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15
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Replacing the PM2.5 Impactor
To maintain the particle-sizing characteristics at 2.5
μ
m and 50 % cut by using the PM2.5
impactor, mount the impactor filter (a
φ
37-mm fiberglass filter) in the impactor well
(coarse particle catcher). Then cover the filter surface with a layer of impactor oil to
prevent the re-scattering of coarse particles.
While holding the lower section of the PM2.5 impactor, rotate the upper
section of the impactor counterclockwise. Loosen the screws and
separate the upper and lower sections of the impactor.
Note: The impactor well (coarse particle catcher) is placed on top of the lower section
of the PM2.5 impactor. Be careful not to drop the impactor well when the upper
and lower sections of the impactor are separated.
Separate the upper and lower sections of the PM2.5 impactor well.
Attach the impactor filter (
φ
37-mm fiberglass filter) onto the catcher at the lower section
of the PM2.5 impactor well. Drop 1 mL of impactor oil onto the surface of the filter to coat
it with a layer of oil.
Reverse the procedure to reassemble the impactor well.
Attach each part carefully, ensuring an airtight seal.
Note: To minimize the re-scattering of coarse particles and changes in sizing
characteristics as the inside of the PM2.5 impactor becomes dirty, replace the
impactor filter and clean the inside of the impactor about once per week. Clean it
with soft cloths or paper, or by using pure water to damp them. If the dirt resists
cleaning with pure water, use ethanol or acetone.
Impactor upper section
Impactor well
Impactor lower section
Impactor well upper section
Impactor filter
Impactor well lower section
