In recent years, automobile manufacturers have been producing gasoline-powered vehicles that have very low tailpipe and evaporative emissions in order to meet very stringent certification standards set by the U.S. Environmental Protection Agency and the California Air Resources Board. These extremely low emitting vehicles are 98% to 99% cleaner than catalyst-equipped vehicles produced in the mid 1980s. To better understand the emission characteristics of these extremely low emitting vehicles as well as their potential impact on future air quality, researchers at the University of California, Riverside have conducted a comprehensive study consisting of: 1) an emission measurement program; 2) the development of specific emission models; and 3) the application of future emission inventories to air quality models. Results have shown that in nearly all cases, these vehicles have emissions that are well below their stringent certification standards and continue to have low emissions as they age. Based on the measurement results, new modal emission models have been created for both ULEV- and PZEVcertified vehicles. The model results compare very well to actual measurements. With these models, it is possible to accurately predict future mobile source emission inventories that will have an increasing number of these extremely low emitting vehicles in the overall vehicle population. It is expected that a large penetration of these vehicles in the vehicle fleet will have a significant role in meeting ozone attainment in many regions.

In recent years, automobile manufacturers have been producing gasoline-fueled vehicles that have very low tailpipe and evaporative emissions to meet stringent certification standards set by the U.S. Environmental Protection Agency and the California Air Resources Board. These extremely low-emitting vehicles are 98% to 99% cleaner than the catalyst-equipped vehicles produced in the mid-1980s. To understand better the emissions characteristics of these extremely low-emitting vehicles, as well as their potential impact on future air quality, researchers at the University of California, Riverside, have conducted a comprehensive study consisting of (a) an emissions measurement program, (b) the development of specific emissions models, and (c) the application of future emissions inventories to air quality models. Results have shown that in nearly all cases, these vehicles have emissions that are well below their stringent certification standards, and the vehicles continue to have low emissions as they age. On the basis of the measurement results, new modal emissions models have been created for both ultra-low-emission-certified vehicles and partial-zero-emission-certified vehicles. The model results compare well with actual measurements. With these models, it is possible to predict accurately future mobile source emissions inventories that will have an increasing number of these extremely low-emitting vehicles in the overall vehicle population. It is expected that the large penetration of these vehicles into the vehicle fleet will have a significant role in meeting ozone attainment levels in many regions

In recent years, automobile manufacturers have been producing gasoline-fueled vehicles that have very low tailpipe and evaporative emissions to meet stringent certification standards set by the U.S. Environmental Protection Agency and the California Air Resources Board. These extremely low-emitting vehicles are 98% to 99% cleaner than the catalyst-equipped vehicles produced in the mid-1980s. To understand better the emissions characteristics of these extremely low-emitting vehicles, as well as their potential impact on future air quality, researchers at the University of California, Riverside, have conducted a comprehensive study consisting of (a) an emissions measurement program, (b) the development of specific emissions models, and (c) the application of future emissions inventories to air quality models. Results have shown that in nearly all cases, these vehicles have emissions that are well below their stringent certification standards, and the vehicles continue to have low emissions as they age. On the basis of the measurement results, new modal emissions models have been created for both ultra-low-emission-certified vehicles and partial-zero-emission-certified vehicles. The model results compare well with actual measurements. With these models, it is possible to predict accurately future mobile source emissions inventories that will have an increasing number of these extremely low-emitting vehicles in the overall vehicle population. It is expected that the large penetration of these vehicles into the vehicle fleet will have a significant role in meeting ozone attainment levels in many regions.

Purpose

Our aim was to introduce a simplified MRI instrument, Rapid OsteoArthritis MRI Eligibility Score (ROAMES), for defining structural eligibility of patients for inclusion in disease-modifying osteoarthritis drug trials using a tri-compartmental anatomic approach that enables stratification of knees into different structural phenotypes and includes diagnoses of exclusion. We also aimed to define overlap between phenotypes and determine reliability.

Methods

50 knees from the Foundation for National Institutes of Health Osteoarthritis Biomarkers study, a nested case-control study within the Osteoarthritis Initiative, were selected within pre-defined definitions of phenotypes as either inflammatory, subchondral bone, meniscus/cartilage, atrophic or hypertrophic. A focused scoring instrument was developed covering cartilage, meniscal damage, inflammation and osteophytes. Diagnoses of exclusion were meniscal root tears, osteonecrosis, subchondral insufficiency fracture, tumors, malignant marrow infiltration and acute traumatic changes. Reliability was determined using weighted kappa statistics. Descriptive statistics were used for determining concordance between the a priori phenotypic definition and ROAMES and overlap between phenotypes.

Results

ROAMES identified 43 of 50 (86%) pre-defined phenotypes correctly. Of the 50 participants, 27 (54%) had no additional phenotypes other than the pre-defined phenotype. 18 (36%) had one and 5 (10%) had two additional phenotypes. None had three or four additional phenotypes. All features of ROAMES showed almost perfect agreement. One case with osteonecrosis and one with a tumor were detected.

Conclusions

ROAMES is able to screen and stratify potentially eligible knees into different structural phenotypes and record relevant diagnoses of exclusion. Reliability of the instrument showed almost perfect agreement.

An important objective of the Pacific Exploratory Mission-West A (PEM-West A) was the chemical characterization of the outflow of tropospheric trace gases and aerosol particles from the Asian continent over the western Pacific Ocean. This paper summarizes the chemistry of this outflow during the period September - October 1991. The vertical distributions of CO, C2H6, and NOx showed regions of outflow at altitudes below 2 km and from 8 to 12 km. Mixing ratios of CO were ≈130 parts per billion by volume (ppbv), ≈1000 parts per trillion by volume (pptv) for C2H6, and ≈100 pptv for NOx in both of these regions. Direct outflow of Asian industrial materials was clearly evident at altitudes below 2 km, where halocarbon tracer compounds such as CH3CCl3 and C2Cl4 were enhanced about threefold compared to aged Pacific air. The source attribution of species outflowing from Asia to the Pacific at 8 -12 km altitude was not straightforward; Above 10 km altitude there were substantial enhancements of NOy, O3, CO, CH4 SO2, C2H6, C3H8, C2H2, and aerosol 210Pb but not halocarbon industrial tracers. These air masses were rich in nitrogen relative to sulfur and contained ratios of C2H2/CO and C3H8/C2H6 (≈1.5 and 0.1 respectively) indicative of several-day-old combustion emissions. It is unclear if these emissions were of Asian origin, or if they were rapidly transported to this region from Europe by the high wind speeds in this tropospheric region (60 - 70 m s-1). The significant cyclonic activity over Asia at this time could have transported to the upper troposphere emissions from biomass burning in Southeast Asia or emissions from the extensive use of various biomass materials for cooking and space heating. Apparently, the emissions in the upper troposphere were brought there by wet convective systems since water-soluble gases and aerosols were depleted in these air masses. Near 9 km altitude there was a distinct regional outflow that appeared to be heavily influenced by biogenic processes on the Asian continent, especially from the southeastern area. These air masses contained CH4 in excess of 1800 ppbv, while CO2 and OCS were significantly depleted (349 - 352 ppmv and 450 - 500 pptv, respectively). This signature seemingly reflected CH4 emissions from wetlands and rice paddies with coincident biospheric uptake of tropospheric CO2 and OCS. Copyright 1996 by the American Geophysical Union.