Document:

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                                                                    EXHIBIT 10.5

                          FORM OF CONVERTIBLE DEBENTURE

                                      129
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THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE UNITED
STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"). THE HOLDER
HEREOF, BY PURCHASING SUCH SECURITIES AGREES FOR THE BENEFIT OF THE COMPANY THAT
SUCH SECURITIES MAY BE OFFERED, SOLD OR OTHERWISE TRANSFERRED ONLY (A) TO THE
COMPANY, (B) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT, OR (C) IF REGISTERED UNDER THE SECURITIES ACT AND ANY APPLICABLE STATE
SECURITIES LAWS. IN ADDITION, A SECURITIES PURCHASE AGREEMENT, DATED AS OF THE
DATE HEREOF, A COPY OF WHICH MAY BE OBTAINED FROM THE COMPANY AT ITS PRINCIPAL
EXECUTIVE OFFICE, CONTAINS CERTAIN ADDITIONAL AGREEMENTS AMONG THE PARTIES,
INCLUDING, WITHOUT LIMITATION, PROVISIONS WHICH (A) LIMIT THE CONVERSION RIGHTS
OF THE HOLDER, (B) SPECIFY VOLUNTARY AND MANDATORY REPAYMENT, PREPAYMENT AND
REDEMPTION RIGHTS AND OBLIGATIONS AND (C) SPECIFY EVENTS OF DEFAULT FOLLOWING
WHICH THE REMAINING BALANCE DUE AND OWING HEREUNDER MAY BE ACCELERATED.

No.  1                                                                  $100,000

                            7% CONVERTIBLE DEBENTURE
                                       of

      eMISSIONS TESTING, Inc., a Georgia corporation (together with its
successors, the "Company"), for value received hereby promises to pay to:

                      GCA STRATEGIC INVESTMENT FUND LIMITED

(The "Holder") and registered assigns, the principal sum of One Hundred Thousand
($100,000) or, if less, the principal amount of this Debenture then outstanding,
on the Maturity Date by wire transfer of immediately available funds to the
Holder in such coin or currency of the United States of America as at the time
of payment shall be legal tender for the payment of public and private debts,
and to pay interest, which shall begin to accrue on the date of this Debenture,
quarterly in arrears, on (i) the last day of March, June, September and December
of each year until the Maturity Date, commencing December 31, 2000 (unless such
day is not a Business Day, in which event on the next succeeding Business Day)
(each an "Interest Payment Date"), (ii) the Maturity Date, (iii) each Conversion
Date, as hereafter defined, and (iv) the date the principal amount of the
Convertible Debentures shall be declared to be or shall automatically become due
and payable, on the principal sum hereof outstanding in like coin or currency,
at the rates per annum set forth below, from the most recent Interest Payment
Date to which interest has been paid on this Convertible Debenture, or if no
interest has been paid on this Convertible Debenture, from the date of this
Convertible Debenture until payment in full of the principal sum hereof has been
made. The Maturity Date is June 1, 2002.

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      The interest rate shall be seven percent (7%) per annum (the "Interest
Rate") or, if less, the maximum rate permitted by applicable law. Past due
amounts (including interest, to the extent permitted by law) will also accrue
interest at the Interest Rate plus 2% per annum or, if less, the maximum rate
permitted by applicable law, and will be payable on demand ("Default Interest").
Interest on this Convertible Debenture will be calculated on the basis of a
360-day year of twelve 30 day months. All payments of principal and interest
hereunder shall be made for the benefit of the Holder pursuant to the terms of
the Agreement (hereafter defined). At the option of the Company, interest may be
paid in cash or in shares of Common Stock. If the Company determines to pay
interest in shares of Common Stock, it shall be required to notify the Holder of
such election on the Closing Date. On each Conversion Date, interest shall be
paid in shares of Common Stock on the portion of the principal balance of the
Convertible Debenture then being converted. The number of shares of Common Stock
issued as interest shall be determined by dividing the dollar amount of interest
due on the applicable Interest Payment Date by the Conversion Price then in
effect.

      This Convertible Debenture (this "Convertible Debenture") is one of a duly
authorized issuance of up to $1,000,000 aggregate principal amount of
Convertible Debentures of the Company referred to in that certain Securities
Purchase Agreement dated as of the date hereof between the Company and the
Purchaser named therein (the "Agreement"). The Agreement contains certain
additional agreements among the parties with respect to the terms of this
Convertible Debenture, including, without limitation, provisions which (A) limit
the conversion rights of the Holder, (B) specify voluntary and mandatory
repayment, prepayment and redemption rights and obligations and (C) specify
Events of Default following which the remaining balance due and owing hereunder
may be accelerated. All such provisions are an integral part of this Convertible
Debenture and are incorporated herein by reference. This Convertible Debenture
is transferable and assignable to one or more Persons, in accordance with the
limitations set forth in the Agreement.

      This Convertible Debenture is secured by a Security Agreement dated June
1, 2000 and amended as of the date hereof (the "Security Agreement") made by the
Company and Holder creating a security interest in favor of the Holder in
certain of the Company's assets described in the Security Agreement.

      The Company shall keep a register (the "Register") in which shall be
entered the names and addresses of the registered holder of this Convertible
Debenture and particulars of this Convertible Debenture held by such holder and
of all transfers of this Convertible Debenture. References to the Holder or
"Holders" shall mean the Person listed in the Register as registered holder of
such Convertible Debentures. The ownership of this Convertible Debenture shall
be proven by the Register.

