The Health Effects Institute (HEI) released a final report on January 27, 2015 from the health effects evaluation stage of the Advanced Collaborative Emissions Study (ACES, Phase 3). After a comprehensive evaluation of lifetime exposure of laboratory animals to “new technology diesel exhaust”—i.e., exhaust produced by heavy-duty, onroad diesel engines meeting the US EPA 2007 emission standards—the study found no evidence of carcinogenic lung tumors. The study also confirmed that the concentrations of PM and toxic air pollutants emitted from new technology engines are more than 90% lower than emissions from traditional older diesel engines.

The study exposed laboratory rats 80 hours a week, for up to 30 months, to emissions from a US EPA 2007 heavy-duty diesel engine equipped with a diesel particulate filter (DPF) and other emission control technologies. In contrast to previous health studies of older diesel engines, the ACES study found that lifetime exposure did not induce tumors or pre-cancerous changes in the lung and did not increase diesel emission related tumors in any other tissue. A few mild changes were seen in the lungs, consistent with long-term exposure to NO2, a diesel emission component that has been substantially reduced in US EPA 2010 and later model year engines.

The ACES results are expected to play an important role in future risk reviews of diesel engines by international and US agencies, said the HEI. Health effect studies of diesel emissions from older, uncontrolled diesel engines—involving exposures of both animals and humans—have led to the classification of diesel exhaust as carcinogenic to humans by the International Agency for Research on Cancer (IARC) in 2012.

Diesel particulate filter technology has been used on many diesel engines meeting the US EPA 2007 and later emission standards for heavy-duty onroad engines, as well as on many US EPA Tier 2 and later light-duty diesels. Over 30% of the trucks and buses in use today on US roads meet the new emission standards—said the HEI—and are equipped with DPFs. However, EPA emission regulations have not succeeded in forcing the DPF technology on new nonroad engines, with a large proportion of Tier 4 engine families being certified without DPFs.

The HEI Statement summarizing HEI Research Report 184, along with the full report and other supporting data and results can be found at http://pubs.healtheffects.org/.

What this means to you
A study exposing laboratory rats 80 hours a week, for up to 30 months, to emissions from a US EPA 2007 heavy-duty diesel engine equipped with a diesel particulate filter and other emission control technologies found no evidence of carcinogenic lung tumors.

MIRATECH can help
Contact MIRATECH to learn more about diesel particulate filter technology and other options for reducing PM, HAPs, or NO2 emissions.