Assessment of the charged aerosol value in copy centers.

This study was performed to examine the potential health effects of copiers on their users and relevant workers by evaluating the charged aerosol current generation characteristics and indoor air quality (IAQ) in the copy center. In the 10 copy centers and one control site that were investigated in this study, the charged aerosol generation characteristics (effective levels, charged aerosol current, and charged aerosol concentration) and air pollutants (fine particles, ozone, and nitrogen oxide) were measured indoors and outdoors, and compared. In addition, a six-day continuous measurement was performed in a copy center to assess the charged aerosol generation characteristics according to the copying volume and the copier operation, and their correlation with indoor air pollutants. The indoor and outdoor charged aerosol effective levels in the 10 copy centers were 93.4% and 82.4%, respectively, and they were about 1.4 times higher than the charged aerosol effective level in the indoor control site (66.2%). The comparison of the negative and positive ion currents by space showed that the positive ion current was about 4.2 times higher indoors than outdoors, and about 2.5 times higher during the operation time than during the non-operation time. The indoor charged aerosol concentration (1,512.3 ions/cm(3)) was about 4.6 times higher than the outdoor concentration (325.8 ions/cm(3)), and 19.5 times higher than the indoor charged aerosol concentration in the control site (77.3 ions/cm(3)). Based on these results, it was found that the operation of the copier was an important influential factor of the charged aerosol generation level in the copy center, and that the positive ions were dominant. In the analysis of the correlation between the indoor charged aerosol generation and the air pollutants, the effective level had high positive correlations with the charged aerosol concentration (r=0.938, p<0.01) and O(3) (r = 0.870, p<0.05). The charged aerosol concentration had positive correlations with O(3) (r=0.700) and PM(10) (r=0.479), although the correlations were not statistically significant. In conclusion, it seems that the ultra-fine particles (UFPs, d < 0.1 um ≤ 100 nm) may affect the human respiratory and circulatory systems because they have charged aerosol characteristics. Based on these results, it was found that the operation of the copier was an important influential factor of the charged aerosol generation level in the copy center, and that the positive ions were dominant.