EPA's Tier 2 Emission Standards for New Motor Vehicles: A Fact Sheet

The Clean Air Act Amendments of 1990 established "Tier 1" standards to limit tailpipe emissions from new motor vehicles. The law also required the Environmental Protection Agency (EPA) to determine if stricter controls would be necessary by model year (MY) 2004 to assist states in attaining or maintaining the National Ambient Air Quality Standards. EPA also was required to assess the availability and cost-effectiveness of technologies necessary to control emissions. In a report submitted to Congress in August 1998, EPA concluded that tougher standards are necessary and that essential technologies are available and cost-effective. (1) As a result, EPA finalized stricter "Tier 2" standards on February 10, 2000. (2) The new standards will be phased in beginning in MY2004 and will require all new passenger cars and light trucks up to 8,500 pounds, and all new heavier passenger vehicles up to 10,000 pounds (including large sport-utility vehicles), to demonstrate full compliance by MY2009. To improve the efficiency of emission control technologies, oil refiners also will be required to limit gasoline sulfur levels to an average of 30 parts per million (ppm) nationwide beginning in 2005, roughly 90% less than the current national average of 340 ppm. 1.  EPA. Office of Air and Radiation. Tier 2 Report to Congress . July 31, 1998. 55 p. 2.  EPA. Federal Register . February 10, 2000. P. 6698-6870.

Order Code RS20247 Updated June 12, 2000 CRS Report for Congress Received through the CRS Web EPA's Tier 2 Emission Standards for New Motor Vehicles: A Fact Sheet (name redacted) Environmental Information Analyst Resources, Science, and Industry Division The Clean Air Act Amendments of 1990 established “Tier 1” standards to limit tailpipe emissions from new motor vehicles. The law also required the Environmental Protection Agency (EPA) to determine if stricter controls would be necessary by model year (MY) 2004 to assist states in attaining or maintaining the National Ambient Air Quality Standards. EPA also was required to assess the availability and cost-effectiveness of technologies necessary to control emissions. In a report submitted to Congress in August 1998, EPA concluded that tougher standards are necessary and that essential technologies are available and cost-effective.1 As a result, EPA finalized stricter “Tier 2” standards on February 10, 2000.2 The new standards will be phased in beginning in MY2004 and will require all new passenger cars and light trucks up to 8,500 pounds, and all new heavier passenger vehicles up to 10,000 pounds (including large sport-utility vehicles), to demonstrate full compliance by MY2009. To improve the efficiency of emission control technologies, oil refiners also will be required to limit gasoline sulfur levels to an average of 30 parts per million (ppm) nationwide beginning in 2005, roughly 90% less than the current national average of 340 ppm. The new Tier 2 standards will require vehicle manufacturers to reduce tailpipe emissions of carbon monoxide (CO), formaldehyde (HCHO), nitrogen oxides (NOx), nonmethane organic gases (NMOG), and particulate matter (PM). However, manufacturers will have the flexibility to average the NOx emissions of their vehicle fleets to demonstrate compliance with the standards instead of certifying each vehicle according to the same stringency. The standards will require the most reductions in emissions of NMOG and NOx to help control the formation of ground-level ozone pollution. Relative to the Tier 1 standards, the fleet average standard for NOx will require vehicle manufacturers to reduce overall tailpipe emissions by 88% to 95%. The standards also will require at least an 80% reduction in PM emissions but will require less stringent reductions in CO emissions. The standard for HCHO is a new requirement that is intended to reduce emissions of carcinogenic pollutants. The table on page 2 compares the current Tier 1 standards, which became effective in MY1994, to the new Tier 2 standards that will be phased in beginning in MY2004. 1 EPA. Office of Air and Radiation. Tier 2 Report to Congress. July 31, 1998. 