HRPA's health and safety competencies require applying the hierarchy of controls and understanding control strategies at the source, along the path, and at the worker. Controlling the path refers to interrupting or redirecting the transmission of a hazard between source and worker (e.g., ventilation, isolation, or barriers). Opening a window to provide ventilation reduces airborne contaminant concentration along its path, fitting this category.

Mopping a spill (A) is housekeeping/source removal after release; replacing equipment (B) is a source/engineering control; hearing protection (C) is PPE at the worker.

Relevant HRPA references: Professional Competency Framework --- Health, Wellness & Safe Workplace (apply the hierarchy of controls; distinguish source, path, and worker controls); Study Guide content on ventilation as a path control.