If we are talking about environmental pollution some very large particles reach 10 micrometers. 

 HEPA filters block them easily. But the truth is that particles smaller 

 than 25 micrometers are the most dangerous. HEPA can stop them as long

as they are larger than 03 micrometers. There is a small space in the system but we cannot deny

that the edges work well against pollution. Things are a little different when it comes to COVID-19.

According to the New England Journal of Medicine COVID-19 particles range 

from 006 to 014 micrometers so this trap cannot be more efficient. 

 However it should be noted that the WHO had corrected the first opinion about

 the airborne virus. Now experts believe that the drops are more likely to spread 

 the respiratory virus.