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First results from HEI/ACES murine study find few biologic effects from exposure to exhaust from new technology diesel engines

13 April 2012

The first results of a comprehensive study of the health effects of exposure to new technology diesel engines has found no evidence of gene-damaging effects in the animals studied, and only a few mild effects on the lungs, according to a report issued today by the Health Effects Institute (HEI). HEI is an independent, non-profit research institute funded jointly by the US Environmental Protection Agency (EPA) and the worldwide motor vehicle industry.

The study—a component of the Advanced Collaborative Engine Study (ACES)—is exposing rats and mice for 16 hours a day to emissions from a heavy duty diesel engine meeting 2007 US EPA standards that reduce emissions of fine particles and other pollutants by more than 90% from levels emitted by older engines.

The study found that exposures lasting one, three, and in some cases up to twelve months had effects on only a few of the many health markers tested; exposures will continue for the lifetime of the rats.

The few effects that were reported for the rats were mild hyperplasia (cell proliferation) in the lungs and slightly reduced lung function, and were most consistent with exposure to nitrogen oxides in the engine exhaust, which are being further reduced under 2010 US EPA standards now in effect.

These results are expected to play an important role in upcoming risk reviews by international and US agencies of older and new technology diesel engines, including a review of the carcinogenicity of diesel exhaust in June, 2012 by the International Agency for Research on Cancer (IARC) in Lyon, France.

We will be communicating these results to IARC, the US National Toxicology Program, and US EPA in order to ensure that the significant improvements in emissions and effects for these new diesel technologies are considered and compared with the data on older engines when those agencies reach their conclusions.

—Dan Greenbaum, President of HEI

The study—HEI Research Report 166: Advanced Collaborative Emissions Study (ACES) Subchronic Exposure Results: Biologic Responses in Rats and Mice and Assessment of Genotoxicity—was conducted by Drs. Jacob D. McDonald of the Lovelace Respiratory Research Institute, Albuquerque, New Mexico; Jeffrey C. Bemis of Litron Laboratories, Rochester, New York, and Lance M. Hallberg of the University of Texas Medical Branch, Galveston, and their colleagues. Their work was overseen by independent experts on the HEI ACES Oversight Committee, and its comprehensive description of all findings was then subjected to peer review by a separate expert ACES Review Panel who had had no part in the conduct of the study.

Part 1 of the report describes the core inhalation study by Drs. Jake McDonald and Joe Mauderly, with results on general organ toxicity, lung histopathology, pulmonary function, and markers of inflammation and oxidative stress in blood and lung lavage fluid. Parts 2 and 3 describe studies by Drs. Jeffrey Bemis and Lance Hallberg assessing genotoxic endpoints in the exposed rodents.

In their Commentary on the study the review panel concluded:

Overall...these results indicate that rats exposed to one of three levels of DE from a 2007-compliant engine for up to 12 months, for 16 hours per day, 5 days a week, and using a strenuous operating cycle that was more realistic than cycles used in previous studies, show few exposure-related effects.

The effects that were observed were limited to the respiratory tract, were mild, and were consistent with previous findings in lungs after long-term exposure to NO2—a major component of the exposure atmosphere. Rats will continue to be exposed for at least 24 months in this study, possibly longer, depending on their survival rates. McDonald and colleagues will submit a future report with complete results from the 12- and 24- month exposures, which will provide a further comprehensive review of the cancer and non-cancer effects of long-term exposure to DE emitted by a 2007-compliant engine.

The panel did note some limitations to the interpretation of the study: the study design did not include a simultaneous comparison with emissions from an older engine built before the 2007 regulations. Noting that including such a “positive control” would have increased the complexity and cost of the study very substantially and would have been logistically impossible, the panel nonetheless thought that a side-by-side evaluation of emissions from an older engine could have enhanced the study.

The panel also identified some other limitations to the study—the lack of some positive assay controls (to identify that an assay was sensitive enough to detect changes) and the use of certain statistical approaches (combining sexes and performing a trend analysis rather than conducting a standard three-way ANOVA). In addition, the panel thought that the histopathology data could have been expanded by more detailed quantitative measures.

ACES is a comprehensive effort, supported by a wide range of public and private entities (The US Department of Energy, US Environmental Protection Agency, California Air Resources Board, Engine Manufacturers Association, American Petroleum Institute, and manufacturers of emission control equipment) and conducted under the independent oversight of HEI and the Coordinating Research Council (an Atlanta-based non-profit specializing in emissions characterization).

The overall goals of ACES are to test the emissions of new technology diesel engines to determine not only whether they are achieving the expected substantial reductions in emissions and health effects, but also whether the new control technologies (that include particle filters and ultra-low sulfur diesel fuel) are resulting in unintended increases in some components of the emissions.

