Chapter NR 404

NR 404.04(8)(a) (a) The primary and secondary standards for PM10 are 150 micrograms per cubic meter (mg/m3) — maximum 24-hour average concentration.

NR 404.04(8)(b) (b) The PM 10 standards are attained when the expected number of days per calendar year with a 24-hour average concentration above 150 mg/m3, the level designated in par. (a), is equal to or less than one.

NR 404.04(8)(c) (c) The expected concentrations and number of days shall be determined by the methodology contained in 40 CFR part 50, Appendix K, incorporated by reference in s. NR 484.04 (6).

NR 404.04(9) (9) PM2.5.

NR 404.04(9)(am) (am) Primary standards.

NR 404.04(9)(am)1. 1. The primary standards for PM2.5 are 12.0 micrograms per cubic meter (mg/m3) — annual arithmetic mean concentration and 35 mg/m3 — 24-hour average concentration, measured in the ambient air as PM2.5 by either of the following methods:

NR 404.04(9)(am)1.a. a. A reference method based on 40 CFR part 50, Appendix L.

NR 404.04(9)(am)1.b. b. An equivalent method designated in accordance with s. NR 404.06 (3) (b).

NR 404.04(9)(am)2. 2. The primary annual standard is met when the annual arithmetic mean concentration, as determined in accordance with 40 CFR part 50, Appendix N, is less than or equal to 12.0 mg/m3.

NR 404.04(9)(am)3. 3. The primary 24-hour standard is met when the 98th percentile 24-hour concentration, as determined in accordance with 40 CFR part 50, Appendix N, is less than or equal to 35 mg/m3.

NR 404.04(9)(bm) (bm) Secondary standards.

NR 404.04(9)(bm)1. 1. The secondary standards for PM2.5 are 15.0 mg/m3 annual arithmetic mean concentration and 35 mg/m3 24-hour average concentration, measured in the ambient air as PM2.5 by either of the following methods:

NR 404.04(9)(bm)1.a. a. A reference method based on 40 CFR part 50, Appendix L.

NR 404.04(9)(bm)1.b. b. An equivalent method designated in accordance with s. NR 404.06 (3) (b).

NR 404.04(9)(bm)2. 2. The secondary annual standard is met when the annual arithmetic mean concentration, as determined in accordance with 40 CFR part 50, Appendix N, is less than or equal to 15.0 mg/m3.

NR 404.04(9)(bm)3. 3. The secondary 24-hour standard is met when the 98th percentile 24-hour concentration, as determined in accordance with 40 CFR part 50, Appendix N, is less than or equal to 35 mg/m3.

NR 404.04 Note Note: 40 CFR part 50, Appendices L and N are incorporated by reference in s. NR 484.04 (6g) and (6r), respectively.

NR 404.04 History History: Cr. Register, March, 1972, No. 195, eff. 4-1-72; r. (1) (b)1. and 2., renum. (1) (b) 3., to be 1., Register, June, 1975, No. 234, eff. 7-1-75; am. (4), Register, August, 1981, No. 308, eff. 9-1-81; reprinted to correct error in (3), Register, November, 1981, No. 311; cr. (7), Register, April, 1983, No. 328, eff. 5-1-83; r. (5), Register, November, 1983, No. 335, eff. 12-1-83; am. Register, July, 1985, No. 355, eff. 8-1-85; renum. from NR 404.03, Register, September, 1986, No. 369, eff. 10-1-86; r. (3) (a), renum. (3) (b) to be (3) and am., cr. (8), Register, September, 1989, No. 405, eff. 10-1-89; am. (5) and (8) (b) 3., Register, May, 1992, No. 437, eff. 6-1-92; am. (5) and (8) (b) 3., Register, December, 1995, No. 480, eff. 1-1-96; am. (8) (b), Register, December, 1996, No. 492, eff. 1-1-97; CR 03-066: am. (2) (a) 1. and 2. and (b), (5) and (6), cr. (5) (b) Register May 2005 No. 593, eff. 6-1-05; CR 07-082: am. (8), cr. (9) Register September 2009 No. 645, eff. 10-1-09; CR 09-088: cr. (5) (c), (7) (a) and (b), renum. (7) to be (7) (intro.) and am. Register May 2010 No. 653, eff. 6-1-10; CR 07-082: r. (3) Register November 2011 No. 671, eff. 12-1-11; CR 15-033: am. (2) (a) (title), renum. (a) (intro.) to (a) and am., r. 1. and 2., r. and recr. (6) Register July 2016 No. 727, eff. 8-1-16; CR 16-041: am. (9) (title), cr. (9) (am) (title), consol. (9) (a) (intro.), 1., 2. and renum. to (9) (am) 1. (intro.) and am., cr. (9) (am) 1. a., b., consol. (9) (b) (intro.), 1. and renum. to (9) (am) 2. and am., renum. (9) (b) 2. to (9) (am) 3. and am., cr. (9) (bm), r. (9) (c) Register December 2017 No. 744, eff. 1-1-18; CR 21-022: cr. (5) (d) Register February 2022 No. 794, eff. 3-1-22.

