첨착 활성탄 개발을 통한 공기청정시스템의 실내공기질 개선에 따른 위해성 평가

Abstract

In this study, the improvement of indoor air quality, through developments of highly effective material for the control of indoor air pollutants with potential negative health effects and air purification system, is determined. Furthermore, the research investigates the possibility of reduction in risks of receptors with the health science perspective. The results from this study can be summarized as follows; First, in order to increase the physical adsorption, coconuts based activated carbons with well developed mirco-pore is used. In order to increase chemical adsorption and to control basic and acidic gases, the activated carbon is chemically treated with phosphoric acid and ethylene urea. The developed material is tested with major noxious gases, namely formaldehyde and toluene, and typical odorous gases which are ammonia, acetaldehyde, and acetic acid and the adsorbent had removal efficiencies of 82%∼100% Second, the air purification system equipped with highly effective adsorbent resulted in 46.3% removal of formaldehyde at schools, 34.1% at offices, and 41.5% at houses. In case of toluene, the air purification system removed 52.2% at schools, 39.5% at offices, and 43.3% at houses. The removal efficiencies of PM10 were 57.6%, 40.7%, and 38.9% at schools, offices, and houses respectively. Lastly 62.6%, 46.5%, and 51.2% of bacteria were removed from schools, offices, and houses respectively. Third, the calculated cancer risk from exposure to formaldehyde showed that male adults had a cancer risk index of 4.87E-11 in general condition and it was reduced to 3.15E-11 when the air purifier was operating. In case of female adults, the risk index was reduced from 5.51E-11 to 3.50E-11 with the operation of air purifier, and had a relatively low risk index. For male children, the cancer risk indexes were 1.00E-10 and 5.76E-11 without and with the operation of air purifier, respectively, and for female children the respective risk indexes were 9.27E-11 and 5.31E-11. The calculated hazard index from exposure to toluene revealed that the hazard indexes decreased from 4.8E-01 to 2.8E-01 for male adults and from 5.9E-01 to 3.5E-01 for female adults without and with the operation of air purifier, respectively. The hazard index of toluene was below 1 for all cases, for the boys the indexes were 7.7E-01 and 4.4E-01, and for girls they were 7.9E-01 and 4.2E-01 without and with the operation of air purifier respectively. However, the calculated hazard indexes at the highest concentration of toluene were 1.0E+00 and 1.2E+01 for male and female adults which meant there are possibility of detrimental health risks. The hazard indexes at the highest concentration of toluene while the air purifier was operating were calculated and the indexes decreased to 5.8E-01 and 7.1E-01 for male and female adults, respectively. For girls the hazard index, when calculated at the highest concentration, was 1.8E+01, well above the tolerable limit, but when the air purifier was operating, the index decreased to 9.2E-01. The calculated safety factors, which shows the potential risks from PM10 and bacteria, for both adults and children were above 1 when the air purifier was not operating and diminished below 1 when it was operating. In the perspective of health science, this research identified the air purification system as one of methods in effectively controlling the indoor air quality and thereby reducing negative health risks of receptors.