Part I: lead peroxide candles and dustfall collectors

A diffusion flame burner was operated to determine the effect of several parameters on the quantity of NO_x and unburned hydrocarbons produced. The statistical analysis indicated the unburned hydrocarbon emissions to be dependent upon the rate of heat release in the system, the amount of excess combustion air, the fuel molecular structure, and the interaction between the fuel structure and the amount of excess air. Analysis of the NO_x emissions, after an adjustment to a common temperature to eliminate the temperature effect, showed them to be dependent upon the fuel molecular structure and the amount of excess air. The NO_x emissions reached a maximum at the conditions which yielded minimum unburned hydrocarbon emissions. Multiple regressions were made which yielded predicting equations for both the unburned hydrocarbon and the NO_x for the apparatus used.     

Temperature effects on particulate emissions from DPF-equipped diesel trucks operating on conventional and biodiesel fuels

Emissions tests were conducted on two medium heavy-duty diesel trucks equipped with a particulate filter (DPF), with one vehicle using a NOx absorber and the other a selective catalytic reduction (SCR) system for control of nitrogen oxides (NOx). Both vehicles were tested with two different fuels (ultra-low-sulfur diesel [ULSD] and biodiesel [B20]) and ambient temperatures (70ºF and 20ºF), while the truck with the NOx absorber was also operated at two loads (a heavy weight and a light weight). The test procedure included three driving cycles, a cold start with low transients (CSLT), the federal heavy-duty urban dynamometer driving schedule (UDDS), and a warm start with low transients (WSLT). Particulate matter (PM) emissions were measured second-by-second using an Aethalometer for black carbon (BC) concentrations and an engine exhaust particle sizer (EEPS) for particle count measurements between 5.6 and 560 nm. The DPF/NOx absorber vehicle experienced increased BC and particle number concentrations during cold starts under cold ambient conditions, with concentrations two to three times higher than under warm starts at higher ambient temperatures. The average particle count for the UDDS showed an opposite trend, with an approximately 27% decrease when ambient temperatures decreased from 70ºF to 20ºF. This vehicle experienced decreased emissions when going from ULSD to B20. The DPF/SCR vehicle tested had much lower emissions, with many of the BC and particle number measurements below detectable limits. However, both vehicles did experience elevated emissions caused by DPF regeneration. All regeneration events occurred during the UDDS cycle. Slight increases in emissions were measured during the WSLT cycles after the regeneration. However, the day after a regeneration occurred, both vehicles showed significant increases in particle number and BC for the CSLT drive cycle, with increases from 93 to 1380% for PM number emissions compared with tests following a day with no regeneration.

Implications:?The use of diesel particulate filters (DPFs) on trucks is becoming more common throughout the world. Understanding how DPFs affect air pollution emissions under varying operating conditions will be critical in implementing effective air quality standards. This study evaluated particulate matter (PM) and black carbon (BC) emissions with two DPF-equipped heavy-duty diesel trucks operating on conventional fuel and a biodiesel fuel blend at varying ambient temperatures, loads, and drive cycles.     

Modeling the impacts of the Finnish Climate Strategy on air pollution

This paper presents an example of how air pollution models can be used together with energy system models to study the impacts of climate change mitigation strategies on air pollution. As many mitigation measures of greenhouse gases (GHGs) affect the use of fossil fuels in energy production, they can have important side-effects on other air pollution problems. This paper studies on a national scale the impacts of the planned GHG reduction measures on multiple air pollution problems in Finland, concentrating on acidification of forest soils and lakes, tropospheric ozone levels harmful to humans and vegetation and on emissions of fine particles. The air pollutant emission scenarios with the alternative energy choices are calculated for about 200 large point sources, assuming the present emission limit legislation. Disperse emissions are treated at municipality level. The analysis extends to the year 2020. The implementation of the Kyoto protocol in Finland would induce notable reductions of multiple air pollutant emissions and related environmental impacts. A 6–11% reduction in ecosystems threatened by acidification in Southern and Central Finland would be achieved with the Finnish Climate Strategy alone. Substantial improvement in ozone levels would be reached in all scenarios compared to the current situation. The measures of the Climate Strategy could reduce the harmful ozone levels by a further 3%. The measures of the Climate Strategy would not significantly affect the primary particulate emissions in the future because the emissions from large power plants are already effectively controlled. Contrary to the fuel choices of the large units, expanded use of small-scale wood combustion can result in considerable increases of both fine particulate and VOC emissions.     

