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This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving the air quality of the city.

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The purpose of this study was to characterize spatial and temporal variations of carbonyl compounds in Gumi city, where a number of large electronic-industrial complexes are located. Carbonyl samples were collected at five sites in the Gumi area: three industrial, one commercial, and one residential area. Sampling was carried out throughout a year from December 2003 to November 2004. At one industrial site, samples were taken every six days, while those of the other sites were for seven consecutive days in every season. Each sample was collected for 150 minutes and at intervals of three times a day (morning, afternoon, and evening). A total of 476 samples were analyzed to determine 15 carbonyl compounds by the USEPA TO-11A (DNPH-cartridge/HPLC) method. In general, acetaldehyde appeared to be the most abundant compound, followed by formaldehyde, and acetone+acrolein. Mean concentrations of acetaldehyde were two to three times higher in the industrial sites than in the other sites, with its maximum of 77.7 ppb. In contrast, ambient levels of formaldehyde did not show any significant difference between the industrial and non-industrial groups. Its concentrations peaked in summer probably due to the enhanced volatilization and photochemical reactivity. These results indicate significant emission sources of acetaldehyde in the Gumi industrial complexes. Mean concentrations of organic solvents (such as acetone+acrolein and methyl ethyl ketone) were also significantly high in industrial areas. In conclusion, major sources of carbonyl compounds, including acetaldehyde, are strongly associated with industrial activities in the Gumi city area.

Mercury is one of the most important metals to environmental researchers due to its toxicity. In recent years, many authors determined the concentration of mercury and its different forms in the environment, such as soil, water, atmosphere and biota, with various analytical techniques, such as atomic absorption spectrometry, spectrophotometry, voltammetry, inductively coupled plasma mass spectrometry, inductively coupled plasma atomic emission spectrometry, spectrofluorometry and chromatography. The objective of this paper is to summarize the recent understanding of the available techniques for the analysis and speciation of mercury in environmental and biological samples reported worldwide during 2010 -2011. We tabulated all the analytical parameters of about 129 research papers published in reputable international journals during 2010 -2011 about mercury determination and speciation studies.

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Ambient air monitoring of particulate hazardous air pollutants was performed from 2005 to 2007 in the Sihwa-Banwol industrial complexes, which is the largest industrial area in Korea. The occurrence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals, their spatial and seasonal distributions, and the factors affecting the variations in concentrations were investigated. The annual average concentration of benzo[a]pyrene was 1.27 ng/m³, with a maximum of 10.41 ng/m³. The PAH levels between the industrial and residential sites did not differ significantly, although heavy metals strongly related to industrial activities showed a clear variation between the two groups. Thus, industrial activities were not the only sources of PAHs; they also included automobile emissions and residential heating fuels. Coal-fired power plants outside the city and transboundary contributions from China and North Korea also affected the PAH levels in the area. Although ambient levels of heavy metals had no specific seasonal pattern, PAH levels showed distinct seasonal variations, with the highest level in winter. Factors affecting the PAH concentrations were vehicle exhaust, domestic heating, industrial activities, incineration within the area, and fuel combustion outside the area. The Sihwa-Banwol industrial complexes can be regarded as a hot-spot of PAH pollution in the Seoul metropolitan area.