Page 1 of 23

**Subpart FF**

**— Underground Coal Mines**  § 98.320 Definition of the source category. (a) This source category consists of active underground coal mines, and any underground mines under development that have operational pre
-mining degasification systems. An underground coal mine is a mine at which coal is produced by tunneling into the earth to the coalbed, which is then mined with underground mining equipment such as cutting machines and continuous, longwall, and shortwall mining machines, and transported to the surface. Underground coal mines are categorized as active if any one of the fol lowing five conditions apply: (1) Mine development is underway. (2) Coal has been produced within the last 90 days. (3) Mine personnel are present in the mine workings. (4) Mine ventilation fans are operative. (5) The mine is designated as an ”intermittent ” mine by the Mine Safety and Health Administration (MSHA). (b) This source category includes the following: (1) Each ventilation system shaft or vent hole , including both those points where mine ventilation air is emitted and those where it is sold, used onsite, or otherwise destroyed (including by ventilation air methane (VAM) oxidizers ).Page 2 of 23

(2) Each degasification system well or gob gas vent hole , including degasification systems deployed before, during, or after mi ning operations are conducted in a mine area. This includes both those wells and vent holes where coal bed gas is emitted, and those where the gas is sold, used onsite, or otherwise destroyed (including by flaring). (c) This source category does not include abandoned or closed mines, surface coal mines, or post
- coal mining activities ( e.g ., storage or transportation of coal). § 98.321 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an active underground coal mine and the facility meets the requirements of §98.2(a)(1). § 98.322 GHGs to report. (a) You must report CH 4 liberated from ventilation and degasification systems. (b) You must report CH 4 destruction from systems where gas is sold, used onsite, or otherwise destroyed (including by VAM oxidation and by flaring). (c) You must report net CH 4 emissions from ventilation and degasification systems. (d) You must report under this subpart the CO 2 emissions from coal mine gas CH 4 destruction occur r ing at the facility,Page 3 of 23

where the gas is not a fuel input for energy generation or use ( e.g ., flaring and VAM oxidation ). (e) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the CO 2 , CH 4 , and N 2O emissions from each stationary fuel combustion unit by following the requirements of subpart C. Report emissions from both the combustion of collected coal mine CH 4 and any other fuels. (f) An underground coal mine that is subject to this part because emissions from source categories described in Tables A

– 3, A

– 4 or A

– 5 of subpart A of this part, or from stationary combustion (subpart C of this part), is not required to report emissions under this subpart unless the coal mine liberates 36,500,000 actual cubic feet (acf) or more of methane per year from its ventilation system. § 98.323 Calculating GHG emissions. (a) For each ventilation shaft, vent hole, or centralized point into which CH 4 from multiple shafts and/or vent holes are collected, you must calcul ate the quarterly CH 4 liberated from the ventilation system using Equation FF

– 1 of this section. You must measure CH 4 content, flow rate, temperature, pressure, and moisture content of the gas using the procedures outlined in §98.324.Page 4 of 23

Where:
CH 4 V = Quarterly CH 4 liberated from a ventilation monitoring point (metric tons CH 4 ) . V = Volumetric flow rate for the quarter ( a cfm ) based on sampling or a flow rate meter. If a flow rate meter is used and the meter automatically corrects to standard temperature and pressure, then use scfm and replace “520°R/T × P/1 atm” with “1”. MCF = Moisture correction factor for the measurement period, volumetric basis.

= 1 when V and C are measured on a dry basis or

if both are measured on a wet basis.
= 1
- (f H2 O ) when V is measured on a wet basis and

C is measured on a dry basis.
= 1/[1
- (f H2 O )] when V is measured on a dry basis

and C is measured on a wet basis. (f H2 O ) = Moisture content of the CH 4 emitted during the measurement period, volumetric basis (cubic feet water per cubic feet emitted gas). C = CH 4 concentration of ventilation gas for the quarter (%). n = The number of days in the quarter where active ventilation of mining operations is taking place at the monitoring point. 0.0423 = Density of CH 4 at 520 °R (60 °F) and 1 atm (lb/scf). 520 °R = 520 degrees Rankine. T = Temperature at which flow is measured (°R) for the quarter. P = Absolute p ressure at which flow is measured (atm) for the quarter. The annual average barometric pressure from the nearest NOAA weather service station may be used as a default. 1,440 = Conversion factor (min/day). 0.454/1,000 = Conversion factor (metric ton/lb).Page 5 of 23

