In Abstract:
I want you to explain the meaning of PM1 and PM2.5
Introduction:
The relationship between the comfort/discomfort and efficiency of respirators.
Talk about the efficiency by look to penetration of the respirators.
You can change the aims (title) of study 1, 2, and 3 if you want.
Study1:
Talk more about Indoor air pollution and PM2.5 vs  ETS
Find resources to add about that ETS is under PM2.5 size.
Add more in SHS Vs THS
Why it is important to use nasal filters in indoor work environment that has ETS such as casinos.
Study 2:
General information about air pollution.
Focus on PM1 (NaCl particles)
Why using nasal filters against PM1 particles.
Study 3:
Add more in APF, MUC, TIL parts.
Explain the relationship between comfort and efficiency of respirators.
Add more about advantages of using nasal filters and focus on the comfort.

Feel  free to add, rewrite, edit, rephrase anything.
I want it to reach 30 pages