Hepa is a kind of air purifier. It is considered to filter the bad air away and keep the area fresh with clean air. Hepa air purifiers and filters have a specific standard which are mostly abided by the energy department of USA. A purifier has to be clinically tested for further use and then it is launched in the market. There are certain standards issued by the government. An air purifier which would be able to clean 99.97% of air would be considered as Hepa. These Hepa air purifiers can be used in the hospitals, households and in the aircrafts as well.