Molecules are 1000 to 10,000 times smaller than the particles that pass through HEPA & ULPA filetrs. Contamination prevention at the molecular level plays a crucial role in highly specialised industries like cleanrooms, pharmacuetical industries etc. Leakage of harmful gases can lead to serious damage in processes, human life and environment. To tackle this, gas phase/ molecular filetrs are necessary. These filters work by utilising a technique called adsorption which ensures that the molecules stick on materials with high surface areas to avoid leakage. These filters comply by ISO 10121 or ASHRAE 145.2 standards.