Where is the cabin air filter located in a BMW 523?

[McPenelope]

The cabin air filter in a BMW 523 is located inside the passenger side compartment. You'll need to remove the panel under the glove box using an E20 spline tool to reveal a small box. After removing the cover plate beneath this box (also requiring an E20 spline tool), you'll find the filter. The cabin air filter helps absorb dust particles, alleviates respiratory discomfort, reduces irritation for allergy sufferers, enhances driving comfort, and protects the air conditioning cooling system. The BMW 523 is a mid-to-large luxury sedan equipped with a 2.0T 184hp L4 engine producing 135kW maximum power and 290Nm peak torque, paired with an 8-speed automatic transmission.