Which statement is true about respirator maintenance?

The statement regarding respirator cartridges needing to be stored in an airtight bag to maintain their effectiveness is accurate. This is important because respirator cartridges contain chemicals that can adsorb contaminants from the environment or degrade due to exposure to air, moisture, or other environmental factors. Storing them in an airtight bag helps preserve their functionality, ensuring that they are effective when needed for protection against harmful substances.

In contrast, the other options do not reflect best practices for respirator maintenance. Regular replacement schedules vary depending on the type of cartridge, usage, and environmental conditions, making the blanket statement regarding monthly replacements incorrect. It's also essential to conduct inspections regularly, regardless of recent use, to identify any damage or wear that may affect performance. Lastly, respirators require careful maintenance and inspection between uses to ensure they are in good working condition, as neglect can compromise user safety.