IMPACT OF METHANOL AND CNG FUELS ON MOTOR VEHICLE TOXIC EMISSIONS

The 1990 Clean Air Act Amendments require that the Environmental Protection Agrncy investigate the need for reduction of motor vehicle toxic emissions such as formaldehyde, acetaldehyde, benzene, 1,3-butadiene, and polycyclic organic matter. Toxic organic emissions can be reduced by utilizing the control technologies employed for regulated THC (NMHC) and CO emissions, and by changing fuel composition. The paper examines emissions associated with the use of of methanol and compressed natural gas fuels. Both tailpipe and evaporative emissions are examined at varied ambient temperatures ranging from 20 C to 105 F. Tailpipe emissions are also examined over a variety of driving cycles with average speeds ranging from 7 to 48 mph. Results suggest that at equivalent ambient temperatures and average speeds, motor vehicle toxic emissions are generally reduced with methanol and compressed natural gas fuels relative to those with gasoline, except for formaldehyde emissions, which may be elevated. As with gasoline, tailpipe toxic emissions with methanol and compressed natural gas fuels generally increa se when ambient temperature or average speed decreases (the sensitivity to these variables is greater with methanol than with compressed natural gas). Evaporative emissions generally increase when fuel volatility or ambient temperrature increases (however, the relative contribution of evaporative sources to the aggregate toxic compound emissions is small).

• Corporate Authors:

  Environmental Protection Agency

  Atmospheric Research and Exposure Assessment Laboratory
  Research Triangle Park, NC  United States  27709
• Authors:
  • Black, F
  • GABELE, P
• Publication Date: 1991

Media Info

• Pagination: 19 p.

Subject/Index Terms

• TRT Terms: Air quality management; Compressed natural gas; Emission control systems; Evaporative emissions; Fuel systems; Fuels; Methanol; Specifications; Toxicity
• Identifier Terms: Clean Air Act
• Old TRIS Terms: Evaporative emission control; Fuel specifications
• Subject Areas: Energy; Highways; Vehicles and Equipment;

Filing Info

• Accession Number: 00623254
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: EPA/600/D-91/240
• Files: TRIS
• Created Date: Jul 31 1992 12:00AM