The finer the filter, the smaller the particles it traps. They can capture up to 99 percent of particles down to 0.3 microns in size. But gas molecules, which include radon, tobacco smoke, etc., are extremely small and can still pass through a hePA filter. An activated carbon or charcoal filter usually is added to trap gas molecules. They are 40 to 95 percent effective and remove most household dust.
Electrical attraction is used in electronic cleaners.
This type of cleaner uses electrostatic precipitation, static charge, or particle ionization to remove particles drawn in by a fan through a foam pre-filter. Larger particles are trapped at this point. Particles are then charged by a high-voltage wire and captured in the precipitating cell. When a pre-filter is used, the electrostatic precipitator can remove mold, bacteria, tobacco smoke, and most household dust. Regular maintenance is a must.