      1. CERTAIN TERMS DEFINED. All terms defined in the Agreement and not
otherwise defined herein shall have for purposes hereof the meanings provided
for in the Agreement.

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      2. COVENANTS. The Company covenants and agrees to observe and perform each
of its covenants, obligations and undertakings contained in the Agreement, which
obligations and undertakings are expressly assumed herein by the Company and
made for the benefit of the holder hereof.

      3. PAYMENT OF PRINCIPAL. The Company shall repay the remaining unpaid
balance of this Convertible Debenture on the Maturity Date. The Company may, and
shall be obligated to, prepay all or a portion of this Convertible Debenture on
the terms specified in the Agreement.

      4. CONVERSION.

      4.1 CONVERSION OF CONVERTIBLE DEBENTURE. Subject to Section 5 hereof, the
      Holder shall have the right, at its option, at any time from and after the
      date of issuance of this Convertible Debenture, convert the principal
      amount of this Convertible Debenture, or any portion of such principal
      amount, into that number of fully paid and nonassessable shares of Common
      Stock (as such shares shall then be constituted) determined pursuant to
      this Section 4.1. The number of shares of Common Stock to be issued upon
      each conversion of this Convertible Debenture shall be determined by
      dividing the Conversion Amount (as defined below) by the Conversion Price
      in effect on the date (the "Conversion Date") a Notice of Conversion is
      delivered to the Company, as applicable, by the Holder by facsimile or
      other reasonable means of communication dispatched prior to 5:00 p.m.,
      E.S.T. The term "Conversion Amount" means, with respect to any conversion
      of this Convertible Debenture, the sum of (1) the principal amount of this
      Convertible Debenture to be converted in such conversion plus (2) accrued
      and unpaid interest, if any, on such principal amount at the interest
      rates provided in this Convertible Debenture to the Conversion Date plus
      (3) Default Interest, if any, on the interest referred to in the
      immediately preceding clause (2) plus (4) at the Holder's option, any
      amounts owed to the Holder pursuant to Section 4.3 hereof, Section 10.1 of
      the Agreement or Section 10.4 of the Agreement.

      4.2 CONVERSION PRICE AND LIMITATION. At the option of the Holder, any
      portion or all of the outstanding principal amount of this Convertible
      Debenture shall be converted into a number of shares of Common Stock at
      the conversion price (the "Conversion Price") equal to the lesser of
      (i)$.50 (the "Fixed Conversion Price") and (ii) 75% of the three lowest
      weighted average sales prices as reported by Bloomberg LP for the ten (10)
      Trading Days immediately preceding but not including the date of the
      related Notice of Conversion (the "Formula Conversion Price").

                                      132
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      4.3 AUTHORIZED SHARES.

            (1) Consistent with Section 7.11 of the Agreement, the Company (i)
      shall promptly irrevocably instruct the Company's transfer agent to issue
      certificates for the Common Stock issuable upon conversion of this
      Convertible Debenture and (ii) agrees that its issuance of this
      Convertible Debenture shall constitute full authority to its officers and
      agents who are charged with the duty of executing stock certificates to
      execute and issue the necessary certificates for shares of Common Stock in
      accordance with the terms and conditions of this Convertible Debenture.

            (2) If at any time a Holder of this Convertible Debenture submits a
      Notice of Conversion (x) the Company does not have sufficient authorized
      but unissued shares of Common Stock available to effect such conversion in
      full in accordance with the provisions of this Article 4 or (y) the
      Company is prohibited by the applicable rules of the OTC Bulletin Board or
      the National Market on which the Common Shares are listed and traded at
      that time to effect such conversion in full as provided in subsection (d)
      below, without stockholder approval (each, a "Conversion Default"), the
      Company shall issue to the Holder all of the shares of Common Stock which
      are then available to effect such conversion. The portion of this
      Convertible Debenture which the Holder included in its Conversion Notice
      and which exceeds the amount which is then convertible into available
      shares of Common Stock (the "Excess Amount") shall, notwithstanding
      anything to the contrary contained herein, not be convertible into Common
      Stock in accordance with the terms hereof until (and at the Holder's
      option at any time after) the date additional shares of Common Stock are
      authorized by the Company, or its stockholders, as applicable, at which
      time the Conversion Price in respect thereof shall be the lower of (i) the
      Conversion Price on the Conversion Default Date (as defined below) and
      (ii) the Conversion Price on the Conversion Date thereafter elected by the
      Holder in respect thereof. The Company shall pay to the Holder payments
      ("Conversion Default Payments") for a Conversion Default in the amount of
      (N/365) x .24 x the Excess Amount on the Conversion Date in respect of the
      Conversion Default (the "Conversion Default Date"), where N = the number
      of days from the Conversion Default Date to the date (the "Authorization
      Date") that the Company, or its stockholders, as applicable, authorizes a
      sufficient number of shares of Common Stock to effect conversion of the
      full outstanding principal balance of this Convertible Debenture. The
      Company shall use its best efforts to authorize, or cause its stockholders
      to authorize within 40 days of the occurrence of a Conversion Default, as
      applicable, a sufficient number of shares of Common Stock as soon as
      practicable following the earlier of (i) such time that the Holder
      notifies the Company or that the Company otherwise becomes aware that
      there are or likely will be insufficient shares to allow full conversion
      thereof and (ii) a Conversion Default. The Company shall send notice to
      the Holder of the authorization of additional shares of Common Stock, the
      Authorization Date and the amount of Holder's accrued Conversion Default
      Payments. The accrued Conversion Default Payments for each calendar month
      shall be paid in cash or shall be convertible into Common Stock (at

