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  • 1. 9/5/07 Air Pollution and Vehicle Laboratory “The greenhouse gas estimates presented here are "full fuel-cycle estimates" and include the three major greenhouse gases emitted by motor vehicles: carbon dioxide, nitrous oxide, and methane. Full fuel-cycle estimates consider all steps in the use of a fuel, from production and refining to distribution and final use. This gives a more complete picture of how using a particular fuel contributes to global warming. Numerous assumptions and calculations are necessary to estimate full fuel-cycle greenhouse gas emissions in carbon dioxide equivalents. Because of this, estimates from different sources will vary somewhat. Our estimates are taken from the U.S. Department of Energy's GREET model, version 1.5 developed by Argonne National Laboratory. Additional information is available at:” http://www.transportation.anl.gov/ttrdc/greet/ “ (EPA, 2005) Smog is a mixture of chemical substances that exist in the atmosphere, most often as a result of human activity. Smog contains molecules that are produced through use and combustion of fuels such gasoline, coal, and diesel fuel. Smog molecules include carbon monoxide and nitrogen dioxide gases and hydrocarbon vapors. (Hydrocarbons include nonmethane organic compounds—NMOGs—and other compounds that contain the elements hydrogen and carbon.) Smog also contains substances that are formed through chemical reactions that involve sunlight, carbon monoxide and nitrogen dioxide gases, and hydrocarbons vapors. Reactions that involve sunlight are termed photochemical reactions. Photochemical reactions in the atmosphere often form substances that can be toxic to humans including ozone and PANs (peroxyacetyl nitrates). Nitrogen dioxide, carbon monoxide and hydrocarbons are released in the exhaust of vehicles that use internal combustion engines. These engines power the great majority of cars and trucks that are used on American highways. Therefore, vehicles are significant source of smog in many urban areas of the United States. Not all vehicles produce the same amounts of air pollutants. Some vehicles, such as electric cars, are considered zero emission vehicles. Even among vehicles that use gasoline or diesel fuel as energy sources there can be a great difference in the amounts and types of air pollutants that are emitted. Exercise 1: Compare a Pickup Truck with a Family Sedan In this exercise, you will compare the amounts of some of the air pollutants that are released from two common types of vehicles on American highways, pickup trucks and family sedans. Start by finding the EPA Air Pollution Scores of a Chevrolet Malibu and a Chevrolet Silverado pickup. To find the Air Pollution Scores for both vehicles, go to the web site below, and record the values for each. 1
  • 2. http://www.fueleconomy.gov/feg/findacar.htm 2005 Chevrolet C1500 Silverado 2WD with 8 an cylinder, 4.8 liter engine and automatic transmission. Air Pollution Score______ Once you have discovered the Air Pollution Score for the pickup truck, place the mouse pointer on question mark near the heading “ EPA Air Pollution Score” or “Air Pollution”, and click the left mouse button. You should now be viewing a table that lists amounts of specific air pollutants that are released by a vehicle, depending on the assigned Air Pollution Score for that vehicle. If you cannot locate this table, use Table 3 located on page 8. Question. How many grams per mile NOx (nitrogen oxides) are released by the Silverado?______ Question. As the Air Pollution Score increases what happens to the amounts of air pollutants released by a vehicle, does it increase or decrease? Now find the Air Pollution Score for the Malibu and record it below. 2005 Chevrolet Malibu with a 6 cylinder, 3.5 liter engine and automatic transmission. Air Pollution Score_____ Question. Which has the greater score, the Malibu or the Silverado? Question. How many grams per mile NOx (nitrogen oxides) are released by the Malibu?_____ Question. How many times greater are the amounts of NOx produced by the truck compared to the sedan?_____ Question. In terms of NOx pollution one Silverado equals how many Malibus? _____ Exercise 2: Compare a Pickup Truck with a Subcompact To show variability of air pollutant amounts produced by noncommercial vehicles, compare a Ford Focus to a Ford F-250 pickup. Go the website listed below. http://www.epa.gov/greenvehicles/ Locate the “Look up a Vehicle” box on the screen. Place the pointer on this box and click the left mouse button. Find and record the Air Pollution Scores for each of the 2
