40 CFR Part 53, Table A-1

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗

Pollutant	Reference or equivalent	Manual or automated	Applicable appendix of part 50 of this chapter	Applicable subparts of this part
A	B	C	D	E \| F
SO2	Reference	Manual	A-2	\| \| \| \| \|
		Automated	A-1	✓ \| ✓ \| \| \| \|
	Equivalent	Manual	A-1	✓ \| \| ✓ \| \| \|
		Automated	A-1	✓ \| ✓ \| ✓ \| \| \|
CO	Reference	Automated	C	✓ \| ✓ \| \| \| \|
	Equivalent	Manual	C	✓ \| \| ✓ \| \| \|
		Automated	C	✓ \| ✓ \| ✓ \| \| \|
O3	Reference	Automated	D	✓ \| ✓ \| \| \| \|
	Equivalent	Manual	D	✓ \| \| ✓ \| \| \|
		Automated	D	✓ \| ✓ \| ✓ \| \| \|
NO2	Reference	Automated	F	✓ \| ✓ \| \| \| \|
	Equivalent	Manual	F	✓ \| \| ✓ \| \| \|
		Automated	F	✓ \| ✓ \| ✓ \| \| \|
Pb	Reference	Manual	G	\| \| \| \| \|
	Equivalent	Manual	G	✓ \| \| ✓ \| \| \|
		Automated	G	✓ \| \| ✓ \| \| \|
PM10-Pb	Reference	Manual	Q	\| \| \| \| \|
	Equivalent	Manual	Q	✓ \| \| ✓ \| \| \|
		Automated	Q	✓ \| \| ✓ \| \| \|
PM10	Reference	Manual	J	✓ \| \| \| ✓ \| \|
	Equivalent	Manual	J	✓ \| \| ✓ \| ✓ \| \|
		Automated	J	✓ \| \| ✓ \| ✓ \| \|
PM2.5	Reference	Manual	L	✓ \| \| \| \| ✓ \|
	Equivalent Class I	Manual	L	✓ \| \| ✓ \| \| ✓ \|
	Equivalent Class II	Manual	L 1	✓ \| \| 2 ✓ \| \| ✓ \| 1 2 ✓
	Equivalent Class III	Automated	L 1	✓ \| \| ✓ \| \| ✓ \| 1 ✓
PM10-2.5	Reference	Manual	L,2 O	✓ \| \| \| \| ✓ \|
	Equivalent Class I	Manual	L,2 O	✓ \| \| ✓ \| \| ✓ \|
	Equivalent Class II	Manual	L,2 O	✓ \| \| 2 ✓ \| \| ✓ \| 1,2 ✓
	Equivalent Class III	Automated	1 L, 1 2 O	✓ \| \| ✓ \| \| ✓ \| 1 ✓

1 Some requirements may apply, based on the nature of each particular candidate method, as determined by the Administrator.

2 Alternative Class III requirements may be substituted.

[89 FR 16382, Mar. 6, 2024]