Transportation and Air Quality
Office of Transportation and Air Quality Frequent Questions
- How much air pollution does a car produce when it’s moving and when it’s idling?
- What can I do about a car, heavy-duty truck, or train idling near my house?
- Why doesn’t my car get the same gas mileage that is listed on the Fuel Economy Label?
- I purchased an ATV in 2012. How will EPA’s 2013 action affect me?
- How will the proposed Tier 3 vehicle and fuel standards create health benefits for Americans?
- Over the past several years, what have been the technological and environmental trends in automotive fuel economy?
- How will the proposed voluntary Quality Assurance Program verifying Renewable Identification Numbers be effective in assuring validity?
- Why did EPA determine that a request to waive the renewable fuel standard should be denied?
- What were the recent fuel waivers EPA granted, where do they apply, and how do they help alleviate disruptions in the fuel supply?
- Do those products that claim to improve fuel economy or lower emissions really work?
- How can I get a copy of the Certificate of Conformity for my car?
- How can I get a copy of the Certificate of Conformity for a nonroad or heavy-duty highway engine?
- I just bought a used car and discovered the catalytic converter is missing. Is that legal?
1. How much air pollution does a car produce when it’s moving and when it’s idling?
The amount of pollution that a vehicle emits depends on many factors, such as the vehicle’s age and accumulated mileage, the type of fuel used, and the weather conditions. EPA has developed computer models that estimate the average emissions for different types of highway vehicles. In order to give a general estimate, we have a fact sheet that gives the average annual emissions and fuel consumption for passenger cars and light trucks. It is available on our website at: www.epa.gov/otaq/consumer/420f08024.pdf.
We have another fact sheet that explains the amount of pollution that is created when vehicles idle that is available on our site at: www.epa.gov/otaq/consumer/420f08025.pdf.
When a car idles for more than 30 seconds, it has several negative effects, such as increasing air pollution unnecessarily, wasting fuel and money, and causing excessive wear or even damaging a car’s engine components, including cylinders, spark plugs, and the exhaust system. Contrary to popular belief, idling isn't an effective way to warm up most car engines. Today's automobile manufacturers recommend driving off right away and urge that drivers wait no more than 30 seconds to begin driving, even on the coldest days. Some people worry that restarting the engine might harm the car, but frequent restarting does little damage. Modern engines require much less fuel at startup than most people think. Idling for only 30 seconds uses up more fuel than restarting the engine.
2. What can I do about a car, heavy-duty truck, or train idling near my house?
EPA does not regulate idling for passenger cars, pick-up trucks, and heavy-duty trucks, but over two dozen states and many cities and local counties have laws that limit the amount of time that a vehicle can idle. For a list of State and local anti-idling laws, please visit the American Transportation Research Institute's (ATRI's) website at: http://atri-online.org/2013/02/20/idling-regulations-compendium/. (Please note that we are providing these links for your reference only. In doing so, EPA does not endorse any non-government websites (or the information they contain), companies, or applications. In addition, EPA cannot attest to the accuracy of non-EPA information provided on these third-party websites.) If there is a law for the area you live in, you could follow up with the proper authorities.
It is common for truck drivers to run their engines to stay warm or cool in their trucks while resting after long hauls. But long-duration idling is costly—to the driver, the fleet owner, and the environment. Some surveys say that trucks idle anywhere from 6-8 hours a day for as many as 250 to 300 days each year. And at current fuel prices, this can cost $6000 or more per year in fuel costs per truck. Each year, long-duration idling of truck engines consume over 500 million gallons of diesel fuel and emits 5.5 million tons of carbon dioxide,100,000 tons of oxides of nitrogen, and 2500 tons of particulate matter into the air. Also, idling can increase engine maintenance costs, shorten engine life, adversely affect driver well-being, and create elevated noise levels. In addition to checking on state or local anti-idling laws, you might also consider contacting the company that owns the vehicle to find out if they have an internal policy against idling.
