Abstract: Improved apparatus for collecting particles from air comprises a cyclone having air inlet and outlet means, means maintaining an airflow there through and means delivering a collecting fluid from a reservoir to particles separated from the air flow in the cyclone, in which the air inlet means is associated with means for heating the incoming air. The apparatus, which is optionally provided with enclosure means for trapping heat, prevents freezing of the collecting fluid at temperatures near to and even below 0° C.