Direct reading instruments enable you to detect and measure worker exposure to gases, vapors, aerosols, and other fine particles that are suspended in the air. Some OSHA standards specifically require the use of such instruments. A large variety of instruments are available, each designed for a specific monitoring purpose. The proper operation of direct reading instruments is vital in order to protect workers from air borne contaminants.

The first step is to evaluate the conditions within which you will be working. What possible exposures will you need to monitor? Which direct reading instrument will be best to monitor it?

Read the manufactures instructions for the instrument, even if it's not the first time you have used it. Ensure that you are clear on how to calibrate and use the equipment properly.

The next step is maintenance. Most devices will require that you charge the internal batteries before use. Inspect all the filters and make sure that they re all in place. Replace dirty or missing filters.

Check the calibration each day, even if you have calibrated it at the start (which you definitely should). You should also check the calibration throughout the day. Check it when you turn it on, around mid-shift and again at the end of the day.