EPA’s SmartWay Program has researched, developed, and encouraged the use of a wide variety of strategies to reduce long-duration idling. To learn more about that program, please visit the SmartWay website at: www.epa.gov/smartway/technology/idling.htm. Furthermore, our Clean Schoolbus USA program launched its National Idle-Reduction Campaign to eliminate unnecessary public school bus idling. You can learn more about this initiative on our website at: www.epa.gov/cleandiesel/sector-programs/antiidling.htm.
For locomotives however, EPA has regulations that require technology that reduces the amount of time a locomotive spends idling and applying tighter emission standards to new locomotives generally. EPA is requiring that all newly manufactured and nearly all remanufactured locomotives be equipped with idle reduction technology that will automatically shut locomotives down if they are left idling unnecessarily. In addition, rail carriers can join the SmartWay Program and save money, reduce fuel consumption, and get recognition for their social responsibility and leadership. Reducing idling is one way these companies can improve overall efficiency and reduce fuel costs. They can accomplish this through a variety of technologies and strategies, including automatic engine stop-start systems, auxiliary power units or diesel-driven heating systems, electrical shorepower connections, and company idle-shutdown policies.
EPA has a series of fact sheets that estimate the amount of pollution that is created when different vehicles idle that are available on our website at:
-- Passenger cars, light-duty trucks, and heavy-duty trucks: www.epa.gov/otaq/consumer/420f08025.pdf
-- Urban buses and school buses: www.epa.gov/otaq/consumer/420f08026.pdf
-- Locomotives: www.epa.gov/otaq/regs/nonroad/locomotv/420f08014.pdf
3. Why doesn’t my car get the same gas mileage that is listed on the Fuel Economy Label?
The purpose of the fuel economy ratings is to provide consumers with estimates to use in comparing the gas mileage of different vehicles. It is not meant as a guarantee of the gas mileage each driver will achieve. Since no test can simulate all the possible conditions that affect fuel economy, such as climate, driver behavior, road condition, and car care habits, your actual mileage will always vary some from the estimates.
Fuel economy is measured under controlled conditions in a laboratory using a standardized test procedure specified by federal law. The fuel economy tests (which EPA updated in 2006 to more accurately account for actual driving conditions that can lower fuel economy, such as high speed, aggressive driving, use of air conditioning, and cold temperature operation), are based on a detailed driving cycle (each car is driven in exactly the same way, for exactly the same distance, with the same second-by-second vehicle speeds, to the maximum extent possible). The tests also are conducted under controlled conditions, using gasoline or diesel fuel that meet very detailed specifications. The goal of the laboratory testing is to control as many of the factors that affect fuel economy as possible, to the maximum degree that it is feasible to do so. Manufacturers test their own vehicles following EPA's test procedures—usually pre-production prototypes—and report the results to EPA. EPA reviews the results and confirms about 10-15 percent of them through our own tests at the National Vehicle and Fuel Emissions Laboratory (www.epa.gov/nvfel/). Additional information about fuel economy testing is available on the following websites:
It is essential that EPA's fuel economy estimates continue to be derived from controlled, repeatable laboratory tests to enable a standardized or "level playing field," comparison between all vehicle models. Although EPA's fuel economy tests are designed to reflect typical driving conditions and driver behavior, several factors can significantly affect how many miles per gallon (mpg) your car gets: how and where you drive; vehicle condition and maintenance; fuel variations; vehicle variations; and engine break-in (the fuel economy of new cars and trucks improves with mileage up to approximately 20,000 miles; it especially improves in the first 1000-2000 miles). These factors are described in my detail on the following websites: www.fueleconomy.gov/feg/factors.shtml. Because some vehicles are more sensitive to these factors than others, the impact of the changes will vary from vehicle to vehicle. For example, the nature of current hybrid technology -- the addition of a battery as a second source of on-board power, sophisticated control systems, and sometimes a smaller engine -- makes a hybrid's fuel economy more sensitive to certain factors, such as colder weather and air conditioning use.
