A study of extractive and remote-sensing sampling and measurement of emissions from military aircraft engines

Aircraft emissions contribute to the increased atmospheric burden of particulate matter (PM) that plays an important role in air quality, human health, visibility, contrail formation and climate change. Sampling and measurement of modern aircraft emissions at the engine exhaust plane (EEP) for engine and fuel certification remains challenging, as no agency-certified method is available. In this paper we summarize the results of three recent field studies devoted to investigate the consistency and applicability of “extractive” and “optical remote-sensing” (ORS) technologies in the sampling and measurement of gaseous and PM emitted by a number of military aircraft engines. Three classes of military engines were investigated; these include T56, TF33, and T700 & T701C types of engines, which consume 70–80% of the military aviation fuel each year. JP-8 and Fischer–Tropsch (FT)-derived paraffinic fuels were used to study the effect of fuels. It was found that non-volatile particles in the engine emissions were in the 20 nm range for the low power condition of new helicopter engines to 80 nm for the high power condition of legacy engines. Elemental analysis indicated little metals were present on particles, while most of the materials on the exhaust particles were carbon and sulfate based. Alkanes, carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, formaldehyde, ethylene, acetylene and propylene were detected. The last five species were most noticeable only under low engine power. The emission indices calculated based on the ORS data deviate significantly from those based on the extractive data. Nevertheless, the ORS techniques were useful in the sense that it provided non-intrusive real-time detection of species in the exhaust plume, which warrants further development. The results obtained in this program help validate sampling methodology and measurement techniques used for non-volatile PM aircraft emissions as described in the SAE AIR6037 (2009).     

Review of Light-Duty Diesel and Heavy-Duty Diesel Gasoline Inspection Programs

Abstract

Emissions from diesel vehicles and gas-powered heavyduty vehicles are becoming a new focus of many inspection and maintenance (I/M) programs. Diesel particulate matter (PM) is increasingly becoming more recognized as an important health concern, while at the same time, the public awareness of diesel PM emissions because of their visibility have combined to increase the focus on diesel emissions in the United States. This has resulted in an increased interest by some states in including heavy-duty vehicle testing in their I/M program.

This paper provides an overview of existing I/M programs focused on testing light-duty diesel vehicles, heavyduty diesel vehicles, and heavy-duty gasoline vehicles (HDGVs). Information on 39 I/M programs in 27 different states in the United States plus 9 international inspection programs is included. Information on the status of diesel emissions technology and current test procedures is also presented. The goal is to provide useful information for air quality managers as they work to decide whether such I/M programs would be worth pursuing in their respective areas and in evaluating the emissions measurement technology to be used in the program. Testing of HDGVs is generally limited to idle testing, because dynamometer testing of these vehicles is not practical, and most were not certified on a chassis basis.

Testing of diesel vehicles has mostly been limited to SAE J1667 “snap-idle” opacity testing. Cost-effective technology for measuring diesel emissions currently does not exist, and, therefore, opacity-type measurements, although not effective at reducing the pollutants of most significant health concern, will continue to be used.     

Mobile Air Quality Monitoring Systems: Present Problems and Future Needs

This overview represents much of the discussion and summarizes many of the concerns emerging from the recent APCA Specialty Conference, “In-Situ Air Quality Monitoring from Moving Platforms.”

Users of mobile air quality monitoring systems have been hampered in their attempts to generate dependable data because of a lack of suitable instrumentation. Most equipment used in mobile systems was designed for laboratory or stationary monitoring applications and cannot cope well with the harsh environment encountered in aircraft or other mobile platforms. Only through innovative modifications have investigators been able to utilize off-the-shelf equipment. The technology exists, however, for manufacturers to build a much higher quality product if only a market incentive could be created.

This paper outlines problem areas which need to be addressed in the production of reliable “mobile quality” instrumentation, and suggests some market incentives.     

Identification of a potential source of chloroform in urban air: Preliminary Communication

A new potential source of elevated chloroform (CHCl₃) concentrations in urban air is reported. The exhaust gases from gasoline internal combustion engines operated on conventional “leaded” fuel and not equipped with catalytic converters contain parts-per-billion concentrations of chloroform which can, in congested urban areas, contribute significantly to the ambient concentration of chloroform. Exhaust gases from engines burning conventional “leaded” gasoline contain much higher levels of chloroform than do exhaust gases from engines equipped with catalytic converters and operating on “nonleaded” gasoline.     

