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Technical Paper

Respirable Particulate Genotoxicant Distribution in Diesel Exhaust and Mine Atmospheres

1992-09-01
921752
Results of a research effort directed towards identifying and measuring the genotoxic properties of respirable particulate matter involved in mining exposures, especially those which may synergistically affect genotoxic hazard, are presented. Particulate matter emissions from a direct injection diesel engine have been sampled and assayed to determine the genotoxic potential as a function of engine operating conditions. Diesel exhaust from a Caterpillar 3304 diesel engine, representative of the ones found in underground mines, rated 100 hp at 2200 rpm is diluted in a multi-tube mini-dilution tunnel and the particulate matter is collected on 70 mm fluorocarbon coated glass fiber filters as well as on 8″ x 10″ hi-volume filters. A six mode steady state duty cycle was used to relate engine operating conditions to the genotoxic potential.
Technical Paper

Acid Deposition in California

1982-02-01
821246
Precipitation chemistry measurements have been made at many California locations, with recorded extreme pH values as low as 2.89 from Pasadena and 3.5 from geologically sensitive Sequoia National Park. However, in northern areas of the state experiencing good air quality, very little acid deposition occurs. California's acid precipitation is apparently locally produced, since there are no major pollution source regions upwind of the state. This is attributable to the extremely rapid rates observed for conversion of NOx to nitric acid and SO2 to sulfuric acid in the atmosphere. Recent monitoring data illustrate extreme variations in precipitation chemistry from adjacent sites and even at the same location from one year to the next. Enrichment factor calculations show that in contrast with data from other locations in the world, nitric acid dominates over sulfuric acid in California's rainfall in many locations.
Technical Paper

Progress in Understanding the Toxicity of Gasoline and Diesel Engine Exhaust Emissions

1999-04-27
1999-01-2250
To help guide heavy vehicle engine, fuel, and exhaust after-treatment technology development, the U.S. Department of Energy and the Lovelace Respiratory Research Institute are conducting research not addressed elsewhere on aspects of the toxicity of particulate engine emissions. Advances in these technologies that reduce diesel particulate mass emissions may result in changes in particle composition, and there is concern that the number of ultrafine (<0.1 micron) particles may increase. All present epidemiological and laboratory data on the toxicity of diesel emissions were derived from emissions of older-technology engines. New, short-term toxicity data are needed to make health-based choices among diesel technologies and to compare the toxicity of diesel emissions to those of other engine technologies.
Technical Paper

Development and Initial Use of a Heavy-Duty Diesel Truck Test Schedule for Emissions Characterization

2002-05-06
2002-01-1753
In characterizing the emissions from mobile sources, it is essential that the vehicle be exercised in a way that reasonably represents typical in-use behavior. A heavy-heavy duty diesel truck (HHDDT) test schedule was developed from speed-time data gathered during two Air Resources Board-sponsored truck activity programs. The data were divided into four modes, termed Idle, Creep, Transient and Cruise Modes, in order of increasing speed. For the last three modes, speed-time schedules were created that represented all the data in that mode. Statistical parameters such as average speed, stops per unit distance, kinetic energy, maximum speed and acceleration and deceleration values were considered in arriving at these schedules. The schedules were evaluated using two Class 8 over-the-road tractors on a chassis dynamometer. Emissions were measured using a full-scale dilution tunnel, filtration for particulate matter (PM), and research grade analyzers for the gases.
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