Although EPA sets emission standards for pollutants that vehicle manufacturers have to meet, we do not set fuel economy standards for the vehicles currently on the market. Therefore, even if a vehicle does not achieve the EPA fuel economy rating, the manufacturers are not required to re-test or change the car for that specific model year. However, if a significant number of specific vehicle complaints are received, EPA has the option of performing confirmatory tests for the vehicle the following model year.
Given the above information, what is the best way to get realistic "city" and "highway" fuel economy numbers for your vehicle? There is no "official" answer to that question, but we can offer you these suggestions.
- Start with a full tank of gas. By "full," we mean filling up using a pump that allows you to lock a lever in place and take your hand off the hose and nozzle. Use the lowest rate of fuel delivery offered (most nozzles have two dispensing rate settings, and some have three). Do not top off -- when the nozzle first shuts off, do not dispense any more fuel.
- Record your odometer mileage (or, if you have a trip odometer, reset it to zero).
- Drive at least half the tank, preferably 3/4 to 7/8 of the tank, before refueling.
- During the time when you are measuring the fuel economy of your vehicle, try to avoid extended idling operation and the use of a remote starter.
- For "city" driving, a minimal amount of freeway/expressway driving can be included; for "highway" driving, measure when you will be taking longer trips that are predominantly freeway, with relatively little stop-and-go and infrequent engine off/engine restarts.
- Refuel at the same station, using the same pump and nozzle if possible. At the least, refill with the same brand and grade of gasoline.
- When refilling, do it as you did in step one -- automatic flow, lowest rate, no top-off.
To calculate the fuel economy in miles per gallon, take the number of miles driven and divide it by the total gallons purchased at refueling. For an even better estimate, take the average of two or three tanks in each case (city, highway). While there are minor variations over time, this allows you to monitor the vehicle's performance. A sudden drop in fuel economy not explained by the reasons noted below tells you that you may need to have maintenance done on your car.
If you are interested in seeing what fuel economy other owners of your vehicle are getting, please visit the following website: www.fueleconomy.gov/mpg/MPG.do?action=browseList.
To find out what you can do to improve the fuel economy of your car, please visit the following website: www.fueleconomy.gov/feg/drive.shtml. Driving efficiently and keeping your car in shape will make a difference.
If your fuel economy is excessively low, your vehicle may need to be serviced or repaired. You may want to contact your dealer and ask them to check your vehicle and to determine that there are no outstanding defect reports or service bulletins which may affect fuel economy. The following are some of the diagnostic checks a mechanic will typically conduct for poor mpg:
- Perform "On-Board Diagnostic System Check" for diagnostic trouble codes (sensors or actuators which may be malfunctioning)
- Check for dragging brakes
- Check transmission shift patterns for slipping, use of all gears, lock-up operation
- Check ignition timing
- Check owner's driving habits including A/C usage, hard accelerations, carrying heavy loads
- Check emission control system
- Check vacuum hoses for leaks, kinks, proper routing
- Check tire pressure
- Check fuel type, quality, and alcohol content
- Check fuel pressure and fuel system for leaks
- Check air cleaner element
- Check coolant level
- Check ignition system for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits, cracking or improperly connected ignition wires
- Check for proper calibration of speedometer
- In extreme cases, there may be engine problems such as poor compression or faulty fuel injectors
If you are not satisfied with the outcome from the dealership, you can take your case to the Service Representative; the contact information should be listed in the owner’s manual. Be sure to document your observations thoroughly.
4. I purchased an ATV in 2012. How will EPA’s 2013 action affect me?
On April 3, 2013, EPA withdrew its approval of the import and sale of over 70,000 gas-powered on- and off-road motorcycles and all-terrain vehicles because the agency believes that it received either incomplete or falsified certification information. The companies are responsible for violations of the Clean Air Act. While your ATV may be a model that was covered by these voided certificates, you are not responsible for these companies’ wrongdoing and can continue to use your vehicle.
