Emission Test Data Research Articles

Analysis of gross polluter cutpoints based on in-use vehicle inspection and maintenance test data in California

Emission cutpoints are used to classify vehicles as “gross polluters” in inspection and maintenance (I/M) testing in the United States. In this study, we use recent data from California I/M tests to examine how sensitive populations of “gross polluters” change as cutpoints are modified. Using statistical analyses of emissions test data, we identify a variety of scenarios that have the potential for efficiently removing a significant portion of the exhibited emissions while minimizing the number of vehicles that are classified as “gross polluters” and required to undergo costly repairs. For each scenario, we compute the resulting vehicle populations and impact on emissions. The conclusions of the research provide support for previous findings that suggests that: 1) a “gross polluting” vehicle for one pollutant, such as carbon monoxide (CO), may not necessarily be a “gross polluter” for another pollutant, such as oxides of nitrogen (NOx) and 2) each of the existing required I/M tests yield similar results and it may not be efficient to use both tests in the identification of gross polluters.

A statistical model for estimating oxides of nitrogen emissions from light duty motor vehicles

Motor vehicle emission rate models for predicting oxides of nitrogen (NO x) emissions are insensitive to vehicle modes of operation such as cruise, acceleration, deceleration, and idle, because they are based on average trip speed. Research has shown that NO x emissions are sensitive to engine load; hence, load-based variables need to be included in emissions models. Ongoing studies attempting to incorporate these `modal' variables have experienced difficulties with: (1) incomplete and/or non-representative data sets of emissions test data vis-a-vis the modal operating profiles of the tested vehicles; (2) lack of information for predicting on-road operating parameters of vehicles; and (3) non-representative vehicles recruited for emissions tests. The objective of this research was to develop a statistical model for predicting NO x emissions from light-duty gasoline motor vehicles. The primary end use of this model is forecasting, rather than explanation of the factors that affect NO x emissions, which brings to bear different requirements from the statistical model. The three challenges noted above are addressed by: (1) analyzing a data set of more than 13 000 hot-stabilized laboratory treadmill tests on 19 driving cycles (specific speed versus time testing conditions), and 114 variables describing vehicle, engine and test cycle characteristics; (2) making the models compatible with empirical data on how vehicles are being operated in-use; and (3) developing statistical weights to account for the differences in model year distributions between the emissions testing database and the current national on-road fleets. The NO x emissions model is estimated using ordinary least-squares regression techniques, with transformed response variable and regression weights. Tree regression is employed as a tool for mining relationships among variables in the data, with particular focus on identifying useful interactions among discrete variables. Details of the model development process are presented, as well as results for the final model showing the predicted emissions algorithm for the current motor vehicle fleet in Atlanta, GA metropolitan region.

Global nitrogen and sulfur inventories for oceangoing ships

We present geographically resolved global inventories of nitrogen and sulfur emissions from international maritime transport for use in global atmospheric models. Current inventories of globally resolved sources of natural and anthropogenic emissions do not include the significant contribution of SO2 or NOx from oceangoing ships [Benkovitz et al., 1996]. We estimate the global inventory of ship emissions, using current emission test data for ships [Carlton et al., 1995] and a fuel‐based approach similar to that used for automobile inventories [Singer and Harley, 1996]. This study estimates the 1993 global annual NOx and SO2 emissions from ships to be 3.08 teragrams (Tg, or 1012 g) as N and 4.24 Tg S, respectively. Nitrogen emissions from ships are shown to account for more than 14% of all nitrogen emissions from fossil fuel combustion, and sulfur emissions exceed 5% of sulfur emitted by all fuel combustion sources including coal. Ship sulfur emissions correspond to about 20% of biogenic dimethylsulfide (DMS) emissions. In regions of the Northern Hemisphere, annual sulfur emissions from ships can be of the same order of magnitude as estimates of the annual flux of DMS [Chin et al., 1996]. Monthly inventories of ship sulfur and nitrogen emissions presented in this paper are geographically characterized on a 2° × 2° resolution. Temporal and spatial characteristics of the inventory are presented. Uncertainty in inventory estimates is assessed: the fifth and ninety‐fifth percentile values for global nitrogen emissions are 2.66 Tg N and 4.00 Tg N, respectively; the fifth and ninety‐fifth percentile values for sulfur emissions are 3.29 Tg S and 5.61 Tg S, respectively. We suggest that these inventories, available via the Ship Emissions Assessment (SEA) web site, be used in models along with the Global Emissions Inventory Activity (GEIA) inventories for land‐based anthropogenic emissions and modeled with ocean‐biogenic inventories for DMS.

