Occupational exposure to VOCs and carbonyl compounds in beauty salons and health risks associated with it in South Korea.

Long-term exposure to volatile organic compounds (VOCs) and carbonyl compounds in beauty products may adversely impact the health of beauty salon technicians. Previous studies have focused on assessing indoor air concentrations of chemicals, such as benzene and toluene, and not on personal exposure concentrations. This study measured the indoor and personal exposure concentrations of VOCs and carbonyl compounds in fifty-three beauty salons in Korea. Non-carcinogenic and carcinogenic risks and sensitivity were analyzed using the Monte Carlo simulation technique. The indoor and personal exposure concentrations of acetone were 82.24 µg/m3 and 104.97 µg/m3, respectively, the highest among all measured chemicals. Beauty salon technicians who experienced adverse health effects had significantly higher concentrations of acetone, benzaldehyde, and toluene than those who did not experience adverse health effects (p-value < 0.05). The average hazard quotients of formaldehyde and acetaldehyde were higher than the acceptable risk level (1), and the average cancer risks of formaldehyde exceeded the acceptable risk level (10-6). Wearing personal protective equipment was the most efficient risk reduction strategy for reducing the non-cancer risks of acetaldehyde and formaldehyde and the carcinogenic risks of formaldehyde. The results of this study can be used as a basis for reducing exposure to VOCs and carbonyl compounds among salon technicians.

The transfer characteristics of heavy metals in electronic cigarette liquid.

In this research, the concentrations of six heavy metals (Zn, Pb, Ni, Fe, Cd, and Cr) in electronic cigarette (EC) solutions were determined to assess their association with EC use patterns. To this end, their contents were analyzed under three conditions: (1) ECL I: EC liquid was directly taken from EC liquid bottles as purchased from retail, (2) ECL II: EC liquid simply stored in the EC clearomizer for a certain period was collected without any puffing, and (3) ECL III: EC liquid remaining in the EC clearomizer after puffing. Each of all three types of electronic cigarette liquid (ECL) samples selected in this study was analyzed after being stored for up to seven days (at elapsed intervals of 1, 3, and 7 days). Zn and Pb were detected in all types of samples while Cd was all below method detection limit (MDL). Fe, Ni, and Cr were generally below MDL in ECL I, while it was not the case for ECL II and III samples. Especially, Zn, Pb, and Ni levels increased significantly with the use of EC. If the consumption of EC causes alterations in elemental content, such changes can be assessed in terms of ratio values such as "after/before use". The maximum ratio values for each target, when assessed using ECL III samples, were seen in the following order: 463 (Zn) > 315 (Ni) > 131 (Fe) > 47.9 (Cr) > 36.0 (Pb). As such, EC use is clearly demonstrated as the transfer route of heavy metals.

Effects of Legal Regulation on Indoor Air Quality in Facilities for Sensitive Populations - A Field Study in Seoul, Korea.

Facilities for sensitive populations have increased in Korea; and its indoor air quality (IAQ) was strictly regulated by the Korean government compared to other facilities. However, merely public facilities on certain level of total floor area were lawfully regulated. This study aims to characterize the indoor environment at facilities for sensitive populations in Korea and investigate the effects of legal regulation on IAQ throughout the duration of 1 year. Sixty facilities for sensitive populations were investigated. Particulate matter (PM10), nitrogen dioxide (NO2), carbon dioxide (CO2), carbon monoxide (CO), total bacteria count (TBC), total volatile organic compound (TVOC), formaldehyde (HCHO), radon (Rn), ozone (O3), asbestos, fine particulate matter (PM2.5), and volatile organic compounds (VOCs) were target pollutants. As a result, none of the rooms' concentration of CO, NO2, O3, Rn, asbestos, and VOCs exceeded the Korean Standard of Indoor Air Quality, while some rooms' concentration of other pollutants exceeded the KSIAQ. Statutory facilities had lower indoor pollutant concentrations and exceedance rates due to efficient ventilation system and the lack of kitchen location within the building, as opposed to non-statutory facilities. In addition, the VOCs had significant differences depending on the number of years it took for the building to be constructed. To reduce the indoor pollutants concentrations, efficient ventilation systems should be installed while controlling the main sources of pollutants. In addition, construction and remodeling using eco-friendly materials should be considered. The standards of IAQ for small size facilities should be included in the KSIAQ in the future.

