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:
A cook developed breathing problems after working with flour dust. She worked in a small, poorly ventilated room, with nothing to control her exposure to the flour dust. She became severely asthmatic and, after retiring early on health grounds, was awarded compensation.
The employer has since installed an extraction system to remove the flour dust and introduced new ways of working such as using a scoop to transfer flour, using sprinklers to spread flour and keeping the work area clean. The risk of other workers developing occupational asthma has been reduced.