Exhibit (10.aa)

AMENDMENT NO. 1 made effective the 24th day of February, 2003 (this "Amendment")
to  PENSION  RESTORATION  AND  SUPPLEMENTAL   EXECUTIVE  RETIREMENT  PLAN  TRUST
AGREEMENT  made  the  11th  day  of  February,  2000,  by  and  between  Met-Pro
Corporation,  a Delaware  corporation  (the  "Company"),  and Mellon Bank,  N.A.
("Trustee").

                                    WITNESSETH:

WHEREAS,  the Company and Trustee are party to an  agreement  entitled  "Pension
Restoration and  Supplemental  Executive  Retirement Plan Trust  Agreement" (the
"SERP Trust  Agreement") made the 11th day of February,  2000 that established a
Trust (as defined  therein)  with respect to the Company's  Pension  Restoration
Plan and Supplemental  Executive  Retirement Plan  (collectively the "Plans" and
each a "Plan").

WHEREAS,  the  Company and  Trustee  reserved  the power to amend the SERP Trust
Agreement by written instrument under Section 13(a) of the SERP Trust Agreement.

WHEREAS,  the Company and Trustee now desires to amend the SERP Trust  Agreement
to the extent and upon the terms set forth in this Amendment.

NOW, THEREFORE, the parties hereto do hereby agree as follows:

    1.  All terms used but not defined in this Amendment shall have such meaning
        as is ascribed to them in the SERP Trust Agreement.

    2.  Section 1(b) of the SERP Trust Agreement is hereby restated as follows:

        "(b) Immediately prior to a Change of Control (as defined in  Section 14
             of the Trust Agreement),  the Company shall contribute to the Trust
             that amount necessary to fully fund all benefits under the Plan and
             the Trustee shall,  immediately upon receipt of such  contribution,
             pay each Plan  participant or  beneficiary  thereof the benefits to
             which  Plan  participants  or  their   beneficiaries  are  entitled
             pursuant  to the  terms of the  Plan as of the  date on  which  the
             Change of Control occurred."

    3.  Section 13(a) of the Trust Agreement is hereby restated as follows:

        "(a) This Trust  Agreement may be amended  only by a written  instrument
             executed by the Trustee and the Company; provided, however, that no
             such  amendment may  adversely  affect any right or interest of any
             Plan participant or beneficiary."

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    4.  The  Company  agrees  that  should  it fail to cure  any  breach  of its
        obligations  under the SERP Trust  Agreement  in less than 30 days after
        receiving  written notice of same from any beneficiary of the Trust, the
        Company  will  be  liable  to pay the  reasonable  attorneys'  fees  and
        expenses incurred by any such beneficiary in filing suit and prosecuting
        such claims  should such  beneficiary  be the  prevailing  party in such
        litigation.

    5.  Except to the extent  expressly set forth herein in this Amendment,  the
        SERP Trust Agreement is unmodified and in full force and effect.

IN WITNESS WHEREOF, the parties hereto,  hereunder bound, do hereby execute this
Amendment as of the day and year first above written.


MET-PRO CORPORATION

BY: Raymond J. De Hont                          ATTEST: Gary J. Morgan
   ------------------------                            -------------------------
                                                          Secretary

MELLON BANK, N.A.

BY:                                             ATTEST:
   ------------------------                            -------------------------
                                                          Secretary