Effects of Variable Vehicular Age and Classification Distributions in Mobile Source Modeling

Jackson Hole Airport is the only air carrier airport located entirely in a National Park, that being Grand Teton. Concerns over noise impacts led to an Airport/Park agreement setting allowable levels, restricting flights and flight paths, and calling for compliance monitoring in the noise sensitive areas. This study documented seven days of continuous noise level measurements made at four sites in the Park during four consecutive seasons in 1985-86. Individual sound exposure level measurements at B-737/200 jets, Swearingen Metro turboprops, and general aviation aircraft permitted computation of “aircraft-only” day/night levels (DNL) at each site for each day. Measurement of half-hourly average sound levels permitted computation of “total” DNL for comparisons. Results showed general compliance with the DNL limits, except when winds necessitated northerly departures, in which case a single B- 737 could cause an exceedance. There were no statistically significant differences in mean aircraft DNL for each site over the seasons, largely because of high variances. At the more remote sites, the total DNL was generally not established by airport activity, but by the 10-dB nighttime DNL penalty added to background levels generated by wind or water. The newer B- 737/300 aircraft, introduced to Jackson in the winter of 1986, were observed to be noticeably quieter on departure.     

Mercury Measurement and Its Control: What We Know,Have Learned,and Need to Further Investigate

ABSTRACT

Based on the available evidence of health effects, the U.S. Environmental Protection Agency (EPA) has been evaluating the need to regulate mercury releases to the environment. In response to the congressional mandates in The 1990 Clean Air Act Amendments (CAAA), the EPA has issued the Mercury Study Report and the Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units Report. In spite of the enormous effort represented by these reports, as well as the efforts of both the U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI), in conducting the field measurement programs that form the basis for these reports, a definitive answer on the need for mercury regulation has not been found. However, the EPA, as well as other regulatory agencies and health researchers, have suggested a “plausible link” between anthropogenic sources emitting mercury and the methylation, bioaccumulation in the food chain, and adverse health effects in humans and wildlife.

Policy-makers have recognized that regulations must be based on good science and that a number of issues still remain. These issues can generally be grouped into four main categories: emissions inventory, control technology, fate of releases, and health effects. This paper will discuss recent, ongoing, and planned studies to address the remaining issues regarding the presence of mercury in the environment, with an emphasis on those studies that are directly related to the DOE/Federal Energy Technology Center’s (FETC) programmatic effort.     

Particulate Matter in New Technology Diesel Exhaust (NTDE) is Quantitatively and Qualitatively Very Different from that Found in Traditional Diesel Exhaust (TDE)

ABSTRACT

Diesel exhaust (DE) characteristic of pre-1988 engines is classified as a “probable” human carcinogen (Group 2A) by the International Agency for Research on Cancer (IARC), and the U.S. Environmental Protection Agency has classified DE as “likely to be carcinogenic to humans.” These classifications were based on the large body of health effect studies conducted on DE over the past 30 or so years. However, increasingly stringent U.S. emissions standards (1988–2010) for particulate matter (PM) and nitrogen oxides (NO_x) in diesel exhaust have helped stimulate major technological advances in diesel engine technology and diesel fuel/lubricant composition, resulting in the emergence of what has been termed New Technology Diesel Exhaust, or NTDE. NTDE is defined as DE from post-2006 and older retrofit diesel engines that incorporate a variety of technological advancements, including electronic controls, ultra-low-sulfur diesel fuel, oxidation catalysts, and wall-flow diesel particulate filters (DPFs). As discussed in a prior review (T. W. Hesterberg et al.; Environ. Sci. Technol. 2008, 42, 6437-6445), numerous emissions characterization studies have demonstrated marked differences in regulated and unregulated emissions between NTDE and “traditional diesel exhaust” (TDE) from pre-1988 diesel engines. Now there exist even more data demonstrating significant chemical and physical distinctions between the diesel exhaust particulate (DEP) in NTDE versus DEP from pre-2007 diesel technology, and its greater resemblance to particulate emissions from compressed natural gas (CNG) or gasoline engines. Furthermore, preliminary toxicological data suggest that the changes to the physical and chemical composition of NTDE lead to differences in biological responses between NTDE versus TDE exposure. Ongoing studies are expected to address some of the remaining data gaps in the understanding of possible NTDE health effects, but there is now sufficient evidence to conclude that health effects studies of pre-2007 DE likely have little relevance in assessing the potential health risks of NTDE exposures.