Comparison of Pure-Tone Average Methods for Estimation of Hearing Loss Caused by Environmental Exposure to Lead and Cadmium: Does the Pure-Tone Average Method Which Uses Low-Frequency Ranges Underestimate the Actual Hearing Loss Caused by Environmental Lead and Cadmium Exposure?

Previous studies have reported that exposure to lead and cadmium can damage the inner ear receptor, which perceives high-frequency sounds. However, few studies have used the pure-tone average (PTA), including high-frequency ranges, for the estimation of hearing loss caused by lead and cadmium exposure. We estimated hearing loss using the PTA test, in low-frequency, speech frequency, and high-frequency ranges and compared the differences in the results using 3 PTA calculation methods. We analyzed the data of 2,387 participants, between the ages of 19 and 85 years, that were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) of 2010-2012. A dose-response relationship between hearing loss and heavy metal exposure was observed in the high-frequency method after adjustment for confounding factors. When using the high-frequency PTA, it was found that doubling of the levels of lead and cadmium in the blood was associated with a 1.88- (95% CI 1.11-3.17) and 1.89-fold (95% CI 1.02-3.50) increase in the OR for hearing loss. In the case of the low-frequency and speech frequency PTA, however, there were no significant relationships between hearing loss and the concentrations of lead and cadmium in the blood. The outcomes of the present study suggest that the estimation of hearing loss caused by environmental exposure to lead and cadmium is affected by the frequencies used in the PTA calculation.

A mechanical pencil lead-supported carbon nanotube/Au nanodendrite structure as an electrochemical sensor for As(iii) detection.

A mechanical pencil lead (MPL), an easily obtainable carbon-based material with a consistent size, was used as a frame to construct an MPL-supported carbon nanotube/Au nanodendrite (MPL-CNT/AuND) sensor through simple electrodeposition of Au onto the MPL in the presence of CNTs. A nanodendrite structure was adopted to ensure large numbers of active electrochemical sites because of its hierarchical structure with well-aligned terraces; the CNTs were used to firmly adhere the fabricated Au nanodendrites to the MPL surface to ensure ruggedness. The MPL-CNT/AuND structure was used to measure As3+ samples in a concentration range from 0.5 to 80 ppb using anodic stripping voltammetry (ASV). The variation in peak intensities was linear (R2: 0.997), and the limit of detection (LOD) was 0.4 ppb. The average relative standard deviation (RSD) of the peak intensities from the voltammograms of each sample collected using three separately prepared MPL-CNT/AuNDs was 8.7%, thereby demonstrating good sensor-to-sensor reproducibility. Furthermore, when three As3+ samples prepared in tap water were measured, the accuracy was maintained without noticeable degradation and the response was steady up to 50-cycle measurements.

Emissions of amides (N,N-dimethylformamide and formamide) and other obnoxious volatile organic compounds from different mattress textile products.

The emission rates of N,N-dimethylformamide (DMF), formamide (FAd), and certain hazardous volatile organic compounds (VOCs) were measured from seventeen mattress textile samples with four different raw material types: polyurethane (PU: n=3), polyester/polyethylene (PE: n=7), ethylene vinyl acetate (EV: n=3), and polyvinyl chloride (PC: n=4). To simulate the emissions in a heated room during winter season, measurements were made under temperature-controlled conditions, i.e., 50°C by using a mini-chamber system made of a midget impinger. Comparison of the data indicates that the patterns were greatly distinguished between DMF and FAd. PU products yielded the highest mean emission rates of DMF (2940 µg m(-2)h(-1): n=3) followed by PE (325 µg m(-2)h(-1): n=7), although its emission was not seen from other materials (EV and PC). In contrast, the pattern of FAd emission was moderately reversed from that of DMF: EV>PC>PE>PU. The results of our analysis confirm that most materials used for mattress production have the strong potential to emit either DMF or FAd in relatively large quantities while in use in children׳s care facilities, especially in winter months. Moreover, it was also observed that an increase in temperature (25°C to 50°C) had a significant impact on the emission rate of FAd and other hazardous VOCs. In addition to the aforementioned amides, the study revealed significant emissions of a number of hazardous VOCs, such as aromatic and carbonyl compounds.

