Is there clear understanding of what is really there?

Is there data to support the findings? – (has testing or other quantification been completed?)
Are there dynamics of process/technology changes? – (are there projects active that could heighten or diminish the need for filtration?)
Are all forms of contaminants considered? – (are solids liquids and gases, including micro biological elements, all part of the decision process?)

Are there Hazardous materials involved?

What kind of materials and what are the concentrations? – (is there data to support the judgment?)
Are other exposure control options considered? – (are special protective gear or isolation protocols a better solution?)
Is expended or used filter disposition an impact? – (were costs and complexity of contaminated filter removal considered?)

Has source control been considered as an alternative to filtration?

Are sources easily identified? – (is there evidence to support the judgment?)
Are control options viable and practical? – (has cost/benefit vs. filtration been considered?)

Have ventilation techniques been considered as an alternative to filtration?

Are acceptable fresh air sources available? – (is there evidence to support the judgment?)
Is re-circulated air acceptable? – (is it in sufficient quality and quantity?)
Is the air handling equipment capable? – (can fresh air make up or re-circulated sources be introduced?)

1. Define Air Filtration Objectives
2. Identify Contaminants to be Removed
3. Understand Operational Constraints
4. Consider Available Options
5. Checklist