Aerosol classification

Particle size	Particle examples	Filter grade	Application examples
Coarse-particle filters, for particles > 10 µm	Insects Textile fibers and hair Sand Flue ash Pollen Spores Cement dust	G1 G2	For simple applications (e.g., as insect protection in compact units)
Coarse-particle filters, for particles > 10 µm		G3 G4	Pre- and circulation filters for civil-defense facilities Extracted air from paint-spray stations and kitchen exhaust, etc. Soiling protection for air conditioners and compact units (e.g., window air conditioners, fans, etc.) Pre-filters for filter grades M6 to F8
Fine-particle filters for particles 1 ... 10 µm	Pollen Spores Cement dust Particles that cause spots and dust deposits Bacteria and microbes on host particles	M5	Outside-air filters for rooms with noncritical requirements (e.g., shop floors, storage rooms, garages)
		M5 M6 F7	Pre- and circulation filters in central ventilation facilities Final filters in air conditioning units for sales rooms, department stores, offices, and certain production rooms Pre-filters for filter grades F9 to E11
	Oil smoke and agglomerated soot Tobacco smoke Metal-oxide smoke	F7 F8 F9	Final filters in air conditioning systems for offices, production rooms, control facilities, hospitals, computer centers Prefilters for filter grades E11 to H13 and activated charcoal
HEPA filters for particles < 1 µm	Microbes, bacteria, viruses Tobacco smoke Metal-oxide smoke	E10 E11 E12	Final filters for rooms with great and maximum requirements (e.g., laboratories; production rooms in the food and beverage, pharmaceutical, precision-mechanical, optical, and electronic industries; medical facilities)
		E11	Final filters for clean rooms of classes 100,000 and 10,000
	Oil vapor and soot in original state Suspended radioactive particulates	E12 H13	Final filters for clean rooms of classes 10,000 and 100 Final filters in civil-defense facilities Extracted-air filters in nuclear facilities
	Aerosols	H14 U15 U16	Final filters for clean rooms of classes 10 and 1