(1) Consistent with MSHA inspections, the quarterly periods
are: (i) January 1

–March 31. (ii) Ap ril 1

– June 30. (iii) July 1

– September 30. (iv) October 1

– December 31. (2) Values of V, C, T, P, and (f H2 O ), if applicable, must be based on measurements taken at least once each quarter with no fewer than 6 weeks between measurements. If measurements are taken more frequently than once per quarter, then use the average value for all measurements taken. If contin uous measurements are taken, then use the average value over the time period of continuous monitoring. (3) If a facility has more than one monitoring point, the facility must calculate total CH 4 liberated from ventilation systems ( CH 4 VTotal ) as the sum of the CH 4 from all ventilation monitoring points in the mine, as follows:

Where:
CH 4VTotal = Total qu arterly CH 4 liberated from ventilation systems (metric tons CH 4 ) . CH 4V = Quarterly CH 4 liberated from each ventilation monitoring point (metric tons CH 4 ) . m = Number of ventilation monitoring points.Page 6 of 23

(b) For each monitoring point in the degasification syst em (this could be at each degasification well and/or vent hole, or at more centralized points into which CH 4 from multiple wells and/or vent holes are collected), you must calculate the weekly CH 4 liberated from the mine using CH 4 measured weekly or more f requently (including by CEMS) according to 98.234(c), CH 4 content, flow rate, temperature, pressure, and moisture content, and Equation FF

– 3 of this section.

= ∑ ∗ ∗ % ∗ 0
.0423 ∗ ° ∗ ∗ 1,440 ∗ .

, (Eq. FF
- 3)

Where:
CH 4 D = Weekly CH 4 liberated from at the monitoring point (metric tons CH 4 ) . Vi = Measured volumetric flow rate for the days in the week when the degasification system is in operation at that monitoring point, based on sampling or a flow rate meter ( a cfm ). If a flow rate meter is used and the meter automatically corrects to standard temperature and pressure, then use scfm and replace “520°R/T i × P i /1 atm” with “1”. MCF i = Moisture correction factor for the measurement period, volumetric basis.

= 1 when Vi and C i are measured on a dry basis or

if both are measured on a wet basis.
= 1
- (f H2 O ) i when Vi is measured on a wet basis and

C i is measured on a dry basis.
= 1/[1
- (f H2 O ) i ] when Vi is measured on a dry basis

and C i is measured on a wet basis.Page 7 of 23

(f H2 O ) = Moisture content of the CH 4 emitted during the measurement period, volumetric basis (cubic feet water per cubic feet emitted gas) C i = CH 4 concentration of gas for the days in the week when the degasification system is in operation at that monitoring point (%). n = The number of days in the week that the system is operational at that measurement point. 0.0423 = Density of CH 4 at 520 °R (60 °F) and 1 atm (lb/scf). 520 °R = 520 degrees Rankine. T i = Temperature at which flow is measured (°R). P i = Absolute p ressure at which flow is measured (atm). 1,440 = Conversion factor (minutes/day). 0.454/1,000 = Conversion factor (metric ton/lb). (1) Values for V, C, T, P, and (f H2 O ), if applicable, must be based on measurements taken at least once each calendar week with at least 3 days between measurements. If measurements are taken more frequently than once per week, then use the average value for all measurements taken that week. If continuous measurements are taken, then use the average val ues over the time period of continuous monitoring when the continuous monitoring equipment is properly functioning. (2) Quarterly total CH 4 liberated from degasification systems for the mine should be determined as the sum of CH 4 liberated determined at ea ch of the monitoring points in the mine, summed over the number of weeks in the quarter, as follows:Page 8 of 23

Where:
CH 4 DTotal = Quarterly CH 4 liberated from all degasification monitoring points (metric tons CH 4 ) . ( CH 4 D ) i,j = Weekly CH 4 liberated from a degasification monitoring point (metric tons CH 4 ) . m = Number of monitoring points.
w = Number of weeks in the quarter during which the degasification system is operated. (c) If gas from a degasification system o r ventilation system is sold, used onsite, or otherwise destroyed (including by flaring or VAM oxidation ), you must calculate the quarterly CH 4 destroyed for each destruction device and each point of offsite transport to a destruction device, using Equatio n FF

– 5 of this section. You must measure CH 4 content and flow rate according to the provisions in §98.324, and calculate the methane routed to the destruction device ( CH 4 ) using either Equation FF

– 1 or Equation FF

– 4 of this section, as applicable.

