Fine dust and mist is invisible in normal lighting. You can make it visible with a 'dust lamp'. Used correctly, a dust lamp is a cheap, powerful tool to help you identify where dust problems such as leaks are and whether an extraction system is working effectively.
The dust lamp should be set up to observe forward-scattering of light. Point the lamp to shine through the area where you think the dust cloud is. If possible, lower the background lighting by turning off workshop lights. Lock the lamp into the 'on' position and walk around the process, looking back up the beam at a slight angle, through the airborne dust:
- note the settlement and spread of contamination on surfaces
- check the airflow indicator on the extraction system
- check for damage and leakage from the process
- speak to the operator and encourage reporting of any defects