55 p. 2 EPA. Federal Register. February 10, 2000. p. 6698-6870. Congressional Research Service ˜ The Library of Congress CRS-2 Comparison of Tier 1 and Tier 2 Tailpipe Emission Standards for Motor Vehicles Intermediate Useful Life (grams/mile) a Vehicle Type/Weight NMHC/ NMOG b CO NOx PM Full Useful Life (grams/mile) a HCHO NMHC/ NMOG b CO NOx PM HCHO Tier 1 Standards LDVs/LDTs (< 3,751 lbs.) LDTs (3,751-5,750 lbs.) LDTs (> 5,750 lbs.) .250 .320 .390 3.4 4.4 5.0 .40 .70 1.10 n/a n/a n/a .125/.160 .075/.140 .100/.125 .075 .075 .075 n/a n/a n/a n/a n/a n/a n/a 3.4/4.4 3.4 3.4 3.4 3.4 3.4 n/a n/a n/a n/a n/a n/a n/a .40 .20 .14 .11 .08 .05 n/a n/a n/a n/a .08 .08 n/a n/a n/a n/a .310 .400 .560 4.2 5.5 7.3 .60 .97 1.53 n/a n/a n/a n/a n/a n/a n/a .015/.018 .015 n/a .015 n/a .015 n/a .015 n/a .015 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a .280 .156/.230 .090/.180 .125/.156 .090 .090 .090 .070 .055 .010 .000 n/a n/a 7.3 4.2/6.4 4.2 4.2 4.2 4.2 4.2 2.1 2.1 2.1 0.0 .07 .20/.30 .90 .60 .30 .20 .15 .10 .07 .04 .03 .02 .00 .10 .10 .12 n/a n/a n/a Tier 2 Standards Final Fleet Average c Interim Fleet Averages d Interim Bin 11 e Interim Bin 10 f, g Interim Bin 9 f, g Bin 8 g Bin 7 Bin 6 Bin 5 Bin 4 Bin 3 Bin 2 Bin 1 n/a n/a n/a n/a .032 .12 .08 .018/.027 .018 .06 .018 .02 .018 .02 .018 .01 .018 .01 .011 .01 .011 .01 .004 .01 .000 .00 a The intermediate useful life standards set a benchmark for the amount of pollutants that a vehicle is expected to emit after being driven for 50,000 miles. The Tier 1 full useful life standards reflect the amount of pollutants that a vehicle is expected to emit after 100,000 miles of vehicle use. The Tier 2 standards increase the full useful life benchmark to 120,000 miles. If a manufacturer voluntarily chooses to certify a vehicle to a higher useful life of 150,000 miles, compliance with the Tier 2 intermediate standards is optional. b Tier 1 vehicles are subject to the testing procedure for NMHC, but Tier 2 vehicles will be subject to the testing procedure for NMOG. Both pollutants are closely related hydrocarbon compounds that can combine with NOx in the presence of sunlight to form ground-level ozone pollution. EPA selected the NMOG testing procedure under Tier 2 because it more accurately measures hydrocarbon levels. c Each manufacturer will have the flexibility to select any set, or “bin”, of emission standards when certifying different models of vehicles, as long as it meets the fleet average requirement for NOx emissions. d During the phase-in period, the interim fleet average for LDVs and LLDTs will be .30 grams/mile and will expire at the end of MY2006. The interim fleet average will be .20 grams/mile for HLDTs and MDPVs and will expire at the end of MY2008. e Bin 11 will only apply to MDPVs and will expire at the end of MY2008 when phase-in is complete. f Bins 9 and 10 will expire at the end of MY2006 for LDVs and LLDTs and at the end of MY2008 for HLDTs and MDPVs. g The higher values will apply only to HLDTs during the phase-in period and will expire at the end of MY2008. LDV = light duty vehicle (<6,001 lbs.) LLDT = (light) light duty truck (<6,001 lbs.) HLDT = (heavy) light duty truck (6,001-8,500 lbs.) MDPV = medium duty passenger vehicle (8,501-10,000 lbs.) NMHC = non-methane hydrocarbons NMOG = non-methane organic gases CO = carbon monoxide NOx = nitrogen oxides PM = particulate matter HCHO = formaldehyde Prepared by the Congressional Research Service based on data from the Environmental Protection Agency. EveryCRSReport.com The Congressional Research Service (CRS) is a federal legislative branch agency, housed inside the Library of Congress, charged with providing the United States Congress non-partisan advice on issues that may come before Congress. EveryCRSReport.com republishes CRS reports that are available to all Congressional staff. The reports are not classified, and Members of Congress routinely make individual reports available to the public. Prior to our republication, we redacted names, phone numbers and email addresses of analysts who produced the reports. We also added this page to the report. We have not intentionally made any other changes to any report published on EveryCRSReport.com. CRS reports, as a work of the United States government, are not subject to copyright protection in the United States. Any CRS report may be reproduced and distributed in its entirety without permission from CRS. However, as a CRS report may include copyrighted images or material from a third party, you may need to obtain permission of the copyright holder if you wish to copy or otherwise use copyrighted material. Information in a CRS report should not be relied upon for purposes other than public understanding of information that has been provided by CRS to members of Congress in connection with CRS' institutional role. EveryCRSReport.com is not a government website and is not affiliated with CRS. We do not claim copyright on any CRS report we have republished.