Effects of sorbent materials on the cryofocusing analysis of gaseous reduced sulphur compounds.

The relative performance of different sorbent materials employed in the cryofocusing (e.g. in cold trap (CT) unit) stage was investigated at sub-ambient temperature by the thermal desorption (TD)-gas chromatography (GC)-pulsed flame photometric detector. To this end, the TD-based calibration of five reduced sulphur compounds (RSC: H2S, CH3SH, CS2, DMS and DMDS) and SO2 was carried out via the Peltier cooling system with five types of sorbent combinations such as two single-bed (Tenax TA and Silica gel) plus three multibed types (a combination of either two from the following three sorbents: Tenax TA, Silica gel and Carbopack B). Relative performance of each of all five CT options, if evaluated in terms of response factors for each compound, demonstrated that each CT composition acts as an important criterion to distinguish detection properties between light and heavy sulphur species. Although the relative response of H2S and CH3 SH was systematically distinguishable between the CT types, that of SO2 was the most complicated to interpret. According to this study, the two CT types consisting of Carbopack B and Silica gel (CS-0.4 and CS-0.6) were the optimum choices for sulphur gas analysis in terms of basic QA parameters (sensitivity, reproducibility and linearity).

Indoor air quality assessment in child care and medical facilities in Korea.

In order to characterize the status of indoor air pollution in some important facilities, a list of key criteria pollutants [particulate matter (PM(10)), carbon dioxide (CO(2)), carbon monoxide (CO), formaldehyde (HCHO), and bioaerosol] was measured from a total of 91 randomly selected sites in 18 different cities, Korea (February 2006 to December 2009). The target facilities include 43 child care facilities, 38 medical facilities, 6 elementary schools, and 4 postnatal care centers. The results showed that some air pollutants (e.g., CO and HCHO) did not exceed the recommended guideline [e.g., the Korean indoor air standard (KIAS) values of 10 ppm and 100 ppb, respectively]. However, concentration of PM(10), CO(2), and bioaerosol occasionally exceeded their respective guidelines (e.g., seven, three, and two cases). Discrete seasonalities were observed from indoor pollutants because of varying ventilation practice (e.g., summer time dominance of PM(10), HCHO, and bioaerosol or winter dominance of CO(2) and CO). However, as the concentrations of the indoor pollutants were scarcely above the recommended guideline level, more diversified approaches are desirable to diagnose the status of indoor pollution and to provide a realistic strategy for the improvement of IAQ.

Analysis of volatile organic compounds released during food decaying processes.

A number of volatile organic compounds (VOCs) including acetone, methyl ethyl ketone, toluene, ethylbenzene, m,p-xylene, styrene, and o- xylene released during food decaying processes were measured from three types of decaying food samples (Kimchi (KC), fresh fish (FF), and salted fish (SF)). To begin with, all the food samples were contained in a 100-mL throwaway syringe. These samples were then analyzed sequentially for up to a 14-day period. The patterns of VOC release contrasted sharply between two types of fish (FF and SF) and KC samples. A comparison of data in terms of total VOC showed that the mean values for the two fish types were in the similar magnitude with 280 ± 579 (FF) and 504 ± 1,089 ppmC (SF), while that for KC was much lower with 16.4 ± 7.6 ppmC. There were strong variations in VOC emission patterns during the food decaying processes between fishes and KC that are characterized most sensitively by such component as styrene. The overall results of this study indicate that concentration levels of the VOCs differed significantly between the food types and with the extent of decaying levels through time.

Monitoring of polyaromatic hydrocarbons and volatile organic compounds in two major traffic tunnels in Seoul, Korea.