                                      133
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      such time as there are sufficient authorized shares of Common Stock) at
      the Market Price, at the Holder's option, as follows:

                  (1) In the event the Holder elects to take such payment in
            cash, cash payment shall be made to Holder by the fifth Business Day
            of the month following the month in which it has accrued; and

                  (2) In the event the Holder elects to take such payment in
            Common Stock, the Holder may convert such payment amount into Common
            Stock at the Conversion Price (as in effect at the time of
            conversion) at any time after the fifth Business Day of the month
            following the month in which it has accrued (at such time as there
            are sufficient authorized shares of Common Stock) in accordance with
            the terms of this Article 4.

            (3) The Holder's election pursuant to this Section 4.3 shall be made
      in writing to the Company at any time prior to 5:00 p.m., E.S.T., on the
      third Business Day of the month following the month in which Conversion
      Default payments have accrued. If no election is made, the Holder shall be
      deemed to have elected to receive cash. Nothing herein shall limit the
      Holders right to pursue actual damages (to the extent in excess of the
      Conversion Default Payments) due to the Company's failure to maintain a
      sufficient number of authorized shares of Common Stock.

            (4) In no event shall the Company issue more than the Maximum Number
      of Shares upon conversion of this Convertible Debenture, unless the
      Company shall have obtained approval by the stockholders of the Company
      ("Stockholder Approval") or a waiver of such requirement by the OTC
      Bulletin Board or the National Market on which the Common Shares are
      listed and traded at that time. Once the Maximum Number of Shares has been
      issued (the date of which is hereinafter referred to as the "Maximum
      Conversion Date"), unless the Company shall have obtained Stockholder
      Approval or a waiver of such requirement by the OTC Bulletin Board or the
      National Market on which the Common Shares are listed and traded at that
      time within 40 days of the Maximum Conversion Date, the Company shall pay
      to the Holder within five (5) Business Days of the Maximum Conversion Date
      (or, if the Company is, in good faith, using its best efforts to obtain
      Stockholder Approval, then the earlier of (x) 40 days following the
      Maximum Conversion Date, and (y) such date that it becomes reasonably
      apparent that Stockholder Approval will not be obtained within such 40
      days period), the Formula Price plus accrued and unpaid Default Interest,
      if any. The Maximum Number of Shares shall be subject to adjustment from
      time to time for stock splits, stock dividends, combinations, capital
      reorganizations and similar events relating to the Common Stock occurring
      after the date hereof as contemplated by Article XI of the Agreement. With
      respect to each Holder of Convertible Debentures, the Maximum Number of
      Shares shall refer to such Holder's pro rata share thereof based upon the
      aggregate principal balance of the Convertible Debentures then
      outstanding. In the event that the Company obtains Stockholder Approval,
      approval of the OTC Bulletin Board or the National Market on

                                      134
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      which the Common Shares are listed and traded at that time, or otherwise
      is able to increase the number of shares to be issued above the Maximum
      Number of Shares (such increased number being the "New Maximum Number of
      Shares"), the references to Maximum Number of Shares above shall be deemed
      to be, instead, references to the New Maximum Number of Shares.

      4.4 METHOD OF CONVERSION.

            (1) Notwithstanding anything to the contrary set forth herein, upon
      conversion of this Convertible Debenture in accordance with the terms
      hereof, the Holder shall not be required to physically surrender this
      Convertible Debenture to the Company unless the entire unpaid principal
      amount of this Convertible Debenture is so converted. Rather, records
      showing the principal amount converted (or otherwise repaid) and the date
      of such conversion or repayment shall be maintained on a ledger
      substantially in the form of ANNEX A attached hereto (a copy of which
      shall be delivered to the Company or transfer agent with each Notice of
      Conversion). It is specifically contemplated that the Holder hereof shall
      act as the calculation agent for conversions and repayments. In the event
      of any dispute or discrepancies, such records maintained by the Holder
      shall be controlling and determinative in the absence of manifest error or
      failure of Holder to record the principal amount converted (or otherwise
      repaid) from time to time, in which events the record of the Company shall
      be controlling and determinative. The Holder and any assignee, by
      acceptance of this Convertible Debenture, acknowledge and agree that, by
      reason of the provisions of this paragraph, following a conversion of a
      portion of this Convertible Debenture, the principal amount represented by
      this Convertible Debenture will be the amount indicated on ANNEX A
      attached hereto (which may be less than the amount stated on the face
      hereof).

            (2) The Company shall not be required to pay any tax which may be
      payable in respect of any transfer involved in the issuance and delivery
      of shares of Common Stock or other securities or property on conversion of
      this Convertible Debenture in a name other than that of the Holder (or in
      street name), and the Company shall not be required to issue or deliver
      any such shares or other securities or property unless and until the
      person or persons (other than the Holder or the custodian in whose street
      name such shares are to be held for the Holder's account) requesting the
      issuance thereof shall have paid to the Company the amount of any such tax
      or shall have established to the satisfaction of the Company that such tax
      has been paid.

