There is provided an aerosol-generating system configured for oral or nasal delivery of a generated aerosol to a user, the system comprising a heater element (20) configured to heat an aerosol-forming substrate to generate an aerosol, a power source (40) connected to the heater element, a controller (30) connected to the heater element and to the power source, wherein the controller is configured to control operation of the heater element, the controller including or being connected to a means to detect a change in air flow past the heater element, first data storage means (56) connected to the controller for recording detected changes in airflow past the heater element and data relating to the operation of the heater element, second data storage means comprising a database (57) relating changes in airflow and data relating to the operation of the heater element to the properties of the aerosol delivered to the user and an indication means (59) coupled to the second data storage means for indicating to the user a property of the aerosol delivered to the user. The property or properties of the aerosol delivered to the user may comprise amounts of particular chemical compounds.