IMPLICATIONS Based on the distinct physical and chemical properties of New Technology Diesel Exhaust (NTDE), it has become clear that findings from the health effects studies conducted on traditional DE (TDE) over the last 30 years have little relevance to NTDE, which is more similar to the exhaust from compressed natural gas (CNG) or gasoline engine emissions than to traditional TDE. Once sufficient health effects data are available for NTDE, it will thus be necessary to conduct new hazard and risk assessments for NTDE that are independent of the DE toxicological database acquired on emissions from pre–2007 diesel technology.     

Aerially guided leak detection and repair: A pilot field study for evaluating the potential of methane emission detection and cost-effectiveness

Novel aerial methane (CH₄) detection technologies were used in this study to identify anomalously high-emitting oil and gas (O&G) facilities and to guide ground-based “leak detection and repair” (LDAR) teams. This approach has the potential to enable a rapid and effective inspection of O&G facilities under voluntary or regulatory LDAR programs to identify and mitigate anomalously large CH₄ emissions from a disproportionately small number of facilities. This is the first study of which the authors are aware to deploy, evaluate, and compare the CH₄ detection volumes and cost-effectiveness of aerially guided and purely ground-based LDAR techniques. Two aerial methods, the Kairos Aerospace infrared CH₄ column imaging and the Scientific Aviation in situ aircraft CH₄ mole fraction measurements, were tested during a 2-week period in the Fayetteville Shale region contemporaneously with conventional ground-based LDAR. We show that aerially guided LDAR can be at least as cost-effective as ground-based LDAR, but several variable parameters were identified that strongly affect cost-effectiveness and which require field research and improvements beyond this pilot study. These parameters include (i) CH₄ minimum dectectable limit of aerial technologies, (ii) emission rate size distributions of sources, (iii) remote distinction of fixable versus nonfixable CH₄ sources (“leaks” vs. CH₄ emissions occurring by design), and (iv) the fraction of fixable sources to total CH₄ emissions. Suggestions for future study design are provided.

Implications: Mitigation of methane leaks from existing oil and gas operations currently relies on on-site inspections of all applicable facilities at a prescribed frequency. This approach is labor- and cost-intensive, especially because a majority of oil and gas–related methane emissions originate from a disproportionately small number of facilities and components. We show for the first time in real-world conditions how aerial methane measurements can identify anomalously high-emitting facilities to enable a rapid, focused, and directed ground inspection of these facilities. The aerially guided approach can be more cost-effective than current practices, especially when implementing the aircraft deployment improvements discussed here.     

Comment on “Methylcyclopentadienyl Manganese Tricarbonyl as an Antiknock: Composition and Fate of Manganese Exhaust Products”

In an article published in the August 1975, Journal of the Air Pollution Control Association entitled “Methylcyclopentadienyl Manganese Tricarbonyl as an Antiknock: Composition and Pate of Manganese Exhaust Products,” the authors conclude that, “… use of MMT in gasoline will result in no public health hazards, because of the low toxicity of manganese and because of the very low concentration of MMT that would be used in gasoline …. If all gasoline contained 0.1 g Mn/gal, the amount of airborne Mn its exhaust would contribute to urban areas would contribute to urban areas would be only 0.02-0.2 μg/m³, with a median value of 0.05 μg/m³.”     

“New” DDT inputs to North America: Atmospheric deposition

Measurement of untransformed (p,p'- and o,p'-) DDT in rain, snow, and peat indicates that input of “new” DDT continues over a large portion of eastern North America. Peat cores obtained from ombrotrophic bogs indicate that current atmospherically derived fluxes are about 10–20% of those which occurred during peak DDT usage (～1960). Since DDT has been banned in North America and considering the magnitude of present fluxes, these residues must result from atmospheric transboundary transport. It is suggested that “new” DDT is being transported from neighboring areas where current use is substantial, Mexico and Central America.     

