On-Road Vehicle Emissions: Regulations, Costs, and Benefits

Abstract

e d m a n * Smog c h e c k data o n 307 of these vehicles.Of these, 126 (41%) showed deliberate tampering, and another 77 (25%) had defective or ~nissi~lg equiptnent that tnay not have been the result of tampering (for ex-I n response to continuing pollution prob-lected 91,679 records with valid H C and ample, missing air pump belts). Overall, 282 lems, in 1990 Congress passed the Clean CO tneasurements (8). T h e etnission distri-(92%) failed the inspection even though all Air A c t Amendments, many parts of which bution is highly skewed; the half of the fleet had valid registrations. Thus, less than 8% deal with motor vehicles. Motor vehicles are with the lowest emissio~ls contributed less of the vehicles identified as gross polluters the ~r i m a r v source of urban carbon tnonox-than 10% of the C O and HC. while a few bv remote sensine nassed a n immediate " L ide (CO) and are an important source of the high-emission vehicles dominated the rdadside test. W h e n r a~l d o~n pullover studhvdrocarbons I H C ) and oxides of nitrogen mean values. I n this instance. 7% of the ies were carried out bv the California BLI--(NO,) that are responsible for the fortnation of photochemical stnog and ground-level ozone (1). Cost estimates for itnplenlenting the act's mobile source provisions range up to $1 2 billion annuallv 12). Thus it is im-,~, portant to analyze the scientific basis for these legislative programs (1 ).For any region violating air quality standards, a State Itnolenle~ltation Plan (SIP) , , must be submitted to and approved by the U.S. Environmental Protection Agency (EPA). In approving the SIP, EPA grants credit for each portion of the plan, including new vehicle emission standards, new fuels, vehicle scrappage, and inspection and maintenance (IM) programs, o n the basis of predictions from a spreadsheet computer tnodel 13). This EPA model treats all cars of ~, a given tnodel year as having the same odometer reading, the same annual mileage accutnulation, and an equal likelihood of emission control systetn probletns. T h e model has had little success in predicting urban on-road vehicle etnissions (4), and the use of unverified computer models as the sole guide for public policy decisions is controversial (5). Calvert et al. (6) criticized the tnodel and recommended in-use vehicles accounted for 50% of'the on-road C O emissions, and 10% of the vehicles accou~lted for 50% of the on-road HC etnissions. These vehicles we call gross polluters. About 5% of the vehicles were gross polluters for both HC and CO (9).It is often assumed that gross poll~tters are sitnply old vehicles. In fact, all model vears of vehicles we have measured o n the road include some proportion of gross polluters, as shown in Fig. l. W e found that the highest emitting 20% of the newest cars were worse polluters than the lowest emitting 40% of vehicles from any tnodel year, even those from model years before the advent of catalytic converters (1970 and earlier). These data are typical of CO and H C results across the United States an...

Characterizing the effects of driver variability on real-world vehicle emissions

“…hard accelerations, heavy loads on steep hills) for well-tuned vehicles, but may occur transiently for malfunctioning vehicles (Black, 1991;Ross, 1994;Ross et al, 1995). A malfunction of either a feedback component or the catalyst causes extremely high emissions that are driver-independent and beyond the scope of this study, but malfunctions have been shown to be an important component in realworld vehicles (Lawson et al, 1990;Bishop et al, 1993;Calvert et al, 1993;Hickman, 1994;Stephens, 1994;Beaton et al, 1995;Bishop et al, 1996;McLaren et al, 1996;Stedman, 1996;Zhang et al, 1996).…”

Assessment of vehicle emissions projections in Madrid (Spain) from 2004 to 2012 considering several control strategies

“…One of the most efficient measures for reducing air pollution is linked to the overhaul of the fleet through scrappage plans (Dill, 2004;Van Wee et al, 2000;Alberini et al, 1996;Beaton et al, 1995). It allows a vehicle fleet with modern technologies that have better efficiency and lower emissions.…”

Real-World Emissions from Conventional Passenger Cars

“…7,[25][26][27] Two important examples of malfunctioning emissions controls are improper fuel metering and failure of the oxygen sensor, which provides feedback for control of the fuel-air ratio. 28 There appear to be at least five possible causes of failure of such components: (1) extensive high power driving of a vehicle; (2) outright tampering of the ECS (by owner or mechanic); (3) inadequate maintenance (by owner); (4) improper repairs (by owner or mechanic); and (5) poor initial ECS design or manufacture.…”