Section 404.04. Ambient air quality standards.

 

(1)   Applicability of air standards. The air standards apply to the entire state without exception.

(2)   Sulfur oxides.

(a) Primary standard. The primary standard for sulfur oxides, measured as sulfur dioxide, is 0.075 ppm — maximum 1-hour concentration. The 1-hour primary standard is met at an ambient air quality monitoring site when the 3-year average of the annual (99 th percentile) of the daily maximum 1-hour average concentrations is less than or equal to 0.075 ppm, as determined by the methodology of 40 CFR part 50 , Appendix T, incorporated by reference in s. NR 484.04 (7m) .

(b) Secondary standard. The secondary standard for sulfur oxides, measured as sulfur dioxide, is: 0.5 ppm — maximum 3-hour average concentration, not to be exceeded more than once per year.

(4)   Carbon monoxide: primary and secondary standards. The primary and secondary standards for carbon monoxide are:

(a) 10 milligrams per cubic meter (9 ppm) — maximum 8-hour average concentration, not to be exceeded more than once per year.

(b) 40 milligrams per cubic meter (35 ppm) — maximum 1-hour concentration, not to be exceeded more than once per year.

(5)   Ozone: primary and secondary standards. The primary and secondary standards for ozone are:

(a) 0.12 ppm (235 micrograms per cubic meter) — maximum 1-hour average concentration. The 1-hour ozone standards are attained when the expected number of days per calendar year with maximum hourly average concentrations above the designated level is equal to or less than one, as determined by the methodology of 40 CFR part 50 , Appendix H, incorporated by reference in s. NR 484.04 (4) .

(b) 0.08 ppm — maximum 8-hour concentration. The 8-hour ozone standards are attained when the arithmetic mean of the fourth highest daily maximum 8-hour concentration at an ambient air quality monitoring site is less than or equal to 0.08 ppm, as determined by the methodology of 40 CFR part 50 , Appendix I, incorporated by reference in s. NR 484.04 (4m) .

(c) 0.075 ppm — maximum 8-hour concentration. The 8-hour primary and secondary ozone ambient air quality standards are attained at an ambient air quality monitoring site when the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentration is less than or equal to 0.075 ppm, as determined in accordance with 40 CFR part 50 , Appendix P, incorporated by reference in s. NR 484.04 (6t) .

(6)   Nitrogen dioxide.

(a) Primary standards. The primary standards for nitrogen dioxide are:

1. 0.053 ppm — primary annual average concentration. The primary annual standard is met when the annual average concentration in a calendar year is less than or equal to 0.053 ppm, as determined by the methodology of 40 CFR part 50 , Appendix S, incorporated by reference in s. NR 484.04 (7) .

2. 0.100 ppm — primary 1-hour average concentration. The primary 1-hour standard is met when the 3-year average of the annual 98th percentile of the daily maximum 1-hour average concentration is less than or equal to 0.100 ppm, as determined by the methodology of 40 CFR part 50 , Appendix S, incorporated by reference in s. NR 484.04 (7) .

(b) Secondary Standard. The secondary standard for nitrogen dioxide is 0.053 ppm. The secondary standard is attained when the annual arithmetic mean concentration in a calendar year is less than or equal to 0.053 ppm, rounded to three decimal places. Fractional parts equal to or greater than 0.0005 ppm shall be rounded up. To demonstrate attainment, an annual mean shall be based upon hourly data that are at least 75% complete or upon data derived from manual methods that are at least 75% complete for the scheduled sampling days in each calendar quarter.

(7)   Lead: primary and secondary standards. The primary and secondary standards for lead and its compounds, measured as elemental lead, are the following:

(a) 1.5 micrograms per cubic meter, maximum arithmetic mean averaged over a calendar quarter, as a constituent of suspended particulate matter. The primary and secondary standards for lead and its compounds, measured as elemental lead are attained when the maximum arithmetic mean averaged over a calendar quarter is less than or equal to 1.5 micrograms per cubic meter, as determined in accordance with 40 CFR part 50 , Appendix B, incorporated by reference in s. NR 484.04 (3) .

(b) 0.15 micrograms per cubic meter – maximum arithmetic mean. The primary and secondary ambient air quality standards for lead are attained when the maximum arithmetic 3-month mean concentration for a 3-year period is less than or equal to 0.15 micrograms per cubic meter, as determined in accordance with 40 CFR part 50 , Appendix R, incorporated by reference in s. NR 484.04 (6v) .

(8)   PM 10 : primary and secondary standards.

(a) The primary and secondary standards for PM 10 are 150 micrograms per cubic meter ( m g/m 3 ) — maximum 24-hour average concentration.

(b) The PM 10 standards are attained when the expected number of days per calendar year with a 24-hour average concentration above 150 m g/m 3 , the level designated in par. (a) , is equal to or less than one.

(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) .

(9)   PM 2.5 : Primary and secondary standards.

(a) The primary and secondary standards for PM 2.5 are:

1. 15.0 micrograms per cubic meter ( m g/m 3 ) — annual arithmetic mean concentration.

2. 35 micrograms per cubic meter ( m g/m 3 ) — 24-hour average concentration.

(b) The PM 2.5 standards are attained when all of the following are met:

1. The annual arithmetic mean concentration is less than or equal to 15.0 m g/m 3 , the level designated in par. (a) 1.

2. The ninety-eighth percentile 24-hour average concentration is less than or equal to 35 m g/m 3 , the level designated in par. (a) 2.

(c) The calculated concentrations shall be determined by the methodology contained in 40 CFR part 50 , Appendix N, incorporated by reference in s. NR 484.04 (6r) .

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.

Note

The Department promulgated the 1-hour and the 8-hour ozone standards, in pars. (a) and (b), respectively, in response to actions by the US EPA. Since the US EPA did not repeal these standards when it promulgated the 8-hour standard reflected in par. (c), the Department has retained them consistent with its statutory obligation under s. 285.21 (1) (a) , Stats. Microsoft Windows NT 6.1.7601 Service Pack 1