• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.370.1-370.1
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• 2016

Volatile organic compounds (VOCs) are considered hazardous air pollutants and these are emitted from building materials and household products. VOCs can cause global warming as well as human sickness, and even cancer. Photocatalysis provides a way of converting VOCs into harmless materials. Various researches have shown that $TiO_2$ is the most efficient photocatalysts due to its excellent activity. In this study, metal/non-metal doped $TiO_2$ particles are synthesized for the enhancement of the photocatalytic properties of pure $TiO_2$. By metal/non-metal doping, band gap energies of prepared samples were analyzed by UV/Visible spectrophotometer. The physical and chemical properties of synthesized powder were characterized by field emission scanning electron microscope, by BET for measuring their specific surface area, and by XRD for phase identification and particle size determination. Degradation ability for p-xylene was evaluated through monitoring the concentration in a closed chamber. Relation between their properties and decomposition abilities for VOC were evaluated based on the experimental results.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.2
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• pp.172-181
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• 2012

Mercury is one of the most hazardous air pollutants. Recently, mercury has been a concern in domestic and overseas because it has lethal toxicity, long distance transport, persistence and bioaccumulation in the environment. Stationary combustion sources such as coal-fired power plants, waste incinerators, and cement kilns are the major sources of mercury emissions. The objectives of this study were to measure the concentration for mercury from coal-fired power plants and to calculate emission factor to estimate its emission. The results showed that the mercury concentrations in the flue gas were 1.63-3.03 mg/$Sm^3$ in anthracite-fired power plants (average 2.32 mg/$Sm^3$) and 1.95-3.33 mg/$Sm^3$ in bituminous-fired power plants (average 2.6 mg/$Sm^3$). Mercury emission factor was estimated as 25.74 mg/ton for anthracite-fired power plants and 12.48 mg/ton for bituminous-fired power plants. Because actual measurements are limited in quantity, it is desirable to refine our estimates by extending the actual measurements.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.2
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• pp.191-206
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• 2018

In this study, the HAPs(Harzard Air Pollutants) emission factor level of Starex and Grand Carnival was tested using PEMS (Portable Emissions Measurement System) on real road driving. As a result of RDE (Real Driving Emission test), the overall vehicle speed pattern showed similar characteristics. The real-road driving test at constant speed revealed emission factor is inversely proportional relationship to constant speed. Results of accelerating with speed limit on the real-road were shown as followings; Uran (less than 45 km/h)>Rural (<45 km/h, less than 80 km/h)>Motorway (>80 km/h). Moreover, the sudden acceleration and deceleration in driving at high speed was the increasing factor to the HAPs emission factor. This tendency is considered to be influenced by the operating environment on real roads.

• Journal of Environmental Health Sciences
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• v.43 no.2
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• pp.157-166
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• 2017

Objectives: Exposure to hazardous air pollutants could be affected by sociodemographic factors such as age, gender and more. Information on time spent in microenvironments has a critical role in exposure assessment. The purpose of this study was to analyze the exposure pathways which influence personal exposure through time-activity patterns and sociodemographic factors. Methods: A total of 379 subjects were collected from the second term of the Korean National Environmental Health Survey. A questionnaire survey in relation to sociodemographic factors and a time-activity diary were carried out for personal exposure to toluene. Focusing on personal exposure to toluene, factors affecting personal exposure were analyzed using multiple regression analysis. Results: Participants spent their time in an indoor house for $16.8{\pm}4.0hr$, workplace or school $2.3{\pm}3.5hr$, and other indoor $2.1{\pm}2.2hr$. Sociodemographic factors were significantly different among each personal exposure and microenvironment. Time of staying at an office turned out to be a main factor from point of exposure in exposure pathway using multiple regression analysis. As a result, this means that exposure may be different according to the time of staying in each microenvironment. Conclusions: Personal exposure to air pollutants might be decided by time-activity pattern indicating when, where, and which activities people pursue, as well as individual sociodemographic factors.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.175-184
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• 2018

Emission characteristics of regulated (NOx, PM, CO, NMHC) and unregulated (VOCs, aldehydes, PAHs) air pollutants were investigated for diesel heavy duty buses equipped with different after-treatment systems (DPF+EGR and SCR) under urban driving cycle. The combustion temperature and the working temperature of SCR catalysts were important to make impact on NOx emissions, whereas PM emissions were low. The alkane groups dominated NMVOCs emissions, making 42.6~59.4% of sum of the NMVOCs emissions. Especially, alkane emissions of DPF+EGR-equipped vehicle included DOC had 14.9~15.5% higher than those of SCR-equipped vehicle due to low efficiency of oxidation catalyst. In the case of individual NMVOCs, n-nonane and propylene emissions highly occupied for DPF+EGR and SCR, respectively. Formaldehyde emissions among aldehydes were the highest and PAHs emissions were hardly detected except naphthalene and phenanthrene. The NMHC speciation has been shown to be the highest of the formaldehyde ranged 20.8~21.5%. The results of this study will be contributed to establish Korean HAPs emission inventory for automobile source.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.468-476
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• 2006

