An air purification device (100, 200) for purifying air, the air purification device (100, 200) comprising: - an air inlet for receiving an air flow, - an air outlet, - a photocatalytic volume (150, 300, 350, 434, 464) comprising a photocatalytic material, the photocatalytic volume (150, 300, 350, 434, 464) being arranged to allow air to flow through the photocatalytic volume (150, 300, 350, 434, 464) such that at least a portion of air flowing through the photocatalytic volume (150, 300, 350, 434, 464) contacts the photocatalytic material, the photocatalytic volume (150, 300, 350, 434, 464) being arranged between the air inlet and the air outlet to ensure that, in use, at least a portion of the air flow received by the air inlet flows through the photocatalytic volume (150, 300, 350, 434, 464), the photocatalytic material being configured to be a catalyst under the influence of UV light in photoreactions between gasses in the air flowing through the photocatalytic volume (150, 300, 350, 434, 464), - a first solid state light emitter (102, 202) arranged to emit UV light and to emit the UV light towards the photocatalytic volume (150, 300, 350, 434, 464) for activating the photocatalytic material to act as the catalyst, characterised by further comprising - a second solid state light emitter (122, 222) arranged to emit deep blue light in a light emission spectrum having peak wavelength (λpeak2) in the range from 400 nanometer to 450 nanometer, the second solid state light emitter (122, 222) being arranged to emit the deep blue light towards the photocatalytic volume, - a controller for controlling an on and off state of the second solid state light emitter (122, 222), wherein the controller is configured to control the second solid state light emitter (122, 222) also into the on state for at least a period of time while the first solid state light emitter (102, 202) is not emitting light. - an air inlet for receiving an air flow, - an air outlet, - a photocatalytic volume (150, 300, 350, 434, 464) comprising a photocatalytic material, the photocatalytic volume (150, 300, 350, 434, 464) being arranged to allow air to flow through the photocatalytic volume (150, 300, 350, 434, 464) such that at least a portion of air flowing through the photocatalytic volume (150, 300, 350, 434, 464) contacts the photocatalytic material, the photocatalytic volume (150, 300, 350, 434, 464) being arranged between the air inlet and the air outlet to ensure that, in use, at least a portion of the air flow received by the air inlet flows through the photocatalytic volume (150, 300, 350, 434, 464), the photocatalytic material being configured to be a catalyst under the influence of UV light in photoreactions between gasses in the air flowing through the photocatalytic volume (150, 300, 350, 434, 464), - a first solid state light emitter (102, 202) arranged to emit UV light and to emit the UV light towards the photocatalytic volume (150, 300, 350, 434, 464) for activating the photocatalytic material to act as the catalyst, characterised by further comprising - a second solid state light emitter (122, 222) arranged to emit deep blue light in a light emission spectrum having peak wavelength (λpeak2) in the range from 400 nanometer to 450 nanometer, the second solid state light emitter (122, 222) being arranged to emit the deep blue light towards the photocatalytic volume, - a controller for controlling an on and off state of the second solid state light emitter (122, 222), wherein the controller is configured to control the second solid state light emitter (122, 222) also into the on state for at least a period of time while the first solid state light emitter (102, 202) is not emitting light.