Question of the Day Q. What is the National Center for Vehicle Emissions Control and Safety?

A. The National Center for Vehicle Emissions Control and Safety (NCVECS) at Colorado State University in Fort Collins, Colorado is the only national university based center dedicated to research and training related to the control and testing of motor vehicle emissions. Research data and training curriculum are developed directly from the testing and repair research projects performed in our high altitude Federal Test Procedure laboratory. Many of these projects include the use of Federal Test Procedure (FTP) protocols, I/M 240 and RG 240 testing, and 4 gas/5 gas in-flight emissions analysis. Training activities encompass Inspection/Maintenance (I/M) programs, Quality Assurance (QA) and Quality Control (QC) programs, alternative fuels, and international efforts. NCVECS training is directed toward state I/M personnel, as well as secondary and post secondary automotive instructors. NCVECS training is presented in an unbiased manner and provides the student with research data and procedures that assist the student in making informed decisions regarding air pollution control strategies.

Q. What About the Perception that the I/M 240 Test is Inaccurate?

A. The largest variable in the I/M 240 test is not the equipment or procedure, but rather, the vehicle itself. Some vehicles can change dramatically from test to test. This is often due to the deterioration of emissions control equipment over time or from poor maintenance. If the I/M 240 has an Achilles tendon, it is the lack of vehicle preconditioning before the test is run.

Q. Why Do Some Inspectors Miss or Not Identify Proper Emission Control Equipment?

A. The perception is that the underhood equipment inspection can be performed by virtually anyone. But our training has shown that underhood inspectors need to have a strong automotive background and extensive training on these systems to identify missing or disconnected equipment. Emission control equipment varies in appearance and location from manufacturer to manufacturer, and often model to model. This, however, is an I/M issue that can be fixed.

Q. Does Centralized I/M 240 Testing Really Offer More Benefits Than Decentralized Idle Testing?

A. It is important to realize that idle testing was designed around non-computerized, carbureted vehicles and did a fairly good job of identifying dirty cars with that technology. The use of idle testing on today's high-tech vehicles creates too many false failures, as well as an extremely high number of false passes, or cars that really are dirty but test clean. Research supports that the I/M 240 offers a means to virtually eliminate errors in vehicle test. It allows I/M programs to gain veritable clean air benefits from groups of cars that would be missed by traditional idle testing, assuming these dirty cars get diagnosed and repaired correctly.

Q. Why the Loose Cutpoints During Program Start-up?

A. The emission standards used in the I/M240 test are expressed in terms of grams per mile rather than as a percentage or in parts per million, as in the case with steady-state tests. Different standards are set for each model year and reflect the technology that was in effect at the time of manufacture. The standards are typically two to three times higher than new vehicle certification standards for the model year. EPA recommends that standards be phased-in over two test cycles. The standards in the first cycle, referred to as phase-in standards, are set much looser than the new vehicle standards. The purpose of setting the standards loosely at first are many-fold:

About 40-45% of vehicles currently operating need emission-related repairs. Failing all of these vehicles in the first cycle would overwhelm the repair industry and make the program much more expensive, since more testing capacity would be needed to conduct retests.

The phase-in standards will fail only the dirtiest vehicles in the first cycle-the vehicles that will yield the largest emission reduction. About 20-30% of the vehicles will fail the phase-in standards. This means the program will quickly see significant reductions even though looser standards are in place.

By failing only the dirtiest vehicles at first, the repair industry will have plenty of time to develop the skills, acquire the training, and purchase the equipment needed to diagnose and repair the less dirty but harder to fix vehicles in the second and subsequent cycles.

The phase-in period also provides an opportunity to fine tune the I/M240 system to ensure that only vehicles that need repairs will fail the test in the second cycle when tighter standars apply. (Courtesy of the USEPA)

Q. What is Ozone?

A. Ozone is a form of molecular oxygen that consists of three oxygen atoms linked together. Ozone in the upper atmosphere (the "ozone layer") occurs naturally and protects life on earth by filtering out ultraviolet radiation from the sun. Ozone at ground level, however, is highly corrosive, damaging plant, animal, and human tissue, and other materials such as metals and masonry. It is the major component of urban smog. (Courtesy of the USEPA)

Q. Why is Ozone a Public Health Problem?

A. Ozone is a severe irritant. It is responsible for the choking, coughing, and stinging eyes associated with smog. Ozone damages lung tissue, aggravates respiratory disease, and makes people more susceptible to respiratory infections. Children are especially vulnerable to ozone's harmful effects, as are adults with existing disease. But even otherwise healthy individuals may experience impaired health from breathing ozone-polluted air. Elevated ozone levels also inhibit plant growth and can cause widespread damage to crops and forests.