Where:
CH 4 Destroyed = Quarterly CH 4 destroyed (metric tons). CH 4 = Quarterly CH 4 routed to the destruction device or offsite transfer point (metric tons). DE = Destruction efficiency (lesser of manufacturer's specified destruction efficiency and 0.99). If the gas is transported off
- site for destruction, use DE = 1.Page 9 of 23

(1) Calculate total CH 4 destroyed as the sum of the methane destroyed at all destruction devices (onsite and offsite), using Equation FF

– 6 of this section.

= ∑ (Eq. FF
- 6)

Where:
CH 4 DestroyedTotal = Quarterly total CH 4 destroyed at the mine (metric tons CH 4 ) . CH 4 Destroyed = Quarterly CH 4 destroyed from each destruction device or offsite transfer point. d = Number of onsite destruction devices and points of offsite transport. (2) [Reserved] (d) You must calculate the quarterly measured net CH 4 emissions to the atmosphere using Equation FF

– 7 of this section.

Where:
CH 4 emitted (net) = Quarterly CH 4 emissions from the mine (metric tons). CH 4VTotal = Quarterly sum of the CH 4 liberated from all mine ventilation monitoring points ( CH 4 V ), calculated using Equation FF

– 2 of this section (metric tons). CH 4 DTotal = Quarterly sum of the CH 4 liberated from all mine degasification monitoring points ( CH 4 D ), calculated using Equation FF

– 4 of this section (metric tons). CH 4 DestroyedTotal = Quarterly sum of the measured CH 4 destroyed from all mine ventilation and degasification systems, calculated using Equation FF

– 6 of this section (metric tons).Page 10 of 23

(e) For the methane collected from degasification and/or ventilation systems that is destroyed on site and is not a fuel input for energy generation or use (those emissions are monitored and reported under Subpart C of this part), you must est imate the CO 2 emissions using Equation FF

– 8 of this section.

Where:
CO 2 = Total quarterly CO 2 emissions from CH 4 destruction (metric tons). CH 4 Destroyedonsite = Quarterly sum of the CH 4 destroyed, calculated as the sum of CH 4 destroyed for each onsite, non - energy use, as calculated individually in Equation FF

– 5 of this section (metric tons). 44/16 = Ratio of molecular weights of CO 2 to CH 4 . § 98.324 Monitoring and QA/QC requirements. (a) For calendar year 2011 monitoring, the facility may submit a reque st to the Administrator to use one or more best available monitoring methods as listed in §98.3(d)(1)(i) through (iv). The request must be submitted no later than October 12, 2010 and must contain the information in §98.3(d)(2)(ii). To obtain approval, the request must demonstrate to the Administrator's satisfaction that it is not reasonably feasible to acquire, install, and operate a required piece of monitoring equipment by January 1, 2011. The use of best available monitoring methods will not be approved beyond December 31, 2011.Page 11 of 23

(b) For CH 4 liberated from ventilation systems, determine whether CH 4 will be monitored from each ventilation shaft and vent hole , from a centralized monitoring point, or from a combination of the two options. Operators are allowed flexibility for aggregating emissions from more than one ventilation point , as long as emissions from all are addressed, and the methodology for calculating total emissions documented. Monitor by one of the following options: (1) Collect quarterly or more frequent grab samples (with no fewer than 6 weeks between measurements) for methane concentration and make quarterly measurements of flow ra te, temperature, pressure, and moisture content, if applicable. The sampling and measurements must be made at the same locations as Mine Safety and Health Administration (MSHA) inspection samples are taken, and should be taken when the mine is operating under normal conditions. You must follow MSHA sampling procedures as set forth in the MSHA Handbook entitled, General Coal Mine Inspection Procedures and Inspection Tracking System Handbook Number: PH

– 08

–V

– 1, January 1, 2008 (incorporated by reference, see § 98.7). You must record the date of sampling, flow, temperature, pressure, and moisture measurements, the methane concentration (percent), the bottle number of samples collected, and the location of the measurement or collection.Page 12 of 23

