Which type of respirator can be powered, providing an air supply through a fan?

The correct choice is the powered air-purifying respirator (PAPR), which is specifically designed to assist in providing airflow to the user. This type of respirator uses a battery-powered fan to pull air through a filter, offering a continuous supply of clean air to the wearer. This mechanism not only enhances comfort by reducing breathing resistance but also provides a higher level of protection in environments with airborne contaminants.

In contrast, non-powered particulate respirators rely solely on the user's breathing to draw air through the filtering material, which can make breathing more strenuous in high-contaminant situations. Supplied-air respirators, while also providing a clean air supply, do so through a separate air source and are not fan-operated. Gas masks with canisters filter air but do not have a powered mechanism to assist airflow like a PAPR does, thus they rely on the natural inhalation of the user.