Problems of Meeting Multiple Air Quality Objectives for Coal-Fired Utility Boilers

Gaseous wastes and particulate emissions are produced in the process of burning coal to produce electrical energy. In attempting to control these gaseous wastes, changes in the operation efficiency of boilers and secondary equipment are likely to result, and in addition liquid and solid waste streams are produced. The interrelationships among the various forms of wastes and the effects of air quality control on process efficiency are often overlooked in studies of environmental quality management.

The study was undertaken to evaluate the technical alternatives for handling gaseous and particulate emissions from coal-fired boilers and to determine the feasibility of meeting several standards simultaneously. The gaseous emissions of major importance in the combustion of coal are parti culates, oxides of sulfur, and oxides of nitrogen. Particulates can be controlled by a tradeoff among further preparation at the mine (for additional ash removal), type of boiler, use of dust control equipment and high stacks for dispersion of residual emissions, if ambient air standards are considered. Oxides of sulfur reduction depends currently on fuel substitution, limestone additives in the boiler and some form of contact process such as wet scrubbing, or the use of high stacks. Oxides of nitrogen control in coal fired boilers is restricted to small reductions by either changes in boiler operation, such as lower excess air levels, adsorption during wet scrubbing or by dispersion from high stacks.     

Influence of storage and release on particle emissions from new and used CRTs

This paper describes the results of three experiments performed with Continuously Regenerating Traps (CRTs^®) in a controlled laboratory setting to elucidate the effects of fuel sulfur content, filter age, and storage and release effects on particle concentration. In the first experiment, a new CRT was tested using near zero sulfur Fischer-Tropsch fuel and low sulfur lubricating oil (420 ppm). The objective was to measure particle emissions from an emission control device that had not previously been exposed to sulfur under a variety of operating and dilution conditions. Next, a used CRT was evaluated using the same fuel and lubricating oil. Finally, the used uncatalyzed Diesel particulate filter (DPF) from the used CRT was replaced with a new, uncatalyzed DPF. The emissions from the used Diesel oxidation catalyst (DOC) + new DPF were evaluated and compared to those of the used CRT.Our laboratory results show that particle number emissions from the new CRTs are 99.9% lower than equivalent used CRT data collected on-road at an exhaust temperature of 370 °C. Even as the new CRT temperature was increased to almost 400 °C, emission levels were still at background levels for roadway aerosol and no nucleation mode was observed. With the used CRT, the nucleation mode particle number concentration increased sharply at an exhaust temperature of about 380 °C and remained high for the duration of the test. Mass emissions were estimated and found to exceed US EPA on-road standards. The used DOC + new DPF led to essentially the same number emissions as the used CRT, suggesting that these emissions arise mainly from release of sulfates stored by the DOC and not the uncatalyzed DPF.     

A Study of Field Burning Under Varying Environmental Conditions

A field study on grass field burning was conducted in the Willamette Valley of Oregon during the summer of 1965. Approximately 230,000 acres of grass fields are burned in the valley during August and September. Serious air pollution problems result from this burning. The purposes of the study were to determine the effect of environmental variables on grass field burning and to determine if conditions exist when significant air pollution reduction can be achieved. The environmental variables investigated were time from harvest to burning, time of day, air temperature, relative humidity, soil and straw moisture, wind speed and direction, and fuel density. The dependent variables measured were particulate emission and size distribution, combustion temperature, burn rate, amount of ash, percent of organics in the particulate, and smoke appearance. The results were analyzed statistically to determine the significant variables and their relationship.     