            (3) Subject to Section 5 hereof, upon receipt by the Company of a
      Notice of Conversion, the Holder shall be deemed to be the holder of
      record of the Common Stock issuable upon such conversion, the outstanding
      principal amount and the amount of accrued and unpaid interest on this
      Convertible Debenture shall be deemed reduced to reflect such conversion,
      and, unless the Company defaults on its obligations under this Article 4,
      all rights with respect to the portion of this Convertible Debenture being
      so converted shall forthwith terminate except the right to receive the
      Common Stock or

                                      135
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      other securities, cash or other assets, as herein provided, on such
      conversion. Subject to Section 5 hereof, if the Holder shall have given a
      Notice of Conversion as provided herein, the Company's obligation to issue
      and deliver the certificates for shares of Common Stock shall be absolute
      and unconditional, irrespective of the absence of any action by the Holder
      to enforce the same, any waiver or consent with respect to any provisions
      thereof, the recovery of any judgment against any person or any action by
      the Holder to enforce the same, any failure or delay in the enforcement of
      any other obligation of the Company to the Holder of record, or any
      setoff, counterclaim, recoupment, limitation or termination, or any breach
      or alleged breach by the Holder of any obligation to the Company, and
      subject to Section 4.4(a) irrespective of any other circumstance which
      might otherwise limit such obligation of the Company to the Holder in
      connection with such conversion. The date of receipt (including receipt
      via telecopy) of such Notice of Conversion shall be the Conversion Date so
      long as it is received before 5:00 p.m., E.S.T., on such date.

            (4) Notwithstanding the foregoing, if a Holder has not received
      certificates for all shares of Common Stock prior to the expiration of the
      Deadline with respect to a conversion of any portion of this Convertible
      Debenture for any reason, then (unless the Holder otherwise elects to
      retain its status as a holder of Common Stock by so notifying the
      Company), the Holder shall regain the rights of a Holder of this
      Convertible Debenture with respect to such unconverted portions of this
      Convertible Debenture and the Company shall, as soon as practicable,
      return such unconverted Convertible Debenture to the holder or, if the
      Convertible Debenture has not been surrendered, adjust its records to
      reflect that such portion of this Convertible Debenture not been
      converted. In all cases, the Holder shall retain all of its rights and
      remedies (including, without limitation, (i) the right to receive
      Conversion Default Payments to the extent required thereby for such
      Conversion Default and any subsequent Conversion Default and (ii) the
      right to have the Conversion Price with respect to subsequent conversions
      determined in accordance with Section 4.3 for the Company's failure to
      convert this Convertible Debenture.

                                      136
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            (5) In lieu of delivering physical certificates representing the
      Common Stock issuable upon conversion, provided the Company's transfer
      agent is participating in the Depository Trust Company ("DTC") Fast
      Automated Securities Transfer program, upon request of the Holder and its
      compliance with the provisions contained in Section 4.1 and in this
      Section 4.4, the Company shall use its best efforts to cause its transfer
      agent to electronically transmit the Common Stock issuable upon conversion
      to the Holder by crediting the account of Holder's Prime Broker with DTC
      through its Deposit Withdrawal Agent Commission System.

5. REDEMPTION BY COMPANY.

      5.1 COMPANY'S RIGHT TO REDEEM. In accordance with the provisions of the
      Purchase Agreement, the Company may elect, or be required, upon receipt of
      a Notice of Conversion, to redeem in whole or in part, the remaining
      unpaid principal amount of this Convertible Debenture, for cash at a
      redemption price (the "Redemption Price") equal to (x) the number of
      shares of Common Stock into which this Convertible Debenture is then
      convertible, times (y) the average Closing Bid Price of Common Stock for
      the five (5) Trading Days as reported by Bloomberg L.P. immediately prior
      to the date that this Convertible Debenture is called for redemption, plus
      accrued and unpaid interest.

      5.2 MECHANICS OF REDEMPTION. The Company shall effect each such redemption
      within 10 business days of giving notice of its election to redeem by
      facsimile with a copy by either overnight or 2-day courier to the Holder
      of this Convertible Debenture to be redeemed at the address and facsimile
      number of such Holder appearing in the Company's register for the
      Convertible Debentures. Such redemption notice shall indicate whether the
      Company will redeem all or part of such portion of the Convertible
      Debenture to be redeemed and the applicable Redemption Price. The Company
      shall not be entitled to send any notice of redemption and begin the
      redemption procedure unless it has (i) the full amount of the Redemption
      Price, in cash, available in a demand or other immediately available
      account in a bank or similar financial institution or (ii) immediately
      available credit facilities, in the full amount of the Redemption Price,
      with a bank or similar financial institution on the date the redemption
      notice is sent to the Holders of this Convertible Debenture. Provided,
      however, the Company will process any Notice of Conversion received prior
      to the issuance of a notice of redemption; and further provided that,
      after a notice of redemption has been issued, the Holder may issue a
      Notice of Conversion which will not be honored unless the Company fails to
      make the redemption payment when due. In the event of such failure, the
      Notice of Conversion will be honored as of the date of the Notice of
      Conversion. Additionally, if the Company fails to make full payments of
      the Redemption Price of this Convertible Debenture being redeemed by the
      tenth day following the notice or redemption, then the Company waives its
      right to redeem any of the remaining then outstanding Debentures, unless
      approved by the Holder.

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      5.3 PAYMENT OF REDEMPTION PRICE. The Redemption Price shall be paid to the
      Holder of this Convertible Debenture within 10 business days of the
      delivery of the notice of such redemption to such Holder.