Review of light-duty diesel and heavy-duty diesel gasoline inspection programs

Emissions from diesel vehicles and gas-powered heavy-duty vehicles are becoming a new focus of many inspection and maintenance (I/M) programs. Diesel particulate matter (PM) is increasingly becoming more recognized as an important health concern, while at the same time, the public awareness of diesel PM emissions because of their visibility have combined to increase the focus on diesel emissions in the United States. This has resulted in an increased interest by some states in including heavy-duty vehicle testing in their I/M program. This paper provides an overview of existing I/M programs focused on testing light-duty diesel vehicles, heavy-duty diesel vehicles, and heavy-duty gasoline vehicles (HDGVs). Information on 39 I/M programs in 27 different states in the United States plus 9 international inspection programs is included. Information on the status of diesel emissions technology and current test procedures is also presented. The goal is to provide useful information for air quality managers as they work to decide whether such I/M programs would be worth pursuing in their respective areas and in evaluating the emissions measurement technology to be used in the program. Testing of HDGVs is generally limited to idle testing, because dynamometer testing of these vehicles is not practical, and most were not certified on a chassis basis. Testing of diesel vehicles has mostly been limited to SAE J1667 "snap-idle" opacity testing. Cost-effective technology for measuring diesel emissions currently does not exist, and, therefore, opacity-type measurements, although not effective at reducing the pollutants of most significant health concern, will continue to be used.     

Validation of the Digital Opacity Compliance System under Regulatory Enforcement Conditions

Abstract

U.S. Environmental Protection Agency (EPA) Emission Measurement Center in conjunction with EPA Regions VI and VIII, the state of Utah, and the U.S. Department of Defense have conducted a series of long-term pilot and field tests to determine the accuracy and reliability of a visible opacity monitoring system consisting of a conventional digital camera and a separate computer software application for plume opacity determination. This technology, known as the Digital Opacity Compliance System (DOCS), has been successfully demonstrated at EPA-sponsored Method-9 “smoke schools,” as well as at a number of government and commercially operated industrial facilities.

Results from the current DOCS regulatory pilot study demonstrated that, under regulatory enforcement conditions, the average difference in opacity measurement between the DOCS technology and EPA Reference Method 9 (Method 9) was 1.12%. This opacity difference, which was computed from the evaluation of 241 regulated air sources, was found to be statistically significant at the 99% confidence level. In evaluating only those sources for which a nonzero visible opacity level was recorded, the average difference in opacity measurement between the DOCS technology and Method 9 was 1.20%. These results suggest that the two opacity measurement methods are essentially equivalent when measuring the opacity of visible emissions.

Given the costs and technical limitations associated with use of Method 9, there is a recognized need to develop accurate, reproducible, and scientifically defensible alternatives to the use of human observers. The use of digital imaging/processing brings current technology to bear on this important regulatory issue. Digital technology offers increased accuracy, a permanent record of measurement events, lower costs, and a scientifically defensible approach for opacity determination.     

Particulate Emission Rates for Unpaved Shoulders along a Paved Road

ABSTRACT

This paper reports the first empirical estimate of particle emissions from unpaved shoulders along paved roads.¹ Its objectives are to develop and demonstrate an emission rate measurement methodology that can be applied in different areas; identify the mechanisms that suspend dust from unpaved shoulders and the observables related to this suspension process; and quantify PM₁₀ mass emissions in the form of an emission rate. To achieve these objectives, fast-response observations from nephelometers and a sonic anemometer were used to characterize shortlived dust plumes generated by passing vehicles. In addition, detailed soil surface measurements determined the mechanical properties of the shoulder surfaces.

Large traffic-induced turbulence events that led to significant dust entrainment were almost exclusively caused by “large” vehicles such as trucks, semis, and vehicles pulling trailers, all traveling 50-65 mph. PM₁₀ emission rates for these large, fast-traveling vehicles were determined to be 8 ± 4 grams per vehicle kilometer traveled under dry conditions. Emissions due to smaller vehicles such as cars, vans, and sport utility vehicles were negligible for normal on-road driving. These results indicate that the majority of PM₁₀ emissions from unpaved shoulders is caused by relatively few vehicles.     

1985 Update,Operating History and Current Status of Fabric Filters in the Utility Industry

Stringent particulate emissions limits and increasing awareness of stack opacity is leading the utility industry to use high efficiency particulate control systems. In response to this trend, the Electric Power Research Institute (EPRI) is conducting several research programs aimed at improving the operation, maintenance and performance of particulate control systems. One of these programs, RP-1401, “Reliability Assessment of Particulate Control Systems,” is developing operation, maintenance and design data bases for both electrostatic precipitators and fabric filters. This paper discusses some of the intermediate findings of the work done on fabric filters.     