Unhealthy ozone levels are a problem across the United States, with about 90 cities exceeding the National Ambient Air Quality Standard (NAAQS). The standard is based on the highest ozone exposure sensitive persons can tolerate. Nine cities, home to 57 million people, are considered "severely" polluted and experience peak ozone levels that exceed the standard by 50% or more. (Courtesy of the USEPA)

Q. How is Ozone Formed?

A. Ozone is not emitted directly but is formed in the atmosphere through a complex set of chemical reactions involving hydrocarbons (HC) and oxides of nitogen (NOx) catalyzed by sunlight. The rate at which these reactions occur is affected by both temperature and intesity of the sunlight. For this reason, high ozone levels occur most often on hot summer afternoons.

Hydrocarbons and nitrogen oxides come from a variety of industrial combustion processes. In typical urban areas, one-third to one-half or more of those pollutants come from cars, trucks, and buses. (Courtesy of the USEPA)

Q. How is Ozone Monitored?

A. Pollutant concentrations are continually monitored by networks of national, state, and local monitoring stations. Most monitoring stations are situated in urbanized areas to measure ozone concentrations to which the population is exposed but some are located in down-wind areas as well. Ozone measurements are averaged over a one hour period and compared to the standard 0.12 parts per million (ppm). Violations of the ozone standard are determined by looking at the second highest daily readings obtained from the monitoring sites in an urbanized area in a year. Hence, more than one day of high ozone readings is needed in order for an area to be in violation of the ambient ozone standard. An area meets the ozone standard if, on average, not more than one annual exceedance is recorded over a three year period. As required by the Clean Air Act, EPA designated 98 areas as ozone nonattainment areas in 1991. Since then, seven areas have been redesignated to attainment based upon a lack of violations over a three year period and a demonstration that the air quality improvements can be maintained over time. Redesignations are pending in several other areas as well. (Courtesy of the USEPA)

Q. How is Ozone Transported?

A. Ozone is usually not formed at the point where the precursors, hydrocarbons and oxides of nitrogen, are emitted. Rather, these chemicals are typically carried some distance on the wind before the right mix and conditions for ozone formation are achieved. Pollutants in one area can contribute to ozone problems in other areas. In regions of the country where several urbanized areas are located close to each other, such as the northeast coastal region, ozone in one part of the area may be caused by a combination of ozone precursors emitted locally and those emitted in other, upwind areas. For example, NOx from an upwind source may combine with locally generated HC to form ozone in a particular area. This means that ozone precursors and ozone itself can move over large areas causing problems wherever the winds take them. Thus, ozone is a regional problem rather than a local problem. (Courtesy of the USEPA)

Q. Why was the Ozone Transport Region Created?

A. Given that ozone is a regional problem, it requires a regional solution. Traditional ozone control stategies, where the ozone problem in a given area is addressed by focusing only on ozone precursors generated in that area, have failed to bring the ozone problem under control in many parts of the country. The Act provided for the establishment of Ozone Transport Regions and directed that an Ozone Transport Region be established in the northeast, comprising the states of Maine, New Hampshire, Vermont, Massachussets, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, and the Washington, D.C. Metropolitan Statistical Area, including the northern Virginia suburbs. The creation of an Ozone Transport Region enables measures which address ozone nonattainment as a regional problem, rather than addressing ozone nonattainment in each urbanized area individually. (Courtesy of the USEPA)

Q. How Does the Establishment of an Ozone Transport Region Affect I/M?

A. Emissions from cars and trucks are a major contributor to ozone nonattainment problems in our cities. For that reason, additional measures are taken in an Ozone Transport Region to bring these emissions under control. In an Ozone Transport Region, the Clean Air Act requires that enhanced I/M be implemented in all Metropolitan Statistical Areas with a population of 100,000 or more regardless of attainment status. This is because hydrocarbons and oxides of nitrogen emitted by vehicles in areas where ozone pollution is not a problem can be transported on the wind to nearby urbanized areas and contribute to ozone nonattainment there. (Courtesy of the USEPA)

Q. What is Carbon Monoxide?

A. Carbon monoxide (CO) is a colorless, odorless, poisonous gas. A product of incomplete burning of hydrocarbon-based fuels, carbon monoxide consists of a carbon atom and an oxygen atom linked together. (Courtesy of the USEPA)

Q. Why is Carbon Monoxide a Public Health Problem?

A. Carbon monoxide enters the bloodstream through the lungs and forms carboxyhemoglobin, a compound that inhibits the bloods capacity to carry oxygen to organs and tissues. Persons with heart disease are especially sensitive to carbon monoxide poisoning and may experience chest pain if they breathe the gas while exercising. Infants, elderly persons, and individuals with respiratory diseases are also particularly sensitive. Carbon monoxide can affect healthy individuals, impairing exercise capacity, visual perception, manual dexterity, learning functions, and ability to perform complex tasks.

In 1992 carbon monoxide levels exceeded the Federal air quality standard in 20 U.S. cities, home to more than 14 million people. (Courtesy of the USEPA)


Rev. March 16, 1999

Copyright © 1999 Colorado State University