A Multipurpose Flare Stack for Control of Chemical Process Wastes

Abstract

To test the effectiveness of California’s vehicle inspection/ maintenance (I/M) program, exclusive of vehicle-owner intervention, a fleet of more than 1,100 vehicles that previously had failed California’s Smog Check test were sent to randomly selected Smog Check stations in the Los Angeles area for covert inspections and repairs. The two-speed idle test was used for repairs. For those vehicles that were repaired at the first inspection, their FTP emission reductions were 25%, 14%, and 11% for hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO_x), respectively, although emissions testing for NO_x was not performed at the Smog Check stations. Idle HC and CO emissions increased for 35% and 43% of the vehicles, respectively, after repairs. This data set shows that most vehicles that fail the Smog Check inspection are only marginal emitters, with 61% and 44% of the total potential for HC and CO emission reductions, respectively, coming from only 10% of the vehicles that currently fail the inspection. When the vehicles were rank-ordered by idle emissions from dirtiest to cleanest, emission reduction costs for the highest-emitting 10% of the fleet averaged $l,100/ton and $250/ton for HC and CO, respectively, attributing all the costs to each pollutant exclusively. For the remaining vehicles, costs increased dramatically.     

Modeling In-Use Vehicle Emissions and the Effects of Inspection and Maintenance Programs

Different ways for modeling the impact of vehicle emission inspection and maintenance programs on fleet hydrocarbon emissions are examined. A dynamic model is developed for forecasting fleet emissions in which individual vehicle performance is modeled as a stochastic process and vehicle emissions are tracked over time. Emissions inspection and repair are incorporated into the model, allowing for the stochastic aspects of both testing and repair. This model is compared to EPA’s model for evaluating the impact of vehicle emissions inspection and maintenance. We find that the way vehicle emission equipment deterioration overtime is modeled is important for forecasting emissions from the fleet and for assessing the success of inspection and maintenance programs. For inspection programs, we find that factors such as the proportion of vehicles tested, and repair effectiveness and duration have the greatest impact on emission reductions. The ability of different emission testing regimes to identify polluting vehicles has less impact on a program’s overall potential for emissions reduction. Policy recommendations for I&M testing and predictions of emission reduction credits from these tests will depend in important ways on the methods used in the underlying emissions models.     

Prospects of inspection and maintenance of two-wheelers in India.

Two-wheeler vehicles in Delhi, India--roughly 70% of the total vehicle fleet--are responsible for a significant portion of the city's vehicle emissions and petroleum consumption. An inspection and maintenance (I/M) program that ensures vehicle emission control systems are well maintained can complement other emission reduction strategies. This paper presents the initial findings of extensive data collected on vehicle characteristics and emissions for two-wheeler vehicles operating in Delhi in a series of I/M camps conducted by the Society of Indian Automobile Manufacturers and various partners in late 1999. The analysis shows idle HC and CO emissions [measured in terms of parts per million (ppm) and volume % (vol %), respectively] in a slow declining trend with subsequent model years, reflecting tighter emission standards and more advanced emission technologies. The I/M benefits--3 vol % and 39% reduction in idle and mass CO, respectively; 40 vol % and 22% reduction in idle and mass HC, respectively; and a 10-20% increase in fuel efficiency--were higher than those reported in the literature. Although these benefits are substantial, any implementation strategy needs to consider cost-effectiveness. In the present study, only 10% of vehicles--contributing 22% of the total vehicle emissions--failed the idle CO standard. Fleet emissions data variability necessitates a large sample size to develop a baseline for the vehicle fleet, but a smaller, scientifically designed sample and better data collection quality could periodically track the benefits at future camps.     

The Effectiveness and Cost of Retrofit For Reducing Automobile Emissions

EPA has recently evaluated several automobile retrofit devices that are potentially applicable to pre-1975 vehicles. The results of this evaluation are described and used to estimate the effectiveness and cost of retrofit for reducing total automobile emissions in the period 1975-1985. It is estimated that retrofit combined with inspection/maintenance can potentially achieve reductions in automobile emissions of 33% to 60% in 1975, depending on pollutant, and 10% to 20% in 1985. The estimated present value discounted to 1972 of the average cost per retrofit vehicle is $30 to $152 over the period 1975-1985 depending on the retrofit system used. The corresponding annualized cost is $6 to $28 per vehicle.     