Exhaust Emissions From Two Intercity Passenger Locomotives

To enhance the effectiveness of intercity passenger rail service in mitigating exhaust emissions in California, the California Department to Transportation (Caltrans) included limits on exhaust emissions in its intercity locomotive procurement specifications. Because there were no available exhaust emission test data on which emission reduction goals could be based, Caltrans funded a test program to acquire gaseous and particulate exhaust emissions data, along with smoke opacity data, from two state-of-the-art intercity passenger locomotives. The two passenger locomotives (an EMD F59PH and a GE DASH8-32BWH) were tested at the Association of American Railroads Chicago Technical Center. The EMD locomotive was eqiupped with a separate Detroit Diesel, Corporation (DDC) 8V-149 diesel engine used to provide 480 V AC power for the trailing passenger cars. This DDC engine was also emission tested. These data were used to quantify baseline exhaust emission levels as a challenge to locomotive manufacturers to offer new locomotives with reduced emissions. Data from the two locomotive engines were recorded at standard fuel injection timing and with the fuel injection timing retarded 4 deg in an effort to reduce NOx emissions. Results of this emissions testing were incorporated into the Caltrans locomotive procurement process by including emission performance requirements in the Caltrans intercity passenger locomotive specification, and therefore in the procurement decision. This paper contains steady-state exhaust emission test results for hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), and particulate matter (PM) from the two locomotives. Computed sulfur dixoide (SO2) emissions are also given, and are based on diesel fuel consumption and sulfur content. Exhaust smoke opacity is also reported.

Mathematical modeling of electrically heated monolith converters: model formulation, numerical methods, and experimental verification

It has been widely recognized that a large fraction of CO and HC emissions occurs during the cold-start portion of the Federal Test Procedure (FTP) driving schedule. The previously-developed transient monolith model has been extended to describe the thermal response and conversion performance of an electrically heated monolith converter during warmup. This paper documents the necessary modifications in the model formulation and in the numerical solution methods to accommodate the more severe operating conditions encountered in heated converters. The validity of the heated converter model was tested by comparing model predictions with vehicle emission test data. Model predictions of converter-bed temperatures and converter-out mass emissions agree well with those measured during the cold-start portion of the vehicle emission tests, thus demonstrating the validity of the heated converter model developed here.

Blast Furnace Casthouse Control Technology and Recent Emissions Test Data

By the fall of 1980, three new and seven retrofit casthouse emission control systems had been installed in North America. A number of prototype systems are being evaluated by steel companies and regulatory agencies. By 1981, the U.S. steel industry had made commitments to install controls on at least 58 additional casthouses in the U.S. This paper describes the current status of casthouse control technology in the U.S. and Canada as of the spring of 1981, addresses future trends, and presents emissions test data collected in 1980 and 1981. Mass emissions and inhalable particulate test results from sampling at DOFASCO’s No. 3 blast furnace casthouse are presented. Roof monitor visible emissions data are also provided to describe performance of installed and demonstration systems including three J&L plants, Wheeling-Pittsburgh and Bethlehem Steel, and Inland’s new furnace.

Brush and trunk burning plant in the City of Detroit.

For many years the City of Detroit was a flagrant violator of its own air pollution laws by the indiscriminate open burning of Dutch Elm diseased trees, brush and trunks. Cited for violation under the city’s air pollution control code as well as under threat of a private legal suit, the City administration approved a $250,000 expenditure for the design and installation of a unique six ton per hour brush and trunk burning incinerator plant. This plant was conceived by engineering personnel of the City Engineer’s office in consultation with engineering staff members of the Air Pollution Control Bureau. Information is provided on the basic plant layout and design, wet fly ash collector configuration, operating and maintenance experience, and recommended changes for any future similar installations. Stack emission test data are also reported. Due to the success of this plant, a similar plant is in the process of being constructed in another part of the city upon completion of which the City of Detroit will no...