(2) Obtain results of the quarterly (or more frequent) testing performed by MSHA for the methane flowrate. At the same location and within seven days of the MSHA sampling, make measurements of temperature and pressure using the same procedures specified in paragraph (b)(1) of this s ection. The annual average barometric pressure from the nearest National Oceanic and Atmospheric Administration (NOAA) weather service station may be used as a default for pressure. If the MSHA data for methane flow is provided in the units of actual cubic feet of methane per day, the methane flow data is inserted into Equation FF

– 1 of this section in place of the value for V and the variables MCF, C/100%, and 1440 are removed from the equation. (3) Monitor emissions through the use of one or more continuou s emission monitoring systems (CEMS). If operators use CEMS as the basis for emissions reporting, they must provide documentation on the process for using data obtained from their CEMS to estimate emissions from their mine ventilation systems. (c) For CH 4 liberated at degasification systems, determine whether CH 4 will be monitored from each well and gob gas vent hole, from a centralized monitoring point, or from a combination of the two options. Operators are allowed flexibility for aggregating emissions from more than one well or gob gas vent hole, as long as emissions from all are addressed, and thePage 13 of 23

methodology for calculating total emissions is documented. Monitor both gas volume and methane concentration by one of the following two options: (1) Monitor emissions through the use of one or more continuous emissions monitoring systems (CEMS). If operators use CEMS as the basis for emissions reporting, they must provide documentation on the process for using data obtained from their CEMS to estimate emissions from their mine ventilation systems. (2) Collect weekly (once each calendar week, with at least three days between measurements) or more frequent samples, for all degasification wells and gob gas vent holes. Determine weekly or more frequent flow rates, methane concentration, temperature, and pressure from these degasification wells and gob gas vent holes. Methane composition should be determined either by submitting samples to a lab for analysis, or from the use of methanometers at the degasification monitoring site. Follow the sampling protocols for sampling of methane emissions from ventilation shafts, as described in §98.324(b)(1). You must record the date of sampling, flow, temperature, pressure, and moisture measurements, the methane concentration (percent), the bottle number of samples collected, and the location of the measurement or collection. (3) If the CH 4 concentration is determined on a dry basis and flow is determined on a wet basis or CH 4 concentration isPage 14 of 23

determined on a wet basis and flow is determined on a dry basis, and the flow meter does not automatically correct for moisture content, determine the moisture content in the gas in a location near or representative of the location of: (i) The gas flow meter at least once each calendar we ek; if measuring with CEMS. If only one measurement is made each calendar week, there must be at least three days between measurements; and (ii) The grab sample, if using grab samples, at the time of the sample. (d) Monitoring must adhere to one of the methods specified in paragraphs (d)(1) through (d)(2) of this section. (1) ASTM D1945

– 03, Standard Test Method for Analysis of Natural Gas by Gas Chromatography; ASTM D1946

– 90 (Reapproved 2006), Standard Practice for Analysis of Reformed Gas by Gas Chromatography; ASTM D4891

– 89 (Reapproved 2006), Standard Test Method for Heating Value of Gases in Natural Gas Range by Stoichiometric Combustion; or ASTM UOP539

– 97 Refinery Gas Analysis by Gas Chromatography (incorporated by reference, see §98.7). (2) As an alternative to the gas chromatography methods provided in paragraph (d)(1) of this section, you may use gaseous organic concentration analyzers and a correction factorPage 15 of 23

to calculate the CH 4 concentration following the requirements in paragraphs (d )(2)(i) through (d)(2)(iii) of this section. (i) Use Method 25A or 25B at 40 CFR part 60, appendix A

– 7 to determine gaseous organic concentration as required in §98.323 and in paragraphs (b) and (c) of this section. You must calibrate the instrument with CH 4 and determine the total gaseous organic concentration as carbon (or as CH 4 ; K=1 in Equation 25A

– 1 of Method 25A at 40 CFR part 60, appendix A

– 7). (ii) Determine a correction factor that will be used with the gaseous organic concentrations measured in pa ragraph (i) of this section. The correction factor must be determined at the routine sampling location no less frequently than once a reporting year following the requirements in paragraphs (d)(2)(ii)(A) through (d)(2)(ii)(C) of this section. (A) Take a mi nimum of three grab samples of the gas with a minimum of 20 minutes between samples and determine the methane composition of the gas using one of the methods specified in paragraph (d)(1) of this section. (B) As soon as practical after each grab sample is collected and prior to the collection of a subsequent grab sample, determine the gaseous organic concentration of the gas using either Method 25A or 25B at 40 CFR part 60, appendix A

