It is in Chapter 13 Structural Restoration- Drying and Completion of the Restoration Process (Category 1 and Post Remediation Category 2 and 3)- Controlling Airlflow that it says:
“Airmoving devices inherently tend to aerosolize soils and particulates present in the environment. As water evaporates from surfaces and materials such as carpet, more particles often become aerosolized, creating possible health, safety, comfort and cleanliness issues. Restorers should perform a preliminary cleaning of materials and surfaces (e.g., carpet, hard surface floors, exposed subfloors) to reduce the amount of soil or particulates that can become aerosolized, before activating airmoving devices. Where preliminary cleaning cannot sufficiently remove soil or particulates, or there are high-risk occupants, restorers can install one or more air filtration devices (AFDs) as a negative air machine, or to control or direct airflow.”
This means that Air Filtration Devices are a good choice when:
1) Precleaning has been deployed as a first measure to reduce the amount of soil or particulates that can become aerosolized, and
2) The restorer cannot sufficiently remove soil or particulates through precleaning, or
3) There are high-risk occupants.
Water Damage Mitigation 
Mold Removal 
Asbestos Abatement 