One kind of passive ventilation system is a roof ventilator, which uses the roof to passively circulate fresh air while expelling hot, stale air from interior spaces. Important components include ventilation blades (for optimal air circulation), weather-resistant housing (for protection), and an exhaust system (for effective airflow). Strong materials like aluminium or galvanised steel, together with modern technology like wind-driven efficiency, are used to make these ventilators, which are often coated to prevent corrosion. They reduce energy expenses, improve indoor air quality, and lower temperatures, all of which lead to a more productive and healthful work environment. They are commonly used in industries like factories, warehouses, and agriculture.