Particulate Emissions from a Stationary Engine Fueled with Ultra-Low-Sulfur Diesel and Waste-Cooking-Oil-Derived Biodiesel

ABSTRACT

Stationary diesel engines, especially diesel generators, are increasingly being used in both developing countries and developed countries because of increased power demand. Emissions from such engines can have adverse effects on the environment and public health. In this study, particulate emissions from a domestic stationary diesel generator running on ultra-low-sulfur diesel (ULSD) and biodiesel derived from waste cooking oil were characterized for different load conditions. Results indicated a reduction in particulate matter (PM) mass and number emissions while switching diesel to biodiesel. With increase in engine load, it was observed that particle mass increased, although total particle counts decreased for all the fuels. The reduction in total number concentration at higher loads was, however, dependent on percentage of biodiesel in the diesel-biodiesel blend. For pure biodiesel (B100), the reduction in PM emissions for full load compared to idle mode was around 9%, whereas for ULSD the reduction was 26%. A large fraction of ultrafine particles (UFPs) was found in the emissions from biodiesel compared to ULSD. Nearly 90% of total particle concentration in biodiesel emissions comprised ultrafine particles. Particle peak diameter shifted from a smaller to a lower diameter with increase in biodiesel percentage in the fuel mixture.

IMPLICATIONS There has been an increased usage of stationary diesel engines, especially backup power generators to meet the growing energy demand. Biodiesel derived from waste cooking oil has received increasing attention as an alternative fuel. However, data are only sparsely available in the literature on particulate emissions from stationary engines, fueled with blends of diesel and biodiesel. This study provides insights into the influence of waste-cooking-oil-derived biodiesel on engine performance and the particulate emissions from a stationary engine. The results of the study form a scientific basis to evaluate the impact of biodiesel emissions on the environment and human health.     

Emissions from Burning Grass Stubble and Straw

The emissions from burning the residue following grass-seed harvest were determined by means of a combined laboratory-field study. Samples of the straw and stubble residue were burned in the laboratory burning tower at the University of California at Riverside. Complete analyses were determined for gaseous and particulate emissions for the important grass species from the Willamette Valley of Oregon. Particulate emissions averaged 15.6 lb/ton of fuel burned. Carbon monoxide averaged 101 lb/ton of fuel burned. Hydrocarbon emission averages, in pounds per ton of fuel burned, were 1.74 for saturates plus acetylene, 2.80 for defines, and 1.68 for ethylene. The NO_x emission, at the temperature peak during the burn, averaged 29.3 ppm. Field studies, conducted by personnel from Oregon State University, measured only particulate emissions, carbon dioxide, and temperature over the burn. The carbon dioxide values were found to be similar to those obtained on the burning table at UCR and it was therefore concluded that the other gaseous emissions were similar and could be used as reasonably accurate for emission inventories. The temperature values obtained in the laboratory and field were also similar and further justifies extrapolating the burning table data to field situations. The particulate matter collected in the field studies averaged 15.55 lb of particulate per ton of fuel burned. This is the same average obtained for the burning table data which again serves to validate the emissions reported from Riverside. Much more variability was found in the particulate emissions obtained in the field which reflects the wider range of environmental conditions encountered in the field.     

