What is the differential pressure of a mask?

The term "differential pressure" in the context of masks refers to the pressure difference between the outside and the inside of the mask. It is a measure of the airflow resistance that the mask material presents, and it is an important factor in evaluating the breathability and filtration efficiency of a mask.

When discussing the performance of medical or protective masks, the differential pressure is often expressed in terms of "Differential Pressure (Delta P)" and is measured in units of pressure, such as millimeters of mercury (mmH2O) or pascals (Pa). A lower differential pressure value indicates lower airflow resistance, meaning that the mask is easier to breathe through. This is particularly important for medical masks as they are worn for extended periods by healthcare workers and patients, and good breathability contributes to user comfort and reduces the potential for moisture build-up within the mask.

Standard test methods, such as ASTM F2100 for medical face masks, specify the requirements for differential pressure testing. These tests help ensure that the mask material provides the necessary balance between filtration efficiency and breathability, thus offering adequate protection while remaining comfortable for the wearer.

In summary, the differential pressure of a mask indicates the resistance to airflow that the mask material presents, and it is an essential parameter for evaluating the performance and comfort of masks, particularly in medical and healthcare settings.