Hazardous air pollutants (HAPs) have high toxicity and bioaccurnulation potentials into human body even inbsmall amount (levels of ng/$m^3$). As the levels of HAPs might be controversial, it has been become essential to establish the analysis method for correct results. In this study, various analysis methods of VOCs and Aldehydes were compared in order to select the proper methods in our condition. Sampling and analysis method of VOCs were followed to EPA TO-14a and TO-17. VOCs were collected in absorption tube and separated by thermal desorption unit then analyzed by GC/MSD. Aldehydes were sampled in DNPH-cartridge and extracted into solution then analyzed by HPLC as the same condition of EPA TO-13a. This study also shows the results of QA/QC system of selected methods. Some experiments could be improving the data assurance blank test, calibration check, repetition precision check, the determination of detection limit and reproducibility of the retention time. Precisions of VOCs and aldehydes were ranged in 2$\sim$9% and 1$\sim$4% RSD, respectively. Recovery rate of VOCs showed variable ranges from 60 to 133.5%. MDL of VOCs and aldehydes were 0.044$\sim$0.284 ppb and 0.14$\sim$1.02 ng, respectively.

• Journal of Sensor Science and Technology
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• v.29 no.2
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• pp.112-117
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• 2020

Xylene is a hazardous volatile organic compound that should be precisely measured to monitor indoor air quality. However, the selective and sensitive detection of ppm-level xylene using oxide-semiconductor gas sensors remains a challenge. In this study, pure and Cr-doped Co₃O₄ nanoparticles (NPs) were prepared using flame spray pyrolysis, and their gas-sensing characteristics to 5-ppm xylene at 250 ℃ were investigated. The 4 at% Cr-doped Co₃O₄ NPs exhibited a high gas response to 5-ppm xylene (resistance ratio to gas and air = 39.1) and negligible cross-responses to other representative and ubiquitous indoor pollutants such as ethanol, benzene, formaldehyde, carbon monoxide, and ammonia. In this paper, the enhancement of the gas response and selectivity of Co₃O₄ NPs to xylene by Cr doping was discussed in relation to the catalytic promotion of the gas-sensing reaction. This sensor can be used to monitor indoor xylene.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.2
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• pp.244-258
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• 2018

We performed this study to investigate the spatial, seasonal, and daily variations of the concentrations of volatile organic compounds (VOCs) in Pohang, where large steel industrial complexes are located. Ambient air sampling was undertaken at 4 sites during 4 seasons. Each sample was taken for 4 hours continuously for 8 consecutive days per season at each site. Three sites were located within the Pohang city, but one as a control site in Gyeongju. A total of 72 individual VOCs were determined by thermal desorption coupled with GC/MS, including aliphatics, aromatics, carbonyls and halides. The most abundant VOC was toluene, being followed by ethylbenzene and xylenes. Benzene concentrations(c.a. 0.7 ppb) were found to be much lower than the national ambient standard of 1.5 ppb. Overall, the VOCs levels in Pohang appeared to be lower than other national industrial complexes in Korea such as Shiwha-Banwol, Yeosu-Gwangyang, Gumi, and Ulsan. This implies that steel industry may not give significant impacts on the atmospheric levels of VOCs as much as petrochemical, electronic, and/or textile industries, where large amounts of organic solvents are used.

• Journal of Environmental Health Sciences
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• v.34 no.3
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• pp.219-225
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• 2008

Many building materials may contain high concentrations of volatile organic compounds (VOCs) and other hazardous pollutants(HAPs). Specifically, VOCs discharged by indoor building material may cause "new house" syndrome, atopic dermatitis etc. The diffusion coefficient and initially contained total VOC quantity were determined using microbalance experiments and small chamber tests. Interactions between volatile organic compounds (VOCs) and vinyl flooring (VF), a relatively homogenous, diffusion-controlled building material, were characterized. Rapid determination of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) for each VOC was achieved by placing thin VF slabs in a dynamic microbalance and subjecting them to controlled sorption/desorption cycles. K and D are shown to be independent of concentration for all of the VOCs and water vapor. This approach can be applied to other diffusion-controlled materials and should facilitate the prediction of their source/sink behavior using physically-based models.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.1-4
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• 2021

Ambient air pollution, in particular, particulate matter (PM) pollution imposes serious health concerns such as hospitalization and premature deaths, worldwide. While commercial breathing masks are in use for protection against this hazardous issue, yet their efficiency in filtering PM was not up to the par, besides several other discomforts such as poor breathability due to reduced air flow, sweat production etc. In this study, commercial face mask coated with β-glucan, a high molecular weight polymer is tested for its efficacy in filtering PM. Quantification of PM before and after filtration and microscopic observation (using scanning electron microscopy (SEM)) of the fabric used in filtering the dust pollutants (generated from wood chips and cigarette) showed that β-glucan coated fabric were significantly efficient in capturing PM (size of 10 and 2.5 ㎛ in diameter) than that of the untreated control fabric, wherein the former had filtration efficacy with fold increase of 11.6 and 2.6 towards capturing PM2.5 and PM10 respectively than the latter. Thus, β-glucan coated fabric was found to be effective in filtering PM.