The Effects of Some Air Pollutants and Meteorological Conditions on Airborne Algae and Protozoa

The purpose of this investigation was to determine the effects of meteorological conditions and specific air pollutants on the viability of airborne algae and protozoa. Such investigations will be of interest to medical researchers because these organisms are the source of many allergies. The three air pollutants that were continuously measured and recorded were sulfur, hydrocarbons, and particulate maiter. During the experiment, 25 different species of algae and 19 species of protozoa were collected from the atmosphere and cultured at the Westinghouse Environmental Station Laboratory in Raleigh, North Carolina. The algae and protozoa were collected over a one-year period (Jan-Dec 1971) by using a sequential sampler that moved air through a membrane filter at the rate of 15 ft³/hr. Every two hours a new filter was sequentially moved in to replace the old one. The results indicated a relationship between wind speed, wind direction, temperature, dew-point, particulate matter, barometric pressure, and rainfall to the percent frequency of positive culture tubes and number of cells/ft³ of air. Further studies are necessary to determine the interrelationships between the physical and chemical character of various air masses and their effect on the survival of algae and protozoa.     

Global Emissions of Nitrogen and Sulfur Oxides from 1860 to 1980

Statistical models have been developed that relate the rate of emissions of a pollutant to the rate of fuel consumption. These relations may be used to estimate emissions in other regions, or at other times, if fuel consumption data are available. This approach has been used to estimate global emissions of nitrogen and sulfur oxides in fossil fuel combustion at ten year intervals from 1860 to 1980. Emissions from each of the populated continents, i.e., North America, South America, Asia, Europe, Africa and Oceania from 1930 to 1980 are also presented. When averaged globally over the 1860 to 1980 period, sulfur emissions increased at the rate of 2.9 percent per year and the nitrogen emissions at the rate of 3.4 percent per year. The ratio of global sulfur emissions to nitrogen emissions has declined steadily; it was nearly 5 in the 19th century and became 3 by 1980. After the second world war, the most rapid increases in emissions have been registered in Asia, South America, and Africa.     

Characterisation and determination of profiles of polycyclic aromatic hydrocarbons in a traffic tunnel in Gothenburg, Sweden

The concentrations of semi-volatile polycyclic aromatic hydrocarbons (PAHs), hydrocarbons (HCs), particulate matter (PM 1, 2.5 and 10 μm) and total suspended particles (TSPs) were measured in a traffic tunnel in Gothenburg, Sweden. Emission factors (EFs) were also calculated. These variables are assumed to provide good estimates of average vehicle emissions, since all types of vehicle, using all types of fuel, pass through this tunnel. It was shown that the majority of particle-associated PAHs were found on particles with an aerodynamic diameter of <1 μm. The concentrations of PAHs were one order higher in magnitude in air samples from the tunnel than in air samples at two urban locations. However, the PAH profiles of air samples from the tunnel and the urban sites were similar. This was demonstrated using principal component analysis (PCA). Finally, and notably, there was no significant change in the total emissions when the proportion of heavy-duty vehicles (HDVs) increased from 8% to 24%. Previously, diesel vehicles had been found to release larger quantities of PAHs and related substances. Advances in fuel quality, and HDV motor and exhaust system design during the last decade may have contributed to this promising result. However, it was shown, using partial least squares regression to latent structures (PLS), that some of the parameters measured displayed correlations with the proportions of HDVs and light-duty vehicles (LDVs). Concentrations of total HCs, TSPs, dibenzothiopene, phenantrene, anthracene and monomethyl-derivatives of phenantrene and anthracene were all correlated to the proportion of HDVs. The concentrations of naphthalene, some mono- and dimethylnaphthalenes and most large PAHs (with 5–7 fused rings) were correlated to the proportion of LDVs.     

Informative Report

Abstract

Chemical composition and particle size data for particulate emissions from stationary sources are required for environmental health effect assessments, air chemistry studies and for air quality modeling investigations such as source apportionment. The Information presented In this paper is directed to those individuals concerned with these environmental Investigations. In this study, particulate emissions from a group of non-ferrous smelters have been physically and chemically characterized. Emission samples were collected at the baghouse outlets from smelter furnaces and at smelter acid plant stacks at three locations; a zinc, a lead, and a copper smelter.