To describe the fundamental aspects of air quality in tunnel environments, field campaigns were conducted to measure polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and some criteria pollutants from two tunnel sites of Nam San (NS) and Hong Ji (HJ) gates in Seoul, Korea. The total PAH values (ngm(-3)) for the NS tunnel (137.8 +/- 10.9) were notably higher than the HJ counterpart (91.3 +/- 7.82), while the total VOC exhibited a reversed pattern with a notable enhancement in the HJ tunnel (178.5 +/- 174.7 ppbC) relative to the NS tunnel (112.5 +/- 64.1 ppbC). A line of evidence, including the molecular diagnostic ratios of PAHs, indicates the relative dominance of diesel vehicles in the NS tunnel compared to the HJ site. The PAHs with high ring numbers (n > 6, such as benzo(g, h, i)perylene and indeno(1,2,3-cd)pyrene) were preferentially enriched in the particle phase, whereas their low ring number counterparts (n = 2-3) were in the gas phase. The results of our study suggest the possibility that the relative source processes for each tunnel site are characterized by the relative dominance of either diesel (NS) or gasoline-powered vehicles (HJ).

Some insights into analytical bias involved in the application of grab sampling for volatile organic compounds: a case study against used Tedlar bags.

In this study, we have examined the patterns of VOCs released from used Tedlar bags that were once used for the collection under strong source activities. In this way, we attempted to account for the possible bias associated with the repetitive use of Tedlar bags. To this end, we selected the bags that were never heated. All of these target bags were used in ambient temperature (typically at or below 30°C). These bags were also dealt carefully to avoid any mechanical abrasion. This study will provide the essential information regarding the interaction between VOCs and Tedlar bag materials as a potential source of bias in bag sampling approaches.

Emission rates of volatile organic compounds released from newly produced household furniture products using a large-scale chamber testing method.

The emission rates of volatile organic compounds (VOCs) were measured to investigate the emission characteristics of five types of common furniture products using a 5 m(3) size chamber at 25°C and 50% humidity. The results indicated that toluene and α-pinene are the most dominant components. The emission rates of individual components decreased constantly through time, approaching the equilibrium emission level. The relative ordering of their emission rates, if assessed in terms of total VOC (TVOC), can be arranged as follows: dining table > sofa > desk chair > bedside table > cabinet. If the emission rates of VOCs are examined between different chemical groups, they can also be arranged in the following order: aromatic (AR) > terpenes (TER) > carbonyl (CBN) > others > paraffin (PR) > olefin (HOL) > halogenated paraffin (HPR). In addition, if emission strengths are compared between coated and uncoated furniture, there is no significant difference in terms of emission magnitude. Our results indicate that the emission characteristics of VOC are greatly distinguished between different furniture products in terms of relative dominance between different chemicals.

A combined application of thermal desorber and gas chromatography to the analysis of gaseous carbonyls with the aid of two internal standards.

In this study, a series of GC calibration experiments were conducted to examine the feasibility of the thermal desorption approach for the quantification of five carbonyl compounds (acetaldehyde, propionaldehyde, butyraldehyde, isovaleraldehyde, and valeraldehyde) in conjunction with two internal standard compounds. The gaseous working standards of carbonyls were calibrated with the aid of thermal desorption as a function of standard concentration and of loading volume. The detection properties were then compared against two types of external calibration data sets derived by fixed standard volume and fixed standard concentration approach. According to this comparison, the fixed standard volume-based calibration of carbonyls should be more sensitive and reliable than its fixed standard concentration counterpart. Moreover, the use of internal standard can improve the analytical reliability of aromatics and some carbonyls to a considerable extent. Our preliminary test on real samples, however, indicates that the performance of internal calibration, when tested using samples of varying dilution ranges, can be moderately different from that derivable from standard gases. It thus suggests that the reliability of calibration approaches should be examined carefully with the considerations on the interactive relationships between the compound-specific properties and the operation conditions of the instrumental setups.

Prediction Model for Airborne Microorganisms Using Particle Number Concentration as Surrogate Markers in Hospital Environment.