– 7 as specified in paragraph (d)(2)(i) of this section.Page 16 of 23

(C) Determine the arithmetic average methane concentration and the arithmetic average gaseous organic concentration of the samples analyzed according to paragraphs (d)(2)(ii)(A) and (d)(2)(ii)(B) of this section, respectively, and calculate the
non -methane organic carbon co rrection factor as the ratio of the average methane concentration to the average total gaseous organic concentration. If the ratio exceeds 1, use 1 for the correction factor. (iii) Calculate the CH 4 concentration as specified in Equation FF

– 9 of this secti on:

Where:
C CH 4 = Methane ( CH 4 ) concentration in the gas (volume %) for use in Equations FF

– 1 and FF

– 3 of this subpart. fNMOC = Correction factor from the most recent determination of the correction factor as specified in paragraph (d)(2)(ii) of this section (unitless). C TGOC = Gaseous organic carbon concentration measured using Method 25A or 25B at 40 CFR part 60, appendix A

– 7 during routine monitoring of the gas (volume %). (e) All flow meters and gas composition monitors that are used to provide dat a for the GHG emissions calculations shall be calibrated prior to the first reporting year, using the applicable methods specified in paragraphs (d), and (e)(1) through (e)(7) of this section. Alternatively, calibrationPage 17 of 23

procedures specified by the flow met er manufacturer may be used. Flow meters and gas composition monitors shall be recalibrated either at the minimum frequency specified by the manufacturer or annually. The operator shall operate, maintain, and calibrate a gas composition monitor capable of measuring the concentration of CH 4 in the gas using one of the methods specified in paragraph (d) of this section. The operator shall operate, maintain, and calibrate the flow meter using any of the following test methods or follow the procedures specified by the flow meter manufacturer. Flow meters must meet the accuracy requirements in §98.3(i). (1) ASME MFC

– 3M

– 2004, Measurement of Fluid Flow in Pipes Using Orifice, Nozzle, and Venturi (incorporated by reference,
see §98.7). (2) ASME MFC

– 4M

– 1986 (Reaffirmed 1997), Measurement of Gas Flow by Turbine Meters (incorporated by reference, see §98.7). (3) ASME MFC

– 6M

– 1998, Measurement of Fluid Flow in Pipes Using Vortex Flowmeters (incorporated by reference, see §98.7). (4) ASME MFC

– 7M

– 1987 (Reaffirmed 1992), Mea surement of Gas Flow by means of Critical Flow Venturi Nozzles (incorporated by reference, see §98.7). (5) ASME MFC

– 11M

– 2006 Measurement of Fluid Flow by means of Coriolis Mass Flowmeters (incorporated by reference, see §98.7).Page 18 of 23

(6) ASME MFC

– 14M

– 2003 Measurement of Fluid Flow Using Small Bore Precision Orifice Meters (incorporated by reference, see §98.7). (7) ASME MFC

– 18M

– 2001 Measurement of Fluid Flow using Variable Area Meters (incorporated by reference, see §98.7). (f) For CH 4 destruction, CH 4 must be monitored at each onsite destruction device and each point of offsite transport for combustion using continuous monitors of gas routed to the device or point of offsite transport. (g) All temperature, pressure, and moisture content monitors must be operated and calibrated using the procedures and frequencies specified by the manufacturer. (h) If applicable, the owner or operator shall document the procedures used to ensure the accuracy of gas flow rate, gas composition, temperature, pressure, and moisture con tent measurements. These procedures include, but are not limited to, calibration of flow meters, and other measurement devices. The estimated accuracy of measurements, and the technical basis for the estimated accuracy shall be recorded. § 98. 325 Procedure s for estimating missing data. (a) A complete record of all measured parameters used in the GHG emissions calculations is required. Therefore, whenever a quality
- assured value of a required parameter is unavailable ( e.g ., if a meter malfunctions during uni t operation or if aPage 19 of 23

