The Advanced Collaborative Emissions Study (ACES) has been issued by the Health Effects Institute (HEI) has confirmed that the concentrations of particulate matter and toxic air pollutants emitted from new technology diesel exhaust (NTDE) are more than 90% lower than emissions from traditional older diesel engines (TDE).
The study exposed lab rats 80 hours a week, for up to 30 months to emissions from a heavy duty diesel engine meeting stringent 2007 US EPA standards that use new filters and other control technology to reduce emissions significantly. In contrast to previous health studies of TDE, the ACES study found that lifetime exposure did not induce tumours or precancerous changes in the lung and did not increase tumours related to NTDE in any other tissue. A few mild changes were seen in the lungs, consistent with long term exposure to NO2, a component of NTDE that has been further substantially reduced in 2010, and later model year engines compliant with US EPA rules.
The study results are expected to pay an important role in future risk reviews of diesel engines by international US agencies. Dan Greenbaum, President, HEI said, “we are already seeing a transition in America’s roads with over 30% of the trucks and buses in use today meeting these new standards and the trend is growing in Europe as well. These results confirm the great strides that government and industry have made to reduce diesel risk, and argue for even greater efforts to accelerate the replacement of older diesel engines.”
Review panel conclusions
In their commentary on the study, the review panel concluded, “overall, these results indicate that rats exposed to one of three levels of NTDE from a 2007 compliant engine for up to 30 months, for 16 hr/d, 5 days a week, with use of a strenuous operating cycle that more accurately reflected the real world operation of a modern engine than cycles used in previous studies, showed few NTDE exposure related biologic effects. In contrast to the findings in rates chronically exposed to TDE, there was no induction of tumours or preneoplastic changes in the lungs and no increase in tumours that were considered to be related to NTDE in any other tissue. The effects that were observed with NTDE were limited to the respiratory tract and were mild and generally seen at only the highest exposure level. These histologic changes in the lungs were consistent with previous findings in rates after long term exposure to NO2, a major component of the exposure atmosphere which is being substantially further reduced in 2010 compliant engines.”
Edited from press release by Claira Lloyd
Read the article online at: https://www.hydrocarbonengineering.com/the-environment/28012015/diesel-not-that-bad/