### Table 1. AMBIENT AIR QUALITY STANDARDS
Standards Air Contaminants (Maximum Permissible Concentrations) lnhalable 150 micrograms per cubic meter, 24-hour average concentration. The standard is attained when the expected number ofdays per calendar year with a 24-houraverage concentration above 150 micrograms per cubic meter, as determined in accordancewith 40 CFR 50, Appendix K, is equal to orless than one. Particulates 

### PM10

PM 2.5

Sulfur Dioxide

Hydrogen Sulfide

Carbon Monoxide 12.0 micrograms per cubic meter annual arithmetic mean concentration. The standard is metwhen the annual arithmetic mean concentration, as determined in accordance with 40 CFR 50, Appendix N, is less than or equal to 12.0 micrograms per cubic meter. 35 micrograms per cubic meter 24-hour average concentration. The standard is metwhen the 9sth percentile 24-hour concentration, as determined in accordance with 40 CFR 50, Appendix N, is less than or equal to 35 micrograms per cubic meter. 0.075 parts per million (196 micrograms per cubic meter) 1-houraverage concentration. The standard is met when the 3-year average ofthe annual 99th percentile ofthe daily maximum 1-houraverage concentration is less than or equal to 0.075 parts per million, as determined in**ac~ordance** with 40 CFR 50, AppendixT. 0.5 parts per million (1309 micrograms per cubic meter of air) maximum 3-hourconcentration, notto be exceeded more than once per calendaryear. 10.0 parts per million (14 milligrams per cubic meter ofair), maximum instantaneous (ceiling) concentration notto be exceeded ·0.20 parts per million (280 micrograms per cubic meter of air), maximum 1-houraverage concentration notto be exceeded more than once per month 0.10 parts per million (140 micrograms per cubic meter of air), maximum 24-houraverage concentration notto be exceeded more than once peryear 0.02 parts per million (28 micrograms percubic meterofair), maximum arithmetic mean concentration averaged over three consecutive months 9 parts per million (1Omilligrams per cubic meterofair), maximum 8-hour concentration not to be exceeded more than once peryear



### 4Ozone

Nitrogen Dioxide

Lead 35 parts permillion (40 milligrams percubic meter ofair), maximum 1-hourconcentration notto be exceeded more than once peryear 0.075 parts per million (147 micrograms per cubic meter of air) daily maximum 8-hour average concentration. The standard is met when the three-year average ofthe annual fourth-highest daily maximum 8-hour average concentration at an ambient airquality monitoring site is less than or equal to 0.075 ppm, as determined in accordance with 40 CFR 50, Appendix P. 0.053 parts per million (100 micrograms per cubic meter of air), maximum annual arithmetic mean 0.100 parts per million (188 micrograms per cubic meter) 1-houraverage concentration. The standard is met when the 3-yearaverage ofthe annual 98th percentile ofthe daily maximum 1-houraverage concentration is less than or equal to 0.100 parts per million, as determined in accordance with 40 CFR 50, Appendix S. 0.15 micrograms per cubic meter ofair, arithmetic mean averaged overa3-month rolling period. The standard is metwhen the maximum 3-month mean concentration for a 3-year period, as determined in accordance with 40 CFR 50, Appendix R, is less than or equal to 0.15 micrograms per cubic meter.
History: Amended effective December 1, 1994; April 1, 2009; April 1, 2011; April 1, 2014.