Review of light-duty diesel and heavy-duty diesel gasoline inspection programs

Emissions from diesel vehicles and gas-powered heavy-duty vehicles are becoming a new focus of many inspection and maintenance (I/M) programs. Diesel particulate matter (PM) is increasingly becoming more recognized as an important health concern, while at the same time, the public awareness of diesel PM emissions because of their visibility have combined to increase the focus on diesel emissions in the United States. This has resulted in an increased interest by some states in including heavy-duty vehicle testing in their I/M program. This paper provides an overview of existing I/M programs focused on testing light-duty diesel vehicles, heavy-duty diesel vehicles, and heavy-duty gasoline vehicles (HDGVs). Information on 39 I/M programs in 27 different states in the United States plus 9 international inspection programs is included. Information on the status of diesel emissions technology and current test procedures is also presented. The goal is to provide useful information for air quality managers as they work to decide whether such I/M programs would be worth pursuing in their respective areas and in evaluating the emissions measurement technology to be used in the program. Testing of HDGVs is generally limited to idle testing, because dynamometer testing of these vehicles is not practical, and most were not certified on a chassis basis. Testing of diesel vehicles has mostly been limited to SAE J1667 "snap-idle" opacity testing. Cost-effective technology for measuring diesel emissions currently does not exist, and, therefore, opacity-type measurements, although not effective at reducing the pollutants of most significant health concern, will continue to be used.     

Inspection and Maintenance for Reducing Automobile Emissions

EPA has recently evaluated several inspection and maintenance approaches for in-use vehicles that are potentially applicable to pre-1975 automobiles. The results of this evaluation are described and used to estimate the effecliveness and cost of inspection/maintenance for reducing total automobile emissions through 1985. It is estimated that inspection/maintenance programs for pre-1975 automobiles may be capable of achieving eight and ten percent reductions in total automobile emissions of HC and CO respectively until 1980 and two to three percent reductions in 1985. The need for inspection of automobiles of model year 1975 and later, and the potential applicability of present short-duration inspection procedures to these vehicles, are also discussed.     

Review of Light-Duty Diesel and Heavy-Duty Diesel Gasoline Inspection Programs

Abstract

Emissions from diesel vehicles and gas-powered heavyduty vehicles are becoming a new focus of many inspection and maintenance (I/M) programs. Diesel particulate matter (PM) is increasingly becoming more recognized as an important health concern, while at the same time, the public awareness of diesel PM emissions because of their visibility have combined to increase the focus on diesel emissions in the United States. This has resulted in an increased interest by some states in including heavy-duty vehicle testing in their I/M program.

This paper provides an overview of existing I/M programs focused on testing light-duty diesel vehicles, heavyduty diesel vehicles, and heavy-duty gasoline vehicles (HDGVs). Information on 39 I/M programs in 27 different states in the United States plus 9 international inspection programs is included. Information on the status of diesel emissions technology and current test procedures is also presented. The goal is to provide useful information for air quality managers as they work to decide whether such I/M programs would be worth pursuing in their respective areas and in evaluating the emissions measurement technology to be used in the program. Testing of HDGVs is generally limited to idle testing, because dynamometer testing of these vehicles is not practical, and most were not certified on a chassis basis.

Testing of diesel vehicles has mostly been limited to SAE J1667 “snap-idle” opacity testing. Cost-effective technology for measuring diesel emissions currently does not exist, and, therefore, opacity-type measurements, although not effective at reducing the pollutants of most significant health concern, will continue to be used.     

