Table B2. Changes in Motor Gasoline Density, 1990-1998 
(Degrees API)

Fuel Grade 1990 1991 1992 1993 1994 1995 1996 1997 1998
Winter Grade  
  Low Octane 62.0 61.8 61.4 61.0 60.1 59.8 60.6 61.5 P61.9
  Mid Octane 60.8 60.4 60.2 59.9 59.4 59.1 59.9 60.7 P61.1
  High Octane 59.0 59.3 59.0 58.7 58.5 58.0 58.5 59.3 P59.6
Summer Grade  
  Low Octane 58.2 58.0 57.4 56.1 55.7 56.1 56.9 57.1 57.6
  Mid Octane 57.4 57.1 56.4 55.5 54.8 55.6 56.2 56.6 56.7
  High Octane 55.5 55.7 55.6 54.4 53.8 55.1 55.3 56.4 55.7
Average Emissions Coefficient
(Million Metric Tons Carbon
per Quadrillion Btu)
19.41 19.41 19.42 19.43 19.45 a19.38 a19.36 a19.35 aP19.33
aEmissions coefficient weighted for reformulated gasoline, which has a lower density than standard gasoline.
P = preliminary data.
Sources: National Institute of Petroleum and Energy Research, Motor Gasoline, Summer and Motor Gasoline, Winter (1990-1998); and M. DeLuchi, Emissions of Greenhouse Gases from the Use of Transportation Fuels and Electricity, ANL/ESD/TM-22, Vol. 2, Appendices A-S (Chicago, IL: Argonne National Laboratory, November 1993), p. c-6. Properties of reformulated fuels from California Air Resources Board.

Back to Appendix B:  Carbon Coefficients Used in This Report