System for sampling aerosols and gaseous iodine contained in an atmosphere comprising: - a device for sampling aerosols comprising: -- an air supply duct, in fluid communication with the atmosphere, -- a first pump adapted to sample and make a main air stream circulate with a main air flow in said duct, -- a filter disposed in said duct and adapted to retain the aerosols contained in the main air stream crossing said filter, and - an iodine sampling module, comprising: -- a cartridge for trapping iodine containing a quantity of adsorbent material, -- an air circulation duct, connected to the air supply duct downstream of the filter with respect to the main air stream, and extending between said duct and the cartridge, the duct forming an air circulation loop downstream of the filter separately from the air supply duct, -- a second pump adapted to sample a secondary air stream with a secondary air flow, within the main air stream circulating in the air supply duct, and make said secondary flow circulate in the circulation duct and the cartridge, -- a device for heating the air flowing in the air circulation duct, and -- a system for regulating the humidity rate of the air circulating in the air circulation duct, said system being adapted to control the device for heating the air flowing in said duct according to the humidity rate of the air. - a device for sampling aerosols comprising: -- an air supply duct, in fluid communication with the atmosphere, -- a first pump adapted to sample and make a main air stream circulate with a main air flow in said duct, -- a filter disposed in said duct and adapted to retain the aerosols contained in the main air stream crossing said filter, and -- an air supply duct, in fluid communication with the atmosphere, -- a first pump adapted to sample and make a main air stream circulate with a main air flow in said duct, -- a filter disposed in said duct and adapted to retain the aerosols contained in the main air stream crossing said filter, and - an iodine sampling module, comprising: -- a cartridge for trapping iodine containing a quantity of adsorbent material, -- an air circulation duct, connected to the air supply duct downstream of the filter with respect to the main air stream, and extending between said duct and the cartridge, the duct forming an air circulation loop downstream of the filter separately from the air supply duct, -- a second pump adapted to sample a secondary air stream with a secondary air flow, within the main air stream circulating in the air supply duct, and make said secondary flow circulate in the circulation duct and the cartridge, -- a device for heating the air flowing in the air circulation duct, and -- a system for regulating the humidity rate of the air circulating in the air circulation duct, said system being adapted to control the device for heating the air flowing in said duct according to the humidity rate of the air. -- a cartridge for trapping iodine containing a quantity of adsorbent material, -- an air circulation duct, connected to the air supply duct downstream of the filter with respect to the main air stream, and extending between said duct and the cartridge, the duct forming an air circulation loop downstream of the filter separately from the air supply duct, -- a second pump adapted to sample a secondary air stream with a secondary air flow, within the main air stream circulating in the air supply duct, and make said secondary flow circulate in the circulation duct and the cartridge, -- a device for heating the air flowing in the air circulation duct, and -- a system for regulating the humidity rate of the air circulating in the air circulation duct, said system being adapted to control the device for heating the air flowing in said duct according to the humidity rate of the air.