This study was conducted to verify the reliability of volatile organic compounds (VOCs) data derived from Selected Ion Flow Tube-Mass Spectrometers (SIFT-MS) measurements. In the previous study, the measurement reliability was validated using simultaneous measurements by SIFT-MS and gas chromatography-mass spectrometry (GS-MS), but in order to ensure more accuracy, and additional analysis was conducted by diluting standard gases (2 ppm) consisting of 10 types of VOCs mainly measured in industrial complexes (concentrations ranged from 0 to 500 ppb). As a result of 2 experiments, the SIFT-MS showed linearity and produced a coefficient of determination of over 0.99 for all cases. SIFT-MS has secured high measurement reliability, and it is considered to be able to efficiently manage VOCs emitted in industrial complexes.

Volatile organic compounds (VOCs) are a paramount factor in air pollution of the environment. VOCs are vastly present in the wastewater discharged by the pharmaceutical industries. As it is evaporative in nature, it enters the environment spontaneously and causes air pollution, global warming, acid rain and climate change. VOCs must be treated before discharging or any other aerobic methods using an efficient catalyst. As the catalytic oxidation in the liquid phase is facile compared to the gas phase, this study investigated on catalytic liquid-phase oxidation of VOCs in model and real pharmaceutical wastewater. The model compounds of toluene-, ethylbenzene- and chlorobenzene-contaminated waters were treated separately along with the VOCs present in real pharmaceutical wastewater using a tungsten-based carbon catalyst. The tungsten was impregnated on the low-cost activated carbon matrix as it has good selectivity and catalytic property toward VOCs for facile catalytic operations. The metal catalysts were characterised by Fourier transform infrared spectroscopy, X-ray diffraction studies, and scanning electron microscopy with elemental and mapping analysis. The treatability was monitored by total organic carbon, ultra-violet spectroscopy and high-pressure liquid chromatography analysis. The tungsten-impregnated activated carbon matrix (WACM) has a catalytic efficiency toward toluene by 85.45 ± 1.78%, ethylbenzene by 93.9 ± 1.16%, chlorobenzene by 85.9 ± 2.26% and pharmaceutical VOCs by 85.05 ± 1.73% in 20 treatment cycles. The results showed that WACM worked efficiently in VOCs treatment, preventing the environment from air pollution. Furthermore, liquid-phase oxidation could easily be implementable on an industrial scale.

Benzene, toluene, ethylbenzene, and xylenes are commonly known as (BTEX) and include volatile organic compounds (VOCs) in ambient air. Exposure to some BTEX has been associated with health risks. This study aimed to reduce BTEX on the environment and human health dramatically. This research targeted decreasing the BTEX in an air environment by producing high surface area activated carbon (KA-AC) under optimized synthesis conditions from Ricinus communis as lignocellulosic waste using ZnCl2 solution, respectively. The influence of several activation parameters was investigated on the surface area, such as impregnation ratio, carbonization time, and carbonization temperature. The KA5-AC prepared under optimized conditions showed BET surface area and total pore volume of 1225 m2/ g, and 0.72 cm3/ g, respectively. The optimized synthesis conditions were as follows: 0.1, 0.5, 1, 2, and 5 M impregnation ratio, 450–950 °C carbonization temperature, and 100 min carbonization time. The characteristics of the optimized KA-AC were analyzed using nitrogen adsorption–desorption isotherm, scanning electron microscopy, and pore structural analysis. The results confirmed that the VOCs adsorption on KA-AC followed a monolayer adsorption isotherm over a homogeneous adsorbent surface. It showed the removal efficiency of benzene, toluene, ethylbenzene, and m, p-xylene (R2 = from 0.991 to 0.997). Moreover, the KA-AC exhibited good performance without considerable loss of efficacy throughout the experiments. Accordingly, it is concluded that developing low-cost activated carbon to use BTEX vapor adsorption research could be practical and developments to overcome for utilization in air pollution control.

Quality standards of activated carbon for gas-phase applications have been deleted from the Korean national standard list since 2007, and the iodine adsorption test is the only measure currently used for quality assurance. This study was performed to propose a suitable test method and a quality standard for gas-phase activated carbon. The "1/2 saturated vapor adsorption" test has been developed as a simple and convenient method to determine the adsorption capacity of activated carbon. In this study, the developed test method was evaluated using model VOCs including toluene, methyl ethyl ketone (MEK), and ethyl acetate (EA). A virgin activated carbon revealed adsorption capacities of 344mg/g, 322mg/g, and 328mg/g for toluene, EA, and MEK, respectively, and the adsorption capacity for a mixture of the three VOCs was 334 mg/g. When a regenerated activated carbon was applied, the adsorption capacities dramatically decreased to 62 mg/g, 52 mg/g, and 61 mg/ g for toluene, EA, and MEK, respectively. In addition, the 1/2 solvent vapor adsorption tests using 13 different specimens of activated carbon showed that their capacities were closely related to the iodine adsorption numbers, and this study suggested the adsorption capacity of 300 mg/g as a new quality standard. The novel test method and its standard may help to guarantee the quality of gas-phase activated carbon used for VOCs abatement processes.

