This application relates to a portable electronic device that includes an integrated pressure sensor. The portable electronic device includes a housing that defines a cavity with a number of components disposed therein. The cavity is sealed to form a volume of air within the cavity that is vented to the external environment through a barometric vent fluidly coupled to a first opening in the housing. A sensor measures a characteristic of a second volume of air within an isolated chamber that is vented to the external environment through a second opening in the housing. The second volume of air is isolated from the first volume of air within the housing of the portable electronic device. In some embodiments, the portable electronic device is a mobile phone and the sensor is a pressure transducer.