Yong Sung Cho

Air Pollution and Asthma Among Children in Seoul, Korea

Background. As information about the health risks associated with air pollution has become available, attention has focused increasingly on susceptible persons such as children and persons with preexisting respiratory diseases, such as asthma. Methods. We investigated the association between outdoor air pollution and asthma attacks among children under 15 years of age in Seoul, Korea. We estimated the relative risks of hospitalization associated with an interquartile range (IQR) increase in pollutant concentrations and used time series analysis of the counts by means of the generalized additive Poisson model. Results. The estimated relative risk of hospitalization for asthma was 1.07 (95% confidence interval [CI] = 1.04–1.11) for particulate matters less than or equal to 10 &mgr;m in aerodynamic diameter (IQR = 40.4 &mgr;g/m3); 1.11 (95% CI = 1.06–1.17) for sulfur dioxide (IQR = 4.4 ppb); 1.15 (95% CI = 1.10–1.20) for nitrogen dioxide (IQR = 14.6 ppb); 1.12 (95% CI = 1.07–1.16) for ozone (IQR = 21.7 ppb); and 1.16 (95% CI = 1.10–1.22) for carbon monoxide (IQR = 1.0 ppm). Conclusions. These findings support the hypothesis that air pollution at levels below the current standards of Korea is harmful to sensitive subjects such as asthmatic children.

Current Status of Trace Metal Pollution in Soils Affected by Industrial Activities

There is a growing public concern over the potential accumulation of heavy metals in soil, owing to rapid industrial development. In an effort to describe the status of the pollutions of soil by industrial activities, relevant data sets reported by many studies were surveyed and reviewed. The results of our analysis indicate that soils were polluted most significantly by metals such as lead, zinc, copper, and cadmium. If the dominant species are evaluated by the highest mean concentration observed for different industry types, the results were grouped into Pb, Zn, Ni, Cu, Fe, and As in smelting and metal production industries, Mn and Cd in the textile industry, and Cr in the leather industry. In most cases, metal levels in the studied areas were found to exceed the common regulation guideline levels enforced by many countries. The geoaccumulation index (I geo), calculated to estimate the enrichment of metal concentrations in soil, showed that the level of metal pollution in most surveyed areas is significant, especially for Pb and Cd. It is thus important to keep systematic and continuous monitoring of heavy metals and their derivatives to manage and suppress such pollution.

Exposure of Workers to Extremely Low Frequency Magnetic Fields and Electric Appliances

Exposure of Workers to Extremely Low Frequency Magnetic Fields and Electric Appliances: Yoon Shin Kim, et al. Institute of Environmental and Industrial Medicine, College of Medicine, Hanyang University, Korea—The purpose of this study was to investigate personal exposure to extremely low frequency magnetic fields. Subjects were randomly assigned to two groups. Thirty‐seven subjects in occupational and 65 subjects in nonoccupational groups were measured for personal 24 h continual exposure, using EMDEX II (for 40‐800 Hz, Enertech Consultant, Inc.), from March 1996 through December 1999. The mean personal exposure levels of the occupational group was 0.46μT, whereas the value for the non‐occupational group was 0.08μT. Occupational groups were exposed more intensely while at work. Among the electric appliances examined, a massage unit showed the highest mean value of 247.07μT, followed by an electric blanket with 5.24μT. Finally, this study was expected to provide significant data for future study of exposure assessment of magnetic fields. A large scale study concerning more detailed exposure assessment should provide important information on health risk assessment of MFs.

Estimation of ELF-MF Exposure Levels in the Korean Population through 24-Hour Personal Exposure

Objectives: The purpose of this study was to estimate the exposure level to extremely low frequency-magnetic fields (ELF-MF) among a selected Korean population using 24-hour personal exposure measurement. Methods: Participants were randomly selected for the measurement of MF exposure under the assumption that the subjects are representative of the overall Korean population. Levels of personal exposure to MF were measured according to the subject’s daily activities. Results: The 24-hour time-weighted average (TWA) of 250 participants was 1.56 ± 4.56 mG (GM, GSD: 0.79, 2.46 mG). Personal exposure levels for females were higher than for males. The highest personal exposure level was shown in the age group between 20-60 years old. Personal exposure levels according to job category were higher for the non-occupational group than for the occupational group. Conclusions: Our results showed MF exposure exceeding 2 mG per day among 11.3% of the Korean population, indicating a somewhat higher percentage compared to the EMF RAPID Program’s results for the U.S

Measurements of Personal Exposure to MF in Korean Population

Industrializing process including marked increase of electric appliances has expanded personal exposure to magnetic fields (MF) whose effects on human health have long been out of scientific concern (London et al., 1991). Numerous epidemiological reports suggest a link between occupational or non-occupational exposures especially to extremely low frequency (ELF 10–1,000Hz) fields and cancer, risk, particularly leukemia, brain tumor and breast cancer (Stevens, 1987; Savitz et al., 1989; Theriault, 1991; Vena et al., 1994). If extremely low frequency (ELF) magnetic fields (MFs) exert health effects, then the parameters of MFs that best predict these effects are not known.