What classification criterion is used for respirator filters?

• A. Oil degradation resistance and filter efficiency
• B. Color and brand
• C. Price and weight
• D. Size and number of straps

Answer: (A)

Filters are classified by how they handle oil and how well they remove particles. The first factor, oil resistance, is shown by whether the filter material is not resistant to oil (N), somewhat resistant (R), or oil-proof (P). The second factor is filtration efficiency, the percentage of particles the filter can remove (common ratings like 95%, 99.97%, etc.). So you’ll see labels like N95 or P100, which tell you both if the filter can handle oil in the air and how effectively it cleans out particles.

This matters in pesticide work because some aerosols and solvents involve oil-based components. If oil is present, an oil-proof option (the P series) is needed to maintain protection, while the exact efficiency rating tells you how much protection you get against fine particles. In contrast, factors like color, brand, price, weight, or how many straps a mask has don’t indicate the filtering capability or oil resistance, so they don’t determine suitability for hazardous aerosols in the field.