In response to the global pandemic (COVID-19), we are responsible for thinking of the solution to prevent the outbreak in our city. In this project, the focus would be the solution to prevent viruses from travelling up through the rooftop ventilating pipe of the foul water stack. It is proposed to customise a sterilising device for ventilating pipe of drainage system with Titanium Dioxide quantum dots photocatalyst technology for disinfection. The design is able to promote inactivation of viruses on surfaces and integrate with current ventilating pipes for lowering the risk of spreading viruses through the system. The device installed on the vent pipe outlet has two main functions: 1. To use the QDs phtocatalyst technologies to sterilise the vent pipe internal surface to provide a long lasting antiviral and antibacterial properties; 2. To use the antibacterial sanitising solution in the spiral section of the device so that the air contact as much solution as possible to minimise the breeding of germs.