A method of maintaining a desired level of an aerosolized compound within a space to be treated with the compound, the method including providing a diffusion device with the compound in liquid form and a control system for operating the device. The control system includes a sensor in fluid communication with the air within the space to be treated configured to sense the concentration of the compound aerosolized within the space. The diffusion device is operated to diffuse the compound into the space. The concentration of the compound within the space to be treated is sensed with the sensor and operation of the diffusion device is altered based on the concentration of the compound sensed to achieve a desired concentration of compound within the space. The sensing and operation altering steps are repeated periodically to maintain the desired concentration of the compound within the space.
