It should be noted that TSI 8534 measures PM concentrations with a light scattering technique, where the
amount of scattered light is proportional to the volume concentration of the aerosol. Affected by RH [10] and
hydrophilic particles such as sulfate, nitrate and some organic PM particles [11], the PM concentration obtained by
this instrument are not actual gravimetric values. The Australia researchers presented a linear regression equation to
convert the PM2.5 concentration obtained by TSI 8534 into the values by the instrument with the principle of
gravimetric sampling method [12].