  • 3. two vehicles. You may need to look at the “Sales Area” box to locate the correct vehicle model. Air Pollution Score of a 2005 Ford Focus, 2WD, 2 liter engine, automatic transmission (5FMXV02.01GB). This model is available in California, but not most other states._____ Air Pollution Score of a 2005 Ford F-250 truck, 5.4 liter engine and 2WD._____ Click of the “Air Pollution Score” box located on the computer screen. You should now be viewing a table that lists amounts of specific air pollutants that are released by a vehicle, depending on the assigned Air Pollution Score for that vehicle. Record the NMOG emission value for the F-250 truck_____ Record NMOG emission value for the Focus_____ How many times greater are the truck emissions compared to the Ford Focus car? For this exercise, one F-250 truck emits an amount of hydrocarbon pollution that would equal how many cars? Question. Many people believe that exhaust emission standards for small trucks, like pickup trucks, should be strengthened (tightened). Is there scientific evidence for this? Explain your answer. Exercise 3: Compare Vehicles That Use Natural Gas and Gasoline as fuels Return to the website listed below. http://www.epa.gov/greenvehicles/ Locate the Air Pollution Scores for the 2005 models of the Honda Civic. Click of the “Air Pollution Score” box located on the computer screen. You should now be viewing a table that lists amounts of specific air pollutants that are released by a vehicle, depending on the assigned Air Pollution Score for that vehicle. Record the PM (particulate matter) values for a Civic with a 1.7 liter engine, 2WD, automatic transmission that used compressed natural gas (CNG) as a fuel (5HNXV01.7BF3 ). This vehicle is available in most states except California._____ 3
  • 4. Record the PM (particulate matter) values for a Civic with a 1.7 liter engine, 2WD, automatic transmission that uses gasoline as a fuel (5HNXV01.7FA6). This vehicle is available in most states except California._____ The PM value of the gasoline powered Civic is how many times greater than the model that uses compressed natural gas as a fuel? ______ Questions: Some cities are switching from diesel to compressed natural gas as a fuel for their buses used in public transportation. Based on your comparison of the two Honda Civic models, why would this be beneficial? Question: Using the two Civic models as an example, by what factor could this reduce air pollution emitted by the buses? Exercise 4: Compare a Hybrid Vehicle to a Traditional Vehicle In this exercise, you will compare the amounts of some of the air pollutants that are released from two similar vehicles, A Honda Civic with a traditional engine and a Honda Civic hybrid. Start by finding the EPA Air Pollution Scores for both vehicles To find the Air Pollution Scores for both vehicles, go to the web site below, and record the values for each. http://www.fueleconomy.gov/feg/findacar.htm Find the 2006 Honda Civic 4 cyl, 1.8 L, Auto(5), Regular, and left click on its link. Now find the Air Pollution Score for the model with the Emission Standard of BIN 5. Record this value_____ Click on the link entitled EPA Air Pollution Score and record the NMOG value for the traditional Civic_____ Locate the Air Pollution Score for a 2006 Honda Civic Hybrid that has an Emission Standard of BIN 2. Record this value._____ Record the NMOG emission value for the hybrid Civic._____ Question Which vehicle produces the greatest amount of hydrocarbons? Question How many times greater are the hydrocarbon emissions of one vehicle compared to the other?_____ Exercise 5: Compare diesel-fueled Heavy-Duty Trucks to Gasoline-Fueled Cars 4
  • 5. In this exercise, you will compare exhaust emissions of European heavy-duty, diesel-fueled trucks to a European gasoline-fueled mid-sized sedan, the Volkswagon Passat. Go to the URL below to find the Air Pollution Score of a 4 cyl, 2 L, Auto(6), Premium Passat http://www.fueleconomy.gov/feg/findacar.htm Click on the link for this vehicle that reads “Volkswagon Passat”. Record the Air Pollution Score for the model with the Emission Standard of BIN 5._____ Now click on the link that reads EPA Air Pollution Score and record the NOx, CO, NMOG and PM exhaust emissions for this vehicle. Question. Grams per mile NOx (nitrogen oxides) released by the Passat______ Question. Grams per mile CO (carbon monoxide) released by the Passat_____ Question. Grams per mile NMOG (nonmethane organic compounds) released by the Passat_____ Question. Grams per mile PM (particulate matter) released by the Passat_____ Now compare the NOx, CO, PM and NMOG exhaust emission values for the heavy-duty diesel trucks (Table 1) Table 1 1992 Exhaust Emissions for European Diesel-Fueled Heavy-Duty Trucks in Urban Driving (grams per mile) (Source: World Bank Emission Standards and Regulations, 1996) Carbon Particulates Hydrocarbons Nitrogen Monoxide (PM) (NMOG) Oxides (CO) (NOX) 30.1 2.6 9.2 25.9 Question. Calculate how many times greater the values for each air pollutant are for the heavy-duty diesel trucks compared to the Passat. 5
