If there are no manufacturer use recommendations, a pesticide applicator should replace the chemical cartridges of his or her respirator:

A pesticide applicator should replace the chemical cartridges of their respirator at the end of each workday when there are no manufacturer use recommendations available. This approach is crucial for ensuring the safety and effectiveness of the respirator, as it helps to mitigate the risks associated with prolonged exposure to harmful pesticide vapors or particles.

Each day, the cartridges may absorb toxins and contaminants, and their effectiveness can diminish over time. By replacing cartridges at the end of the workday, the applicator ensures that they start each day with a fully functional and effective respirator, reducing the likelihood of inhalation of hazardous substances.

While there are other practices mentioned that might suggest different schedules for replacement, these may not provide adequate protection for the applicator, especially when working in potentially harmful environments like those involving pesticide applications. Regular replacement at the end of each day is a precautionary measure that aligns with safety protocols in environments where exposure risk is a continuous concern.