Air filters are designed to remove at least 99.97% of dust, pollen, mold, bacteria and any particles suspended in the air with a size of 0.3 microns (µm). Donaldson air filters in Donaldson air filter housings have a minimum total efficiency greater than 99.90%. This level of efficiency is determined by introducing air containing a known concentration of standard test dust into the air filter until the filter reaches the end of its useful life. The CADR (Clean Air Delivery Rate) number of each contaminant indicates how quickly the unit will filter the air to detect contaminants in a given size range. Portable and low-cost air purifiers (APs) have the potential to reduce people's exposure to biological contaminants in indoor air, but more research is needed, in particular on the airborne reemission process of APs.
The higher the CADR, the more particles the air purifier can filter and the larger the area it can cover (ASHRAE, 201).High-efficiency air filters are much more effective at cleaning indoor air than lower-efficient ones. Dust bottles show the actual amount of fine test dust that passes through the air filter medium for every kilogram of dust introduced into the air filter, which is equivalent to 100 hours* of equipment operation. This means that you can get maximum protection for your engine and save money by allowing your air filter to operate throughout its lifespan. In addition to filtering particles, some air purifiers use other methods to clean indoor air. Ozone-generating air purifiers create ozone to clean the air through chemical interactions that alter the compounds of the pollutants.
Bipolar ionization releases positive and negative ions into the air which surround and destroy germs and pathogens present, and add mass to help particles fall to the ground and pass through the building's air filter. Filtering air filters pass air through a filter, where polluting particles or gases accumulate, and return clean air to the room. That's why it's important to allow the air filter to do its job properly and not to change it prematurely. There is some popular controversy surrounding the extent to which air filters can reduce the presence of larger particles (such as pollen, allergens from household dust, mold spores, and animal dander), but most of these large particles settle on surfaces in the home or office and cannot be removed by an air filter unless they are altered and re-suspended in the air. The efficiency and ecological costs of air purifiers in terms of improving the microbiological quality of indoor air in homes: a case study. To get maximum protection for your engine and save money, it is important to allow your air filter to operate throughout its lifespan.