Project at a Glance

Title: Effects of methanol fuel substitution on multi-day air pollution episodes

Principal Investigator / Author(s): Carter, William P. L.

Contractor: Statewide Air Pollution Research Center, UC Riverside

Contract Number: A3-125-32

Research Program Area: Atmospheric Processes


A series of indoor and outdoor environmental chamber experiments were conducted to investigate the effects on ambient air quality of widespread conversion of motor vehicles to methanol fuel. Three organic surrogates were compared in two- to three-day NOx-air irradiations: a base case mixture representing present emissions into the California South Coast Air Basin; a mixture in which 33% (by carbon) of the base mix was substituted by methanol; and a mixture in which 33% of the base mix was substituted by a 90% methanol, 10% formaldehyde mix. The organic / NOx ratio was varied from 3 to 15.

Substitution by methanol alone resulted in reduced day one ozone and PAN formation in all experiments, with the ozone benefit being less on day two. However, if 10% formaldehyde is co-emitted with methanol, no clear-cut ozone benefit from methanol substitution was observed, though PAN is still reduced. Methanol substitution resulted in increased formaldehyde levels, even if formaldehyde is not co-emitted, though the increase was usually less than 50%. The magnitudes of the substitution effects, especially for ozone and PAN, were found to be highly dependent on meteorological conditions and the organic / NOx ratio.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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