Indoor microbiological air quality, including airborne bacteria and fungi, is associated with hospital-acquired infections (HAIs) and emerging as an environmental issue in hospital environment. Many studies have been carried out based on culture-based methods to evaluate bioaerosol level. However, conventional biomonitoring requires laborious process and specialists, and cannot provide data quickly. In order to assess the concentration of bioaerosol in real-time, particles were subdivided according to the aerodynamic diameter for surrogate measurement. Particle number concentration (PNC) and meteorological conditions selected by analyzing the correlation with bioaerosol were included in the prediction model, and the forecast accuracy of each model was evaluated by the mean absolute percentage error (MAPE). The prediction model for airborne bacteria demonstrated highly accurate prediction (R2 = 0.804, MAPE = 8.5%) from PNC1-3, PNC3-5, and PNC5-10 as independent variables. Meanwhile, the fungal prediction model showed reasonable, but weak, prediction results (R2 = 0.489, MAPE = 42.5%) with PNC3-5, PNC5-10, PNC > 10, and relative humidity. As a result of external verification, even when the model was applied in a similar hospital environment, the bioaerosol concentration could be sufficiently predicted. The prediction model constructed in this study can be used as a pre-assessment method for monitoring microbial contamination in indoor environments.

Indoor Thermal Environment Long-Term Data Analytics Using IoT Devices in Korean Apartments: A Case Study.

IoT-based monitoring devices can transmit real-time and long-term thermal environment data, enabling innovative conversion for the evaluation and management of the indoor thermal environment. However, long-term indoor thermal measurements using IoT-based devices to investigate health effects have rarely been conducted. Using apartments in Seoul as a case study, we conducted long-term monitoring of thermal environmental using IoT-based real-time wireless sensors. We measured the temperature, relative humidity (RH), and CO2 in the kitchen, living room, and bedrooms of each household over one year. In addition, in one of the houses, velocity and globe temperatures were measured for multiple summer and autumn seasons. Results of our present study indicated that outdoor temperature is an important influencing factor of indoor thermal environment and indoor RH is a good indicator of residents' lifestyle. Our findings highlighted the need for temperature management in summer, RH management in winter, and kitchen thermal environment management during summer and tropical nights. This study suggested that IoT devices are a potential approach for evaluating personal exposure to indoor thermal environmental risks. In addition, long-term monitoring and analysis is an efficient approach for analyzing complex indoor thermal environments and is a viable method for application in healthcare.

Development and Verification of a Risk Index for Evaluating the Chemical Accident Risk of Korean Chemical Enterprises.

The scale of the damage due to chemical accidents in Korea is significant, and appropriate preparation and response are required. Currently, Korean enterprises are managed on the basis of the presence of certain substances. However, chemicals other than these also cause chemical accidents. It is necessary to develop a relative ranking risk index that can be calculated through use of the chemical enterprise information on chemical enterprises that is available. The Korean chemical accident risk index (KCARI), which consists of the flammability, reactivity, explosiveness, corrosiveness, toxicity, and inventory sub-indices, was developed and verified by determining the for difference in KCARI was performed by accident, and accident severity category, calculating the correlation between the KCARI values, the factors, and some sub-indices, determining how an increase in the KCARI would impact how the incident rate changed as KCARI increased and how well the KCARI can predict the chemical accident risk of chemical handling enterprises, and confirming the consistency of the proposed index and the current system. These results indicated that the frequency and severity of chemical accidents, and the presence of accidental substances, showed significant differences in the KCARI values. However, there were limitations in the ability of the fitted model to precisely predict the accident. Thus, this model can be used as a tool for the early screening and management of enterprises with a high risk of chemical accident.

Exposure to inhalable aerosols and their chemical characteristics from different potential factors in urban office environments.