Generation and Characterization of Diesel Exhaust in a Facility for Controlled Human Exposures

Abstract

An idling medium-duty diesel truck operated on ultralow sulfur diesel fuel was used as an emission source to generate diesel exhaust for controlled human exposure. Repeat tests were conducted on the Federal Test Procedure using a chassis dynamometer to demonstrate the reproducibility of this vehicle as a source of diesel emissions. Exhaust was supplied to a specially constructed exposure chamber at a target concentration of 100 µg · m^-3 diesel particulate matter (DPM). Spatial variability within the chamber was negligible, whereas emission concentrations were stable, reproducible, and similar to concentrations observed on the dynamometer. Measurements of nitric oxide, nitrogen dioxide, carbon monoxide, particulate matter (PM), elemental and organic carbon, carbonyls, trace elements, and polycyclic aromatic hydrocarbons were made during exposures of both healthy and asthmatic volunteers to DPM and control conditions. The effect of the so-called “personal cloud” on total PM mass concentrations was also observed and accounted for. Conventional lung function tests in 11 volunteer subjects (7 stable asthmatic) did not demonstrate a significant change after 2-hr exposures to diesel exhaust. In summary, we demonstrated that this facility can be effectively and safely used to evaluate acute responses to diesel exhaust exposure in human volunteers.     

Isokinetic Sampler for Continuous Airborne Aerosol Measurements

For aerosol measurements, especially those concerned with the aerosol particle size distribution, it is important to sample in isokinetic conditions. Most available instrumentation for aerosol measurements is intended for use on the ground under light wind conditions; intake air speeds rarely exceed a few meters per second. If the same instrumentation is used onboard an aircraft, the air must be decelerated 60 or more m/sec before It is sampled by individual instruments.

On The Pennsylvania State University Meteorology research aircraft, the air for all aerosol instruments is decelerated in a single isokinetic sampler located above the roof of the cabin outside the aircraft boundary layer. The air enters the sampler through a carefully designed circular intake. Its velocity is reduced as the cross section increases along a 7° conical diffuser. The expansion cone terminates in a cylindrical chamber in which the air velocity is 1/16 the aircraft speed. Behind the sampling chamber the air is accelerated in a second conical section to an end exhaust port. Exhaust porf "pumping" is used to compensate internal losses and, thus, helps preserve the isokinetic nature of the sampler.

Tubes leading to individual instruments are located in the sampling chamber and may be individually adapted to match the air sampling velocity with the local air speed inside the sampling chamber. The level of turbulence (u_rms/û) in the sampling section is =^0.05.

The sampler has been thoroughly wind tunnel and flight tested and successfully used in August and November, 1974, for field programs in the St. Louis and Tucson metropolitan areas, respectively.     

Assessment of the emissions and air quality impacts of biomass and biogas use in California

It is estimated that there is sufficient in-state “technically” recoverable biomass to support nearly 4000 MW of bioelectricity generation capacity. This study assesses the emissions of greenhouse gases and air pollutants and resulting air quality impacts of new and existing bioenergy capacity throughout the state of California, focusing on feedstocks and advanced technologies utilizing biomass resources predominant in each region. The options for bioresources include the production of bioelectricity and renewable natural gas (NG). Emissions of criteria pollutants and greenhouse gases are quantified for a set of scenarios that span the emission factors for power generation and the use of renewable natural gas for vehicle fueling. Emissions are input to the Community Multiscale Air Quality (CMAQ) model to predict regional and statewide temporal air quality impacts from the biopower scenarios. With current technology and at the emission levels of current installations, maximum bioelectricity production could increase nitrogen oxide (NO_x) emissions by 10% in 2020, which would cause increases in ozone and particulate matter concentrations in large areas of California. Technology upgrades would achieve the lowest criteria pollutant emissions. Conversion of biomass to compressed NG (CNG) for vehicles would achieve comparable emission reductions of criteria pollutants and minimize emissions of greenhouse gases (GHG). Air quality modeling of biomass scenarios suggest that applying technological changes and emission controls would minimize the air quality impacts of bioelectricity generation. And a shift from bioelectricity production to CNG production for vehicles would reduce air quality impacts further. From a co-benefits standpoint, CNG production for vehicles appears to provide the best benefits in terms of GHG emissions and air quality.

