Sec. 03.03.06.03. Oxygen Content Determination

A. The requirements of §§B-D of this regulation apply only in a control area and for control periods after:

(1) A monitored violation of the CO standard for that control area or in a larger area of which the control area is required by federal law to be treated as a unit; and

(2) Notice has been published in the Maryland Register not later than July 1 of the year in which §§B-D of this regulation become applicable that the requirements apply to the control area, and that §§B-D of this regulation remain applicable in that control area until a notice is published in the Maryland Register stating that the sections no longer apply.

B. During the period from November 1 through the following February 28 or, in leap years, the following February 29, the Bureau and the Department shall determine the oxygen content of gasoline in accordance with the requirements specified in §§C-D of this regulation. Regulated parties are free to use other accepted test methods for quality assurance programs. However, these programs do not exempt regulated parties from enforcement action. Regulated parties are encouraged to develop a correlation program with the Bureau and the Department to reduce the probability of inconsistent test results.

C. Test Methods.

(1) Throughout each control period beginning before January 1, 1994, the percent by volume of component oxygenates in gasoline shall be determined in accordance with:

(a) For single-carbon through four-carbon alcohols and methyl tertiary butyl ether, ASTM Test Method D-4815-89;

(b) For ethyl tertiary butyl ether, ASTM Test Method D-4815-89 with an appropriate internal standard; and

(c) For other oxygenates, a method developed by the Bureau and the Department in consultation with refiners, importers, and blenders registered under Regulation .04 of this chapter, and approved by the United States Environmental Protection Agency.

(2) Throughout each control period beginning on or after January 1, 1994, the percent by volume of component oxygenates in gasoline shall be determined in accordance with Regulation .03C(1) of this chapter or the methodology described in Appendix C of the United States Environmental Protection Agency's Supplemental Notice of Proposed Guidelines for Oxygenated Gasoline Credit Programs as published in the February 5, 1992 Federal Register (57 FR 4413).

D. Oxygen Calculation.

(1) The oxygen content of gasoline shall equal the sum of the density-corrected oxygen weight fractions of all component oxygenates divided by the sum of the density-corrected volumes of gasoline and all component oxygenates. The density-corrected oxygen weight fraction of each component oxygenate shall be calculated by multiplying the percent by volume of each oxygenate, as measured in accordance with §C of this regulation, by the oxygen weight fraction and specific gravity of the oxygenate. The density-corrected volume of gasoline and component oxygenates shall be calculated by multiplying the percent by volume of gasoline or oxygenate, as applicable, by the specific gravity of the gasoline or oxygenate.

(2) The oxygen weight fraction of oxygenates is as follows:

(a) 0.4993 for methyl alcohol;

(b) 0.3473 for ethyl alcohol;

(c) 0.2662 for propyl alcohols;

(d) 0.2158 for butyl alcohols;

(e) 0.1815 for methyl tertiary butyl ether (MTBE);

(f) 0.1566 for tertiary amyl methyl ether (TAME);

(g) 0.1566 for ethyl tertiary butyl ether (ETBE); and

(h) 0.1566 for diisopropyl ether (DIPE).

(3) For purposes of this chapter, the specific gravity of oxygenates is as follows:

(a) 0.7963 for methyl alcohol;

(b) 0.7939 for ethyl alcohol;

(c) 0.8080 for n-propyl alcohol;

(d) 0.7899 for isopropyl alcohol;

(e) 0.8137 for n-butyl alcohol;

(f) 0.8058 for isobutyl alcohol;

(g) 0.8114 for sec-butyl alcohol;

(h) 0.7922 for tert-butyl alcohol;

(i) 0.7460 for methyl tertiary butyl ether (MTBE);

(j) 0.7752 for tertiary amyl methyl ether (TAME);

(k) 0.7452 for ethyl tertiary butyl ether (ETBE); and

(l) 0.7257 for diisopropyl ether (DIPE).

(4) For purposes of this chapter, the specific gravity of gasoline is 0.7420.

(5) For purposes of this chapter, the oxygen weight fraction of oxygenates not included in §D(2) of this regulation and the specific gravity of oxygenates not included in §D(3) of this regulation shall be specified by the Bureau and the Department.