For more information, please visit http://www.epa.gov/otaq/recveh.htm.
5. How will the proposed Tier 3 vehicle and fuel standards create health benefits for Americans?
Starting in 2017, Tier 3 would set new vehicle emissions standards and lower the sulfur content of gasoline, considering the vehicle and its fuel as an integrated system. Tier 3 is among the most highly cost-effective air quality control measures available. The program would cost about a penny per gallon of gasoline, and about $130 per vehicle. The annual cost of the overall program in 2030 would be approximately $3.4 billion; however, we estimate that in 2030, the annual monetized health benefits of the proposed Tier 3 standards would be between $8 and $23 billion.
By 2030, the Tier 3 standards would annually prevent:
- Between 820 and 2,400 premature deaths
- 3,200 hospital admissions and asthma-related emergency room visits
- 22,000 asthma exacerbations
- 23,000 upper and lower respiratory symptoms in children
- 1.8 million lost school days, work days and minor-restricted activities
Over 158 million Americans are currently experiencing unhealthy levels of air pollution which are linked with adverse health impacts such as hospital admissions, emergency room visits, and premature mortality. Motor vehicles are a particularly important source of exposure to air pollution, especially in urban areas.
The proposed vehicle emission standards combined with the proposed reduction of gasoline sulfur content would significantly reduce motor vehicle emissions, including nitrogen oxides (NOX), volatile organic compounds (VOCs), direct particulate matter (PM2.5), carbon monoxide (CO) and air toxics. Tier 3 would also reduce exposure to vehicle pollution for the millions of people living, working, and going to school near major roads.
For more information, please visit http://www.epa.gov/otaq/tier3.htm
6. Over the past several years, what have been the technological and environmental trends in automotive fuel economy?
EPA’s annual “Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel Economy Trends: 1975 through 2012” report that tracks the fuel economy of vehicles sold in the United States is signaling a significant 1.4 mile per gallon (mpg) increase for 2012 cars and trucks – along with a continued decrease in carbon pollution.
The expected 1.4 mpg improvement in 2012 is based on sales estimates provided to EPA by automakers. EPA’s projections show a reduction in carbon dioxide (CO2) emissions to 374 grams per mile and an increase in average fuel economy to 23.8 mpg. If achieved, these would be among the largest annual improvements since EPA began reporting on fuel economy. These improvements would more than make up for a slight 0.2 mpg decrease in 2011 that resulted primarily from earthquake and tsunami-related disruptions to vehicle manufacturing in Japan. From 2007 to 2012, EPA estimates that CO2 emissions have decreased by 13 percent and fuel economy values have increased by 16 percent.
Fuel economy is expected to continue improving significantly under the Obama administration’s historic National Clean Car Program standards. The program cuts greenhouse gas emissions and would double fuel economy standards by 2025. The standards will save American families $1.7 trillion dollars in fuel costs, and by 2025 will result in an average fuel savings of more than $8,000 per vehicle. The program will also save 12 billion barrels of oil, and by 2025 will reduce oil consumption by more than 2 million barrels a day – as much as half of the oil imported from OPEC every day.
The report attributes the improvements to the rapid adoption of more efficient technologies, the increasing number of high fuel economy choices for consumers, and the fact that many automakers are already selling vehicles that can meet more stringent future fuel economy and greenhouse gas emissions standards.
Compared to five years ago, consumers have twice as many hybrid and diesel vehicle choices, a growing set of plug-in electric vehicle options, and a six-fold increase in the number of car models with combined city/highway fuel economy of 30 mpg or higher.
The new report can be found at: http://www.epa.gov/otaq/fetrends.htm.
7. How will the proposed voluntary Quality Assurance Program for verifying Renewable Identification Numbers be effective in assuring their validity?
