When oil may be present, which particulate filter must be used?

When oil is present in the environment, the use of a P-series particulate filter is essential. The P-series filters, often referred to as "Particulate Respirators," are specifically designed to be resistant to oil aerosols, making them suitable for use in situations where there might be a presence of oil mist or vapor.

The "P" designation stands for "oil-proof," meaning that these filters can effectively capture particulates in environments where oils are present, ensuring worker safety and air quality. This type of filter can be used for a more extended period when exposed to oil, compared to other filter series that may become ineffective when faced with such conditions.

In contrast, the other types of filters have their specific limitations. For instance, N-series filters are not rated for use with oily particulates, meaning they are not suitable in environments where oil is present. R-series filters are somewhat oil-resistant but have limitations on the duration of effectiveness in oily conditions. V-series filters do not address the issue of oil presence and are unrelated to the particulate filtering requirements of scenarios involving oil.

Therefore, the P-series is the only option that ensures adequate protection when oil may be a factor, making it the correct choice in this context.