IEC 60079-10-1 edition 2.0, the global standard for hazardous area classification, was newly revised in 2015. There are many differences compared to the previous edition 1.0 version, first released in 2008, so it has caused confusion in the industry. In case of edition 1.0, the hazardous area extent can be derived through the mathematical formula, but in case of edition 2.0, there was the problem that the exact hazardous area extent was not known because of the mathematical formula of the plot for applying the hazardous area extent was not presented. In this study, we converted the plot introduced in edition 2.0 to CAD format and derived the plot as the mathematical equations. Through this, we suggest the hazardous area extent formula of three states (heavy gas, diffusive, jet). As the IEC committee did not provide the mathematical formula of the hazardous area extent according to the release characteristic, it is impossible to apply the exact hazardous area extent. In this study, a mathematical approach was derived for the plot introduced in edition 2.0, which can reduce the confusion of the applying hazardous area extent.

This study was conducted to evaluate the health risk of workers exposed to phenyl glycidyl ether to prevent themfrom developing occupational diseases. The workplaces that coat floor with epoxy were selected and the sampleswere collected and analyzed with NIOSH 1619 Method. Unit risk was calculated according to the animalcarcinogenicity study. Excess cancer risk was also calculated by multiplying unit risk by exposure concentration.Monte Carlo simulation was performed to calculate the median, cumulative 90%, and cumulative 95% value.Phenyl glycidyl ether is a skin, eye irritator and can result in allergic reaction, nausea, intoxication. Unit risk wascalculated as 0.04 (mg/m³)-¹ based on the tumor incidence in rats. Geometric mean and geometric standarddeviation was also calculated as 0.112 ppm and 0.223, respectively by the workplace environment measurements.The median, cumulative 90%, and cumulative 95% value of excess cancer risk were calculated as 0.0244, 0.1328,0.1596, respectively. Not only cumulative 90% and cumulative 95% value but also the median of excess cancerrisk is much higher than 1×10-⁴ by the risk characterization, so there is a possibility of carcinogenesis to workers.Therefore, supervisors or managers of each workplace have to keep doing the risk management of their workplacesfor workers to reduce exposure to phenyl glycidyl ether.

According to the measurements at Seoul Metro subway, the sound level at the time of subway arrival ranged from 77.0 to 92.5 dB(A). The highest level was 92.5 dB(A) at Line-1, and the lowest level was 77.0 dB(A) at Line-5. The sound level of departure ranged from the lowest level of 82.9 dB(A) at Line-5 and the highest level of 95 dB(A) at Line-1. The indoor sound level at subway ranged from the lowest level of 87.2 dB(A) (Line-6) to the highest value of 92.1 dB(A) (Line-1). The results of this study also showed that the sound level at subway platform with Platform Screen Door(PSD) showed 81.8 dB(A) but 89.1 dB(A) without PSD. The sound reduction effect of PSD showed 7.3 dB(A) at platform. Consequently, the sound level in Korean subway was found to exceed the standard set for the American Public Transportation Association (85dB(A)).

This study was undertaken to determine the concentrations of volatile organic compounds (VOCs) in the indoor air between houses of atopy, asthma patients and new houses. Total volatile organic compounds (TVOCs) in the indoor and outdoor air of normal houses were measured as 92.6 and 72.5 ㎍/㎥, respectively. TVOCs in the indoor and outdoor air of atopy patient's houses were 152 and 42.1 ㎍/㎥. TVOCs in the indoor and outdoor air of asthma patient's houses was 165 and 50.1 ㎍/㎥. TVOCs in the indoor and outdoor air of new houses was 158 and 78.3 ㎍/㎥. It was found that the concentrations of VOCs were higher in the indoor air of atopy, asthma patient's and new houses than the normal houses. This suggests that the concentration of VOCs can influence atopy and asthma.

This study was performed to investigate the health status of 600 owner-driver of taxi in Seoul City during from August 1, 2003 to February 28, 2004. The prevalence of subjective symptoms were surveyed by a general health questionnaires such as Todai Health Index (THI) and the Cornell Medical Index (CMI). In the THI health check table, prevalence of the complaints of mental subjective symptom by age was high in the items of fabrication (L), digestion (C), and aggressiveness (F) from 31 to 40 years old drivers and mental subjective symptom by age was high in all items except for tiredness (I), melancholia (N), and hypersensitivity (P) for the 60 years old drivers and showed in the items of melancholia (N) and hypersensitivity (P) for the 40 years old. From the complaints of mental and physical subjective symptoms about work satisfaction in the THI health check table, the strong dissatisfaction showed in the all items except for eye and skin trouble (B). All items except hypersensitivity (P) showed dissatisfaction in prevalence of complains of mental and physical subjective symptoms about work satisfaction in the CMI health check table. From the complains of mental and physical subjective symptoms on salary satisfaction in the THI health check table, the taxi driver who earn the salary of 1 million won showed statistically significant symptom of eye and skin trouble (B) and showed high tendency in all items except for respiratory (A) and digestion (C) systems. It is suggested that the appropriate health control for owner-driver of taxi should be applied to reduce the prevalence of complaints that showed mainly in the irregular working time and sleeping disorders.