The proposal would provide a recognized means for independent third parties to audit the production of renewable fuel and the generation of Renewable identification Numbers (RINs). Minimum requirements for the Quality Assurance Program (QAP), including such things as verification of type of feedstocks, verification that volumes produced are consistent with amount of feedstocks processed, and verification that RINs generated are appropriately categorized and match the volumes produced will be enacted. There will also be qualifications for independent third-party auditors and requirements for audits of renewable fuel production facilities, including minimum frequency, site visits, review of records, and reporting. The impacts of this proposal intend to improve RIN market liquidity and efficiency and improve the ability of smaller renewable fuel producers to sell their RINs. As the program is voluntary, there would be no required costs. For more information, please visit our renewable fuels regulations and standards page.
8. Why did EPA determine that a request to waive the renewable fuel standard should be denied?
EPA recognizes that this year’s drought has created significant hardships in many sectors of the economy, particularly for livestock producers. However, the agency’s extensive analysis makes clear that Congressional requirements for a waiver have not been met and that waiving the Renewable Fuels Standard (RFS) would have little, if any, impact on ethanol demand over the time period analyzed.
EPA has not found evidence to support a finding of severe “economic harm” that would warrant granting a waiver of the RFS. The decision is based on economic analyses and modeling done in conjunction with the U.S. Department of Agriculture (USDA) and U.S. Department of Energy (DOE).
For more information about EPA's decision, please visit the RFS notices page.
9. What were the recent fuel waivers EPA granted, where do they apply, and how do they help alleviate disruptions in the fuel supply?
EPA has authority to temporarily waive certain fuel requirements in emergency situations when the fuel supply suffers major disruption. In such circumstances EPA works closely with state and other federal agencies to determine an appropriate response.
As a result of the potential disruption in the supply of fuel following Hurricane Sandy, EPA has exercised its authority under the Clean Air Act to temporarily waive certain federal clean gasoline requirements for gasoline sold and distributed in Tennessee, North Carolina, South Carolina, Mississippi, Georgia, Alabama, District of Columbia, New York, Maryland, Connecticut, Delaware, Massachusetts, New Jersey, Pennsylvania, Virginia, New Hampshire, and Rhode Island. The waivers were granted by EPA in coordination with the Department of Energy.
Former EPA Administrator Lisa P. Jackson determined that extreme and unusual supply circumstances exist, which may result in a temporary shortage of gasoline compliant with federal regulations, and allows for the use of home heating oil as a fuel use in most emergency generators, in a select area The federal waivers will help ensure an adequate supply of fuels in the impacted states.
The first waiver applies to the blending of reformulated gasoline into conventional gasoline in the Northeast. Hurricane Sandy impacted the ability to off-load reformulated gasoline into New York and New Jersey terminals, potentially impacting the pipeline’s ability to deliver fuel to additional terminals across the Northeast. The waiver will provide the pipelines with the ability to off-load either reformulated or conventional gasoline into terminals, allowing the pipeline to continue to supply fuel to areas impacted by the hurricane.
The second waiver is for the state of New Jersey and applies to the use of home heating oil in most emergency generators and pumps. The waiver temporarily allows the use of heating oil in emergency generators and pumps if ultra low-sulfur fuel is not available. The waiver will not apply to a small subset of diesel engines used in generators and pumps that could be damaged by the high sulfur fuel.
10. Do those products that claim to improve fuel economy or lower emissions really work? Some say that they are EPA-certified.
There are many fuel additives and/or aftermarket devices on the market that claim to save fuel and/or lower emissions. Some even claim they are approved or certified by EPA.
Under the Clean Air Act, a fuel additive (any substance or compound intended to be added to gasoline or diesel fuel) must be registered with EPA. This means that the manufacturer of the product must provide EPA with certain information concerning the chemical composition of the additive, as well as submitting data to EPA that provides reasonable assurance that the use of the additive will not increase emissions of regulated air pollutants and will not pose a health or safety threat to the public. The registration requirements do not address the efficiency of the product or require any demonstration that the claims made for the product are valid (typically, "better fuel economy," and sometimes also "reduced emissions" or "engine life benefits").
