Mississippi Administrative Code › Title 11 - Mississippi Department of Environmental Quality › Part 2 - Air Regulations › Chapter 1 - Mississippi Commission on Environmental Quality, Air Emission Regulations for the Prevention, Abatement, and Control of Air Contaminants › Rule 11-2-1.9 - Stack Height Considerations

Current through June 25, 2024
A. Definitions
(1) "Emission limitation" and "emission
				standard." A requirement established which limits the quantity, rate, or
				concentration of emissions of air pollutants on a continuous basis, including
				any requirements which limit the level of opacity, prescribe equipment, set
				fuel specifications, or prescribe operation or maintenance procedures for a
				source to assure continuous emission reduction.
(2) "Stack." Any point in a source designed
				to emit solids, liquids, or gases into the air, including a pipe or duct but
				not including flares.
(3) "A stack
				in existence." The owner or operator had either:
(a) Begun, or caused to begin, a continuous
				program of physical on-site construction of the stack, or
(b) Entered into binding agreements or
				contractual obligations, which could not be cancelled or modified without
				substantial loss to the owner or operator, to undertake a program of
				construction of the stack to be completed in a reasonable time.
(4) "Dispersion technique." Any
				technique which attempts to affect the concentration of a pollutant in the
				ambient air by using that portion of a stack which exceeds good engineering
				practice stack height, varying the rate of emission of a pollutant according to
				atmospheric conditions or ambient concentrations of that pollutant, or
				increasing final exhaust gas plume rise by manipulating source process
				parameters, exhaust gas parameters, stack parameters, or combining exhaust
				gases from several existing stacks into one stack; or other selective handling
				of exhaust gas streams so as to increase the exhaust gas plume rise. The
				preceding sentence does not include:
(a) The
				reheating of a gas stream, following use of a pollution control system, for the
				purpose of returning the gas to the temperature at which it was originally
				discharged from the facility generating the gas stream:
(b) The merging of exhaust gas streams where:
(1) The source owner or operator demonstrates
				that the facility was originally designed and constructed with such merged gas
				streams;
(2) After July 8, 1985,
				such merging is part of a change in operation at the facility that includes the
				installation of pollution controls and is accompanied by a net reduction in the
				allowable emissions of a pollutant. This exclusion from the definition of
				"dispersion techniques" shall apply only to the emission limitation for the
				pollutant affected by such change in operation; or
(3) Before July 8, 1985, such merging was
				part of a change in operation at the facility that included the installation of
				emissions control equipment or was carried out for sound economic or
				engineering reasons. Where there was an increase in the emission limitation or,
				in the event that no emission limitation was in existence prior to the merging,
				an increase in the quantity of pollutants actually emitted prior to the
				merging, the reviewing agency shall presume that merging was significantly
				motivated by an intent to gain emissions credit for greater dispersion. Absent
				a demonstration by the source owner or operator that merging was not
				significantly motivated by such intent, the reviewing agency shall deny credit
				for the effects of such merging in calculating the allowable emissions for the
				source;
(c) The use of
				smoke management in agricultural or silvicultural prescribed burning programs;
				or
(d) Episodic restrictions on
				residential wood burning and open burning; or
(e) Techniques under Rule 1.9.A.(4) which
				increase final exhaust gas plume rise where the resulting allowable emissions
				of sulfur dioxide from the facility do not exceed 5,000 tons per
				year.
(5) "Good
				engineering practice (GEP) stack height." The greater of:
(a) 65 meters measured from the ground-level
				elevation at the base of the stack;
(b)
(1) For
				stacks in existence on January 12, 1979, and for which the owner or operator
				had obtained all applicable preconstruction permits or approvals required, Hg =
				2.5 H, provided the owner or operator produces evidence that this equation was
				actually relied on in establishing an emission limitation;
(2) For all other stacks,
Hg = H + 1.5L, where
Hg = good engineering practice stack height, measured from
				  the ground-level elevation at the base of the stack,
H = height of nearby structure(s) measured from the
				  ground-level elevation at the base of the stack, and
L = lesser dimension (height or projected width) of nearby
				  structure(s), provided that the U. S. Environmental Protection Agency or the
				  Commission may require the use of a field study or fluid model to verify GEP
				  stack height for the source; or
(3) The height demonstrated by a fluid model
				or a field study approved by the U. S. Environmental Protection Agency or the
				Commission, which ensures that the emissions from a stack do not result in
				excessive concentrations of any air pollutant as a result of atmospheric
				downwash, wakes, or eddy effects created by the source itself, nearby
				structures, or nearby terrain features.
