What are the size ranges for the E1, E2, and E3 categories in ANSI/ASHRAE 52.2?

The E1, E2, and E3 categories in ANSI/ASHRAE 52.2 are defined based on specific particle size ranges relevant to air filtration performance assessment. For particulate matter, the E1 category includes particles with diameters between 0.3 to 1.0 microns, while the E2 category covers particles from 1.0 to 3.0 microns, and the E3 category spans from 3.0 to 10 microns. Understanding these categories is crucial for evaluating the efficiency and effectiveness of air filters in capturing different sizes of airborne particles. This classification system helps in selecting the appropriate filters based on their intended application in heating, ventilation, and air conditioning (HVAC) systems, ensuring that filtering solutions are optimized for specific environmental conditions and pollutants.