required fuel sample is not taken), a substitute data value for the missing parameter shall be used in the calculations, in accordance with paragraph (b) of this section. (b) For each missing value of CH 4 concentration, flow rate, tempe rature, pressure, and moisture content for ventilation and degasification systems, the substitute data value shall be the arithmetic average of the quality
- assured values of that parameter immediately preceding and immediately following the missing data in cident. If, for a particular parameter, no quality
- assured data are available prior to the missing data incident, the substitute data value shall be the first quality
assured value obtained after the missing data period. § 98.326 Data reporting requirements. In addition to the information required by §98.3(c), each annual report must contain the following information for each mine: (a) Quarterly CH 4 liberated from each ventilation monitoring point , (metric tons CH 4 ) . (b) Weekly CH 4 liberated from each degasification system monitoring point (metric tons CH 4 ) . (c) Quarterly CH 4 destruction at each ventilation and degasification system destruction device or point of offsite transport (metric tons CH 4 ) .Page 20 of 23

(d) Quarterly CH 4 emissions (net) from all ventilation and degasification systems (metric tons CH 4 ) . (e) Quarterly CO 2 emissions from on
- site destruction of coal mine gas CH 4 , where the gas is not a fuel input for energy generation or use ( e.g ., flaring) (metric tons CO 2 ) . (f) Quarterly vo lumetric flow rate for each ventilation monitoring point and units of measure (scfm or acfm ), date and location of each measurement, and method of measurement (quarterly sampling or continuous monitoring), used in Equation FF

– 1 of this subpart. (g) Quarter ly CH 4 concentration for each ventilation monitoring point, dates and locations of each measurement and method of measurement (sampling or continuous monitoring). (h) Weekly volumetric flow rate used to calculate CH 4 liberated from degasification systems and units of measure (acfm or scfm), and method of measurement (sampling or continuous monitoring), used in Equation FF

– 3 of this subpart. (i) Quarterly CH 4 concentration (%) used to calculate CH 4 liberated from degasification systems and if the data is based
on CEMS or weekly sampling . (j) Weekly volumetric flow rate used to calculate CH 4 destruction for each destruction device and each point of offsite transport , and units of measure ( a cfm or scfm ).Page 21 of 23

(k) Weekly CH 4 concentration (%) used to calculate CH 4 flow to each destruction device and each point of offsite transport (C). (l) Dates in quarterly reporting period where active ventilation of mining operations is taking place. (m) Dates in quarterly reporting period where degasification of mining operations is taking place. (n) Dates in quarterly reporting period when continuous monitoring equipment is not properly functioning, if applicable. (o) Temperatures (° R), pressure (atm), moisture content , and the moisture correction factor (if applicable) used in Equation FF

– 1 and FF

– 3 of this subpart ; and the gaseous organic concentration correction factor, if Equation FF

– 9 was required. (p) For each destruction device, a description of the device, including an indication of whether destruction occurs at the coal mine or off
- site. If destruction occurs at the mine, also report an indication of whether a back
- up destruction device is present at the mine, the annual operating hours for the primary destruction device, the annual operating hours for the back
- up destruction device (if present), and the destruction efficiencies assumed (percent). (q) A description of the gas collection system (manufacturer, capacity, and number of wells) the surface areaPage 22 of 23

of the gas collection system (square meters), and the annual operating hours of the gas collection system. (r) Identification information and description for each well , shaft, and vent hole, including paragraphs (r)(1) through (r)( 3 ) of this section: (1) I ndication of whether the well , shaft , or vent hole is monitored individually, or as part of a centralized monitoring point. Note which method (sampling or continuous monitoring) was used. (2) Start date and close date of each well , shaft , and vent hole . (3) Number of days the well , shaft , or vent hole was in operation during the reporting year . (s) For each centralized monitoring point, identification of the wells and shafts included in the point. Note which method (sampling or continuous monitoring) was used. ( t ) Mine Safety and Health Administration (MSHA) identification for this coal mine. § 98.327 Records that must be retained. In addition to the information required by §98.3(g), you must retain the following records: (a) Calibration records for all monitoring equipment, including the method or manufacturer's specification used for calibration.Page 23 of 23

(b) Records of gas sales. (c) Logbooks of parameter measurements. (d) Laboratory analyses of samples. § 98.328 Definitions. All terms used in this subpart have the same meaning given in the Clean Air Act and subpart A of this part.