  • 6. Question NOx exhaust emissions are _____ times greater than the Passat. Question CO exhaust emissions are _____ times greater than the Passat. Question NMOG exhaust emissions are _____ times greater than the Passat. Question PM exhaust emissions are _____times greater than the Passat. Some people have argued that diesel-fueled, heavy-duty commercial vehicles produce a disproportionate share of air pollution. Based on your data analysis above, what do you think? Explain your answer. Exercise 6: Compare Older Models Cars to Newer Models To reduce air pollution, exhaust emission standards for American vehicles have changed much in the last 50 years. In 1967, there were no emission standards for gasoline-powered cars and light trucks. Average emissions for these vehicles are listed below in Table 1. Table 2 Pre-1968 Exhaust Emissions for Gasoline-Fueled Cars and Light-Duty Trucks (grams per mile) (Source: World Bank Emission Standards and Regulations, 1996) Carbon Monoxide Hydrocarbons Nitrogen Oxides (CO) (NMOG) (NOX) 90.0 15.0 6.2 In this exercise, you will compare the amounts of some of the air pollutants that are released from older and newer model vehicles. Start by finding the EPA Air Pollution Score for the newer vehicle, a 2006 Toyota Camry, at the URL below: http://www.fueleconomy.gov/feg/findacar.htm Left click on the 2006 Toyota Camry (4 cyl, 2.4 L, Auto(5), Regular) link and find the air pollution score for the model with the BIN 5 Emission Standard. Record its Air Pollution Score______ Once you have discovered the Air Pollution Score for the Camry, place the mouse pointer on question mark near the heading “ EPA Air Pollution Score” or “Air Pollution”, 6
  • 7. and click the left mouse button. You should now be viewing a table that lists amounts of specific air pollutants that are released by a vehicle, depending on the assigned Air Pollution Score for that vehicle. Question. How many grams per mile NOx (nitrogen oxides) are released by the Camry?______ Question. How many grams per mile CO (carbon monoxide) are released by the Camry?_____ Question. How many grams per mile NMOG (nonmethane organic compounds) are released by the Camry?_____ Now compare the NOx, CO and NMOG exhaust emission values for the Camry with those of a pre-1968 U.S. vehicle (Table 2) Question. Calculate how many times greater the values for each air pollutant are for the pre-1968 vehicle compared to the Camry. Question NOx exhaust emissions are _____ times greater than the Camry. Question CO exhaust emissions are _____ times greater than the Camry. Question NMOG exhaust emissions are _____ times greater than the Camry. Based on data analysis conducted in 1999, according to the U.S. EPA (2006) On- road mobile sources produce 51% of the CO, 29% of the hydrocarbons (NMOG) and 10% of the PM2.5, and 34% of the NOx. (“Pollution sources that move, such as trucks, snowblowers, bulldozers, and trains, are known as "mobile sources." Examples of all other (non-mobile) sources of air pollution include power plants, factories, and manufacturing processes.” EPA, 2006) Question. In your opinion, have the U.S. laws governing vehicle air pollution had a significant impact on air quality in this country? Explain your answer. Question. If one wanted to reduce smog in cities by changing driving habits how might it be accomplished without reducing the number of vehicles on the highway? 7
  • 8. Table 3 (Source:U.S. Environmental Protection Agency, 2007 http://www.epa.gov/greenvehicles/) Air Pollution The Air Pollution Score reflects pollutants that cause health problems and smog. The score is from 0 to 10, where 10 is best. The air pollutants coming out of a vehicle's tailpipe are tightly controlled by EPA's emissions regulations. Thanks to efforts from both EPA (on the regulation side) and the automotive industry (on the compliance side), today's vehicles are significantly cleaner than in the past. Technology advances such as catalytic converters, exhaust gas recirculation and electronic fuel controls have made tighter pollution control from vehicles possible. However, emission levels will still vary between vehicles due to differences in emissions standards. Emissions performance should be an important environmental consideration when buying a vehicle. This chart shows the expected amounts of emissions per mile at each score. Air Emission Limits at Full Useful Life (100,000-120,000 miles) Pollution Maximum Allowed Grams per Mile Score NOx NMOG CO PM HCHO 10 0.00 0.00 0.0 0.0 0.0 9 0.02 0.010 2.1 0.01 0.004 8 0.03 0.055 2.1 0.01 0.011 7 0.04 0.070 2.1 0.01 0.011 6 0.07 0.090 4.2 0.01 0.018 5 0.10 0.090 4.2 0.01 0.018 4 0.15 0.090 4.2 0.02 0.018 3 0.2 0.156 4.2 0.02 0.018 2 0.3 0.180 4.2 0.06 0.018 1 0.6 0.280 6.4 0.08 0.027 0 0.9 0.280 7.3 0.12 0.032 NOx=Oxides of Nitrogen: Compounds containing nitrogen and oxygen; they combine with hydrocarbons in the sunlight to form smog NMOG=Non-Methane Organic Compounds: Compounds containing carbon; they combine with NOx in the sunlight to form smog CO=Carbon Monoxide: A colorless, odorless, poisonous gas PM=Particulate Matter: Tiny particles of solid matter that lodge in the lungs and deposit on buildings HCHO=Formaldehyde: A lung irritant and carcinogen 8
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