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Memorandum, transmitted electronically as an email attachment, from Paul Wishinski of VTAPCD to Michael Turner, representing VCE. The subject is how Vermont determines annual statewide NOx emissions.


TO: Michael Turner, Representing Vermonters for a Clean Environment (

FROM: Paul Wishinski, Planning Chief, VTAPCD

CC: Richard A. Valentinetti, Director VTAPCD; Conrad Smith, VTAPCD

DATE: 2/11/00

Per our discussions on the phone earlier today and your request, I have summarized below the numbers and the definitions which tend to be confusing when discussing NOX emissions from stationary sources in Vermont in regard to the Section 182(f) waiver request which the State has made to EPA.

These are best estimates as of 2/11/00

  1987    1250  Tons/Year
  1988    1357
  1989    1379
  1990    1132
  1991    1045
  1992    1266
  1993    1285
  1994    1963
  1995    2034
  1996    1976
  1997    1830


1. The registration process by which the Division obtains these estimates of annual NOX emissions from Vermont sources, began in 1987 and addresses only POINT Sources with estimated actual emissions of all air pollutants combined greater than 5 tons/Year. The number of sources included in the totals above for each year is not constant. The number of sources registered fluctuates from year to year because of three effects; a) newly built sources are added, b) some marginal existing sources may drop below the 5 Ton/Year cutoff and not be required to register for a given year, c) some marginal existing sources may increase emissions and emit greater than the 5 Ton/Year cutoff and become subject to registration requirements for a given year.

2. Until 1994 we had been unaware of the NOX emissions potential from point sources at ski areas. Starting in 1994 these sources are included in the totals; ski area emissions of NOX are NOT included in the entries before that year.

3. The NOX waiver request identified 575 Tons/Year of NOX emissions from 42 facilities in Vermont during 1990. This is a subtotal of the 1132 Tons/Year listed above. The subtotal results because under the NOX waiver request the Division only considered sources that met the federal major source definition in the Ozone Transport Region (as defined by the Clean Air Act Amendments of 1990). This federal major source definition is 50 Tons/Year of NOX, or 10 Tons/Year of VOCs, or 100 Tons/Year of CO. The 42 facilities for which 575 Tons of NOX were estimated included some VOC sources and some CO sources which may have had very low NOX emissions.

4. The NOX waiver petition requests that Vermont be allowed to permit new major stationary point sources of NOX without these sources being required to obtain offsetting emissions of NOX. The petition limits how much new actual NOX emission would be allowed under this waiver. It asks for up to a total of 1725 Tons/Year of additional NOX emissions.

5. The calculation of additional NOX emissions beyond the 575 Tons/Year that existed in 1990 applies only to emissions from federally defined major stationary sources, not to the entire population of Vermont registered sources. The 575 Tons/Year represents a baseline annual NOX level for federally defined major stationary sources in Vermont. Under the waiver (if granted) this baseline level would be allowed to increase by 1725 Tons/Year and NOT BEYOND that level, This is in effect asking that NOX emissions from federally defined major stationary point sources in Vermont be capped at a level of 2300 Tons/Year, in exchange for the offset requirement waiver.

6. Because some of the ski area NOX emissions were not included in the baseline and some of these sources meet the federal major source definition, it is likely that some of the 1725 Tons/Year additional annual emissions identified in the waiver request have already been allocated by default. The Division has not done any calculation to determine what the annual total NOX emissions have been during the years since 1990 for federally defined major sources in Vermont because it has not been something we have needed to track for any reason to date.

Vermonters for a Clean Environment, Inc.
Updated: February 22, 2000