Kenneth T. Knapp

The Effect of Ethanol Fuel on the Emissions of Vehicles over a Wide Range of Temperatures

The emissions from a fleet of 11 vehicles, including three from the State of Alaska, were tested at 75, 0, and -20 °F with base gasolines and E10 gasolines, that is, gasolines with 10% by volume ethanol added. The data for the changes in emissions for the test run at 75 °F are included, since most other studies on the effects of E10 gasoline on emissions were run at that temperature. The three Alaskan vehicles were also tested at 20 °F. The testing followed the Federal Test Procedure, and regulated emissions-CO, total hydrocarbons (THC), and nitrogen oxides (NOx)-CO2, speciated organics, and fuel economy were measured. A total of 490 FTP tests were run. The data obtained indicated that with most vehicles, at the temperatures tested, improvements in both CO and THC emissions were obtained with the use of E10 fuel. At the lowest temperature used, -20 °F, most vehicles had an increase in NO emissions with the use of E10 fuel. At the other temperatures, however, more vehicles showed a decrease in NOx emissions with the use of E10. With all vehicles at all temperatures tested, the emissions of acetaldehyde increased significantly when E10 fuel was used. The highest increase was about 8 to 1. Benzene, formaldehyde, and 1,3 butadiene showed both increases and decreases in the emissions when using E10 fuel. Unexpected results were obtained with the fuel economy, with about half of the tests showing an increase in fuel economy with the use of E10 fuel.

Characterization of particulate emissions from municipal wastewater sludge incinerators.

Particulate emissions from a group of municipal sludge incinerators, three with multiple-hearth furnaces and one with a fluidized-bed furnace, were characterized. Three plants operated at or near autogenous burning conditions. Chemical element composition was determined for total and sized emission samples by X-ray fluorescence analysis. Objectives of the investigation were to obtain specific elemental emission factors and to provide source inventories and source signatures, especially in terms of particle size, to assist the development and evaluation of source apportionment models. Considerable enrichment of several elements (S, V, Cu, Zn, Cd, Sn, Pb) in the particulate emissions compared to their content in the sludge feed was observed. The largest average enrichment ratios were found with cadmium (31), zinc (13), lead (Q), and sulfur (8).

INFLUENCE OF ETHANOL-BLENDED FUELS ON THE EMISSIONS FROM THREE PRE-1985 LIGHT-DUTY PASSENGER VEHICLES

Tailpipe and evaporative emissions from three pre-1985 passenger motor vehicles operating on an ethanol oxygenated and on a nonoxygenated (base) fuel were characterized. Emission data were collected for vehicles operating over the Federal Test Procedure at 90 °F, 75 °F, and 40 °F to simulate ambient driving conditions. The two fuels tested were a commercial summer-grade regular gasoline (the nonoxygenated base fuel) and an oxygenated fuel containing 8.8% ethanol, more paraffins and olefins, and less aromatics than the base fuel. The Reid vapor pressure (RVP) was adjusted to correspond to that of the base fuel. The emissions measured were total hydrocarbons (THCs), speciated hydrocarbons, spedated aldehydes, carbon monoxide (CO), and oxides of nitrogen (NOX). This study showed a general reduction in tailpipe emissions of THC, CO, benzene, and 1,3-butadiene when tested with the ethanol fuel. The ethanol fuel significantly reduced these emissions from the high emitting vehicle, MU098, at 90 °F, 75 °F, and 40 °F test temperatures. Additionally, the ethanol fuel reduced CO emissions from vehicle BU950, with and without catalyst, and from vehicle CI415 at 40 °F. Both formaldehyde and acetaldehyde emissions generally increased when tested with the oxygenated fuel. The acetaldehyde emissions were about double with this fuel. The limited data indicate that most emissions, including toxics, occur during the first 124 seconds of vehicle start-up. Diurnal evaporative emissions were less from the oxygenated fuel, while hot-soak evaporative emissions were greater from the oxygenated fuel (for all vehicles except MU098). Evaporative emissions were generally greatest at the 90 °F test temperature.

Real-world vehicle emissions: a summary of the third annual CRC-APRAC on-road vehicle emissions workshop

The CRC-APRAC On-Road Vehicle Emissions Workshop provided an informal atmosphere for the exchange of information on real-world vehicle emissions issues. Topics addressed included: emissions inventories; mobile source emission factor models; evaporative emissions; dynamometer studies of exhaust emissions; remote sensing studies; and tunnel studies of vehicle emissions. It is now widely accepted that emissions inventories have significantly underestimated the carbon monoxide (CO) and hydrocarbon (HC) emissions from on-rpad vehicles. Since these inventories are used to develop emission control strategies, it is critical that they accurately reflect on-road emissions. Research is currently being conducted by a variety of organizations to address this issue. For the past three years, the Coordinating Research Council - Air Pollution Research Advisory Committee (CRC-APRAC) has sponsored an onroad vehicle emissions workshop whose purpose is to provide an informal forum in which recent real-world vehicle emission...

