Recently Korean government introduced and strengthened the environmental polices to manage and enhance indoor air quality as a major assignment. As a result,“Indoor Air Quality Management Act”has been activated since May 2004. However, among many multi-usage facilities, the school environment has been excluded from such regulations. Thus, the purpose of this study is to survey indoor aerosol and CO2 concentrations in a university library which is one of major school facilities. Concentrations of PM10, PM2.5, and PM1 were intensively measured every 5 minute interval by means of a dust monitor with light-scattering principle. The mini-volume air samplers were used further to analyze inorganic elemental compositions of PM10 and to inter-compare with the dust monitor. Carbon dioxide was simultaneously monitored by a multi-gas monitor equipped with a non-dispersive infrared system. PM10 concentrations did not exceed the indoor air quality standard(150㎍/㎥) for all the sampling places. However, quick and steep increases of aerosol concentration were observed during the Asian Dust storm period. In addition, the concentration of PM10(74.1㎍/㎥) in the main university office was the highest among the entire sampling places. Although there was no specific pollution source in the library, the levels of aerosol and CO2 increased quickly due to various outdoor sources and human activities. The average CO2 concentration measured in three reading rooms, where ventilation was not fully operated, exceeded the indoor air quality standard of 1,000 ppm. Based on these case studies, effective management and reduction plans for indoor aerosol and CO2 were suggested for the large scale public buildings including university libraries.

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.

2003년 10월 26~29일까지 고비사막으로부터 강릉시로 황사의 유입 전, 후의 매 시각별 PM10, PM2.5와 PM1농도의 영향을 미치는 대기경계층과 PM농도 간의 상관관계 및 회귀식을 조사되었다. 고비사막에서 유입된 황사와 차량에서 방출되는 대기오염물질 및 도로의 비산먼지가 결합되고, 열적내부경계층이 수축되어 강릉시내 PM농도가 09시 매우 높았다. 수축된 야간접지역전층 내에서 황사, 차량의 배기가스와 주거지역의 난방보일러에서 방출된 대기오염물질이 추척되어 퇴근시간인 17시에 최대농도가 나타났다. 황사의 유입 전에 PM10과 PM2.5(PM2.5와 PM1, PM10과 PM1) 간의 상관계수는 0.90(0.99, 0.84)이었고, 황사 유입 기간에는 0.98(1.00, 0.97), 황사의 유입이 종료된 후에는 0.23(0.81, -0.36)로 매우 낮았다.

Hourly concentrations of PM1, PM2.5 and PM10, were investigated at Gangneung city in the Korean east coast on 0000LST October 26~1800LST October 29, 2003. Before the intrusion of Yellow dust from Gobi Desert, PM10(PM2.5, PM1) concentration was generally low, more or less than 20 (10, 5) μg/m3, and higher PM concentration was found at 0900LST at the beginning time of office hour and their maximum ones at 1700LST around its ending time. As correlation coefficient of PM10 and PM2.5(PM2.5 and PM1, and PM10 and PM1) was very high with 0.90(0.99, 0.84), and fractional ratios of (PM10-PM2.5)/PM2.5((PM2.5-PM1)/PM1) were 1.37~3.39(0.23~0.54), respectively. It implied that local PM10 concentration could be greatly affected by particulate matters of sizes larger than 2.5 μm, and PM2.5 concentration could be by particulate matters of sizes smaller than 2.5 μm. During the dust intrusion, maximum concentration of PM10(PM2.5, PM1) reached 154.57(93.19, 76.05) μg/m3 with 3.8(3.4, 14.1) times higher concentration than before the dust intrusion. As correlation coefficient of PM10 and PM2.5(vice verse, PM2.5, PM1) was almost perfect high with 0.98(1.00, 0.97) and fractional ratios of (PM10-PM2.5)/PM2.5((PM2.5-PM1)/PM1) were 0.48~1.25(0.16~0.37), local PM10 concentration could be major affected by particulates smaller than both 2.5 μm and 1 μm (fine particulate), opposite to ones before the dust intrusion. After the ending of dust intrusion, as its coefficient of 0.23(0.81, - 0.36) was very low, except the case of PM2.5 and PM1 and (PM10-PM2.5)/PM2.5((PM2.5-PM1)/PM1) were 1.13~1.91(0.29~1.90), concentrations of coarse particulates larger than 2.5 μm greatly contributed to PM10 concentration, again. For a whole period, as the correlation coefficients of PM10, PM2.5, PM1 were very high with 0.94, 1.00 and 0.92, reliable regression equations among PM concentrations were suggested.

