this work, a theoretical evaluation of the interactions between furan and zigzag single-wall carbon nanotubes takes into account different positions and orientations of the furan molecule, within a density-functional theory first-principles approach. The van der Waals interactions are considered using different exchange-correlation functionals (BH,C09, DRSLL and KBM). The results indicate that vdW-functionals do not significantly affect geometry; however, the binding energy and the distance between furan and nanotube are strongly dependent on the selected exchange-correlation functional. On the other hand, the effects of single and double vacancies on carbon nanotube are considered. It was found that the redistribution of charge around the single-vacancy affects the bandgap, magnetic moment, and binding energy of the complex, while furan interaction with a double-vacancy does not considerably change the electronic structure of the system. Our results suggest that to induce changes in the electronic properties of carbon nanotubes by furan, it is necessary to change the nanotube surface, for example, by means of structural defects.

The concentrations of odor and volatile organic compound (VOC)-inducing substances were measured using selected ion flow tube mass spectrometers (SIFT-MS). SIFT-MS can continuously measure the concentration of odor-causing substances and VOCs in real time without pre-treatment steps. Measurements were conducted during the day and at night at 10 spots in the chemical block of the Sihwa industrial complex. Similar measurement results were observed in the daytime and nighttime for materials except methyl ethyl ketone with high concentrations. A high concentration of hydrogen sulfide was also measured at night. It is expected that an amount of emissions of VOCs and odor-causing substances under the absence of inspection can be traced if measured at other industrial complexes in vulnerable times.

In the current study, oxidative decomposition of a volatile organic compound was investigated at room temperature and pressure. The experiment was carried out in lower ethylene concentration and with various higher gas flow rates. The reactor has 7 different compartments in which the reaction takes place independently. Plasma was generated inside each compartment by the application of alternating current (AC) voltage. 5 wt% manganese loaded and 5 wt% silver loaded 13X zeolite were used as catalysts. Bare zeolite showed higher ethylene decomposition efficiency than Ag loaded and Mn loaded zeolite. Ozone concentration was increased slightly while increasing the SIE, reached a maximum and started decreasing. Ag loaded zeolite also showed similar decomposition efficiency, but the concentration of ozone was greatly lowered.

초지 또는 농경지에 살포되는 퇴비와 액비에 의해 발생될 수 있는 악취민원에 대처하기 위하여, 돼지의 분과 뇨에 존재하는 악취물질 농도를 비교 분석하였다. 1.비육돈의 분과 뇨에 함유된 휘발성유기물의 농도 비교페놀, p-크레졸 및 페놀류 농도는 분 보다 뇨에서 높았으며(p<0.05), 분 보다 뇨에 축적된 비율이 페놀은 138배, p-크레졸은 545배 높았다. 인돌 농도는 분 보다 뇨에서 높았으며, 스카톨은 뇨 보다 분에서 높았다(p<0.05). 휘발성유기물은 대부분 뇨로 배설되었으며, 이 중 농도 및 악취강도가 가장 높은 물질인 p-크레졸이 뇨에 많이 함유되어 있다. 돼지 분뇨를 고액분리 하였을 때 퇴비로 이용되는 고체보다 액비로 이용되는 액상물질에서 악취가 훨씬 강할 것으로 예측된다. 2.비육돈의 분과 뇨에 함유된 휘발성지방산의 농도 비교아세트산과 단쇄지방산 농도는 분 보다 뇨에서 높았으며 (p<0.05), 부티르산과 프로피온산은 차이가 없었다(p> 0.05). 이성체지방산 중 I-부티르산의 농도는 뇨 보다 분에서 높았지만(p<0.05), I-발레르산과 이성체지방산은 차이가 없었다(p>0.05). 휘발성지방산 중에서 아세트산과 프로피온산은 분에서 각각 65와 20%, 뇨에서는 각각 93과 4%로 휘발성지방산의 대부분을 차지하였지만 아세트산과 프로피온산을 포함하는 단쇄지방산은 악취강도가 낮다. 반면에 악취강도가 상대적으로 높은 이성체지방산은 분과 뇨 간에 차이가 없기 때문에 휘발성지방산이 악취강도에 미치는 영향은 크지 않을 것으로 판단된다. 이상의 연구결과를 종합하면, 돼지 분뇨의 악취물질 중 악취강도가 높은 p-크레졸은 뇨에 많이 함유되어 있기 때문에 퇴비와 액비 생산과정 중 액상처리 시 악취강도가 매우 높을 것으로 추정된다. 다만, 악취강도는 휘발성지방산의 농도 변화에 따라 차이가 있을 것으로 생각된다.