      6. HOLDER'S RIGHT TO ADVANCE NOTICE OF ELECTION REDEEM.

      6.1 HOLDER'S RIGHT TO ELECT TO RECEIVE NOTICE OF CASH REDEMPTION BY
      COMPANY. The Holder of this Convertible Debenture shall have the right to
      require Company to provide advance notice stating whether the Company will
      elect to redeem all or part of the redeemable portion in cash, pursuant to
      the Company's redemption rights discussed in Section 5.1 above.

      6.2 MECHANICS OF HOLDER'S ELECTION NOTICE. Holder shall give notice to the
      Company by facsimile (the "Election Notice"), requiring that the Company
      disclose whether the Company would elect to redeem the redeemable portion
      of this Convertible Debenture (in whole or in part) if the Holder were to
      provide a Notice of Conversion and sought to convert the Convertible
      Debenture in such principal amount as is specified in the Notice of
      Election.

      6.3 COMPANY'S RESPONSE. Company must respond, disclosing its election,
      within two (2) business days of receipt of Holder's Election Notice via
      facsimile. If Company does not respond to Holder within two (2) business
      days (by 12:00 noon, if required above) via facsimile, Company shall be
      deemed to have forfeited its right to exercise redemption pursuant to
      Section 5(a) upon its receipt of (but only with respect to) that Notice of
      Conversion.

      7. MISCELLANEOUS. This Convertible Debenture shall be deemed to be a
contract made under the laws of the State of Georgia, and for all purposes shall
be governed by and construed in accordance with the laws of said State. The
parties hereto, including all guarantors or endorsers, hereby waive presentment,
demand, notice, protest and all other demands and notices in connection with the
delivery, acceptance, performance and enforcement of this Convertible Debenture,
except as specifically provided herein, and asset to extensions of the time of
payment, or forbearance or other indulgence without notice. The Company hereby
submits to the exclusive jurisdiction of the United States District Court for
the Middle District of Georgia and of any Georgia state court sitting in
Atlanta, Georgia for purposes of all legal proceedings arising out of or
relating to this Convertible Debenture. The Company irrevocably waives, to the
fullest extent permitted by law, any objection which it may now or hereafter
have to the laying of the venue of any such proceeding brought in such a court
and any claim that any such proceeding brought in such a court has been brought
in an inconvenient forum. The Company hereby irrevocably waives any and all
right to trial by jury in any legal proceeding arising out of or relating to
this Convertible Debenture.

                                      138
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      The Holder of this Convertible Debenture by acceptance of this Convertible
Debenture agrees to be bound by the provisions of this Convertible Debenture
which are expressly binding on such Holder.

      IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

      Dated: September 15, 2000

                                        eMissions Testing, Inc.

                                        By: /s/ William S. Estroff
                                           ------------------------------------
                                           Name: William S. Estroff
                                                -------------------------------
                                           Title: President
                                                 ------------------------------

                                      139
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                                     ANNEX A

                         CONVERSION AND REPAYMENT LEDGER
<TABLE>
<CAPTION>

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                                    INTEREST       PRINCIPAL CONVERTED
   DATE     PRINCIPAL BALANCE    CONVERTED PAID          OR PAID          NEW PRINCIPAL BALANCE    ISSUER INITIALS   HOLDER INITIALS
------------------------------------------------------------------------------------------------------------------------------------
<S>         <C>                  <C>               <C>                    <C>                      <C>               <C>
------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------

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------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------

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</TABLE>

                                      140
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FULL NAME AND ADDRESS OF SUBSCRIBER FOR REGISTRATION PURPOSES:

NAME:

ADDRESS:

TEL NO:

FAX NO:

CONTACT
NAME:

DELIVERY INSTRUCTIONS (IF DIFFERENT FROM REGISTRATION NAME):

NAME:

ADDRESS:

TEL NO:

FAX NO:

CONTACT
NAME:

SPECIAL INSTRUCTIONS:
                     -----------------------------------------------------------

                                      141
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                              NOTICE OF CONVERSION

                    (To be Executed by the Registered Holder

                 in order to Convert the Convertible Debenture)

      The undersigned hereby irrevocably elects to convert $________ of the
principal balance of the Convertible Debenture into shares of Common Stock, no
par value per share (the "Common Stock"), of eMissions Testing, Inc. (the
"Company") according to the conditions hereof, as of the date written below. No
fee will be charged to the Holder for any conversion, except for transfer taxes,
if any. The undersigned, as contemplated by Section 5.1 of the Securities
Purchase Agreement pursuant to which the Convertible Debenture was issued,
hereby states that the representations and warranties of the undersigned set
forth therein are true and correct in all material respects as of the date
hereof (provided, the undersigned makes no representations concerning its
investment intent with respect to the Common Stock received upon this
conversion).

