05-12-2019, 09:28 PM
The same study concluded that the 5um carbon block filters stopped the larvae. That's an equally valid result. To those of us who read the report and discussed it over on the thread about rat lungworm, this omission is conspicuous.
It is important in all this to understand the limitations in any technology. The idea that a filter labeled 10um may have many 50um holes in it may seem wrong but the rating system allows for it and if you are only concerned with stopping sediment like pollen drifting in on the wind then 10um being an average still does the job. The average consumer didn't have to concern themselves before about the difference between nominal and absolute ratings.
It is important in all this to understand the limitations in any technology. The idea that a filter labeled 10um may have many 50um holes in it may seem wrong but the rating system allows for it and if you are only concerned with stopping sediment like pollen drifting in on the wind then 10um being an average still does the job. The average consumer didn't have to concern themselves before about the difference between nominal and absolute ratings.