### FOR INCLUSION IN WYOMING STATE IMPLEMENTATION PLAN FROM WYOMING AIR QUALITY STANDARDS AND REGULATIONS

Ambient Standards CHAPTER2
Section 2. 

### Ambient standards for particulate matter. (a) PM 10 : The ambient air standards for PM 10 particulate matter are: (i) 150 micrograms per cubic meter--24-hour average concentration with not more than one expected exceedance per year. (A) Attainment ofthe 24-hour standard is determined in accordance with Appendix K of40 CFR part 50. (ii) For the purpose ofdetermining attainment ofthe standards, particulate matter shall be measured in the ambient air as PM 10 (particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers), by a reference method based on 40 CFR part 50, Appendix J and designated in accordance with 40 CFRpart 53 or an equivalent or alternate method designated in accordance with 40 CFRpart 53. (b) PM2.5: The primary and secondary ambient air quality standards for PM2

_ 5 particulate matter are: (i) 15 micrograms per cubic meter**(~g/m )**  annual arithmetic mean concentration and; (ii) 35 micrograms per cubic meter**(~g )--98** **111** percentile 24-hour average concentration. (iii) Attainment ofthe annual and 24-hour standards is determined in accordance with Appendix N of40 CFR part 50. (iv) For the purpose ofdetermining attainment ofthe standards, particulate matter shall be measured in the ambient air as PM2.5 (particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers), by a reference method based on 40 CFR part 50, Appendix L and designated in accordance with 40 CFR part 53 or an equivalent or alternate method designated in accordance with 40 CFRpart 53

. (c) Ambient air, for the area bounded by Townships 40 through 52 North, and Ranges 69 through 73 West, inclusive, ofthe Sixth Principal Meridian, Campbell and Converse Counties, in the Powder River Coal Basin, is defined as that portion ofthe

### atmosphere, external to buildings, to which the general public has access. For surface mining operations, the application ofthis definition will be limited to only those lands that are necessary to conduct mining operations as determined by the Administrator of the Wyoming Air Quality Division.

### Section 10. Ambient standards for lead. (a) The primary and secondary ambient air quality standards for lead (Pb) and its compounds are 0.15 micrograms per cubic meter, arithmetic mean concentration over a 3-month period, measured in the ambient air as Pb either by: (i) A reference method based on 40 CFR part 50, Appendix G (Reference Method for the Determination ofLead in Suspended Particulate Matter Collected From Ambient Air), and designated in accordance with 40 CFRpart 53 or; (ii) An 

### equivalent method designated in accordance with 40 CFR part 53. (b) The primary and secondary ambient air quality standards for Pb are met when the maximum arithmetic 3-month mean concentration for a 3-year period, as determined in accordance with Appendix R (Interpretation ofthe National Ambient Air Quality Standards for Lead) of40 CFR part 50, is less than or equal to 0.15 micrograms per cubic meter.

### Section 12. 

### Incorporation 

### by reference. (a) Code ofFederal Regulations (CFR). All Code ofFederal Regulations (CFRs) cited in this chapter, including their Appendices, revised and published as ofJuly 1, 2008, 

### not including any later amendments, are incorporated by reference

. Copies of the Code ofFederal Regulations are available for public inspection and copies can be obtained at cost from the Department ofEnvironmental Quality, Division ofAir Quality, 122 

### W

. 25th 

### Street, Cheyenne, Wyoming 82002. 

### Copies ofthe CFRs can also be obtained at cost from Government Institutes, 15200 

### NBN Way, Building B, Blue Ridge Summit, PA 17214.