Mass emission rate determinations were made by EPA reference methods. Cascade impactors were used to collect in-stack samples for particle size distribution measurements. Particulate samples for chemical characterization were collected on membrane filters for analysis by X-ray fluorescence spectroscopy. Development of measurement techniques required to determine the elemental composition of the total mass and sized fractions of the emission are discussed. Results of the tests at the three smelters include total mass and elemental emission rates, particle size distribution, and the elemental composition of the total particulate mass and of sized fractions from both the smelter furnaces and acid plants. The results obtained at the copper smelter may not be representative of the emissions at the many copper smelters where reverbatory furnaces have been replaced.     

Particulate organic compounds emitted from motor vehicle exhaust and in the urban atmosphere

The emission rate of particle-phase petroleum biomarkers in vehicular exhaust compared to the concentrations of these biomarkers in ambient air is used to determine the particulate organic compound concentration due to primary particle emissions from motor vehicles in the southern California atmosphere. A material balance on the organic particulate matter emitted from motor vehicle traffic in a Los Angeles highway tunnel first is constructed to show the proportion which is solvent-extractable and which will elute from a GC column, the ratio of resolved to unresolved compound mass, the portion of the resolved material that can be identified as single organic compounds, and the contribution of different classes of organic compounds to the overall identified fraction. It is shown that the outdoor ambient concentrations of the petroleum biomarkers track primary emissions measured in the highway tunnel, confirming that direct emissions of these compounds from vehicles govern the observed ambient petroleum biomarker concentrations. Using organic chemical tracer techniques, the portion of fine organic particulate matter in the Los Angeles atmosphere which is attributable to direct particle emissions from vehicle exhaust is calculated to vary from 7.5 to 18.3% at different sites throughout the air basin during a summertime severe photochemical smog episode. A similar level of variation in the contribution of primary motor vehicle exhaust to fine particulate organic matter concentrations during different times of day is seen. While peak atmospheric concentrations of fine particulate organic carbon are observed during the 1200–1600 PDT afternoon sampling period, only 6.3% of that material is apportioned to the directly emitted particles from vehicle exhaust. During the morning traffic peak between 0600–1000 PDT, 19.1% of the fine particulate organic material is traced to primary emissions from motor vehicles.     

Impacts of biodiesel on pollutant emissions of a JP-8-fueled turbine engine

The impacts of biodiesel on gaseous and particulate matter (PM) emissions of a JP-8-fueled T63 engine were investigated. Jet fuel was blended with the soybean oil-derived methyl ester biofuel at various concentrations and combusted in the turbine engine. The engine was operated at three power settings, namely ground idle, cruise, and takeoff power, to study the impact of the biodiesel at significantly different pressure and temperature conditions. Particulate emissions were characterized by measuring the particle number density (PND; particulate concentration), the particle size distribution, and the total particulate mass. PM samples were collected for offline analysis to obtain information about the effect of the biodiesel on the polycyclic aromatic hydrocarbon (PAH) content. In addition, temperature-programmed oxidation was performed on the collected soot samples to obtain information about the carbonaceous content (elemental or organic). Major and minor gaseous emissions were quantified using a total hydrocarbon analyzer, an oxygen analyzer, and a Fourier Transform IR analyzer. Test results showed the potential of biodiesel to reduce soot emissions in the jet-fueled turbine engine without negatively impacting the engine performance. These reductions, however, were observed only at the higher power settings with relatively high concentrations of biodiesel. Specifically, reductions of approximately 15% in the PND were observed at cruise and takeoff conditions with 20% biodiesel in the jet fuel. At the idle condition, slight increases in PND were observed; however, evidence shows this increase to be the result of condensed uncombusted biodiesel. Most of the gaseous emissions were unaffected under all of the conditions. The biodiesel was observed to have minimal effect on the formation of polycyclic aromatic hydrocarbons during this study. In addition to the combustion results, discussion of the physical and chemical characteristics of the blended fuels obtained using standard American Society for Testing and Materials (ASTM) fuel specifications methods are presented.     

