Bio-aerosols may attach to other particles (rafting) and be
transported together, and this highly polluted outdoor air
(excluding auto vehicle emission) is the main source of particulate
matter in the indoor environment. It follows that in air with high
concentrations of particulates, the typical size distribution of bioaerosols
can be changed, resulting in altered size distributions of
respirable bacteria and other bio-aerosols [14,18,34]. Bio-aerosols
of 5e10 mm diameter deposited in the upper respiratory tract can
cause rhinitis, and aerosols of less than 5 mm may induce allergies
through the alveoli