Abstract: A ventilation duct to eradicate indoor odor and microbes includes an air purifying enclosure, a hydroxyl generator, a centrifugal duct fan, an air directing duct. The air purification process is completed through the ventilation duct to eradicate indoor odor as the air purifying enclosure, the hydroxyl generator, the centrifugal duct fan, and the air directing duct are in fluid communication with each other. The hydroxyl generator disinfects and converts a flow of contaminant air into a flow of purified air after the flow of contaminant air is drawn into the air purifying enclosure. The flow of purified air is then respectively discharged from the air purifying enclosure to the centrifugal duct fan and the air directing duct, before exiting the ventilation duct.