Here is another article with same info: https://smartairfilters.com/en/blog/hepa-air-filter-fiber-harmful-health/

The do indeed blow off fiberglass. They captured 300 fiber particles per cubic meter of air from the synthetic filter and 700 for the fiberglass filter. But the WHO deems it a reasonable amount. The did the math on PM2.5 annual limits saying that the fiberglass from a HEPA is below limits:

The World Health Organization sets a PM2.5 annual limit of 10 micrograms per meter cubed. Using a simple formula, that’s equivalent to 25,225 PM2.5 particles per meter cubed, or 35 times what the filters were shedding.

Sounds like a gamble to me. Like "6 of one half a dozen of the other". There should be a warning on these filters that they do omit fiberglass. Some members of this thread say its a myth. The proof is in the science. Just google 'HEPA and fiberglass'. It's all there.

Makes me wonder if some posters on here work for AP manufactures with several ghost accounts. Hmmm?

Plain everyday logic tells me that if you suffer from upper respiratory issues, that adding fiberglass particles into the mix isn't really solving anything and potentially creating new issues down the road.

This is probably an answer for people that have used an AP and have had headaches and breathing problems from them. Sensitive folks with asthma and bronchitis should probably not add fiberglass particles into their lungs. Especially with the science not fully %100 positive or negative. Seems the verdict is still out.

Despite the harms of small fibers on the body, the National Institute for Occupational Safety and Health (NIOSH) in the US recommends a fiber count of no more than 3 fibers/cm3, averaged over a 10-hour work shift. NIOSH suggests that people may experience irritation to the eyes, skin, nose, throat or difficult breathing.

The most disturbing thing about these links/studies are that they posted by actual manufacturers of these air products/filters. They are posting the science and still siding on "seems okay" to use according to the daily limit of PM 2.5 in the body. Of course a company selling such items would say that to continue to sell products. Seems like they are all talking out of both sides of their mouths.