NR 404.05 NR 404.05 Ambient air increments.

NR 404.05(1) (1)  Scope. The ambient air increments apply to all attainment areas of the state.

NR 404.05(2) (2) Class I increments. In any area of this state classified under the Act as a class I area, the ambient air increments for PM10, PM2.5, sulfur dioxide, and nitrogen dioxide may not exceed the following amounts:

NR 404.05(2)(a) (a) PM10 .

1. Annual arithmetic mean   4 micrograms per cubic meter

2. Twenty-four hour maximum   8 micrograms per cubic meter

NR 404.05(2)(am) (am) PM2.5 .

1. Annual arithmetic mean   1 microgram per cubic meter

2. Twenty-four hour maximum   2 micrograms per cubic meter

NR 404.05(2)(b) (b) Sulfur dioxide.

1. Annual arithmetic mean   2 micrograms per cubic meter

2. Twenty-four hour maximum   5 micrograms per cubic meter

3. Three hour maximum   25 micrograms per cubic meter

NR 404.05(2)(c) (c) Nitrogen dioxide.

1. Annual arithmetic mean   2.5 micrograms per cubic meter

NR 404.05(3) (3) Class II increments. In any area of this state classified under the Act as a class II area, the ambient air increments for PM10, PM2.5, sulfur dioxide, and nitrogen dioxide may not exceed the following amounts:

NR 404.05(3)(a) (a) PM10 .

1. Annual arithmetic mean   17 micrograms per cubic meter

2. Twenty-four hour maximum   30 micrograms per cubic meter

NR 404.05(3)(am) (am) PM2.5 .

1. Annual arithmetic mean   4 micrograms per cubic meter

2. Twenty-four hour maximum   9 micrograms per cubic meter

NR 404.05(3)(b) (b) Sulfur dioxide.

1. Annual arithmetic mean   20 micrograms per cubic meter

2. Twenty-four maximum   91 micrograms per cubic meter

3. Three hour maximum   512 micrograms per cubic meter

NR 404.05(3)(c) (c) Nitrogen dioxide.

1. Annual arithmetic mean   25 micrograms per cubic meter

NR 404.05(4) (4) Class III increments. In any area of this state classified under the Act as a class III area, the ambient air increments for PM10, PM2.5, sulfur dioxide, and nitrogen dioxide may not exceed the following amounts:

NR 404.05(4)(a) (a) PM10 .

1. Annual arithmetic mean   34 micrograms per cubic meter

2. Twenty-four hour maximum   60 micrograms per cubic meter

NR 404.05(4)(am) (am) PM2.5 .

1. Annual arithmetic mean   8 micrograms per cubic meter

2. Twenty-four hour maximum   18 micrograms per cubic meter

NR 404.05(4)(b) (b) Sulfur dioxide.

1. Annual arithmetic mean   40 micrograms per cubic meter

2. Twenty-four hour maximum   182 micrograms per cubic meter

3. Three hour maximum   700 micrograms per cubic meter

NR 404.05(4)(c) (c) Nitrogen dioxide.

1. Annual arithmetic mean   50 micrograms per cubic meter

NR 404.05(5) (5) Exception for non-annual concentrations. Notwithstanding subs. (2) (intro.), (3) (intro.) and (4) (intro.), the ambient air increment of an air contaminant based on concentrations for any period other than an annual period may be exceeded during one such period per year.

NR 404.05(6) (6) Maximum concentration. The maximum allowable concentration of any air contaminant in any attainment area may not exceed a concentration for such contaminant for each period of exposure equal to the maximum concentrations permitted under the primary or secondary air standards in s. NR 404.04.

NR 404.05 History History: Cr. Register, April, 1983, No. 238, eff. 5-1-83; renum. from NR 155.035, Register, July, 1985, No. 355, eff. 8-1-85; renum. from NR 404.04, Register, September, 1986, No. 369, eff. 10-1-86; am. (2) (intro.), (3) (intro.) and (4) (intro.), cr. (2) (c), (3) (c) and (4) (c), Register, May, 1992, No. 437, eff. 6-1-92; am. (2) (intro.), (a), (3) (intro.), (a), (4) (intro.), (a), Register, April, 1995, No. 472, eff. 5-1-95; am. (3) (intro.) and (4) (intro.), Register, December, 1996, No. 492, eff. 1-1-97; CR 15-077: am. (2) (intro.), cr. (2) (am), am. (3) (intro.), cr. (3) (am), am. (4) (intro.), cr. (4) (am) Register July 2016 No. 727, eff. 8-1-16.

NR 404.06 NR 404.06 Measurement of ambient air quality.

NR 404.06(1) (1)  Applicability.

NR 404.06(1)(a) (a) The department and any person conducting ambient air quality monitoring on its behalf shall use only reference or equivalent methods as specified in sub. (2) or (3) for all ambient air quality monitoring for any air contaminant identified in s. NR 404.04. The ambient monitoring shall conform with the department's guidebooks, plans and procedures for air monitoring quality assurance.

