This study was conducted to investigate the actual condition of fine particles (PM2.5) pollution and to verify the necessity of managing PM2.5 in the indoor environment of public use facilities in Gyeonggi-do. As a result, it was found that PM2.5 concentrations measured for 24 hours ranged from 15.9 to 113.5 μg/m3 and averaged 42.5 μg/ m3, and for 6 hours, ranged from 20.4 to 167.1 μg/m3 and averaged 65.6 μg/m3. Average concentration was highest in subway stations, followed by nursery schools and indoor parking lots. 49 of the 55 sites investigated exceeded the 24hr-PM2.5 standard specified in WHO guidelines (25 μg/m3). The ratio of PM2.5 to PM10 was 70.2% for 24hr and 70.7% for 6hr on average. This means that PM2.5 tends to account for a large proportion of the total particulate pollution in the indoor environment, and that it is essential to control fine particulate matter in order to reduce total particulate matter in the indoor environment. In addition, it was found that the time to be sampled and total sampling time are one of important factors which affect PM2.5 concentration in indoor air quality; therefore, I think that it is necessary to concretely specify the time to be sampled and maximum range of total sampling time in the test method of PM2.5. Recently, regulations on PM2.5 in indoor environments have been strengthened in other countries due to its high risk to human health; however, there is currently no enforceable regulation in Korea. Given that PM2.5 is more harmful to human health than PM10, it is urgently necessary to establish proper policies and regulations to control PM2.5 in indoor environments.

This study was conducted to evaluate the dilution accuracy of the dynamic olfactometer made in Republic of Korea and analyze the correlation of odor levels from the olfactometry method and Liquid Chromatography/Mass Spectrometry (LC/MS). The evaluation of dilution accuracy using CH₄ standard gas for the dynamic olfactometer at lower dilution ratios of 3, 10, 30, 100 and 300, and at higher dilution ratios of 100, 300, 1000, 3000 and 10000 showed the relative errors of 1.48~3.40% and 2.06~4.76% respectively showing a good dilution accuracy. Twenty odor samples from the stacks of odor-monitoring factories in the industrial complex located at the western coastal area of ROK were analyzed with the dynamic olfactometer for complex odor and LC/MS for five types of aldehydes, and a very weak correlation of R² = 0.1276 between OU(Odor Unit) from the olfactometer data and SOQ (Summation of Odor Quotient) from LCjMS data was obtained. Because of the complexity of the odor composition, using concentration of single or group of gases to represent odor level has not been proved to fully estimate the presence or level of odors. Therefore, the dynamic olfactometry which has a good dilution accuracy and a standardized odor evaluation system is considered as a very resonable method to assess complex odor.