StacksVerified U.S. regulatory reference

40 CFR Part 53, Table B-3

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov
PollutantAnalyzer type 2Hydro-chloric acidAmmoniaHydrogen sulfideSulfur dioxideNitrogen dioxideNitric oxideCarbon dioxideEthyleneOzoneM-xyleneWater vaporCarbon monoxideMethaneEthaneNaphthalene
SO2Ultraviolet fluorescence|5 0.14 0.140.50.5|0.50.220,000|| 6 0.05
SO2Flame photometric|0.014 0.14|750|| 3 20,00050
SO2Gas chromatography|0.14 0.14|750|| 3 20,00050
SO2Spectrophotometric-wet chemical (pararosanaline)0.20.10.14 0.140.5| 750| 0.5
SO2Electrochemical0.20.10.14 0.140.50.5| 0.20.5| 3 20,000
SO2Conductivity0.20.1| 4 0.140.5| 750
SO2Spectrophotometric-gas phase, including DOAS|| 4 0.140.50.5|0.50.2
O3Ethylene Chemiluminescence|3 0.1|| 750| 4 0.08| 3 20,000
O3NO-chemiluminescence|3 0.1| 0.5| 750| 4 0.08| 3 20,000
O3Electrochemical| 3 0.1| 0.50.5|| 4 0.08| 3 20,000
O3Spectrophotometric-wet chemical (potassium iodide)| 3 0.1| 0.50.53 0.5|4 0.08
O3Spectrophotometric-gas phase, including ultraviolet absorption and DOAS|| 0.50.53 0.5|4 0.080.0220,000
CONon-dispersive Infrared|||750|| 20,0004 10
COGas chromatography with flame ionization detector|||||20,0004 10| 0.5
COElectrochemical||| 0.5| 0.2|20,0004 10
COCatalytic combustion-thermal detection| 0.1||7500.2|20,0004 1050.5
COIR fluorescence|||750|| 20,0004 10| 0.5
COMercury replacement-UV photometric|||| 0.2|| 4 10| 0.5
NO2Chemiluminescent| 3 0.1| 0.54 0.10.5||20,000
NO2Spectrophotometric-wet chemical (azo-dye reaction)|| 0.54 0.10.5750| 0.5
NO2Electrochemical0.23 0.1| 0.54 0.10.5750| 0.5| 20,00050
NO2Spectrophotometric-gas phase| 3 0.1| 0.54 0.10.5|0.5| 20,00050

1 Concentrations of interferent listed must be prepared and controlled to ±10 percent of the stated value.

2 Analyzer types not listed will be considered by the Administrator as special cases.

3 Do not mix interferent with the pollutant.

4 Concentration of pollutant used for test. These pollutant concentrations must be prepared to ±10 percent of the stated value.

5 If candidate method utilizes an elevated-temperature scrubber for removal of aromatic hydrocarbons, perform this interference test.

6 If naphthalene test concentration cannot be accurately quantified, remove the scrubber, use a test concentration that causes a full-scale response, reattach the scrubber, and evaluate response for interference.

[89 FR 16383, Mar. 6, 2024]