NR 404.06(1)(b) (b) Any person required by the department to conduct ambient air quality monitoring shall use only reference or equivalent methods for sampling and analysis as specified in sub. (2) or (3) and shall comply with quality assurance and quality control procedures and the data reporting format which are specified and approved by the department for the collection, analysis, processing and reporting of ambient air quality monitoring data.

NR 404.06(1)(c) (c) Any person who voluntarily conducts ambient air quality monitoring in Wisconsin may request the department to determine that the data being collected are comparable to the air quality data collected under par. (a) or (b). The department may determine that the data are comparable if the voluntary ambient air quality monitoring and the data meet the requirements specified in par. (b).

NR 404.06(1)(d) (d) The department may determine that air quality data submitted to the department for purposes of demonstrating compliance with existing regulations under chs. NR 400 to 499 or in support of a permit or permit application are unacceptable if such monitoring was not conducted in compliance with pars. (a) to (c).

NR 404.06(2) (2) Reference methods. Ambient air quality monitoring which utilizes a reference monitoring method shall use monitoring methods which conform to the federal reference methods which are specified in 40 CFR part 50, Appendices A to T, incorporated by reference in s. NR 484.04 (2), or which have been so designated by the department.

NR 404.06(3) (3) Equivalent methods.

NR 404.06(3)(a) (a) Ambient air quality monitoring which utilizes an equivalent monitoring method shall use monitoring methods which have been published by the department under sub. (4) (a).

NR 404.06(3)(b) (b) The department may list a monitoring method as an equivalent method if the department determines that the method satisfies the same requirements for a federal equivalent method as specified in 40 CFR part 53, incorporated by reference in s. NR 484.03.

NR 404.06(3)(c) (c) The department shall maintain a list of equivalent methods and shall send a copy of the list to any person upon request. A current copy of the list shall be available for inspection or copying at the department's headquarters office.

NR 404.06 Note Note: The department's headquarters office is located at 101 South Webster Street, Madison, Wisconsin. Mail requests should be addressed to the Department of Natural Resources, Bureau of Air Management, PO Box 7921, Madison WI 53707.

NR 404.06(4) (4) Air quality publications. The department shall publish documents relating to air quality or to air monitoring, including the following:

NR 404.06(4)(a) (a) The department shall publish or revise a list of equivalent monitoring methods as specified in sub. (3).

NR 404.06(4)(b) (b) The department shall publish, revise and maintain quality assurance plans and guidebooks which describe the activities and procedures of the quality assurance and quality control systems.

NR 404.06(4)(c) (c) The department shall publish reports on air quality and related information and data.

NR 404.06 History History: Cr. Register, July, 1985, No. 355, eff. 8-1-85; renum. from NR 404.05, Register, September, 1986, No. 369, eff. 10-1-86; am. (2) and (3) (b), Register, May, 1992, No. 437, eff. 6-1-92; am. (1) (a), (2), (3) (b) and (4) (b), Register, December, 1995, No. 480, eff. 1-1-96; CR 03-066: am. (2) Register May 2005 No. 593, eff. 6-1-05; CR 15-033: am. (2) Register July 2016 No. 727, eff. 8-1-16.

NR 404.07 NR 404.07 Interpretation of air quality data with respect to air standards. The department shall, for implementation purposes, take into account levels and variations in natural background levels of contaminants, the quality of air entering a region, abnormal local short-term activities and the numbers and types of persons and property affected.

NR 404.07 History History: Cr. Register, March, 1972, No. 195, eff. 4-1-72; renum. from NR 155.05, Register, July, 1985, No. 355, eff. 8-1-85; renum. from NR 404.06, Register, September, 1986, No. 369, eff. 10-1-86.

NR 404.08 NR 404.08 Guidelines for application of air standards.

NR 404.08(1) (1)  Limitations on local programs. No local programs may grant variances or construction or operation permits in conflict with the implementation plan for that region.

NR 404.08(2) (2) More restrictive limits. Any person may be required to reduce emissions below limits established in an implementation plan or by air pollution control rules where emissions cause or substantially contribute to exceeding an air standard in a localized area. In this case, appropriate special orders, which are not general in application, may be issued.

NR 404.08(3) (3) Fuels and raw materials. The department may prescribe characteristics of fuels and raw materials for existing and planned facilities in order to assure attainment or maintenance of an air standard, to prevent the degradation of air quality or to prevent air pollution.

NR 404.08 History History: Cr. Register, March, 1972, No. 195, eff. 4-1-72; r. (4), Register, April, 1983, No. 328, eff. 5-1-83; renum. from NR 155.06 and am. (3), Register, July, 1985, No. 355, eff. 8-1-85; correction in (2) made under s. 13.93 (2m) (b) 5., Stats., Register, July, 1985, No. 355; renum. from NR 404.07, Register, September, 1986, No. 369, eff. 10-1-86; am. (1), Register, December, 1996, No. 492, eff. 1-1-97.