where ζ is the particulate collection efficiency, φinlet is the
concentration of the dust particle entering the scrubber and
φWHO is the WHO [26] emission standard. From Table-1,
the concentration of the exhaust dust laden entering the
proposed scrubber is 22, 859μg/m3 using (18), the required
particulate collection efficiency standard for the annual
mean emission was obtained to be 99.9125% while that
for the 24-hour emission is 99.7813%. These values
described the collection efficiency needed by any air
pollution control device in order to control the PM10
concentration to the WHO [26] standard. Therefore for 24-
hour mean emission, ζ ≥ 99.7813% and for annual mean
emission, ζ ≥ 99.9125%.