Those marketing such products take advantage of this distinction, citing the fact that the product is "registered with the US EPA" and sometimes citing the applicable section of the Code of Federal Regulations (i.e., "under the provisions of 40 CFR Part 79") to foster the impression that EPA has somehow "approved of" or endorsed the product. For more information on the process by which fuel additives must be registered with EPA, and exactly what this does and does not imply, please see our Fuels and Fuel Additives Registration site.
We have a program under which formal evaluation test programs are performed on aftermarket devices (generally, mechanical objects that are attached to or installed on a vehicle by the consumer) and on certain fuel additives. However, EPA does not certify, approve, or endorse any product tested in this program nor the results of any independent laboratory testing. EPA issues a technical report for those products and additives that we have tested and evaluated; these reports are available on our site at: www.epa.gov/otaq/consumer/reports.htm.
None of these products were found to produce statistically significant benefits in terms of fuel economy or exhaust emissions. When we explain all this to someone, the usual question we get back is "Why doesn't EPA stop them from doing this?" EPA does not have the authority (or the resources) to attempt to stop such products from being marketed. When the Federal Trade Commission (FTC), which can go after companies for false advertising, does manage to stop a company from marketing anything along these lines, the company and/or the product simply resurface under new names.Many people want to believe that there are in fact such "magic products" that will somehow greatly improve your vehicle's fuel economy (and hence reduce the costs of fuel), but when it comes to products and claims such as this, it’s wise for drivers to be skeptical. For more information, please read the following fact sheets on gas-saving products:
- "Devices and Additives to Improve Fuel Economy and Reduce Pollution - Do They Really Work?" (5 pp, 115K, EPA-420-F-11-036, August 2011)
- "Gas-Saving Products: Fact or Fuelishness?" (Federal Trade Commission, September 2006)
- "Gas-Saving Products: Proceed with Caution" (Federal Trade Commission, July 2001)
- "BBB Warns Drivers to Be Wary of Gas-Saving Gadgets and Additives" (Better Business Bureau, June 2008)
11. How can I get a copy of the Certificate of Conformity for my car?
To request or find a Certificate of Conformity and/or Certificate Summary Information sheet, you need to know the Test Group number (for light-duty cars and trucks – model year 2001 or later) or the Engine Family number (for pre-2001 light-duty cars and trucks). This information is listed on the “Vehicle Emission Information” label/sticker located under the vehicle’s hood. The number has 11 characters using both numbers and letters.
For Vehicles 2003 or Later
If your vehicle’s model year is 2003 or later, you can get the Certificate of Conformity and the Certificate Summary Information sheet by:
- Going to the advanced search page for the Document Index System.
- Choosing “Certificates of Conformity” for Compliance Document Type
- Choosing the industry (e.g., “Light-Duty Vehicles and Trucks” for passenger cars, trucks, vans, and SUVs)
- Choosing the appropriate model year of the vehicle
- Choosing the appropriate manufacturer of the vehicle
- Typing in the vehicle model
- Skip the “Keyword Search,” “Engine Displacement, Number of Cylinders, “Emission Control System,” and “Document Date on and after” fields
- Typing in the Test Group or Engine Family number
- Clicking on the “Search” button
- Saving and/or printing the PDF file.
For Vehicles 2003 or Before
If you need a Certificate of Conformity or Certificate Summary Information for a vehicle with a model year before 2003, send the following information to EPA’s Imports Hotline (Imports@epa.gov). For telephone assistance, please call the Imports Team at (734)-214-4100. Or send fax requests to (734) 214-4676.
