Abstract: A dry deposition sampling apparatus having at least one thin dry deposition plate with sample collection film is maintained on a support structure which is rotatable about a vertical axis and has a vane to maintain the sharp leading edge of the dry deposition plate(s) headed into the wind. Covers are positioned over the sample collection films automatically upon commencement of precipitation and are automatically moved to a position exposing the sample collection films to the atmosphere upon cessation of precipitation. The duration of exposure of the collection films to the atmosphere is timed, thus providing a dry deposition sampling apparatus which may be left unattended for long periods of time.