REMOVAL EFFICIENCY OF PARTICLES BY COMBINING NEGATIVE IONS WITH MECHANICAL FILTERS

The purpose of this work is to combine negative air ions and mechanical filters to remove indoor suspended particulates. Various factors, including the particle size, the face velocity, the species of aerosol, relative humidity, and the concentration of negative ions were considered to evaluate their effects on the aerosol collection characteristics. Experimental results show that the aerosol penetration through the mechanical filter without negative air ions (NAI) is higher than that through the mechanical filter with 2 × 104, 1 × 105, and 2 × 105 NAI/cm3. This finding implies that the removal efficiency of the aerosol by combining negative ions with mechanical filter would be increased. The results also indicate that the variation of the aerosol penetration through the mechanical filter with NAI increased with the aerosol size. That is due to that the aerosol was easier to be charged when aerosol size was getting larger. Moreover, the aerosol penetration decreased with the NAI concentration increasing. The aerosol penetration through the mechanical filter with NAI increased with the face velocity and relative humidity. The filters with NAI performed better against solid aerosol than against liquid aerosol