Deriving fuel-based emission factor thresholds to interpret heavy-duty vehicle roadside plume measurements

Remote sensing devices have been used for decades to measure gaseous emissions from individual vehicles at the roadside. Systems have also been developed that entrain diluted exhaust and can also measure particulate matter (PM) emissions. In 2015, the California Air Resources Board (CARB) reported that 8% of in-field diesel particulate filters (DPF) on heavy-duty (HD) vehicles were malfunctioning and emitted about 70% of total diesel PM emissions from the DPF-equipped fleet. A new high-emitter problem in the heavy-duty vehicle fleet had emerged. Roadside exhaust plume measurements reflect a snapshot of real-world operation, typically lasting several seconds. In order to relate roadside plume measurements to laboratory emission tests, we analyzed carbon dioxide (CO₂), oxides of nitrogen (NO_X), and PM emissions collected from four HD vehicles during several driving cycles on a chassis dynamometer. We examined the fuel-based emission factors corresponding to possible exceedances of emission standards as a function of vehicle power. Our analysis suggests that a typical HD vehicle will exceed the model year (MY) 2010 emission standards (of 0.2 g NO_X/bhp-hr and 0.01 g PM/bhp-hr) by three times when fuel-based emission factors are 9.3 g NO_X/kg fuel and 0.11 g PM/kg using the roadside plume measurement approach. Reported limits correspond to 99% confidence levels, which were calculated using the detection uncertainty of emissions analyzers, accuracy of vehicle power calculations, and actual emissions variability of fixed operational parameters. The PM threshold was determined for acceleration events between 0.47 and 1.4 mph/sec only, and the NO_X threshold was derived from measurements where after-treatment temperature was above 200°C. Anticipating a growing interest in real-world driving emissions, widespread implementation of roadside exhaust plume measurements as a compliment to in-use vehicle programs may benefit from expanding this analysis to a larger sample of in-use HD vehicles.

Implications: Regulatory agencies, civil society, and the public at large have a growing interest in vehicle emission compliance in the real world. Leveraging roadside plume measurements to identify vehicles with malfunctioning emission control systems is emerging as a viable new and useful method to assess in-use performance. This work proposes fuel-based emission factor thresholds for PM and NOx that signify exceedances of emission standards on a work-specific basis by analyzing real-time emissions in the laboratory. These thresholds could be used to prescreen vehicles before roadside enforcement inspection or other inquiry, enhance and further develop emission inventories, and potentially develop new requirements for heavy-duty inspection and maintenance (I/M) programs, including but not limited to identifying vehicles for further testing.     

Real-world vehicle emissions: a summary of the tenth coordinating research council on-road vehicle emissions workshop

The Coordinating Research Council (CRC) held its tenth workshop in March 2000, focusing on results from the most recent real-world vehicle emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles, new methods for measuring mobile source emissions, improvements in vehicle emission control systems (ECSs), and evaluation of motor vehicle inspection/maintenance (I/M) programs, as well as topics for future research.     

New Jersey Repair Project: Tune-Up at Idle

Idle hydrocarbon and carbon monoxide measurements have been made on over 2500 cars at a New Jersey Inspection Station. These studies have shown that the idle test can be integrated into the present periodic motor vehicle inspection system with a minimum cost, testing time, and ease of operation.

Instrumentation at a low cost has recently become available, test procedures have been developed and potential emission reductions have been demonstrated for idle testing. High emissions indicate a car malfunction and the need for a tune-up. Effective low cost tune-ups can be made with exhaust instrumentation and garage training.

In the New Jersey REPAIR Project, preliminary idle cut-off levels were selected at 6% carbon monoxide and 1000 ppm hydrocarbon for pre-68 cars, 4% and 500 ppm for 1968–69 cars, and 3% and 300 ppm for later years. Volunteered vehicles which exceeded these levels were further tested at the New Jersey laboratory. Federal hot cycles, ACID mass cycles, Key Mode, and Idle tests were conducted before and after maintenance.

At idle, uncontrolled pre-1968 vehicles had an average reduction from 8.2 to 3.3% carbon monoxide and 2153 to 459 ppm hydrocarbons as hexane. Average mass reductions from the ACID-cycle were 45 g/mi CO and 6.3 g/mi hydrocarbons. Carbon monoxide idle reductions obtained for emission controlled 1968, 1969, and 1970 cars were about equal to those obtained for the pre-emission controlled vehicles, but hydrocarbon reductions were lower. Reductions obtained in federal hot cycles were from 4.1 to 2.1% CO and 1418 to 580 ppm hydrocarbons for pre-1968 cars, and 2.6 to 0.7% and 502 to 308 ppm for 1968–1969 cars.

