HEPA filters are widely regarded as highly effective in purifying the air from pollutants and allergens due to their ability to capture particles as small as 0.3 microns. A research review from the Current Allergy and Asthma journal reports that, “[i]nexpensive, low-efficiency HVAC filters offer no better particle removal than no filter.” This emphasizes the value of investing in machines with better, ideally HEPA, filters, which are frequently used in clinical settings like hospitals and are renowned for their high efficiency in trapping particles, with a reported efficiency of up to 99.97% according to the EPA.