OAR 340-202-0050
Ambient Air Quality Standards: Purpose and Scope of Ambient Air Quality Standards
(1)
An ambient air quality standard is an established concentration, exposure time, and frequency of occurrence of an air contaminant or multiple contaminants in the ambient air that must not be exceeded. The ambient air quality standards set forth in OAR 340-202-0050 (Ambient Air Quality Standards: Purpose and Scope of Ambient Air Quality Standards) through 340-202-0130 (Ambient Air Quality Standards: Lead) were established to protect both public health and public welfare.(2)
Ambient air quality standards are not generally used to determine the acceptability or unacceptability of emissions from a specific source of air contamination. More commonly, the measured ambient air quality is compared with the ambient air quality standards to determine the adequacy or effectiveness of emission standards for all sources in a general area. However, if a source or combination of sources are singularly responsible for a violation of ambient air quality standards in a particular area, it may be appropriate to impose emission standards that are more stringent than those otherwise applied to the class of sources involved. Similarly, proposed construction of new sources or expansions of existing sources, that may prevent or interfere with the attainment and maintenance of ambient air quality standards are grounds for issuing an order prohibiting such proposed construction as authorized by ORS 468A.055 (Notice prior to construction of new sources) and pursuant to OAR 340-210-0205 (Notice of Construction and Approval of Plans: Applicability) through 340-210-0250 (Notice of Construction and Approval of Plans: Approval to Operate), and OAR 340-218-0190 (Construction/Operation Modifications). No source may cause or contribute to a new violation of an ambient air quality standard or PSD increment even if the single source impact is less than the significant impact level.(3)
In adopting the ambient air quality standards in this division, the EQC recognizes that one or more of the standards are currently being exceeded in certain parts of the state. It is hereby declared to be the policy of the EQC to achieve, by application of a timely but orderly program of pollution abatement, full compliance with ambient air quality standards throughout the state at the earliest possible date.
Source:
Rule 340-202-0050 — Ambient Air Quality Standards: Purpose and Scope of Ambient Air Quality Standards, https://secure.sos.state.or.us/oard/view.action?ruleNumber=340-202-0050.