In Scottsdale, everyone wants to drive a fuel efficient and earth-friendly car. Scottsdale is full of smog and you don't want to be a part of the problem. The EPA is responsible for determining what is and is not considered "green". But, how do the decide what is green or killing the planet? Well, read on and find out.
What are EPA's emission standards and why are they important?
Cars, trucks and other mobile sources account for almost a third of the total air pollution in the United States. EPA's vehicle emission standards for cars and trucks have been in place since the early 1970's. Since that time, vehicle emissions standards have been made increasingly stringent to address this national air quality problem. View the summary of current and historical emission standards.
EPA's newest standards, called "Tier 2," provide auto manufacturers with an array of emissions standards they can choose for any particular vehicle model, as long as all the new vehicles they sell in a given model year fall below a required average (bin 5). The emission standards are in effect from the time the vehicle is produced until the vehicle reaches the legally-defined end of its useful life (10 years or 120,000 miles for most cars) - manufacturers are responsible for designing vehicles that will pollute no more than the emission standard limits. More information about EPA's Tier 2 standards can be found here.
Due to its unique air quality problems, California has separate emission standards for cars and trucks. Manufacturers wishing to sell vehicles in California must certify that they comply with the California standards. Other states are permitted to adopt California emission standards as well. For the 2008 model year, the following states have adopted the California LEV 2 emission standards: NY, ME, MA, PA, RI, CT, VT. Also, states which border those states may also sell California-certified vehicles. Information about California's emission standards program can be found at www.arb.ca.gov/msprog/msprog.htm.
How are vehicles tested for emissions?
Before a vehicle manufacturer can offer a new vehicle for sale, EPA requires that various laboratory emission tests be conducted on a vehicle representative of the vehicles that will be sold to car buyers to ensure that the vehicles will meet the emission standards. The tests are designed to simulate a wide variety of actual on-road operating conditions (such as highway driving and city driving). The data from these tests are also used to calculate city and highway fuel economy (mpg) values which appear on the window stickers of new vehicles. More information about vehicle testing can be found here.
What do the Air Pollution Scores mean?
Each score reflects one set of emissions standards for four different air pollutants: oxides of nitrogen (NOx), carbon monoxide (CO), volatile organic compounds (VOC), and particulate matter (PM). The manufacturer is liable for ensuring that a properly maintained vehicle will emit no more than the given limit of each of these pollutants for each mile that the vehicle is driven. The Air Pollution Score which is a surrogate for the actual emission standards, is on a scale of 0-10, with 10 being the cleanest or best score.
Why do some apparently identical vehicles have different Air Pollution Scores?
A number of vehicles have different Air Pollution Scores even though they are, by all outward appearances, identical. This is usually due to the fact that there are separate EPA and California emission standards. Manufacturers wishing to sell vehicles in California as well as the rest of the U.S. must separately certify them to comply with EPA and California standards. California standards are generally more stringent than EPA standards due to the unique air quality problems in that state, so this can result in a higher Air Pollution Score for the California version. This does not necessarily mean that the vehicle sold in the rest of the U.S. is "dirtier." In general, if the Underhood Label ID is the same, the vehicle design will be the same as well, meaning that the vehicle has been designed to comply with both sets of standards, so that in reality, the emissions will be at the level of the more stringent of the two standards (California or EPA).
What is EPA doing to control pollution from vehicles?
EPA has a number of programs underway to ensure that vehicles operate cleanly from the time they are produced until the legally defined end of their useful life (10 years or 120,000 miles for most cars). Information about these and many other programs can be found in the Office of Transportation and Air Quality web site at www.epa.gov/otaq. A few of these are:
• New vehicle certification program: This program ensures that vehicles are designed to meet the emission standards set by Congress and EPA. For more information see http://www.epa.gov/otaq/cert.htm.
• On-board diagnostics (OBD): OBD is a computer-controlled system which alerts a driver via a dashboard light that there is a potential problem with the emissions control system of his or her vehicle. OBD is required on all 1994 and newer passenger cars and trucks. OBD systems were also required on trucks up to 14,000 pounds beginning in 2005. More information about these OBD requirements can be found at http://www.epa.gov/obd/regtech/light.htm. EPA has also proposed OBD requirements for heavy-duty trucks over 14,000 pounds beginning in the 2010 model year. More information on heavy-duty OBD can be found at http://www.epa.gov/obd/regtech/heavy.htm
• Inspection and maintenance: Many cities and metropolitan areas have established inspection and maintenance (I/M) programs that require owners to have their vehicle emissions checked periodically. For more information about I/M programs see www.epa.gov/otaq/im.htm.
