What is the main use of a P100 filter in a respirator?

The primary purpose of a P100 filter in a respirator is to provide a high level of filtration efficiency for airborne particles, particularly those that may contain oil. The "P" designation indicates that the filter is oil-proof and can effectively filter solid and liquid aerosols, including those from oil-based pesticides and other similar substances.

P100 filters are designed to remove at least 99.97% of airborne particles, making them suitable for environments where there is a risk of exposure to hazardous particulates, including those from certain types of pesticides. This level of filtration is particularly important in agricultural or pest control settings, where workers may be applying products that could be aerosolized and inhaled.

While some filters can effectively deal with various gases and vapors, the unique capability of the P100 filter to handle oil-based substances sets it apart for use in scenarios involving pesticides containing oil. This feature is crucial for ensuring the safety of individuals working with these chemicals, thus making it the correct answer in the context of the question.