Implications:?This investigation provides a consistent analysis of air quality impacts and greenhouse gas emissions for scenarios examining increased biomass use. Further work involving economic assessment, seasonal or annual emissions and air quality modeling, and potential exposure analysis would help inform policy makers and industry with respect to further development and direction of biomass policy and bioenergy technology alternatives needed to meet energy and environmental goals in California.     

Aircraft measurement of ozone turbulent flux in the atmospheric boundary layer

In May 1995, the “Chimie-Creil 95” experiment was undertaken in the north of France. The field data are first used to validate the methodology for airborne measurement of ozone flux. A certain number of methodological problems due to the location of the fast ozone sensor inside the airplane are, furthermore discussed. The paper describes the instrumentation of the ARAT (Avion de Recherche Atmosphérique et de Télédétection), an atmospheric research and remote-sensing aircraft used to perform the airborne measurements, the area flown over, the meteorological conditions and boundary layer stability conditions. These aircraft measurements are then used to determine ozone deposition velocity and values are proposed for aerodynamic, bulk transfer coefficients (ozone and momentum). The paper also establishes the relationship between the normalised standard deviation and stability parameters (z/L) for ozone, temperature, humidity and vertical velocity. The laws obtained are then presented.     

Economic Impact of Mass Production of Alternative Low Emission Automotive Power Systems

The study considers a range of possible effects on the transportation industry, satellite industries, the labor market, and the economy which may be anticipated in the event mass production of unconventional low emission automotive propulsion systems should occur, whether as a consequence of federal intervention, or not. A postulated 1 976 Otto Cycle Internal Combustion Engine equipped with a dual catalyst manifold reactor and other “conventional” emission control devices was compared in detail with a Regenerative Free Turbine Engine and a Rankine Cycle Engine, as specified by the contracting agency. Manufacturing costs, operating and ownership costs, consumer demand, inter-industry effects, employment, resource requirements, and international trade implications were analyzed in depth under a number of plausible sets of policy constraints and parametric variations. Principal conclusions are that conversion over a 10 year period is feasible, that manufacturing cost differentials are less critical than fuel consumption and cost differentials, that industry/employment impacts are minor, and that resource/trade effects are dominated by petroleum imports. Implications for federal policy are discussed.     

Characterization of particulate matter and gaseous emissions of a C-130H aircraft

The gaseous and nonvolatile particulate matter (PM) emissions of two T56-A-15 turboprop engines of a C-130H aircraft stationed at the 123rd Airlift Wing in the Kentucky Air National Guard were characterized. The emissions campaign supports the Strategic Environmental Research and Development Program (SERDP) project WP-1401 to determine emissions factors from military aircraft. The purpose of the project is to develop a comprehensive emissions measurement program using both conventional and advanced techniques to determine emissions factors of pollutants, and to investigate the spatial and temporal evolutions of the exhaust plumes from fixed and rotating wing military aircraft. Standard practices for the measurement of gaseous emissions from aircraft have been well established; however, there is no certified methodology for the measurement of aircraft PM emissions. In this study, several conventional instruments were used to physically characterize and quantify the PM emissions from the two turboprop engines. Emissions samples were extracted from the engine exit plane and transported to the analytical instrumentation via heated lines. Multiple sampling probes were used to assess the spatial variation and obtain a representative average of the engine emissions. Particle concentrations, size distributions, and mass emissions were measured using commercially available aerosol instruments. Engine smoke numbers were determined using established Society of Automotive Engineers (SAE) practices, and gaseous species were quantified via a Fourier-transform infrared-based gas analyzer. The engines were tested at five power settings, from idle to take-off power, to cover a wide range of operating conditions. Average corrected particle numbers (PNs) of (6.4-14.3) x 10(7) particles per cm3 and PN emission indices (EI) from 3.5 x 10(15) to 10.0 x 10(15) particles per kg-fuel were observed. The highest PN EI were observed for the idle power conditions. The mean particle diameter varied between 50 nm at idle to 70 nm at maximum engine power. PM mass EI ranged from 1.6 to 3.5 g/kg-fuel for the conditions tested, which are in agreement with previous T56 engine measurements using other techniques. Additional PM data, smoke numbers, and gaseous emissions will be presented and discussed.