Indoor air quality (IAQ) is one of important issues in indoor environment due to exposure to inhalable aerosol which is affected by indoor and outdoor factors. To demonstrate the effect of indoor and outdoor to the IAQ, this study presents three fractions of particulate matter (PM) (PM2.5, PM4, PM10), characterization of I/O ratios for PM under potential indoor (average occupancy) and outdoor factors (Asian dust, rain, wind, and snow days) and evaluation of chemical components in aerosols. In the chemical characteristics of PM, organic carbon (OC), elemental carbon (EC), and trace elements were analyzed in indoors and outdoors. There was no significant difference of respirable aerosol (PM2.5 and PM4) concentration in different indoor environments. The concentration of OC in PM10 was lower in indoor than outdoor in summer and winter seasons, while the concentration of OC in PM2.5 was higher in indoor than outdoor. Also, the OC/EC ratios in PM2.5 were higher than those in PM10. Further, the ratios of trace elements in PM2.5 and PM10 were different at various locations within the building. This study demonstrated that the exposure to PM2.5 is greatly affected by outdoor environment. Although there was no difference in inhalable and respirable aerosol concentration at different locations within the building, the impact of outdoor factors is strongly supported by OC/EC ratios and PM2.5/PM10 ratios of trace elements. This study shows that chemical components through the HVAC system affected the exposure to the indoor respirable aerosol, which could lead to adverse effect on the indoor air quality.

Research Progress of M13 Bacteriophage-Based Biosensors.

Recently, new virus-based sensor systems that operate on M13 bacteriophage infrastructure have attracted considerable attention. These systems can detect a range of chemicals with excellent sensitivity and selectivity. Filaments consistent with M13 bacteriophages can be ordered by highly established forms of self-assembly. This allows M13 bacteriophages to build a homogeneous distribution and infiltrate the network structure of nanostructures under mild conditions. Phage display, involving the genetic engineering of M13 bacteriophages, is another strong feature of the M13 bacteriophage as a functional building block. The numerous genetic modification possibilities of M13 bacteriophages are clearly the key features, and far more applications are envisaged. This paper reviews the recent progress in the application of the M13 bacteriophage self-assembly structures through to sensor systems and discusses future M13 bacteriophage technology.

Flammable Substances in Korea Considering the Domino Effect: Assessment of Safety Distance.

Benzene, toluene, and xylene (BTX) are flammable substances used in a wide range of raw materials and products. Chemical accidents caused by flammable substances are different from leakage accidents of toxic materials. Initial explosions and fires may cause secondary or tertiary explosions, or fires with nearby flammable materials. This is called the domino effect. In cases of leakage accidents, it is possible to prevent accidents through early control of the leakage to the outside or by bypassing, but it is difficult to cope with explosions because they occur instantaneously. To prevent explosions due to the domino effect, a safety distance must be set. Safety distances vary widely by country. In the case of the United States (US) or the European Union (EU), safety distances are set in various ways depending on the chemical industry and the amount of flammable substances being handled. However, countries such as Korea, Taiwan, and Dubai have comprehensive regulation, and the safety distances are small. In this study, we simulated the range of overpressure at which other chemical equipment could explode when an explosion occurs in a flammable BTX storage tank. There are three types of analysis methods of vapor cloud explosion. PHAST (Process Hazard Analysis Software Tool) and ALOHA (Areal Location of Hazardous Atmosphere) were selected to model explosions using three methods (trinitrotoluene equivalence method, the Netherlands Organization multi-energy method, and Baker-Strehlow-Tang method). The results indicated that the safety distances in the US and EU showed low probability of a domino effect, but those in Korea, Dubai, and Taiwan could lead to a secondary explosions. Therefore, it is necessary to propose a reasonable method to determine safety distances considering the amount and physicochemical characteristics of the flammable substances being used.

Priority Setting for the Management of Chemicals Using the Globally Harmonized System and Multivariate Analysis: Use of the Mahalanobis-Taguchi System.

This study aims to provide a new methodology using the Globally Harmonized System (GHS) and the Mahalanobis-Taguchi System (MTS) that can be used to assess the overall hazard of a chemical using GHS information. Previously, hazardous chemicals were designated and managed by the Chemical Management Act, but many more chemicals are now in use. Damage prediction modeling programs predict the extent of damage and proactively manage high-risk chemicals, but the lack of physical and chemical characterization information relating to chemicals has limitations that cannot be modeled. To overcome such limitations, a new method of chemical management prioritization was developed using the GHS and Mahalanobis-Taguchi System (MTS). For effective management, the risk of a chemical can be ranked according to a comprehensive risk assessment and calculated through multivariate analysis using the GHS. Relative hazards are then identified using MTS multivariate analysis with GHS information, even when there is insufficient information about the chemical's characteristics, and the method can be applied to a large number of different chemicals.