Coffee is the most popular beverage in the world and various pollutants, including volatile organic compounds (VOCs), are emitted from the coffee manufacturing workplace (roasting process). In this study, we analyzed the characteristics of VOCs emissions from roasted Arabica coffee bean powder using a VOCs emission chamber with a PTR-ToF-MS. The emission test was maintained under constant temperature (20 ± 2oC) and humidity (50 ± 5%) conditions. As a result of the emission test, most of the target compounds had a high concentration in the initial period, and decreased emissions as time lapsed. Acetaldehyde showed the highest concentration and was initially 78 ppm during the test period. Acetaldehyde was followed by propionic acid at 61 ppm, propanal at 51 ppm, and isobutanal at 50 ppm. As a result of comparing the occupational exposure limits (OELs) of individual VOC emitted during the coffee roasting process, the OELs of four substances, including acetaldehyde, propionic acid, acetic acid, and pyridine were identified. Of all four substances, only pyridine exceeded the OELs, and the other compounds had levels of 10% to 30% of the OELs.

In this study, the adsorption/desorption performance of toluene was evaluated using zeolite adsorbent to replace activated carbon with one-off and ignition characteristics. For the proper operation of the VOCs adsorption/desorption and condensate recovery steps, the operating range by various adsorption/desorption temperatures was selected. The adsorbent is a bead-type zeolite, which was put into an adsorption tower of 10 LPM scale. As a result, it was demonstrated that 0.079 mg/g was adsorbed at a low temperature (20°C) during adsorption. In the case of desorption, it was found that VOCs adsorbed on the adsorbent were completely recovered after the desorption operation at 220°C for about 160 minutes. However, in the heating rate step for desorption, it was not possible to maintain an appropriate heating rate by filling the tower with zeolite. This was complemented by applying a copper plate with high thermal conductivity, and it was shown that the time was shortened by about 10 minutes or more. When VOCs are emitted at high concentrations during the desorption process, they can be reused as energy resources through low-temperature maintenance, and a condensation method was attempted. The efficiency of condensing chiller (cooler) with temperature control and liquid nitrogen condensing was compared. It was found that the chiller condensing efficiency increased as the temperature decreased. In the case of liquid nitrogen condensation, the liquid nitrogen temperature was maintained at -196°C, showing a stable efficiency of 90%.

Volatile organic compounds (VOCs) are chemicals to which humans are exposed frequently via various mediums, including vehicle emissions that contain fine dust and heavy metals, use of organic solvent building materials, furniture, and smoking. Exposure to high concentrations of VOCs may result in loss of consciousness, paralysis, convulsions, and, in the most severe cases, death. Therefore, the present study investigated the indoor and outdoor concentrations of total volatile organic compounds (TVOC) and five types of VOCs (benzene, toluene, styrene, m,p-xylene, and o-xylene) in apartments, a representative residential environment accounting for ~55% of the housing in the Seoul metropolitan area. The research was conducted over four seasons from May 2020 to February 2021, and the levels of VOC concentrations were analyzed by classifying them by season, weekday/weekend, and indoor/outdoor locations. The seasonal trend in VOC concentrations showed that TVOC concentration was highest in summer, with values of 1630.93 ± 1184.10 μg/m3 and 1610.36 ± 1363.43 μg/m3 for indoor and outdoor environments, respectively. The seasonal trends of the concentrations of the five types of VOCs showed that concentrations of benzene and toluene were highest in spring, the concentrations of m,p-xylene and o-xylene were highest in summer, and the concentration of styrene was highest in winter, irrespective of spatial characteristics such as indoor/outdoor environments. In all four seasons, the indoor concentrations were higher than the outdoor concentrations. These results reveal the spatial and temporal distribution characteristics of the VOCs and so can serve as useful basic data for managing indoor and outdoor levels of VOCs.