Secondary air pollution can be caused by aerosol formation through reactions of ozone and volatile organic compounds (VOCs) emitted from household products used in the indoor environment. In this study, we investigated the potential for aerosol production during the reactions of ozone and VOCs emitted from a home insecticide, a popular commercial product extracted from natural ingredients, in a 1-m³ reaction chamber. The major chemical component of the test product was prallethrin, which has very high efficacy of mosquito and housefly elimination. Toluene, α-pinene, cymene, d-limonene, α-terpinene, and α-thujone were also identified as constituents of the insecticide. Injected ozone concentrations of 50, 100, and 200 ppb generated particle mass concentrations, corrected for wall loss and air exchange loss, of 7.3, 33.1, and 40.0 μg/m³, respectively, after a 4-h reaction time. These concentrations are lower than those generated by an air freshener in a previous study under the same experimental conditions. It was concluded that the home insecticide tested had the potential to initiate secondary aerosol formation under ozone exposure due to the biogenic VOCs it contained.

전도성 고분자인 poupyrrole과 polyaniline을 이용하여 센서를 제조하고 휘발성 유기화합물에 대한감응특성 및 감지막의 물성을 조사하여 지금까지 알려지지 않은 감응 기구를 설명하고자 하였다. Polypyrrole과 polyaniline은 두께가 얇은 경우가 두꺼운 경우보다 감도가 높았으며, 1분간 도펀트를 제거한 센서가 가장 높은 감도를 나타내었다. 또한 두 가지 센서 모두 극성이 강한 분자가 흡착될수록 감도가 증가하였는데, 이는 극성을 갖는 분자가 감지막 내부로 침투하여 polaron 및 자유 carrier를 고착시키거나 추가의 자유 carrier를 형성하여 전도도에 변화를 주기 때문인 것으로 판단된다.

This study investigated the effect of leaf form or phenotype and light intensity on the toluene, xylene, and ethylbenzene removal of three foliage plants. Green and variegated forms of Ardisia pusilla, Scindapsus aureus, and Hedera helix plants were grown under 10 and 20 μmol･m-2･s-1 light intensities for 8 months and were tested for their volatile organic compound (VOC) removal efficiency for 15 h. In general, variegated forms of the plant species have higher VOC removal after 15 h of VOC exposure than green plants, particularly when grown in 10 μmol･m-2･s-1. This is more evident in A. pusilla and S. aureus than in H. helix. The highest rate of toluene, m-, p-, and o-xylene removal per hour by plants grown under 10 μmol･m-2･s-1 was achieved by variegated A. pusilla, while for ethylbenzene, variegated A. pusilla and variegated H. helix had the highest removal rate per hour. In plants grown in 20 μmol･m-2･s-1 light intensity, variegated and green H. helix have the highest removal rate per hour of toluene and m-, p-, and o-xylene. For ethylbenzene, variegated A. pusilla and green and variegated H. helix had the highest removal rates per hour. The plant with the lowest removal rate per hour for all five VOCs was green S. aureus grown under both light intensities. The percentage VOC removal rate of variegated over green plants was 22% higher at a lower light intensity

Recently, volatile organic compound(VOC) has been noted as a main cause of air pollution. VOC, with its toxic and offensive odor, is hazardous to health. Furthermore indoor, underground and high-rise buildings are preferable living spaces. People spend more than 80% of the day indoor, so indoor air pollution is a matter of importance. In Korea, from 2004, 10 types of indoor pollutants in public facilities have been identified. However, there is no standard for individual VOC, so the regulation has not yet effectively been carried out. In this study, we have studied on the diffusion of Benzene in a room using a numerical analysis for various air-controlled conditions consisted of door, window and ventilation system. This study investigates spatial concentration distribution and time-history of room-averaged benzene concentration for several cases. The results of this study show that when the room is ventilated by a small fan only for 30 minutes, the average concentration of benzene is decreased a very little, thus the impact to human body would be serious compared to the case of natural ventilation by window and door. In the case of natural ventilation by window and door, if the wind speed is higher than 0.5m/s, it takes small than 4 minutes for benzene to spread to the target concentration of 1.2mg/㎥.

Vehicle occupant exposure to volatile organic compounds (VOCs) has been a subject of concern in recent years because of higher levels of VOCs inside vehicles as compared to the surrounding ambient atmosphere and because of the toxicity of VOCs. The effectiveness of two commercial ACDs for the removal of selected VOCs in the interior of automobiles was evaluated on 115 commutes through urban (Taegu) commutes by two cars and 9 idles. The idling and commuting studies conducted under four different driving conditions showed that the two commercial ACDs were not effective for the removal of VOCs in the interior of vehicles. The concentrations of all target VOCs except benzene were significantly higher (p<0.05) in the interior of older car than of newer car. The mean levels of benzene and toluene measured in this study were well excess of earlier other studies in the United States, besides Los Angeles with which was comparable. It was reported that the in-vehicle exposure to benzene and corresponding upper-bound cancer risk were about 8 times higher than those for outdoor environment, while they were about half of those from indoor environment.