• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.772-790
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• 2011

In this paper, we use the HDDM (High-order Decoupled Direct Method)-driven ozone sensitivity to predict change in ozone concentrations in response to domain-wide $NO_x$(Oxides of Nitrogen) and VOC (Volatile Organic Compound) emission controls over the Seoul Metropolitan Area during June 11~19, 2007. In order to validate the applicability of HDDM to $NO_x$ and VOC control scenarios, the HDDM results are compared to Brute Force Method (BFM). For VOC controls, NME (Normalized Mean Error) between BFM and HDDM remains less than 2% until the domain-wide VOC emissions are reduced by 80%. The NME for a 40% reduction in the domain-wide $NO_x$ emissions is less than 5% but increases abruptly after further reductions in the $NO_x$ emissions (i.e., 80% reduction). The results indicates that it may be inaccurate to use ozone sensitivity coefficients estimated at a given base emission condition in predicting ozone after $NO_x$ reductions larger than ~50% of the domain total in the SMA. Therefore, HDDM application on piecewise emissions is desirable to predict ozone response to emission controls with accuracy (i.e., truck emissions rather than the domain total). For computational efficiency, HDDM shows approximately 30% faster than the BFM sensitivity approach.

• Journal of the Korean Chemical Society
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• v.63 no.3
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• pp.213-215
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• 2019

• International Journal of Industrial Entomology and Biomaterials
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• v.48 no.2
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• pp.67-77
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• 2024

This study aims to assess the efficacies of exogenous enzymes, derived from invertebrate gut-associated microbes, as feed additives, in reducing volatile organic compound (VOC) emissions using an in vitro pig intestine continuous fermentation system. An in vitro continuous fermentation model was used to simulate a comparable bionic digestion system by co-reacting feed, enzymatic additives (arazyme, mannanase, and xylanase, derived from the gut bacteria of Nephila clavata, Eisenia fetida, and Moechotypa diphysis, respectively), and gastrointestinal microbes, followed by an analysis of their correlations. A significant correlation was observed between exogenous enzyme supplementation and reduced VOC emissions in the fecal phase of continuous fermentation (p < 0.05). The concentration of VOCs decreased by 3.75 and 2.75 ppm in the treatment group following arazyme and multi-enzyme supplementation, respectively, compared to that in the control group (7.83 ppm). In addition, supplementation with arazyme and multiple enzymes significantly affected the microbial composition of each fermentation phase (p < 0.05). In particular, Lactiplantibacillus pentosus and Pediococcus pentosaceus, which changed in abundance according to arazyme or multi-enzyme supplementation, exhibited a positive relationship with VOC emissions. These results suggest that exogenous enzymes derived from invertebrate gut-associated bacteria can be efficiently applied as feed additives, leading to a reduction in VOC emissions.

• Journal of Environmental Science International
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• v.30 no.3
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• pp.219-234
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• 2021

Industrial emissions, mainly from industrial complexes, are important sources of ambient Volatile Organic Compounds (VOCs). Identification of the significant VOC sources from industrial complexes has practical significance for emission reduction. VOC samples were collected from July 2019 to June 2020. A Positive Matrix Factorization (PMF) receptor model was used to evaluate the VOC sources in the area. Four sources were identified by PMF analysis, including coating-1, coating-2, printing, and vehicle exhaust. The coating-1 source was revealed to have the highest contribution (41.5%), followed by coating-2 (23.9%), printing (23.1%), and vehicle exhaust (11.6%). The source showing the highest contribution was coating emissions, originating from the northwest to southwest of the sample site. It also relates to facilities that produce auto parts. The major components of VOC emissions from the coating facilities were toluene, m,p-xylene, ethylbenzene, o-xylene, and butyl acetate. Industrial emissions should be the top priority to meet the relevant control criteria, followed by vehicular emissions. This study provides a strategy for VOC source apportionment from an industrial complex, which is helpful in the development of targeted control strategies.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1035-1041
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• 2002

The adhesion characteristics of adsorbent during impregnation of Y-type and ZSM-5type zeolites into ceramic paper were analyzed, as the amount of silica sol in slurry for impregnation was varied. 31 wt% of zeolite particle, which is useful for VOC adsorption, was evenly dispersed and adhered on ceramic paper and original crystal structure of the zeolite remained unchanged even after binder application and heat treatment. Surface area of the impregnated ceramic paper was decreased compared with that of zeolite powder. And it was found to be attributed to the reduction of volume of mesopore while the volume of micropore under $20{\AA}$ was unchanged. Zeolite-impregnated honeycomb cylinder, whose diameter and length were 10 cm and 40 cm, respectively, was subjected to adsorption/desorption test with respect to toluene, MEK, cyclohexanone. All of the VOC's were removed by adsorption with efficiency higher than 97% and from the static adsorption test, $42 Nm^3/h$ of 300 ppmv-VOC-laden air was calculated be treated continuously, when the honeycomb was used in an adsorptive rotor system.

