"Clean Diesel" Engine Emissions: Still Not Clean Enough
When a fire department acquires a new fire truck equipped with advanced diesel exhaust technologies, fire personnel should be aware that while the health risks associated with exhaust emissions are reduced, hazards still remain.
The Plymovent team reviewed several studies in which researchers measured the emissions of New Technology Diesel Engines (NTDE), including a diesel particulate filter (DPF), a selective catalytic reducer (SCR), and a diesel oxidation catalyst (DOC). The studies indicate that the occupational health hazards from the emissions have been lessened, but not eliminated, by NTDE. Here are three threats that NTDE exhaust still poses to firefighters.
Threat #1: The 10% or More of Pollutants Still Being Emitted: In 2015, The Advanced Collaborative Emissions Study (ACES), managed by the Health Effects Institute (HEI), published research showing that concentrations of PM and toxic air pollutants emitted from NTDE were more than 90% lower than emissions from TDE. While this was received with great optimism, not all researchers agree with the "90%" finding.
Threat #2: The Increase in Ultrafine Particles: Diesel exhaust contains “ultrafine particles” (UP), which are easily absorbed into lung tissue and the bloodstream, through the blood-brain barrier, triggering adverse effects such as cardiovascular inflammation or causing blood clots.
A 2016 Health Canada report stated that NTDE removes “more than 70%” of compounds from diesel exhaust. Whether the actual number is 10% or 30%, there is no acceptable limit of diesel exhaust, as the exhaust is complex and contains both carbon particulates and 40 chemicals that are classified as “hazardous air pollutants” under the Clean Air Act.