This study was performed to investigate indoor air quality and to characterize the concentration of particulate matters followed by human activities in preschool classrooms. Concentrations of PM10, PM2.5, and PM1 were measured every 5-minute intervals by means of a dust monitor adopting the principle of light scattering. Two mini-volume air samplers were used further to measure the I/O concentration ratio of PM10 and to calibrate the dust monitor since the photometric method often exaggerates the mass of fine particles. The calibration factor in the study environment was determined as 0.64. In the preschool classrooms, the ranges of average indoor PM10, PM2.5, and PM1 concentrations were 51.5~117.6, 21.5~98.4, and 16.2~84.5 ㎍/ ㎥, respectively, while that of I/O concentration ratio was 0.8~1.3. Based on correlation analysis among various environmental parameters, PM1 was slightly correlated with humidity (r=0.416, p<0.01). However, outdoor PM10 was strongly related with indoor PM2.5 (r=0.95, p<0.01), with PM1 (r=0.94, p<0.01), and with PM10 (r=0.84, p<0.01). The trend of PM2.5 and PM1 concentrations appeared to be very similar unlike the case of PM10. Since the elevated coarse particle concentration (2.5㎛<dp<10㎛) and the average PM2.5/PM10 ratio were highly dependent on classroom activities, the parameter of PM2.5/PM10 ratio was intensively studied with 7 different indoor activities in the preschool classrooms.

A ventilation system comprising a dielectric barrier discharger and UV‐TiO2 photocatalyst filters was designed and tested for simultaneous removal of gaseous and particulate contaminants in a test chamber. The DBD was used as the 1st stage of ESP for particle charging and gas decomposition. Charged particles were collected in the 2nd stage of ESP by an applied DC electric field. The UV‐TiO2 photocatalyst filters were used for decomposing gaseous species including O3 which was inherently produced by the DBD. Particle removal efficiencies based on mass and number were approximately 83.0% and 88.8%, respectively, after the ventilation system was operating for 5 hours. HCHO removal efficiency was approximately 100% for 1∼5ppm of upstream concentration condition. TVOC removal efficiency was 99.0% and 99.6% for 1 ppm and 5 ppm of upstream concentration conditions, respectively.

Scanning electron microscopy / energy dispersive X-ray analyzer(SEM/EDX) has played an important role for evaluation the source of atmospheric particle because it is a powerful tool for characterizing individual particles. The SEM/EDX system provides various physical parameters like optical diameter, as well as chemical information for a particle-by-particle basis. The purpose of the study was to classify individual particle emitted from the point sources based on clustering analysis and physico-chemical analysis by SEM/EDX. The total of 490 individual particle were analyzed at 8 point sources including coal-fired power plant, incinerator, B-C oil boiler, and metal manufacturing industry. The main components were Si and Al in the coal-fired power plant, Cl and Na in the domestic waste Incinerator, S in the B-C oil boiler and S and Fe in the metal manufactory industry, respectively.