• Analytical Science and Technology
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• v.18 no.5
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• pp.431-435
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• 2005

In order to evaluate the hazardous effects of environmental tobacco smoking (ETS), we measured the concentrations of major aromatic VOC from those who decided to participate in a program to quit smoking. By acquiring the air samples both before and after quitting smoking (QS), we were able to compare their BTEX concentration levels in their breathing air. The results of our study clearly showed that BTEX levels in respiring air samples were significantly high prior to the QS period. It was found that toluene maintained the highest concentration levels both before and after the QS period. However, the level of reduction was most significant in the case of benzene, as it was decreased 10 times from 4.8 to 0.46 ppb. When their reduced BTEX levels are compared to those who never smoked before, differences were not significant enough to distinguish in statistical terms. The overall results of this preliminary study suggest that BTEX levels in breathing air samples can be used as one of the most sensitive signals to judge the effect of QS.

• Journal of Environmental Impact Assessment
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• v.19 no.1
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• pp.99-106
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• 2010

The project of Cheonggyecheon revived the 5.8 kilometer stream and it removed the cover of stream and Cheonggye elevated road. It was begin October of 2003 and completed October of 2005. The purpose of this study is to analyze the air pollution change of Cheonggyecheon area and neighboring area from before and after the project. The change of concentration is compared with an air monitoring station data and measurement data. The analyzed pollutants are $NO_2$, $PM_{10}$, heavy metal, VOC which are measured at Cheonggyecheon and neighboring area. As the results, $NO_2$ concentration shows 10 % decreases in Cheonggyecheon area and neighboring area shows 16 % decreases by Chenoggyecheon restoration, and $PM_{10}$ concentration shows 15 % decreases in Cheonggyecheon area and neighboring area shows 16 % increases. One of VOC, benzene is increased in Cheonggyecheon area compared with neighboring area but Toluene, Ethylbenzene, m+p Xylene increased in neighboring area. After the Cheonggyecheon restoration, The heavy metals are not shows the improvement, but $PM_{10}$ and $NO_2$ concentration improved more than the changes of neighboring area. These improvements of pollution due to reduction of transportation and clearing of elevated road by Cheonggyecheon restoration project.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.615-621
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• 2018

Recently, various environmentally friendly products have been developed for improving the indoor air quality while pursuing a well-being nature-friendly healthy life as a core value. In this research, we not only solve the problems of existing environmentally friendly paints, but also developed a charcoal composite seats that can reduce radon, which is a natural radioactive substance, and evaluated the reduction effect of radon, formaldehyde and volatile organic compounds. In the charcoal composite seats, a sodium silicate emulsion and charcoal were mixed to prepare an charcoal liquid coating material, and the composite seats was fabricated by air-spray coating method. In order to analyze the hazardous substance reduction performance of the fabricated charcoal composite seats, radon was designed to comply with the Ministry of the Environment standard, formaldehyde and volatile organic compounds were designed to comply with KCL-FIR-1085 standard. As a result of the experiment, the fabricated charcoal composite seats was evaluated as having a radon reduction capability of about 90.8% from 20 hours, formaldehyde and volatile organic compounds were 3 hours, and the reduction capability of 96.7% and 96.6% was found respectively. It is considered that these results can be utilized as basic data at the time of product development for improvement of indoor air quality.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.504-522
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• 2011

Simulations of CMAQ with the High-order Decoupled Direct Method (HDDM) for a 2010 June episode are applied to estimate the influence of local and neighborhood emissions on ozone concentrations in the Kwang-Yang Bay (KYB) area. In order to examine ozone response to reductions in $NO_x$ and VOC emissions from KYB and Gyeongsang, ozone isopleths are generated with the first and second-order sensitivity coefficients from HDDM simulations at three sites; Taein, Samil, and Gwangmoo. Simulations show that reduction in KYB $NO_x$ may increase ozone over the sites. On the contrary, $NO_x$ reduction from Gyeongsang may decrease ozone at the sites when transport of ozone and its precursors from upwind Gyeongsang is potentially high. However, VOC reductions from KYB and Gyeongsang are favorable to lower ozone over KYB. The study implies that emission reductions for both local and neighboring areas are likely more effective to bring KYB to ozone attainment.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.563-576
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• 2023

In this study nitrogen dioxide (NO₂), formaldehyde (HCHO) from the Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI), OMI/ Microwave Limb Sounder (MLS) tropospheric column ozone (TCO), and Airkorea ground-based O₃ data were analyzed to examine the photochemical reaction relationship between tropospheric ozone and its precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs). As a result of analyzing the trend of long-term changes from 2006 to 2020 using OMI satellite data, TCO showed an increasing trend, NO₂ steadily decreased, and HCHO continued to increase in Northeast Asia. In addition, formaldehyde nitrogen dioxide ratio (FNR; HCHO/NO₂ ratio), an indicator of ozone sensitivity, is gradually increasing, which means that the VOC-limited regime is decreasing. This study conducted a sensitivity analysis of ozone generation using TROPOMI FNR and ground-based ozone (O₃) over the recent years (2019~2022) to identify the possible cause for the continuous increase of ozone in Korea. Similar to the previous studies, VOC-limited and transitional regimes appeared in megacities, and VOC-limited regimes also appeared in areas where major power plants were located. In VOC-limited regimes, in other words, areas where NOx is excessively saturated, the reduction in NOx emissions may have weakened the ozone titration and thus led to the increase of ozone. Therefore, VOC emissions should be reduced in the short term rather than NOx emissions to reduce ozone concentrations under the VOC-limited regime.