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February, 1981 PSD Significance Levels for Monitoring 7.4

THE TEXT YOU ARE VIEWING IS A COMPUTER-GENERATED OR RETYPED VERSION OF A PAPER PHOTOCOPY OF THE ORIGINAL. ALTHOUGH CONSIDERABLE EFFORT HAS BEEN EXPENDED TO QUALITY ASSURE THE CONVERSION, IT MAY CONTAIN TYPOGRAPHICAL ERRORS. TO OBTAIN A LEGAL COPY OF THE ORIGINAL DOCUMENT, AS IT CURRENTLY EXISTS, THE READER SHOULD CONTACT THE OFFICE THAT ORIGINATED THE CORRESPONDENCE OR PROVIDED THE RESPONSE.

7.4

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711

DATE: February, 1981

SUBJECT: PSD Significance Levels for Monitoring

FROM: Darryl D. Tyler, Acting Director
Control Programs Development Division (MD-15)

TO: Director, Air and Waste Management Division, Regions I - X

The August 7, 1980, PSD promulgation introduced significance levels of projected ambient impacts for the purpose of determining whether a proposed source or modification would be eligible for an exemption from the requirement for ambient monitoring. 40 CFR 51.24(i)(8) and 52.21(i)(8). Typographical errors and miscalculations caused the numbers for either concentration or averaging time printed in the August 7, 1980, document to be incorrect for four pollutants. Those pollutants are nitrogen dioxide, lead, beryllium, and hydrogen sulfide.

Attached is a copy of Table A-2 from Ambient Monitoring Guidelines for Prevention of Significant Deterioration (PSD) (EPA-450/4-80-012, Nov. 1980, revised Feb. 1981). In case these revisions have not yet come to your attention, please note that the table contains the correct values and supersedes earlier documents. We expect these values to be the subject of future technical and conforming amendments, to appear in the Federal Register. Should you have any further questions on this topic, you may contact Michael Trutna at FTS 629-5591.

Attachment

TABLE A-2. SIGNIFICANT MONITORING CONCENTRATIONS
Pollutant Air Quality Concentration (ug/m3)
and Averaging Time
Carbon monoxide 575 (8-hour)
Nitrogen dioxide 14 (annual) [see d]
Sulfur dioxide 13 (24-hour)
Total suspended particulates 10 (24-hour)
Ozone (see a below)
Lead 0.1 (3-month) [see d]
Asbestos (see b below)
Beryllium 0.001 (24.hour)[see e]
Mercury 0.25 (24-hour)
Vinyl chloride 15 (24-hour)
Fluorides 0.25 (24-hour)
Sulfuric acid mist (see b below)
Total reduced sulfur (also H2S) (see c below)
Reduced sulfur (including H2S) (see c below)
Hydrogen sulfide 0.2 (1-hour) [see e]

  1. No specific air quality concentration for ozone is prescribed. Exemptions are granted when a source's VOC emissions are <100 tons/year.

  2. No acceptable monitoring techniques available at this time. Therefore, monitoring is not required until acceptable techniques are available.

  3. No acceptable monitoring techniques available at this time. However, techniques are expected to be available shortly.

  4. The averaging times are corrected to be consistent with the averaging time of the standard.

  5. These concentrations are corrected from the previous printing and are approximately five times the minimum detectable concentrations. These are consistent with other values in this table.

A-6

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