Impacts of Biodiesel on Pollutant Emissions of a JP-8–Fueled Turbine Engine

Abstract

The impacts of biodiesel on gaseous and particulate matter (PM) emissions of a JP-8–fueled T63 engine were investigated. Jet fuel was blended with the soybean oil-derived methyl ester biofuel at various concentrations and combusted in the turbine engine. The engine was operated at three power settings, namely ground idle, cruise, and takeoff power, to study the impact of the biodiesel at significantly different pressure and temperature conditions. Particulate emissions were characterized by measuring the particle number density (PND; particulate concentration), the particle size distribution, and the total particulate mass. PM samples were collected for off-line analysis to obtain information about the effect of the biodiesel on the polycyclic aromatic hydrocarbon (PAH) content. In addition, temperature-programmed oxidation was performed on the collected soot samples to obtain information about the carbonaceous content (elemental or organic). Major and minor gaseous emissions were quantified using a total hydrocarbon analyzer, an oxygen analyzer, and a Fourier Transform IR analyzer. Test results showed the potential of biodiesel to reduce soot emissions in the jet-fueled turbine engine without negatively impacting the engine performance. These reductions, however, were observed only at the higher power settings with relatively high concentrations of biodiesel. Specifically, reductions of ～15% in the PND were observed at cruise and takeoff conditions with 20% biodiesel in the jet fuel. At the idle condition, slight increases in PND were observed; however, evidence shows this increase to be the result of condensed uncombusted biodiesel. Most of the gaseous emissions were unaffected under all of the conditions. The biodiesel was observed to have minimal effect on the formation of polycyclic aromatic hydrocarbons during this study. In addition to the combustion results, discussion of the physical and chemical characteristics of the blended fuels obtained using standard American Society for Testing and Materials (ASTM) fuel specifications methods are presented.     

Characterization of emissions from a variable gasoline/methanol fueled car.

In response to the occurrence of the increasingly severe ambient ozone exceedances, regional environmental managers are examining the possibility of a cleaner fuel for automobiles. At this time the leading candidate appears to be methanol. In anticipation of a shift to methanol, flexible-fueled automobiles capable of operating on gasoline and/or methanol are being developed. This study examines both the exhaust and evaporative emissions from a prototype General Motors Variable Fuel Corsica. Results are reported for tests conducted at temperatures of 40 degrees, 75 degrees, and 90 degrees F, and for fuels M0 M25, M50, M85, and M100. In addition to regulated emissions and fuel economy, emission rates for methanol, aldehydes, and a large number of hydrocarbon compounds were measured. The data indicate that increasing the fuel's methanol content does not affect the exhaust organic emission rate (calculated in accordance with the regulation) from flexible-fueled cars, but formaldehyde and methanol comprise increasingly greater portions of the organic material while hydrocarbons comprise less. Increasing fuel methanol content has no significant effect on exhaust regulated emission rates (organic material, carbon monoxide, and nitrogen oxides) nor on the composition of total hydrocarbons, except for methane, which increases substantially. The effect of ambient temperature on both exhaust and evaporative emissions is similar to its effect on gasoline cars: organic and carbon monoxide exhaust emissions increase substantially at the lower temperatures, and evaporative emissions increase steadily with increases in temperature.     

The challenges of reducing greenhouse gas emissions and air pollution through energy sources: evidence from a panel of developed countries

The objective of the study is to investigate the long-run relationship between climatic factors (i.e., greenhouse gas emissions, agricultural methane emissions, and industrial nitrous oxide emission), air pollution (i.e., carbon dioxide emissions), and energy sources (i.e., nuclear energy; oil, gas, and coal energy; and fossil fuel energy) in the panel of 35 developed countries (including EU-15, new EU member states, G-7, and other countries) over a period of 1975–2012. In order to achieve this objective, the present study uses sophisticated panel econometric techniques including panel cointegration, panel fully modified OLS (FMOLS), and dynamic OLS (DOLS). The results show that there is a long-run relationship between the variables. Nuclear energy reduces greenhouse gases and carbon emissions; however, the other emissions, i.e., agricultural methane emissions and industrial nitrous oxide, are still to increase during the study period. Electricity production from oil, gas, and coal sources increases the greenhouse gases and carbon emissions; however, the intensity to increase emissions is far less than the intensity to increase emissions through fossil fuel. Policies that reduce emissions of greenhouse gases can simultaneously alter emissions of conventional pollutants that have deleterious effects on human health and the environment.     