As the demand for the monitoring of VOCs increases, various unpowered colorimetric sensors are being developed, but the performance evaluation method of the developed sensors has not been systematically established. In this study, the device, experimental process, and data calculation methods for the performance evaluation of the colorimetric sensors were proposed. An aluminum chamber (70W× 128 L × 40 mm H) was designed to expose the sensor to a constant concentration of VOCs. In addition, an experimental apparatus was devised to evaluate the effect of environmental factors (temperature and humidity) affecting the ability of the sensor to detect VOCs. To calculate the color change value of the sensor corresponding to the concentration of VOCs, the ‘peak wavelength method’ that analyzes the wavelength of the highest intensity for high-concentration VOCs and the ‘spectral centroid method’ using a weighted arithmetic average for low-concentration VOCs were used. As a result of evaluating the ability of the colorimetric sensor to detect VOCs, which was made of polydimethylsiloxane (PMDS) by the method proposed in this study, the wavelength change values (bandgap shift) of the sensor for 1,000 ppm of benzene, toluene, oxylene, and acetone were 0.898 nm, 2.304 nm, 5.775 nm, and 0.249 nm, respectively. The precision was calculated by repeatedly measuring the sensing ability of the sensor 5 times for each type of VOCs. The precision of the sensor responses to benzene, toluene, o-xylene, and acetone were 15.23%, 7.84%, 4.14%, and 30.00% RSD, respectively. The method proposed in this study can be used to evaluate the performance of various types of VOCs colorimetric sensors.

The objective of this study is to identify the emission characteristics of VOCs from small-scale painting facilities, such emissions being pollutants that impact nearby living areas and to devise improvement measures to enhance management plans regarding pollutant emissions from painting facilities. VOCs emissions from painting facilities were estimated according to Clean Air Policy Support System (CAPSS) data based on the National Institute of Environmental Research (NIER)'s emission list in 2017. Three automotive painting facilities in Seoul were chosen for evaluation of the adsorption system. We analyzed the characteristics of VOCs generated by type of different operation and measured the removal efficiency of the adsorption system. Therefore, we analyzed current emissions of VOCs from automotive painting facilities based on field measurements. According to such detailed analysis, a systematic management plan was proposed.

The emission of particulate matter and volatile organic compounds (VOCs) from a motor vehicle painting booth was quantitatively evaluated. Most particulate matter was emitted during the spraying process, in which the PM10 concentration was 16.5 times higher than that of the drying process. When the paint was being sprayed, the particles with a diameter of 1.0~2.5 μm accounted for 39.4% and particles greater than 2.5 μm in diameter accounted for 30.6% of total particles. On the other hand, small particles less than 0.5 μm in diameter accounted for 52.4% of total particles during the drying process. In contrast to the particulate matter, high concentrations of VOCs were emitted during both spraying and drying processes. Butyl acetate, xylene, toluene, and m-ethyltoluene were the most abundant VOCs emitted from the motor vehicle painting booth. Additionally, xylene, butyl acetate, toluene, and 1,2,3-trimethylbenzene were the dominant ozone precursors. Especially, xylene exhibited the highest ozone production contribution (32.5~44.4%) among 34 species of the ozone precursors. The information obtained in this study can be used to establish a suitable management strategy for air pollutants from motor vehicle painting booths.

Activated carbon fibers (ACFs) were treated by electroless plating of CuO to improve their removal performance for volatile organic compounds (VOCs). The properties of these samples(CuO@ACFs) were evaluated by X-ray photoelectron spectroscopy (XPS), BET and N2O chemisorption to determine the area and dispersion of metallic CuO. The removal efficiency for benzene was investigated by gas chromatography (GC). The breakthrough time of CuO@ACFs increased by approximately 120% compared to that of untreated ACFs at benzene of 100 ppm. CuO@ACFs removed 100% of the benzene in 20 h, indicating this material can be used as a removal technology for VOCs.

Organic-inorganic hybrid perovskite nanocrystals have attracted a lot of attention owing to their excellent optical properties such as high absorption coefficient, high diffusion length, and photoluminescence quantum yield in optoelectronic applications. Despite the many advantages of optoelectronic materials, understanding on how these materials interact with their environments is still lacking. In this study, the fluorescence properties of methylammonium lead bromide (CH3NH3PbBr3, MAPbBr3) nanoparticles are investigated for the detection of volatile organic compounds (VOCs) and aliphatic amines (monoethylamine, diethylamine, and trimethylamine). In particular, colloidal MAPbBr3 nanoparticles demonstrate a high selectivity in response to diethylamine, in which a significant photoluminescence (PL) quenching (~ 100%) is observed at a concentration of 100 ppm. This selectivity to the aliphatic amines may originate from the relative size of the amine molecules that must be accommodated in the perovskite crystals structure with a narrow range of tolerance factor. Sensitive PL response of MAPbBr3 nanocrystals suggests a simple and effective strategy for colorimetric and fluorescence sensing of aliphatic amines in organic solution phase.