- Model year of vehicle
- Manufacturer of vehicle
- Model of vehicle
- Test Group number (only applies to light-duty cars and trucks – model year 2001 or later)
- Engine Family number (only for pre-2001 light-duty cars and trucks, and nonroad and heavy-duty engines/vehicles)
- Your name
- Contact information (address, email address, or fax number where you want EPA to send the Certificate of Conformity to)
If you have any questions, please call the EPA Imports Hotline at 734-214-4100 or email them at Imports@epa.gov.
12. How can I get a copy of the Certificate of Conformity for a nonroad or a heavy-duty highway engine?
To obtain the Certificate of Conformity data for a heavy-duty highway or nonroad engine, please send the following information to EPA’s Imports Hotline (Imports@epa.gov). For telephone assistance, please call the Imports Team at (734) 214-4100. Or send fax requests to (734) 214-4676.
- Model year of engine
- Type of engine (e.g., nonroad gasoline or diesel, heavy-duty highway gasoline or diesel)
- Engine Family # (11 characters using both numbers and letters – printed on the emission label, which is located on the engine or in the engine compartment of the equipment)
- Your name
- Contact information (address, email address, or fax number where you want EPA to send the Certificate of Conformity to)
If you are exporting a heavy-duty highway engine/vehicle or nonroad engine/equipment to another country, the government sometimes requests the test data. You will need to know the Engine Family number (found on the emission label) to obtain this information. You can access test data for heavy-duty highway engines or nonroad engines for 1998 to the present on EPA’s websites as follows:
- Go to http://www.epa.gov/otaq/certdata.htm
- Choose the type of engine
- Choose the model year
- Depending upon the model the information will be in either Excel spreadsheet and/or File Maker (in File Maker search by the manufacturer or engine family name).
If you have any questions, please call the EPA Imports Hotline at (734) 214-4100 or email them at Imports@epa.gov.
13. I just bought a used car and discovered the catalytic converter is missing. Is that legal?
The act of removing a catalytic converter without replacing it with an approved replacement (known as "tampering") is illegal under federal law and is of great concern to EPA because of the high pollution levels that are emitted by vehicles without properly functioning emission controls. The original antitampering law was part of the Clean Air Act of 1970; it applied only to manufacturers and car dealers. The antitampering law was expanded by the 1977 Clean Air Act Amendments to apply to all automobile repair facilities, commercial mechanics, and fleet operators. And the 1990 Clean Air Act Amendments (CAAA) broadened the tampering provision even further; it now applies to everyone, including car owners. Here is the text from the 1990 CAAA:
"Section 288 – Enforcement: (b) TAMPERING WITH VEHICLE EMISSION CONTROLS –
(1) Section 203(a)(3) (42 U.S.C. 7522(a)(3)) is amended to read as follows:
'(3)(A) for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or
'(B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use; or '
(2) At the end of section 203(a) (42 U.S.C. 7522(a)) insert the following:
'No action with respect to any device or element of design referred to in paragraph (3) shall be treated as a prohibited act under that paragraph if (i) the action is for the purpose of repair or replacement of the device or element, or is a necessary and temporary procedure to repair or replace any other item and the device or element is replaced upon completion of the procedure, and (ii) such action thereafter results in the proper functioning of the device or element referred to in paragraph (3). No action with respect to any device or element of design referred to in paragraph (3) shall be treated as a prohibited act under that paragraph if the action is for the purpose of a conversion of a motor vehicle for use of a clean alternative fuel (as defined in this title) and if such vehicle complies with the applicable standard under section 202 when operating on such fuel, and if in the case of a clean alternative fuel vehicle (as defined by rule by the Administrator), the device or element is replaced upon completion of the conversion procedure and such action results in proper functioning of the device or element when the motor vehicle operates on conventional fuel.'."
The resale of a vehicle which has already had the catalytic converter removed is not specifically addressed by federal law. Therefore, the person who removed the converter violated federal law, but not necessarily the person who sold the vehicle. However, the sale of vehicles that have had the emission control system removed, disabled, or tampered with may be further governed by state or local laws.