Respiratory protection is a widely used control measure in many industries to protect workers from exposure to diesel emissions.
Recent research by the same authors (Coal Services Health & Safety Trust 2015-16 Project 20634 & WorkCover Applied Research grant 2015/005356) evaluated penetration of DPM through eight commonly used negative pressure respirator filters at the flow rate designated in the Australian standard, as well as at two higher flow rates representative of medium to heavy work. The filtering efficiency assumed by P2 certification (<6%) was not achieved for some respirators after a reasonably short wear time.
Powered air purifying respirators (PAPRs) are also used extensively in workplaces to protect workers against DPM and may be used increasingly due to changing standards on recommendations on work rates outlined in ISO/TS 16976-4:2012.
Without data on the filtration efficiency of PAPRs against DPM, there is uncertainty around whether these devices are fit for purpose and wearers are adequately protected.
Further research was conducted (Coal Services Health & Safety Trust 2016 -18 Project 20641) to determine whether PAPRs certified and used in Australian workplaces, effectively filter out Diesel Particulate Matter.
The methodology included:
•challenging three PAPR filters commonly used in mining workplaces with DPM and measuring the % Elemental Carbon and the ultrafine particles that penetrated the filters, and
•challenging the same three PAPR filters using current Sodium Chloride and Paraffin standard certified methods and challenge aerosols
This research raises concerns regarding the adequacy of the respiratory protection commonly provided against DPM.