Idle adjustments lower emissions in the idle, deceleration, and cruise modes up to 30 mph, thus urban driving areas should show the greatest reduction. Total motor vehicle emission reduction in New Jersey would be about 920,000 ton/yr of CO and 101,000 ton/yr of hydrocarbon; a 20 and 32% reduction.     

enforcement of diesel smoke emissions for the state of new jersey

This paper reports on the research program undertaken by the State of New Jersey to determine those tests and instruments which can be used by authorized state agencies for the enforcement of diesel smoke emissions. The state agencies under consideration for the enforcement of diesel smoke emissions are the following: (1) The Division of Motor Vehicles, in its system of state owned inspection stations, will be able to inspect all diesel-powered trucks, and tractors which are registered in New Jersey. (2) The Public Utilities Commission will be able to inspect at their home garages all buses registered in the State. (3) The New Jersey State Police will be able to inspect diesel-powered vehicles on the road. It was decided that the maximum inspection time for each vehicle was not to exceed one minute. On the basis of the one minute per vehicle requirement, eight different tests were evaluated to determine which ones correlated well with normal vehicle operation. These tests included acceleration of a fixed external inertia, free acceleration of only the moving parts of the engine, three ramp tests, a test in which a heavy vehicle was towed, and a driving test in which the vehicle being tested was actually accelerated. The results of tests demonstrated that the modified free acceleration method correlates reasonably well with a loaded steady state cycle, distinguishes the high emitters and is simple to perform. Consequently, the free acceleration test method is recommended for use in inspection stations and on the road. Finally, nearly two hundred vehicles have been tested by this procedure to determine present and potential levels of diesel smoke emissions. Another phase of the program consisted of the determination of smoke measuring techniques and instrumentation. The use and design of smokemeters were extensively investigated, as well as the use of the visual and photographic techniques. Of the various smokemeters tested for this application, several measured smoke satisfactorily in the laboratory, but none were found adequate for field use; they either lacked portability or were unstable due to the deposition of soot on the optics. At the time of writing, specifications for the necessary smokemeter have been drafted and published for bid to interested manufacturers.     

The effect of reformulated gasoline on ambient carbon monoxide concentrations in southeastern Wisconsin

Reformulated gasoline (RFG) contains oxygen additives such as methyl tertiary butyl ether or ethanol. The additives enable vehicles to burn fuel with a higher air/fuel ratio, thereby lowering the emission of carbon monoxide (CO) and volatile organic compounds (VOCs). Because VOCs react with sunlight to form ozone (O3), the Clean Air Act requires severe O3 nonattainment areas such as southeastern Wisconsin to use RFG. On July 17, 2001, the U.S. Environmental Protection Agency (EPA) granted Milwaukee, WI, and Chicago, IL, a waiver from the VOC reduction requirement of Phase II RFG. The VOC reduction requirement was lowered from 27.4% of the 1990 baseline fuel to 25.4%. The assumption was that ethanol-blended RFG would lower summertime CO concentrations sufficiently to offset the increased VOC emissions. The waiver is estimated to increase VOC emissions by approximately 0.8%, or 0.4 t of VOC on a hot summer weekday. This study evaluates whether RFG has been effective in lowering southeastern Wisconsin ambient CO concentrations. Three years of ambient CO data before RFG was introduced were compared with the first three years of ambient CO data after RFG was introduced. This paper also evaluates how the meteorology, vehicle inspection/maintenance program, vehicle miles traveled, and stationary source emissions influence CO concentrations. The winter decrease in ambient CO concentrations was found to be statistically significant, while the summer data showed no statistically significant change, indicating that RFG is most effective lowering ambient CO concentrations in cold weather.     

Real-World Vehicle Emissions: A Summary of the Tenth Coordinating Research Council On-Road Vehicle Emissions Workshop

ABSTRACT

The Coordinating Research Council (CRC) held its tenth workshop in March 2000, focusing on results from the most recent real-world vehicle emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles, new methods for measuring mobile source emissions, improvements in vehicle emission control systems (ECSs), and evaluation of motor vehicle inspection/maintenance (I/M) programs, as well as topics for future research.     