ACES was conceived in 2005, and has three phases:

  • Phase 1: Extensive emissions characterization of four production-ready heavy heavy-duty diesel (HHDD; i.e., gross vehicle weight higher than 33,000 lb) engines equipped with control systems designed to meet the 2007 standards for reduced PM. This phase was conducted at the Southwest Research Institute (SwRI) in 2007 and 2008 and was the basis for selecting one HHDD engine/ control system for health testing in Phase 3. A report from this phase found substantial reductions in particulate matter and other pollutants in the emissions from 2007 engines.

  • Phase 2: Extensive emissions characterization of a group of diesel engine and control systems intended for production that met the more stringent 2010 standards (including more advanced NOx controls). This phase is being conducted at SwRI in 2012.

  • Phase 3: Health effects assessment in rodents using one selected 2007-compliant heavy-duty diesel engine system—i.e., the basis of the new report. This phase started in 2008 with the installation of a specially designed emissions-generation and animal exposure facility at the Lovelace Respiratory Research Institute (LRRI).

In the health studies, rats will continue to be exposed for their lifetime. Results and Commentary on another ancillary study, assessing the effects of subchronic exposure to diesel exhaust on vascular markers, will be published during the fall of 2012. The final results from the animal bioassay and all the ancillary studies will be published at the end of the program, when the animals have been exposed to diesel exhaust for 24 or 30 months. The final results and commentary are expected to be published near the end of 2013 or in early 2014.

Resources

  • Advanced Collaborative Emissions Study (ACES). 2012. Advanced Collaborative Emissions Study (ACES) Subchronic Exposure Results: Biologic Responses in Rats and Mice and Assessment of Genotoxicity. Research Report 166. Health Effects Institute, Boston, MA.

April 13, 2012 in Diesel, Emissions, Safety | Permalink | Comments (13) | TrackBack (0)

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Comments

Big problems if the lab rats die of old age before they get cancer from the exhaust...

Who financed the study? Is it the same people who would benefit from a favorable report as did tobacco and asbestos firms?

Hidden in the 1st paragraph:

"funded jointly by the US Environmental Protection Agency (EPA) and the worldwide motor vehicle industry."

The second partners certainly have their own agenda.

As do the 1st.

@HarveyD
You always bring up the theory of conspiracy when results are in contrast with your opinion... What is your agenda?

Have you ever heard about HEI, the Health Effects Institute? Note that they have always been very critical to diesel engines - in the past.

Synthetic diesel has no sulfur and no aromatics so it burns cleaner with less particulates and NOx that cause respiratory problems.

While it might not be as clean as CNG/LNG, no modification is required to the vehicle and no fueling depot expense is required. It can be blended with refined product in whatever ratios you require.

@SJC
These engines have particulate filters, so it does not matter if the fuel burns cleaner or not, the particulate level will be the same anyway, i.e. practically zero. I could recognize other advantages of synthetic fuels.

Shell has had good success promoting their GTL diesel on the basis that it is cleaner. I do not know that much about diesel particulate filters, but it seems that if you are producing fewer particulates, the filters would last longer.

Peter-XX...It is well known that tobacco, asbestos, oil, coal and many other health damaging industries have and are still using a multitude of (directed) studies to influence potential buyers. This is factual and you do not have to have an agenda to see what they are trying to do. Another way to get us to believe just about anything is to repeat it often enough. The majority will start to believe the biggest lies if they are repeated over 100 times with smart Ads. Harmful Junk food (sweet drinks and cigarettes) are/were sold by the million with that very same formula.

It could work the other way around. The use of (banned) texting while driving is not effectively controlled by police. A Nation wide smart Ads campaign, repeated 10+ times a day, showing the bad accidents an injuries created (to the drivers and others), is very effective. Who should pay for such campaign? Why not have the users pay with a special levy on the monthly bill?

@HarveyD
Before making up your mind, you should perhaps also look at the previous work from the ACES project (e.g. work carried out SwRI). If you do that, you will find that the 2007 engines have ultra-low emissions of practically any emission compound that could pose a health hazard. In fact, the levels were often so low that normal (filtered) background air in the test cell used in the dilution process had equal levels. Therefore, it is not very surprising to find that the lab animals do not suffer from any health effects from inhaling this exhaust. The only “remaining” emission compound is NOx. However, the level of NOx was also reduced significantly (from the 2007 level) in 2010.

I definitely cannot be healthy for you to look for conspiracy in every corner. You might need some help for that.

I often have doubts on the value of a study, when the organisation or producer pays researchers and scientists to produce it. The results are too often in favor of the product. Otherwise, the study will not be fully finished or the results not fully published.

Many well known University researchers where knowingly or unknowingly involved in the the last 40+ years. Have a second look in the Shale Gas and Tar Sands studies and you will find that it is still going on.

However, it many areas GHG has been reduced, ICEVs efficiency has increased, batteries are improving, hybrids are getting better, but Canada is producing more GHG and not less.

@HarveyD
The US government paid for this research. This means that you do not trust governmental agencies either. Who will you ever trust? In view of that, I find no reason to comment on your other examples. Of course, it is up to anyone to believe what you want. So, please, continue to uphold your position.

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