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Technology Transfer Network - OAR Policy and Guidance

OAR Policy and Guidance Metarecord

Document Title/Subject:
Areas Affected by PM-10 Natural Events
Related Documents:
Fact Sheet: EPA's Natural Events policy for Particulate Matter
Signed by: Mary D. Nichols

Signature Date: May 30, 1996

Kenneth Woodard
Air Quality Strategies and Standards Division, OAQPS



Regulatory Authority:
Title 1

Air Quality Strategies and Standards Division (OAQPS)
Submitted By:
Document Type:
Policy & Guidance Memos
EPA Document Number:

Federal Register:
Guideline on the Identification and Use of Air Quality Data Affected by Exceptional Events
Subject Category:
Particulate matter
high winds
seismic activity
nonattainment areas air pollution control policy public health National Ambient Air Quality Standards
Air qualityChemical accidentsNatural disasters
This memorandum sets forth the Environmental Protection Agency's (EPA's) policy for protecting public health in areas where the PM-10 (particulate matter having a nominal aerodymanic diameter less than or equal to 10 microns) national ambient air quality standards (NAAQS) are violated due to natural events. This policy will be followed in implementing the PM-10 NAAQS until it is superseded. Three categories of natural events have been identified as affecting the PM-10 NAAQS: (1) volcanic and seismic activity, (2) wildland fires, and (3) high wind events. The policy described in this document addresses PM-10 NAAQS violations caused by natural events in areas designated unclassifiable or attainment. It also addressed certain reclassification and redesignation questions for PM-10 nonattainment areas. This policy applies at the time the State determines that a PM-10 NAAQS has been violated due to natural events and addresses the question of what should be done to protect public health. The policy provides that EPA will: (1) exercise its descretion under section 107(d)(3) not to redesignate areas as nottainment if the State develops and implements a plan to respond to the health impacts of natural events, and (2) redesignate nonattainment areas as attainment by applying Appendix K [of 40 CFR Part 50] on a case-by-case basis, to discount data in circumstances where an area would attain but for exceedances that result from uncontrollable natural events. The guiding principles followed in developing this policy are: (1) Protection of public health is the highest priority of Federal, State, and local air pollution control agencies. (2) The public must be informed whenever the air quality in an area is unhealthy. (3) All valid ambient air quality data should be submitted to the Aerometric Information Retrieval System and made available for public access. (4) State and local agencies must take appropriate reasonable measures to safeguard public health regardless of the source of PM -10 emissions. (5) Emissions controls should be applied to sources that contribute to exceedances of the PM-10 standards when those controls will result in fewer violation of the standards. This memorandum can be downloaded in both PDF and WP format. The related document is also available in both forms. The files are sixteen and three pages in PDF format, respectively.

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