Indoor air contaminated with various pollutants commonly poses a risk to human health, and the need for installing air purifiers has been increasing. However, in commercial air purifiers pollutants-removal efficiency and durability are generally low. Since silver nano-composites are known to have catalytic oxidation and antibacterial capacities, it was anticipated to be applicable for indoor air purifiers. In this study, silver nano-composites were applied to granular activated carbon and scrubber solutions to treat a mixture of three air pollutants including toluene, formaldehyde, and bioaerosol. In the activated carbon deposited with silver nano-particles, the specific surface area decreased, resulting in a 10% loss of adsorption capacity for toluene. However, the removal efficacy of formaldehyde and bioaerosol increased by 10% due to the catalytic oxidation and antibacterial capacities. In the scrubber operation with silver nano-particles, the removal rates of formaldehyde and bioaerosol improved by 20%, while toluene removal was not observed. When the activated carbon column and the scrubber was connected in series, toluene was mainly removed by the activated carbon, and the removal rates of formaldehyde and bioaerosol increased in the presence of silver nano-particles. Consequently, for the improvement of indoor air quality, it is deemed appropriate to apply silver nano-material to indoor environments contaminated with pollutant mixtures.

This study was performed to investigate the characteristics of VOCs and carbonyl compounds emitted by smallscale master, offset, and screen printing facilities. During the printing process, concentration measurements of indoor samples were made at each on the printer equipment and the indoor center of the facility. In each case, the window or door served as natural ventilation, and concentration measurements of outdoor samples were made at each air exit point. The results showed that in all printing facilities, the levels of VOCs and carbonyl compounds were much higher in printer equipment compared to indoor levels. Comparative examination of VOCs between printer equipment and the indoors of the facility, the main species of master and offset printer equipment were Methyl isocyanide, 2,2,6-Trimethyloctane, 2,2-Dimethyldecane, 3,7-Dimethyldecane, Toluene, Acetonitrile, and 3- Methoxy-3-methylbutanol. The main species of the indoors of master and offset facilities were Toluene, 2,2,6- Trimethyl-octane, Isopropyl alcohol, 3-Methoxy–3- methylbutanol, Nonane, and Acetone. However, in the screen printing facility, the printer and indoor emission compounds were the same such as 2-Methyl-cyclopentanone, Cyclohexanone, Ethylbenzene, and p-Xylene. Among the compounds released to the outside, Toluene and Acetone were the most abundant species of VOCs and carbonyl compounds, respectively.

The use of printing inks containing organic solvents by the master, offset and screen printing process implies the release of volatile organic compounds (VOCs) to the work environment. In this study, the volatile content of inks was evaluated by using a thermogravimetric analyzer (TGA), in which the solvent is evaporated. And, to identify the the characterization of VOCs emissions from printing inks, air samples were collected in a thermal extractor (TE) and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Weight loss curves suggest that there are two main stages, such as dry fastening and chemical curing. As the result, the first stage of mass loss (below 100oC) was due to VOC evaporation. At this stage, master and offset inks are slightly stable thermally up to 100oC, but screen inks weight loss increases distinctly beyond 25oC. The volatile content is higher in screen inks than in the master and offset inks. The results of the mass-specific TVOC emission rate of the master, offset, and screen inks were 6.3 μg/(g·h), 8.4 μg/(g·h), and 212.2 μg/(g·h), respectively. Then the TVOC emission rate of the screen inks was 25~33 times higher than that of the master and offset inks. The main species were 1-Ethyl-2-pyrrolidinone, 1,2,4-Trimethylbenzene, 1,2,3-Trimethylbenzene, 1,2,4,5-Tetramethylbenzene, 1-Methoxy-2- propanol, Decane, Undecane, and Nonane.

In this study, 38 residents of the Jeonnam areas in Korea were assessed for their level of exposure to VOCs. The aim was to understand the difference in levels of indoor, outdoor, and personal exposure to VOCs (benzene, toluene, ethylbenzene) and a health effect assessment was conducted to determine whether there was any fatal cause from carcinogenic or non-carcinogenic elements from case and control group. Personal exposure to benzene showed a higher distribution than indoor and outdoor concentrations, and it was found that the average concentration of the case group was higher than that of the control group in all indoor, outdoor, and personal exposures. With regard to benzene, in the CTE, RME, and Monte-Carlo analysis, all subjects in the case group were seen to exceed the lifetime cancer risk of 10−6 defined by the US EPA and in the RME analysis the control group subjects were also seen to exceed the lifetime cancer risk of 10−6 defined by the US EPA. In the case of toluene, ethylbenzene on the CTE, RME, and Monte-Carlo analysis, the non-carcinogenic standard of 1 was not exceeded.

