there are numerous air purifiers with which the markets have been flooded. But, the question arises here that what sort of air purifiers and with which functions are the best to buy. Previously, there were HEPA (high-efficiency particulate air) filters, which can eradicate 99.97% of airborne particles as little as 0.3 micrometers. However, with the coronavirus pandemic, the need has become the change, and now the PECO (photoelectrochemical oxidation) filters are also available that can purify the microns as small as 0.1, unlike HEPA filters. But, the efficacy of the PECO filters has yet to be approved.