Conversion calculations:

                                       Date of Conversion

                                       Applicable Conversion Price

                                       Number of Shares

                                       Name/Signature

                                       Address:

                                      142<PAGE>

                                                                    EXHIBIT 10.6

                      FORM OF COMMON STOCK PURCHASE WARRANT

                                      143
<PAGE>

THIS COMMON STOCK PURCHASE WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"). THE HOLDER HEREOF, BY PURCHASING
THIS COMMON STOCK PURCHASE WARRANT, AGREES FOR THE BENEFIT OF THE COMPANY THAT
SUCH SECURITIES MAY BE OFFERED, SOLD OR OTHERWISE TRANSFERRED ONLY (A) TO THE
COMPANY, (B) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT, OR (C) IF REGISTERED UNDER THE SECURITIES ACT AND ANY APPLICABLE STATE
SECURITIES LAWS. IN ADDITION, A SECURITIES PURCHASE AGREEMENT ("PURCHASE
AGREEMENT"), DATED THE DATE HEREOF, A COPY OF WHICH MAY BE OBTAINED FROM THE
COMPANY AT ITS PRINCIPAL EXECUTIVE OFFICE, CONTAINS CERTAIN ADDITIONAL
AGREEMENTS AMONG THE PARTIES, INCLUDING, WITHOUT LIMITATION, PROVISIONS WHICH
LIMIT THE EXERCISE RIGHTS OF THE HOLDER AND SPECIFY MANDATORY REDEMPTION
OBLIGATIONS OF THE COMPANY.

                     ---------------------------------------

                             EMISSIONS TESTING, INC.

                          COMMON STOCK PURCHASE WARRANT

--------------------------------------------------------------------------------
                                                      No. 2

Number of shares: 50,000                   Holder:  GCA Strategic Investment
                                                    Fund Limited
Expiration Date:  September 15, 2005                c/o Prime Management Limited

                                                    Mechanics Building
Purchase Price Per Share:  $1.00                    12 Church Street
                                                    Hamilton, Bermuda, HM11

   For identification only. The governing terms of this Warrant are set forth
                                     below.
--------------------------------------------------------------------------------

eMissions Testing, Inc., a Georgia corporation (the "COMPANY"), hereby certifies
that, for value received, GCA Strategic Investment Fund Limited or assigns, is
entitled, subject to the terms set forth below, to purchase from the Company at
any time or from time to time after the date hereof and prior to the fifth
anniversary hereof (the "EXERCISE PERIOD"), at the Purchase Price hereinafter
set forth, Fifty Thousand (50,000) shares of the fully paid and nonassessable
shares of common stock of the Company, no par value per share (the "Common
Stock"). The number and character of such shares of Common Stock and the
Purchase Price are subject to adjustment as provided herein.

      The purchase price per share of Common Stock issuable upon exercise of
this Warrant (the "PURCHASE Price") shall initially be $1.00; PROVIDED, HOWEVER,
that the Purchase Price shall be adjusted from time to time as provided herein.

                                      144
<PAGE>

      Capitalized terms used herein not otherwise defined shall have the
meanings ascribed thereto in the Purchase Agreement. As used herein the
following terms, unless the context otherwise requires, have the following
respective meanings:

            (a) The term "COMPANY" shall include eMissions Testing, Inc. and any
      corporation that shall succeed or assume the obligations of such
      corporation hereunder.

            (b) The term "COMMON STOCK" includes (a) the Company's common stock,
      no par value per share, (b) any other capital stock of any class or
      classes (however designated) of the Company, authorized on or after such
      date, the Holders of which shall have the right, without limitation as to
      amount, either to all or to a share of the balance of current dividends
      and liquidating dividends after the payment of dividends and distributions
      on any shares entitled to preference, and the Holders of which shall
      ordinarily, in the absence of contingencies, be entitled to vote for the
      election of a majority of directors of the Company (even though the right
      so to vote has been suspended by the happening of such a contingency) and
      (c) any other securities into which or for which any of the securities
      described in (a) or (b) may be converted or exchanged pursuant to a plan
      of recapitalization, reorganization, merger, sale of assets or otherwise.

            (c) The term "OTHER SECURITIES" refers to any stock (other than
      Common Stock) and other securities of the Company or any other person
      (corporate or otherwise) that the Holder of this Warrant at any time shall
      be entitled to receive, or shall have received, on the exercise of this
      Warrant, in lieu of or in addition to Common Stock, or that at any time
      shall be issuable or shall have been issued in exchange for or in
      replacement of Common Stock or Other Securities pursuant to Section 4 or
      otherwise.

      1. EXERCISE OF WARRANT.

            1.1 METHOD OF EXERCISE.

            (a) This warrant may be exercised in whole or in part (but not as to
      a fractional share of Common Stock), at any time and from time to time
      during the Exercise Period by the Holder hereof by delivery of a notice of
      exercise (a "NOTICE OF EXERCISE") substantially in the form attached
      hereto as EXHIBIT A via facsimile to the Company. Promptly thereafter the
      Holder shall surrender this Warrant to the Company at its principal
      office, accompanied by payment of the Purchase Price multiplied by the
      number of shares of Common Stock for which this Warrant is being exercised
      (the "EXERCISE PRICE"). Payment of the Exercise Price shall be made, at
      the option of the Holder, (i) by check or bank draft payable to the order
      of the Company, or (ii) by wire transfer to the account of the Company.
      Upon exercise, the Holder shall be entitled to receive, promptly refund
      the excess to the Holder. Upon exercise, the Holder shall be entitled to
      receive, promptly after payment in full, one or more certificates, issued
      in the Holder's name or in such name or names as the Holder may direct,
      subject to the

                                      145
<PAGE>

      limitations on transfer contained herein, for the number of shares of
      Common Stock so purchased. The shares of Common Stock so purchased shall
      be deemed to be issued as of the close of business on the date on which
      the Company shall have received from the Holder payment in full of the
      Exercise Price (the "EXERCISE DATE").