We used three gas sensors to monitor hydrogen sulfide, ammonia, and volatile organic compounds (VOCs), which were frequently emitted from environmental facilities, such as municipal wastewater treatment, livestock manure treatment, and food waste composting facilities. Two electrochemical (EC) sensors for detecting hydrogen sulfide and ammonia, and a photoionization detector (PID) sensor for detecting VOCs were characterized in this study. The performance of their linearity by concentration levels, lower detection limit (LDL), repeatability, reproducibility, precision, and response time were tested under the laboratory condition. The linearity according to concentration levels were favorable for all three sensors with high correlation coefficients (R2 > 0.98). The ammonia sensor showed the highest LDL (18.6 ppb) and the hydrogen sulfide and VOC sensors showed 22.3 ppb and 26.7 ppb of LDL, respectively. The reproducibility and precision were favorable for all three sensors, indicating a lower relative standard deviation (RSD) than 0.9% in the reproducibility test and 7.2% in the precision test. The response times to reach target concentration were varied from 1 to 12 minutes. The ammonia sensor needed 12 minutes of response time at 1 ppm target the NH3 concentration and the hydrogen sulfide and VOC sensors needed less than 2 minutes of response time.

This study aims to evaluate the concentration of biomarkers for heavy metals and volatile organic compounds (VOCs) for the residents living in the Gwangyang industrial complex to compare with residents in the residential area as a control. A total of 810 healthy adults participated in this study, and their urinary and blood samples were analyzed for metals, including As, Pb, Cd, or Hg, and VOC compounds. All study participants also completed questionnaire surveys to collect more detailed information on personal lifestyles, dietary and drinking habits, residential housings types, and their health conditions. The geometric means of urinary levels of Cd were 1.06 g/g creatinine for those living in the vicinity of Gwangyang industrial complex and 1.41 g/g creatinine for those in residential areas (p<0.05). Furthermore, urinary mean levels of Hg were 1.39 μg/g creatinine in the industrial area and 1.23 μg/g creatinine in the control area, respectively. The concentrations of individual VOCs in blood were significantly different between the two population groups. Therefore, urinary levels of Cd and Hg were significantly higher in the local residents compared to the Gwangyang industrial areas. A further study is needed to identify adverse health effects due to environmental exposures to heavy metals, VOCs, and other pollutants in the Gwangyang industrial complex areas in the future.

In this study, we listed the VOCs focusing on ozone precursors emitted from printing shops in urban areas. The emission characteristics of the VOCs from workplaces were evaluated in terms of the used inks. As a result of field measurements, more than 80% of detected VOCs showed high values of photochemical ozone creation potential (POCP). The main species were aromatic hydrocarbons such as ethylbenzene, toluene, ethyltoluene, xylene, trimethylbenzene and their isomers, and paraffin hydrocarbons such as nonane, decane, and octane. Comparative examination between pristine ink and the printing process revealed the emission of hydrocarbons with 8 to 12 carbons such as o-xylene to n-dodecane from the used inks and with 3 to 7 carbons such as acetone to 3-methylhexane from the printing process. The major contributors to ozone production in printing industries were toluene (12.2%), heptane (7.43%), and 1,2,3-trimethylbenzene (7.21%) in every step.

In this study, volatile organic compounds (VOCs) emitted from printing industries were analyzed, and an inorganic adsorbent, γ-alumina, was selected for the effective control of the VOC emissions. Printing processes commonly require inks, thinners, and cleaners, and they were mixed organic solvents containing aromatic compounds, ketones, and alcohols. Therefore, toluene, methyl ethyl ketone (MEK), and isopropyl alcohol (IPA) were selected as model compounds for this study. The adsorptive properties using γ-alumina were determined for the model compounds. Both batch isotherm and continuous flow column tests demonstrated that the adsorption capacity of MEK and IPA was 3~4 times higher than that of toluene. The column test performed at an inlet toluene concentration of 100 ppm showed that an 80% breakthrough for toluene was observed after 3 hours, but both MEK and IPA were continuously adsorbed during the same time period. A numerical model simulated that the γ-alumina could remove toluene at a loading rate of 0.4 mg/min only for a 4-hour period, which might be too short of a duration for real applications. Consequently, lifetime enhancement for γ-alumina must be implemented, and ozone oxidation and regeneration would be feasible options.