The sampling of reactive atmospheric species by transition-flow reactor: Application to nitrogen species

Concentrations of nitric acid vapor and fine particulate nitrate were measured during the 1985 Nitrogen Species Methods Comparison Study at Claremont, California, with a transition-flow reactor. This system separates atmospheric gases and particles by differential diffusion in a transition-flow stream and thereby minimizes sampling artifacts for these reactive species. Error analysis showed that [HNO3] was determined with typical uncertainties (1σ) of 5–8% and fine particulate [NO3−] at typical uncertainties of 5–11%. Both species showed a strong diurnal pattern with daytime maxima. Daytime [HNO3] ranged from 25 to 495 nmole m−3, while night-time values ranged from less than 1 to 107 nmole m −3. The time-weighted average concentrations of 12- and 10-h samples were equivalent to the corresponding 22-h sample for each day. Simple filtration with Teflon® and nylon filters in series over-estimated [HNO3] by 30–50 % for 10- and 12-h samples, and by 70% for 22-h samples. Analysis of ionic balance suggests that the cause of the overestimate was dissociation of NH4NO3 from equilibrium changes, and not displacement by strong acids.

Comparison of auto emission measurement techniques

Abstract The Clark and Washoe Remote Sensing Study (CAWRSS) field season took place in September 1994. The study was designed to characterize the exhaust emissions of the on-road vehicle fleet in the two major urban centers of the State of Nevada. The air quality in Las Vegas (Clark County) and Reno (Washoe County) is significantly worse than the surrounding rural areas and vehicle emissions have been identified as one of the primary sources of the pollution. Inspection and maintenance programs, mandated by the federal government, have been implemented in both urban areas. The study compated the State-approved test, a no-load, two-speed idle test, to two other measurement techniques: remote sensing devices (RSDs) and the IM240 test, a loaded-mode test run on a dynamometer. Results were viewed from two different perspectives. Fleet-wide characteristics showed that concentrations of CO (%) measured with RSDs were higher than those obtained with the no-load idle tests. Characteristics of pollution distributions derived from the two techniques were similar in range and shape. Observations for individual vehicles were then compared. CAWRSS is in agreement with earlier studies in that high emitters in the idle test are also high emitters on-road.

On-road vehicle emissions: US studies

Abstract Several recent events in mobile sources emissions measurements have caused a major reassessment of the amounts of volatile organic compounds (VOC) and carbon monoxide (CO) in the ambient air attributed to mobile sources. These include the comparison of real-world in-use vehicle emissions with those predicted by mobile emission factor models and the development of cross-road remote sensors for measuring emissions from in-use passing vehicles. The real-world measurements were generally higher than model predictions. A tunnel study in the Southern California Air Quality Study (SCAQS) found two-fold to seven-fold differences. Additional real-world studies, including the remote sensor, roadside I/M inspections and testing on the US Environmental Protection Agency portable dynamometer have shown that 50% of the tailpipe emissions come from only 10% of the vehicles and 80% come from 20% of the vehicles. This paper describes the portable dynamometer study and several tunnel studies.

Nitric Acid and Particulate Measurements by Transition-Flow Reactor During the Carbonaceous Species Methods Comparison Study

Measurements of gaseous nitric acid and fine and total particulate nitrate and sulfate were made by the transition-flow reactor (TFR) during the Carbonaceous Species Methods Comparison Study (CSMCS) at Glendora, CA, in August 1986. The TFR is a modular sampler especially suited for measuring reactive species that occur in both gas and particle phases. It consists of a tube operated in transition flow that has a short section lined with a sink for the gaseous species of interest. For gaseous nitric acid, the linear is nylon and it removes a constant 9%. Following the transition-flow tube is a filter pack containing a Teflon filter to remove particles and a nylon filter to remove the remaining gaseous nitric acid and any nitric acid liberated from the particles on the Teflon filter during sampling. In the CSMCS, a dual TFR system sampling through a cyclone, which had a cutpoint of 2 μm, one TFR was changed every 12 hours, the other was changed every 24 hours. A third TFR was also used that had an inverted f...

Central Carolina Vehicle Particulate Emissions Study

A vehicle emission study was carried out in the Research Triangle Park area in North Carolina to determine the PM (particulate matter) emission rates and emission profiles of the fleet of in-use vehicles in North Carolina. The NERL (National Exposure Research Laboratory) transportation Dynamometer was set up in the parking lot of Home Depot in Cary, NC. Vehicles from the general area were recruited and tested for their particulate and gaseous emissions. The study was divided into two phases: a winter phase and a summer phase. In the winter phase, 121 gasoline fueled vehicles were tested in Cary and 14 gasoline fueled and three diesel fueled vehicles were tested at NERL, cold cell dynamometer located in the ERC annex at 35 F. In the summer phase, 120 gasoline fueled and five diesel fueled vehicles were tested on the transportation dynamometer in Cary. Samples were collected for all tests for PM 10, regulated gaseous emissions, and aldehydes.

AMBIENT TEMPERATURE AND DRIVING CYCLE EFFECTS ON CNG MOTOR VEHICLE EMISSION

This paper describes an emissions study of two vans powered by compressed natural gas (CNG). One van was relatively new, while the other had been driven more than 120,000 mi. The purpose of the study was to obtain emissions information which could be used to predict the impact of CNG use on ambient air quality and air toxic concentrations, and to develop a better understanding of the effect of ambient temperature variations on CNG emissions. Using four different driving cycles, emission tests were carried out at 20{degree}F, 75{degree}F, and 105{degree}F. Test results agree with previous findings that document low emissions of nonmethane hydrocarbons from CNG vehicles. Results also confirm the expectation that CNG emissions are not significantly affected by ambient temperature variations, although an increase in formaldehyde emission was noted for the 20{degree}F cold-start tests.