RR994 - Non destructive techniques for analysis of diesel engine exhaust emissions (DEEE) on filters

Diesel engine exhaust emissions represent a hazard to worker health. The amount of elemental carbon (EC) is the routine measure of DEEE. Historically, an instrument, the Bosch meter, has been used in underground mines in the UK. The meter measures 'blackness' of a filter paper as a proxy for EC and HSL showed that there was a relationship between blackness and EC.

The Bosch meter is no longer available and this report details the investigations into a replacement system. The instruments tested were those that were commercially available at the time the research was undertaken: a Magee Scientific OT21 transmissometer, a DR-Lange Micro colour II and a system where a filter is scanned using a normal office scanner and then measured using a tool in the Adobe Photoshop software program.

Each has been assessed against the Bosch meter and the amount of EC as determined by two-stage combustion on an Analytik Jena elemental analyser.

The DR-Lange Micro colour II was found to be the closest like for like replacement for the Bosch meter.

When compared with EC, the Magee Scientific OT21 transmissometer was found to be the most effective instrument, having the best precision and range of analysis. The DR-Lange Micro Colour II and scanner/Photoshop were found to be acceptable for normal use and each was an improvement on the Bosch meter.

The scanner/Photoshop method is considerably less expensive to purchase.

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Updated 2021-04-26