A particle separation system for separating particles in an airflow upstream of a detection chamber in an aspirating smoke detector is disclosed. The particle separation system includes an airflow path for directing the airflow from an inlet to an outlet. The airflow path includes a first airflow path section in a first direction and a second airflow path section in a second direction, the first and second directions being different relative to each other. The airflow path also includes at least one electrically charged surface such that the airflow undergoes electrostatic precipitation as it traverses the airflow path. A method of separating particles in an airflow upstream of a detection chamber in an aspirating smoke detector is also disclosed.