Aerosol generating system and cartridge with leakage protection

A cartridge for an electrically heated aerosol-generating system, the cartridge comprising a cartridge housing, the cartridge housing comprising:

• an aerosol-forming substrate;
• an air inlet situated at a first portion of the cartridge housing;
• an air outlet situated at a second portion of the cartridge housing;
• an airflow passage extending through the cartridge housing from the air inlet to the air outlet;
• an atomisation chamber within the airflow passage;
• an aerosol-generating element within the atomisation chamber configured to atomise the aerosol-forming substrate to generate an aerosol;
• and
• an inlet filter in the airflow passage between the air inlet and the atomisation chamber;
• wherein the inlet filter comprises a plurality of meshes, wherein interstices of a first mesh of the plurality of meshes has a different aperture size to interstices of a second mesh of the plurality of meshes, wherein the first mesh and the second mesh are arranged in parallel with one another and spaced apart from one another along the airflow passage.