机动车尾气VOCs排放特征及减排措施研究

分析了机动车尾气挥发性有机物(VOCs)的排放特征,发现尾气VOCs排放具有明显的日变化和季节变化特征。不同区域不同车型机动车尾气VOCs成分谱略有差异,轻型汽油车尾气VOCs中芳香烃和烷烃含量较高,柴油车烷烃含量较高。尾气排放受机动车保有量、行驶里程、维护保养水平、行驶速度和燃油标准、排放标准等因素影响。从优先控制汽油车、加快机动车更新、采取本地化减排措施、加强多元管理措施、提高科研水平等方面提出了针对性的减排措施。     

Investigating the real-world emission characteristics of light-duty gasoline vehicles and their relationship to local socioeconomic conditions in three communities in Los Angeles,California

This paper discusses results from a vehicular emissions research study of over 350 vehicles conducted in three communities in Los Angeles, CA, in 2010 using vehicle chase measurements. The study explores the real-world emission behavior of light-duty gasoline vehicles, characterizes real-world super-emitters in the different regions, and investigates the relationship of on-road vehicle emissions with the socioeconomic status (SES) of the region. The study found that in comparison to a 2007 earlier study in a neighboring community, vehicle emissions for all measured pollutants had experienced a significant reduction over the years, with oxides of nitrogen (NO_X) and black carbon (BC) emissions showing the largest reductions. Mean emission factors of the sampled vehicles in low-SES communities were roughly 2–3 times higher for NO_X, BC, carbon monoxide, and ultrafine particles, and 4–11 times greater for fine particulate matter (PM_2.5) than for vehicles in the high-SES neighborhood. Further analysis indicated that the emission factors of vehicles within a technology group were also higher in low-SES communities compared to similar vehicles in the high-SES community, suggesting that vehicle age alone did not explain the higher vehicular emission in low-SES communities.

Evaluation of the emission factor distribution found that emissions from 12% of the sampled vehicles were greater than five times the mean from all of the sampled fleet, and these vehicles were consequently categorized as “real-world super-emitters.” Low-SES communities had approximately twice as many super-emitters for most of the pollutants as compared to the high-SES community. Vehicle emissions calculated using model-year-specific average fuel consumption assumptions suggested that approximately 5% of the sampled vehicles accounted for nearly half of the total CO, PM_2.5, and UFP emissions, and 15% of the vehicles were responsible for more than half of the total NO_X and BC emissions from the vehicles sampled during the study.

Implications: This study evaluated the real-world emission behavior and super-emitter distribution of light-duty gasoline vehicles in California, and investigated the relationship of on-road vehicle emissions with local socioeconomic conditions. The study observed a significant reduction in vehicle emissions for all measured pollutants when compared to an earlier study in Wilmington, CA, and found a higher prevalence of high-emitting vehicles in low-socioeconomic-status communities. As overall fleet emissions decrease from stringent vehicle emission regulations, a small fraction of the fleet may contribute to a disproportionate share of the overall on-road vehicle emissions. Therefore, this work will have important implications for improving air quality and public health, especially in low-SES communities.     

Real-world vehicle emissions: a summary of the Ninth Coordinating Research Council On-Road Vehicle Emissions Workshop

In April 1999, the Coordinating Research Council sponsored a workshop focusing on our understanding of real-world emissions from motor vehicles. This summary presents the latest information on in-use light- and heavy-duty vehicle tailpipe and evaporative emissions, the effects of fuels on emissions, field programs designed to understand the contribution of mobile sources to emission inventories, efforts to evaluate and improve mobile source emission models, progress of vehicle inspection/maintenance programs, and topics for future research. While significant progress has been made in understanding in-use vehicle emissions, further improvements are necessary. Moreover, the impact of current and future changes in emission control technologies and control programs will have to be monitored for effectiveness and incorporated into the emission factor models.     