(c) "Nearby." As used in Rule 1.9.A.(5)(b)(2)
				is defined for a specific structure or terrain feature and means:
(1) For purposes of applying the formulae
				provided in Rule 1.9.A.5(b) that distance up to five times the lesser of the
				height or the width dimension of a structure, but not greater than 0.8 km (1/2
				mile), and
(2) For conducting
				demonstrations under Rule 1.9.A(5)(c) that distance not greater than 0.8 km (1
/2
mile), except that the portion of a terrain feature may be
				considered to be nearby which falls within a distance of up to 10 times the
				maximum height (Ht) of the feature, not to exceed 2 miles if such feature
				achieves a height (ht) 0.8 km from the stack that is at least 40 percent of the
				GEP stack height determined by the formulae provided in Paragraph 1.9.A(5)(2)
				of this part or 26 meters, whichever is greater, as measured from the
				ground-level elevation at the base of the stack . The height of the structure
				or terrain feature is measured from the ground-level elevation at the base of
				the stack.
(d) "Excessive
				concentration." For the purpose of determining good engineering practice stack
				height under Rule 1.9.A(5)(c) excessive concentration means:
(1) For sources seeking credit for stack
				height exceeding that established under Rule 1.9.A(5)(b) a maximum ground-level
				concentration due to emissions from a stack due in whole or part to downwash,
				wakes, and eddy effects produced by nearby structures or nearby terrain
				features which individually is at least 40 percent in excess of the maximum
				concentration experienced in the absence of such downwash, wakes, or eddy
				effects and which contributes to a total concentration due to emissions from
				all sources that is greater than an ambient air quality standard. For sources
				subject to the Prevention of Significant Deterioration program, an excessive
				concentration alternatively means a maximum ground-level concentration due to
				emissions from a stack due in whole or part to downwash, wakes, or eddy effects
				produced by nearby structures or nearby terrain features which individually is
				at least 40 percent in excess of the maximum concentration experienced in the
				absence of such downwash, wakes, or eddy effects and greater than a prevention
				of significant deterioration increment. The allowable emission rate to be used
				in making demonstrations under this part shall be prescribed by the new source
				performance standard that is applicable to the source category unless the owner
				or operator demonstrates that this emission rate is infeasible. Where such
				demonstrations are approved by the U. S. Environmental Protection Agency or the
				Commission, an alternative emission rate shall be established in consultation
				with the source owner or operator.
(2) For sources seeking credit after October
				11, 1983, for increases in existing stack heights up to the heights established
				under Rule 1.9.A(5)(b) either a maximum ground-level concentration due in whole
				or part to downwash, wakes, or eddy effects as provided in Rule 1.9.A(5)(b) of
				this rule, except that the emission rate specified by the State implementation
				plan (or, in the absence of such a limit, the actual emission rate) shall be
				used, or the actual presence of a local nuisance caused by the existing stack,
				as determined by the Commission, and
(3) For sources seeking credit after January
				12, 1979, for a stack height determined under Rule 1.9.A(5)(b) where the U. S.
				Environmental Protection Agency or the Commission requires the use of a field
				study or fluid model to verify GEP stack height, for sources seeking stack
				height credit after November 9, 1984, based on the aerodynamic influence of
				cooling towers, and for sources seeking stack height credit after December 31,
				1970, based on the aerodynamic influence of structures not adequately
				represented by the equations in Rule 1.9.A(5)(b) a maximum ground-level
				concentration due in whole or part to downwash, wakes, or eddy effects that is
				at least 40 percent in excess of the maximum concentration experienced in the
				absence of such downwash, wakes, or eddy effects.