            (b) Notwithstanding anything to the contrary set forth herein, upon
      exercise of all or a portion of this Warrant in accordance with the terms
      hereof, the Holder shall not be required to physically surrender this
      Warrant to the Company. Rather, records showing the amount so exercised
      and the date of exercise shall be maintained on a ledger substantially in
      the form of ANNEX B attached hereto (a copy of which shall be delivered to
      the Company or transfer agent with each Notice of Exercise). It is
      specifically contemplated that the Holder hereof shall act as the
      calculation agent for all exercises of this Warrant. In the event of any
      dispute or discrepancies, such records maintained by the Holders shall be
      controlling and determinative in the absence of manifest error. The Holder
      and any assignee, by acceptance of this Warrant, acknowledge and agree
      that, by reason of the provisions of this paragraph, following an exercise
      of a portion of this Warrant, the number of shares of Common Stock
      represented by this Warrant will be the amount indicated on ANNEX B
      attached hereto (which may be less than the amount stated on the face
      hereof).

            1.2 REGULATION D RESTRICTIONS. The Holder hereof represents and
warrants to the Company that it has acquired this Warrant and anticipates
acquiring the shares of Common Stock issuable upon exercise of the Warrant
solely for its own account for investment purposes and not with a view to or for
resale of such securities unless such resale has been registered with the
Commission or an applicable exemption is available therefore. At the time this
Warrant is exercised, the Company may require the Holder to state in the Notice
of Exercise such representations concerning the Holder as are necessary or
appropriate to assure compliance by the Holder with the Securities Act.

            1.3 COMPANY ACKNOWLEDGMENT. The Company will, at the time of the
exercise of this Warrant, upon request of the Holder hereof, acknowledge in
writing its continuing obligation to afford to such Holder the registration
rights to which such Holder shall continue to be entitled after such exercise in
accordance with the provisions of a Registration Rights Agreement dated the date
hereof (the "Registration Rights Agreement"). If the Holder shall fail to make
any such request, such failure shall not affect the continuing obligation of the
Company to afford such Holder any such rights.

            1.4 LIMITATION ON EXERCISE. Notwithstanding the rights of the Holder
to exercise all or a portion of this Warrant as described herein, such exercise
rights shall be limited, solely to the extent set forth in the Purchase
Agreement as if such provisions were specifically set forth herein. In addition,
the number of shares of Common Stock issuable upon exercise of this Warrant is
subject to reduction as specified in Section 10.3 of the Purchase Agreement.

                                      146
<PAGE>

      2. DELIVERY OF STOCK CERTIFICATES, ETC., ON EXERCISE. As soon as
practicable after the exercise of this Warrant, and in any event within five (5)
business days thereafter, the Company at its expense (including the payment by
it of any applicable issue, stamp or transfer taxes) will cause to be issued in
the name of and delivered to the Holder thereof, or, to the extent permissible
hereunder, to such other person as such Holder may direct, a certificate or
certificates for the number of fully paid and nonassessable shares of Common
Stock (or Other Securities) to which such Holder shall be entitled on such
exercise, plus, in lieu of any fractional share to which such Holder would
otherwise be entitled, cash equal to such fraction multiplied by the then
applicable Purchase Price, together with any other stock or other securities and
property (including cash, where applicable) to which such Holder is entitled
upon such exercise pursuant to Section 1 or otherwise.

      3. ADJUSTMENT FOR EXTRAORDINARY EVENTS. The Purchase Price to be paid by
the Holder upon exercise of this Warrant, and the consideration to be received
upon exercise of this Warrant, shall be adjusted in case at any time or from
time to time pursuant to Article XI of the Purchase Agreement as if such
provisions were specifically set forth herein.

      4. NO IMPAIRMENT. The Company will not, by amendment of its Certificate of
Incorporation or through any reorganization, transfer of assets, consolidation,
merger, dissolution, issue or sale of securities or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms of this
Warrant, but will at all times in good faith assist in the carrying out of all
such terms and in the taking of all such action as may be necessary or
appropriate in order to protect the rights of the Holder of this Warrant against
impairment. Without limiting the generality of the foregoing, the Company (a)
will not increase the par value of any shares of stock receivable on the
exercise of this Warrant above the amount payable therefor on such exercise, (b)
will take all such action as may be necessary or appropriate in order that the
Company may validly and legally issue fully paid and unassessable shares of
stock on the exercise of this Warrant, and (c) will not transfer all or
substantially all of its properties and assets to any other person (corporate or
otherwise), or consolidate with or merge into any other person or permit any
such person to consolidate with or merge into the Company (if the Company is not
the surviving person), unless such other person shall expressly assume in
writing and will be bound by all the terms of this Warrant.

      5. ACCOUNTANT'S CERTIFICATE AS TO ADJUSTMENTS. In each case of any
adjustment or readjustment in the shares of Common Stock (or Other Securities)
issuable on the exercise of this Warrant, the Company at its expense will
promptly cause independent certified public accountants of national standing
selected by the Company to compute such adjustment or readjustment in accordance
with the terms of this Warrant and prepare a certificate setting forth such
adjustment or readjustment and showing in detail the facts upon which such
adjustment or readjustment is based, including a statement of (a) the
consideration received or receivable by the Company for any additional shares of
Common Stock (or Other Securities) issued or sold or deemed to have been issued
or sold, (b) the number of shares of Common Stock (or Other Securities)
outstanding or deemed to be outstanding, and (c) the Purchase Price and the
number of shares of Common Stock to be received upon exercise of this Warrant,
in effect immediately prior to such issue or sale and as adjusted and readjusted
as provided in this Warrant. The Company will forthwith mail a copy of each such
certificate to the Holder of this Warrant, and will, on the written request at
any time of the Holder of this Warrant, furnish to such Holder a

                                      147
<PAGE>

like certificate setting forth the Purchase Price at the time in effect and
showing how it was calculated.

