I've found that tacking 'pdf' onto search queries gets through some of the SEO garbage. For instance I did 'home dust filtration pdf' and found this pdf:

https://www.epa.gov/sites/default/files/2018-07/documents/re...

which cites this paper about deposition rates of different particle sizes:

https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=86094...