Mass Loading Measurements in Amargosa Valley

This work will be conducted under Task DRI-FI-001, “Mass Loading Measurements in Amargosa Valley.” The objective of this task is to measure, with known accuracy, the levels of atmospheric mass loading (mass concentration of suspended particulates) accompanying soil surface disturbing activities in Amargosa Valley. Mass loading is used in the biosphere model to calculate inhalation exposure for the human receptor, the maximally reasonably exposed individual (RMEI). The mass loading currently used in the biosphere model is based on literature data from the analog sites rather than on site-specific conditions. This work is subject to the Nevada System of Higher Education (NSHE, previously UCCSN) QA program requirements

Olfaction-based Detection Distance: A Quantitative Analysis of How Far Away Dogs Recognize Tortoise Odor and Follow It to Source

The use of detector dogs has been demonstrated to be effective and safe for finding Mojave desert tortoises and provides certain advantages over humans in field surveys. Unlike humans who rely on visual cues for target identification, dogs use primarily olfactory cues and can therefore locate targets that are not visually obvious. One of the key benefits of surveying with dogs is their efficiency at covering ground and their ability to detect targets from long distances. Dogs may investigate potential targets using visual cues but confirm the presence of a target based on scent. Everything that emits odor does so via vapor-phase molecules and the components comprising a particular scent are carried primarily though bulk movement of the atmosphere. It is the ability to search for target odor and then go to its source that makes dogs ideal for rapid target recognition in the field setting. Using tortoises as targets, we quantified distances that dogs detected tortoise scent, followed it to source, and correctly identified tortoises as targets. Detection distance data were collected during experimental trials with advanced global positioning system (GPS) technology and then analyzed using geographic information system (GIS) modeling techniques. Detection distances ranged from 0.5 m to 62.8 m for tortoises on the surface. We did not observe bias with tortoise size, age class, sex or the degree to which tortoises were handled prior to being found by the dogs. The methodology we developed to quantify olfaction-based detection distance using dogs can be applied to other targets that dogs are trained to find

Comparison of Auto Emission Measurement Techniques

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 compared 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

High-end exposure relationships of volatile air toxics and carbon monoxide to community-scale air monitoring stations in Atlanta, Chicago, and Houston

Evaporative and exhaust mobile source air toxic (MSAT) emissions of total volatile organic compounds, carbon monoxide, BTEX (benzene, toluene, ethylbenzene, and xylenes), formaldehyde, acetaldehyde, butadiene, methyl tertiary butyl ether, and ethanol were measured in vehicle-related high-end microenvironments (ME) under worst-case conditions plausibly simulating the >99th percentile of inhalation exposure concentrations in Atlanta (baseline gasoline), Chicago (ethanol-oxygenated gasoline), and Houston (methyl tertiary butyl either-oxygenated gasoline) during winter and summer seasons. High-end MSAT values as ratios of the corresponding measurements at nearby air monitoring stations exceeded the microenvironmental proximity factors used in regulatory exposure models, especially for refueling operations and MEs under reduced ventilation. MSAT concentrations were apportioned between exhaust and evaporative vehicle emissions in Houston where methyl tertiary butyl ether could be used as a vehicle emission tracer. With the exception of vehicle refueling operations, the results indicate that evaporative emissions are a minor component of high-end MSAT exposure concentrations

Real-world Automotive Emissions—Summary of Studies in the Fort McHenry and Tuscarora Mountain Tunnels

Motor vehicle emission rates of CO, NO, NOx, and gas-phase speciated nonmethane hydrocarbons (NMHC) and carbonyl compounds were measured in 1992 in the Fort McHenry Tunnel under Baltimore Harbor and in the Tuscarora Mountain Tunnel of the Pennsylvania Turnpike, for comparison with emission-model predictions and for calculation of the reactivity of vehicle emissions with respect to O3 formation. Both tunnels represent a high-speed setting at relatively steady speed. The cars at both sites tended to be newer than elsewhere (median age was \u3c 4 yr), and much better maintained as judged by low CO/CO2 ratios and other emissions characteristics. The Tuscarora Mountain Tunnel is flat, making it advantageous for testing automotive emission models, while in the underwater Fort McHenry Tunnel the impact of roadway grade can be evaluated. MOBILE4.1 and MOBILES gave predictions within ± 50% of observation most of the time. There was a tendency to overpredict, especially with MOBILES and especially at Tuscarora. However, light-duty-vehicle CO, NMHC, and NOx, all were underpredicted by MOBILE4.1 at Fort McHenry. Light-duty-vehicle CO/NOx ratios and NMHC/NOx, ratios were generally a little higher than predicted. The comparability of the predictions to the observations contrasts with a 1987 experiment in an urban tunnel (Van Nuys) where CO and HC, as well as CO/NOx, and NMHC/NOx, ratios, were grossly underpredicted. The effect of roadway grade on gram per mile (g mi−1) emissions was substantial. Fuel-specific emissions (g gal−1), however, were almost independent of roadway grade, which suggests a potential virtue in emissions models based on fuel-specific emissions rather than g mi−1) emissions. Some 200 NMHC and carbonyl emissions species were quantified as to their light- and heavy-duty-vehicle emission rates. The heavy-duty-vehicle NMHC emissions were calculated to possess more reactivity, per vehicle-mile, with respect to O3 formation (g O3 per vehicle-mile) than did the light-duty-vehicle NMHC emissions. Per gallon of fuel consumed, the light-duty vehicles had the greater reactivity. Much of the NMHC, and much of their reactivity with respect to O3 formation, resided in compounds heavier than C10, mostly from heavy-duty diesel, implying that atmospheric NMHC sampling with canisters alone is inadequate in at least some situations since canisters were found not to be quantitative beyond ∼ C10 The contrasting lack of compounds heavier than C10 from light-duty vehicles suggests a way to separate light- and heavy-duty-vehicle contributions in receptor modeling source apportionment. The division between light-duty-vehicle tailpipe and nontailpipe NMHC emissions was ∼ 85% tailpipe and ∼ 15% nontailpipe (evaporative running losses, etc.). Measured CO/CO2 ratios agreed well with concurrent roadside infrared remote sensing measurements on light-duty vehicles, although remote sensing HC/CO2 ratio measurements were not successful at the low HC levels prevailing. Remote sensing measurements on heavy-duty diesels were obtained for the first time, and were roughly in agreement with the regular (bag sampling) tunnel measurements in both CO/CO2 and HC/CO2 ratios. A number of recommendations for further experiments, measurement methodology development, and emissions model development and evaluation are offered