• Emission recall: EPA monitors the emission performance of vehicles on the road to assure that they continue to comply with the emission standards. Vehicle manufacturers are required to build their vehicles to meet emission standards for the useful life of the vehicle. Under the Clean Air Act, if EPA determines that a substantial number of vehicles in a category or class do not meet the stadards in use even though they are properly maintained EPA can require the manufacturer to recall and fix the affected vehicles. View EPA's emission recall activities at www.epa.gov/otaq/recall.htm
• Emission warranty federally required emission control warranties protect you, the vehicle owner, from the cost of repairs for certain emission related failures that result from manufacturer defects in materials and workmanship or that cause your vehicle to exceed federal emission standards. There are two types of emission warranties: a defect warranty and a performance warranty. The defect warranty covers the repair of emission-related parts that become defective during normal vehicle operation. The performance warranty covers repairs that are necessary because the vehicle failed an EPA-approved I/M inspection. Check your owner's manual for more details about your emission warranties or see http://www.epa.gov/obd/warranties.htm.
Why do some diesel vehicles receive low Air Pollution Scores even though they have good fuel economy?
Despite their higher fuel efficiency which results in a better Greenhouse Gas Score, diesel vehicles emit higher levels of NOx (a lung irritant which contributes to smog formation) and particulate matter (a likely human carcinogen). Because these pollutants are more difficult to control in diesel exhaust, manufacturers certify them to comply with less stringent emission standards, resulting in lower Air Pollution Scores. However, manufacturers are working on developing more effective ways to control this pollution in diesels, and we expect to see higher scores in the future.
Is biodiesel fuel better to use than regular diesel fuel?
Biodiesel has the potential to provide a number of important benefits. As an alternative to diesel, it can help reduce U.S. dependence on foreign oil. Biodiesel also provides significant greenhouse gas (GHG) emission reductions. B100 (100 percent biodiesel) reduces lifecycle greenhouse gas emissions by more than 50 percent, while B20 (20 percent biodiesel / 80 percent conventional, petroleum diesel fuel) reduces GHG emissions by at least 10 percent. In addition, biodiesel offers several criteria emissions benefits for the existing vehicle fleet. It reduces emissions of carbon monoxide, particulate matter (PM), and sulfates, as well as hydrocarbon and air toxics emissions. On the other hand, a 2002 EPA summary analysis of existing data suggests that vehicles using biodiesel may emit slightly more oxides of nitrogen (NOx) (about two percent for B20 and 10 percent for B100). Subsequent studies have yielded mixed results, with some showing small increases and others showing small decreases. EPA plans a further investigation to fully assess this issue, including the emissions impact of using biodiesel in vehicles equipped with PM traps and NOx aftertreatment designed to meet strict new emission standards. Most diesel engines can run on biodiesel without needing any special equipment. If you are interested in using biodiesel in your vehicle or equipment, check with the manufacturer for any recommendations and information regarding engine warranties. In addition, once you have determined the proper blend for your vehicle, make sure to purchase your fuel from a reputable dealer selling commercial grade biodiesel.
Why is the fuel economy for a flex-fuel vehicle lower when using E85 than when using gasoline?
Ethanol has a lower energy content than gasoline as measured in British Thermal Units per gallon, so you travel fewer miles per gallon when using a fuel that contains ethanol. Compared to gasoline, E85 typically gets about 25-30 percent fewer miles per gallon in ethanol flexible fuel vehicles.
What are the benefits of ethanol (E85)?
Ethanol contains less carbon than gasoline, and thus produces fewer greenhouse gas emissions (carbon-containing compounds such as CO2), than gasoline. It also can be produced from renewable sources such as corn or other vegetative matter, and thus helps to reduce dependency on fossil fuels.
Why is fuel economy important?
Vehicles with lower fuel economy create more carbon dioxide - the most prevalent greenhouse gas - than vehicles with higher fuel economy. Every gallon of gasoline your vehicle burns puts about 20 pounds of carbon dioxide into the atmosphere because air has weight and mass, and it takes a lot of it to burn a gallon of gasoline. One of the most important things you can do to reduce your contribution to global warming is to buy a vehicle with higher fuel economy. The difference between 25 miles per gallon and 20 miles per gallon can amount to the prevention of 10 tons of carbon dioxide over a vehicle's lifetime. Buying a more fuel efficient vehicle will also will help to reduce our nation's dependence on fossil fuels. And of course, you will save money by having to fuel up less often.
How are vehicles tested for fuel economy?
The fuel economy estimates are determined by laboratory test procedures prescribed by EPA regulations. The test procedures are performed by auto manufacturers, and EPA audits the results at its own test laboratory to ensure manufacture accuracy. The vehicles are driven by professional drivers in controlled laboratory conditions. Using standardized test methods ensures that the fuel economy of all vehicles can be compared.
EPA recently revised the methods it uses to determine the city and highway estimates posted on the Green Vehicle Guide and on the window stickers of all new cars and light trucks. The methods are expected to provide consumers with better fuel economy estimates, based on more realistic driving conditions, such as cold temperatures, higher speeds, and use of air conditioning. The new methods take effect with 2008 and later models.
Why is my fuel economy different than the estimates and how can I improve it?
Even with the improved test methods for measuring fuel economy, no test can simulate all the possible conditions that affect fuel economy such as climate, driver behavior, road condition, and car care habits. Thus your actual mileage will always vary some from the estimates. Tips for improving fuel economy can be found on the EPA-DOE fuel economy web site at http://www.fueleconomy.gov.
courtesy of http://www.epa.gov/greenvehicles/Faq.do