황사발생 전과 후인 2003년 10월 26일 00시부터 29일 18시까지 한국의 동쪽 연안에 있는 강릉시에서 PM10, PM2.5와 PM1 매 시각별 분포를 조사하였다. 황사가 고비사막으로부터 유입되기 전까지는 매 시각 PM10 농도가 20μg/m3 내외, PM2.5가 10μg/m3 내외, PM1가 5μg/m3 내외로 매우 낮은 농도를 나타내지만 황사가 유입된 10월 27일 09시부터 28일 05시까지는 PM10의 농도의 범위가 48.20~154.57μg/m3이며, 평상시 비해PM10의 농도가 3.8배로 높았다. 유사하게 PM2.5의 농도는 26.92~93.19μg/m3의 변화폭을 나타내며, 최대 3.4배로 높게 나타났고, PM1의 농도는 19.63~76.05μg/m3의 변화폭을 갖고, 최대 14.1배가 되었다. 황사가 나타나는 동안에는 수송된 황사먼지의 집중적인 유입과 동시에 도로 위의 차량의 밀집과 일몰 후 주거지역에서의 보일러 가동으로 출근시각인 09시와 퇴근시각인 17시에 PM의 고농도가 나타났다. 황사가 관측되기 전에는 미세입자와 극미세입자의 비율을 나타내는 (PM10-PM2.5)/PM2.5는 0.75~7.12, 극미세입자와 초극미세입자의 비율을 나타내는 (PM2.5-PM1)/PM1는 0.23~1.90로 나타났으며, 황사가 관측되는 기간에는 0.60~1.25와 0.21~0.37을 각각 나타내었다. 강릉시에 황사가 나타나기 전에는 2.5μm 큰 입자들이 2.5μm 이하의 극미세입자보다 PM10의 농도에 큰 영향을 주었으나, 황사가 관측되는 기간에는 2.5μm 이하의 극미세입자들이 PM10의 고농도 출현에 크게 기여하였다. 황사가 관측되는 기간에는 지역의 PM고농도에 2.5μm 이상의 큰 입자가 기여하는 일반적인 양상과 반대였다.

In order to investigate the variations and corelation among PM10, PM2.5 and PM1 concentrations, the hourly concentrations of each particle sizes of 300 ηm to 20 μm at a city, Gangneung in the eastern mountainous coast of Korean peninsula have been measured by GRIMM aerosol sampler-1107 from March 7 to 17, 2004. Before the influence of the Yellow Dust event from China toward the city, PM10, PM2.5 and PM1 concentrations near the ground of the city were very low less than 35.97 μg/m3, 22.33 μg/m3 and 16.77 μg/m3, with little variations. Under the partial influence of the dust transport from the China on March 9, they increased to 87.08 μg/m3, 56.55 μg/m3 and 51.62 μg/m3. PM10 concentration was 1.5 times higher than PM2.5 and 1.85 times higher than PM1. Ratio of (PM10-PM2.5)/PM2.5 had a maximum value of 1.49 with an averaged 0.5 and one of (PM2.5-PM1)/PM1 had a maximum value of 0.4 with an averaged 0.25. PM10 and PM2.5 concentrations were largely influenced by particles smaller than 2.5 μm and 1 μm particle sizes, respectively. During the dust event from the afternoon of March 10 until 1200 LST, March 14, PM10, PM2.5 and PM1 concentrations reached 343.53 μg/m3, 105 μg/m3 and 60 μg/m3, indicating the PM10 concentration being 3.3 times higher than PM2.5 and 5.97 times higher than PM1. Ratio of (PM10-PM2.5)/PM2.5 had a maximum value of 7.82 with an averaged 3.5 and one of (PM2.5-PM1)/PM1 had a maximum value of 2.8 with an averaged 1.5, showing PM10 and PM2.5 concentrations largely influenced by particles greater than 2.5 μm and 1 μm particle sizes, respectively. After the dust event, the most of PM concentrations became below 100 μg/m3, except of 0900LST, March 15, showing the gradual decrease of their concentrations. Ratio of (PM10-PM2.5)/PM2.5 had a maximum value of 3.75 with an averaged 1.6 and one of (PM2.5-PM1)/PM1 had a maximum value of 1.5 with an averaged 0.8, showing the PM10 concentration largely influenced by corse particles than 2.5 μm and the PM2.5 by fine particles smaller than 1 μm, respectively. Before the dust event, correlation coefficients between PM10, PM2.5 and PM1 were 0.89, 0.99 and 0.82, respectively, and during the dust event, the coefficients were 0.71, 0.94 and 0.44. After the dust event, the coefficients were 0.90, 0.99 and 0.85. For whole period, the coefficients were 0.54, 0.95 and 0.28, respectively.