用后处理装置减少DMDF发动机的有害排放

在一台增压中冷电控单体泵的四缸柴油机上采用柴油/甲醇双燃料（DMDF）燃烧方式进行台架实验,研究了甲醇替代率和不同后处理装置对有害气体、烟度和微粒排放特性的影响。结果表明：在排气管加装柴油机氧化催化转化器（DOC）耦合微粒催化转化器（POC）可以大幅降低双燃料燃烧产生的THC和CO,基本可以实现零排放;与催化前相比,微粒的总数量浓度和总质量浓度均有大幅度降低,平均降幅分别为91.7%和88.1%;烟度排放得到改善,平均降幅为21.9%;同时,该后处理装置对DMDF发动机的NOx排放无明显影响。与之不同,双DOC耦合的后处理装置对THC和CO的催化效率略优于DOC+POC,但在大部分工况下会导致NOx和烟度排放的同时增加。     

An assessment of air emissions from liquefied natural gas ships using different power systems and different fuels

The shipping industry has been an unrecognized source of criteria pollutants: nitrogen oxides (NOx), volatile organic compounds, coarse particulate matter (PM10), fine particulate matter (PM2.5), sulfur dioxide (SO2), and carbon monoxide (CO). Liquefied natural gas (LNG) has traditionally been transported via steam turbine (ST) ships. Recently, LNG shippers have begun using dual-fuel diesel engines (DFDEs) to propel and offload their cargoes. Both the conventional ST boilers and DFDE are capable of burning a range of fuels, from heavy fuel oil to boil-off-gas (BOG) from the LNG load. In this paper a method for estimating the emissions from ST boilers and DFDEs during LNG offloading operations at berth is presented, along with typical emissions from LNG ships during offloading operations under different scenarios ranging from worst-case fuel oil combustion to the use of shore power. The impact on air quality in nonattainment areas where LNG ships call is discussed. Current and future air pollution control regulations for ocean-going vessels (OGVs) such as LNG ships are also discussed. The objective of this study was to estimate and compare emissions of criteria pollutants from conventional ST and DFDE ships using different fuels. The results of this study suggest that newer DFDE ships have lower SO2 and PM2.5/PM10 emissions, conventional ST ships have lower NOx, volatile organic compound, and CO emissions; and DFDE ships utilizing shore power at berth produce no localized emissions because they draw their required power from the local electric grid.     

Heavy Duty Diesel Particulate Emission Factors

For the past several years, EPA has been measuring particulate emissions from a variety of heavy-duty diesel engines through contracts with Southwest Research Institute. Particulate emissions samples have been collected using an exhaust splitter to divert a fraction of the engine exhaust into a standard dilution tunnel. A small fraction of the diluted exhaust from the tunnel is pulled through a filter from which particulate mass and, in some cases, organic content of the particulate is determined. This paper discusses the sampling system and gives particulate emission factors that have been computed from truck and bus fuel consumption data as well as average truck and bus speed data from New York and Los Angeles (freeway and nonfreeway usage). Average particulate emission test results (steady state tests) for 2-stroke engines were 4.74 g/kg fuel and for 4-stroke engines were 2.64 g/kg fuel. Using average particulate emissions results, a particulate emission factor range of 0.8 to 1.3 g/km was computed. Nationwide diesel particulate emissions were calculated to be 88,000 metric tons per year.