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Title 40Chapter ISubchapter CPart 51Subpart X → §51.904

Title 40: Protection of Environment
Subpart X—Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard

§51.904   How do the classification and attainment date provisions in section 172(a) of subpart 1 of the CAA apply to areas subject to §51.902(b)?

(a) Classification. The Administrator may classify an area subject to §51.902(b) as an overwhelming transport area if:

(1) The area meets the criteria as specified for rural transport areas under section 182(h) of the CAA;

(2) Transport of ozone and/or precursors into the area is so overwhelming that the contribution of local emissions to observed 8-hour ozone concentration above the level of the NAAQS is relatively minor; and

(3) The Administrator finds that sources of VOC (and, where the Administrator determines relevant, NOX) emissions within the area do not make a significant contribution to the ozone concentrations measured in other areas.

(b) Attainment dates. For an area subject to §51.902(b), the Administrator will approve an attainment date consistent with the attainment date timing provision of section 172(a)(2)(A) of the CAA at the time the Administrator approves an attainment demonstration for the area.

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