Techniques of tracking a user's location are disclosed. In some embodiments, a mobile device captures first sensor data using at least one sensor, determines that a predetermined hazard criteria is not satisfied by an environment of a user of the mobile device, suppresses transmission of a representation of the captured first sensor data to a remote computing device based on the determination that the predetermined hazard criteria is not satisfied, captures second sensor data using the sensor(s), determines that the predetermined hazard criteria is satisfied by the environment of the user, and transmits a representation of the captured second sensor data to the remote computing device based on the determination that the predetermined hazard criteria is satisfied by the environment of the user.