Real-world vehicle emissions: a summary of the Eleventh Coordinating Research Council On-Road Vehicle Emissions Workshop

The Coordinating Research Council (CRC) held its eleventh workshop in March 2001, focusing on results from the most recent real-world vehicle emissions research. We summarize the presentations from researchers engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models and emission inventories, the role of on-board diagnostic (OBD) systems in inspection and maintenance (I/M) programs, particulate matter (PM) emissions, contributions of diesel vehicles to the emission inventory, on-road emissions measurements, fuel effects, unregulated emissions, and microscale and modal emission models, as well as topics for future research.     

An Analysis of Michigan and California CO Remote Sensing Measurements

Abstract

Remote sensing measurements of CO emissions from on-road vehicles were made in California in 1991 and in Michigan in 1992. It was determined that both fleets had a small linear increase in the high emitter frequency (vehicles emitting more than 4% CO) as a function of vehicle age for 1986 and newer model vehicles. Although high emitting vehicles were only a small minority of the fleet, they had a dominant impact on the mean CO and total CO emitted by the fleet. In Michigan, the highest emitting 5% of passenger cars generated 45% of the CO from cars. In California, the highest emitting 5% of passenger cars generated 38% of the CO from cars. There was a high correlation between the mean CO emitted by each model year of vehicle and the frequency of high emitting vehicles within the model year for both the Michigan and California fleets. The frequency of high emitters within any model year had no obvious relation to that model year’s certification standards. The high emitter frequencies for vehicles less than nine years old were very similar for the California and Michigan fleets. An increase in the high emitter frequency in the ten-year-old and older Michigan passenger car fleet (relative to the California passenger car fleet), suggests, but does not conclusively demonstrate, that the rate of high emitters in Michigan and California is reduced by the inspection and maintenance (I/M) programs.     

The Effect of Reformulated Gasoline on Ambient Carbon Monoxide Concentrations in Southeastern Wisconsin

Abstract

Reformulated gasoline (RFG) contains oxygen additives such as methyl tertiary butyl ether or ethanol. The additives enable vehicles to burn fuel with a higher air/fuel ratio, thereby lowering the emission of carbon monoxide (CO) and volatile organic compounds (VOCs). Because VOCs react with sunlight to form ozone (O₃), the Clean Air Act requires severe O₃ nonattainment areas such as southeastern Wisconsin to use RFG. On July 17, 2001, the U.S. Environmental Protection Agency (EPA) granted Milwaukee, WI, and Chicago, IL, a waiver from the VOC reduction requirement of Phase II RFG. The VOC reduction requirement was lowered from 27.4% of the 1990 baseline fuel to 25.4%. The assumption was that ethanol-blended RFG would lower summertime CO concentrations sufficiently to offset the increased VOC emissions. The waiver is estimated to increase VOC emissions by ～0.8%, or 0.4 t of VOC on a hot summer weekday. This study evaluates whether RFG has been effective in lowering southeastern Wisconsin ambient CO concentrations. Three years of ambient CO data before RFG was introduced were compared with the first three years of ambient CO data after RFG was introduced. This paper also evaluates how the meteorology, vehicle inspection/maintenance program, vehicle miles traveled, and stationary source emissions influence CO concentrations. The winter decrease in ambient CO concentrations was found to be statistically significant, while the summer data showed no statistically significant change, indicating that RFG is most effective lowering ambient CO concentrations in cold weather.     

Real-World Vehicle Emissions: A Summary of the Ninth Coordinating Research Council On-Road Vehicle Emissions Workshop

ABSTRACT

In April 1999, the Coordinating Research Council sponsored a workshop focusing on our understanding of real-world emissions from motor vehicles. This summary presents the latest information on in-use light- and heavy-duty vehicle tailpipe and evaporative emissions, the effects of fuels on emissions, field programs designed to understand the contribution of mobile sources to emission inventories, efforts to evaluate and improve mobile source emission models, progress of vehicle inspection/ maintenance programs, and topics for future research. While significant progress has been made in understanding in-use vehicle emissions, further improvements are necessary. Moreover, the impact of current and future changes in emission control technologies and control programs will have to be monitored for effectiveness and incorporated into the emission factor models.