      6. NOTICES OF RECORD DATE, ETC. In the event of

                  (a) any taking by the Company of a record of the Holders of
      any class or securities for the purpose of determining the Holders thereof
      who are entitled to receive any dividend or other distribution, or any
      right to subscribe for, purchase or otherwise acquire any shares of stock
      of any class or any other securities or property, or to receive any other
      right, or

                  (b) any capital reorganization of the Company, any
      reclassification or recapitalization of the capital stock of the Company
      or any transfer of all or substantially all the assets of the Company to
      or consolidation or merger of the Company with or into any other person,
      or

                  (c) any voluntary or involuntary dissolution, liquidation or
      winding- up of the Company,

then and in each such event the Company will mail or cause to be mailed to the
Holder of this Warrant a notice specifying (i) the date on which any such record
is to be taken for the purpose of such dividend, distribution or right, and
stating the amount and character of such dividend, distribution or right, and
(ii) the date on which any such reorganization, reclassification,
recapitalization, transfer, consolidation, merger, dissolution, liquidation or
winding-up is to take place, and the time, if any, as of which the Holders of
record of Common Stock (or Other Securities) shall be entitled to exchange their
shares of Common Stock (or Other Securities) for then and in each such event the
Company will mail or cause to be mailed to the Holder of this Warrant a notice
specifying (i) the date on which any such record is to be taken for the purpose
of such dividend, distribution or right, and stating the amount of character of
such dividend, distribution or right, and (ii) the date on which any such
reorganization, reclassification, recapitalization, transfer, consolidation,
merger, dissolution, liquidation or winding-up is to take place, and the time,
if any, as of which the Holders of record of Common Stock (or Other Securities)
shall be entitled to exchange their shares of Common Stock (or Other Securities)
for securities or other property deliverable on such reorganization,
reclassification, recapitalization, transfer, consolidation, merger,
dissolution, liquidation or winding-up. Such notice shall be mailed at least 20
days prior to the date specified in such notice on which any action is to be
taken.

      7. RESERVATION OF STOCK, ETC. ISSUABLE ON EXERCISE OF WARRANT. The Company
will at all times reserve and keep available, solely for issuance and delivery
on the exercise of this Warrant, all shares of Common Stock (or Other
Securities) from time to time issuable on the exercise of this Warrant.

                                      148
<PAGE>

      8. EXCHANGE OF WARRANT.

            (a) On surrender for exchange of this Warrant, properly endorsed and
in compliance with the restrictions on transfer set forth in the legend on the
face of this Warrant, to the Company, the Company at its expense will issue and
deliver to or on the order of the Holder thereof a new Warrant of like tenor, in
the name of such Holder or as such Holder (on payment by such Holder of any
applicable transfer taxes) may direct, calling in the aggregate on the face or
faces thereof for the number of shares of Common Stock called for on the face of
the Warrant so surrendered.

            (b) Upon written notice from the Purchasers that the Purchasers have
elected to transfer amongst each other a portion of this Warrant, and on
surrender for amendment and restatement of this Warrant, the Company at its
expense will issue and deliver to or on the order of the Holder thereof a new
Warrant of like tenor, in the name of such Holder as the Purchasers (on payment
by such Holder of any applicable transfer taxes) may direct, calling in the
aggregate on the face or faces thereof for the number of shares of Common Stock
as set forth in such notice reflecting such transfer.

      9. REPLACEMENT OF WARRANT. On receipt of evidence reasonably satisfactory
to the Company of the loss, theft, destruction or mutilation of this Warrant
and, in the case of any such loss, theft or destruction of this Warrant, on
delivery of an indemnity agreement or security reasonably satisfactory in form
and amount to the Company or, in the case of any such mutilation, on surrender
and cancellation of this Warrant, the Company at its expense will execute and
deliver, in lieu thereof, a new Warrant of like tenor.

      10. REMEDIES. The Company stipulates that the remedies at law of the
Holder of this Warrant in the event of any default or threatened default by the
Company in the performance of or compliance with any of the terms of this
Warrant are not and will not be adequate, and that such terms may be
specifically enforced by a decree for the specific performance of any agreement
contained herein or by an injunction against a violation of any of the terms
hereof or otherwise.

      11. NEGOTIABILITY, ETC.. This Warrant is issued upon the following terms,
to all of which each Holder or owner hereof by the taking hereof consents and
agrees:

            (a) title to this Warrant may be transferred by endorsement and
delivery in the same manner as in the case of a negotiable instrument
transferable by endorsement and delivery.

            (b) any person in possession of this Warrant properly endorsed is
authorized to represent himself as absolute owner hereof and is empowered to
transfer absolute title hereto by endorsement and delivery hereof to a BONA FIDE
purchaser hereof for value; each prior taker or owner waives and renounces all
of his equities or rights in this Warrant in favor of such BONA FIDE purchaser,
and each such BONA FIDE purchaser shall acquire absolute title hereto and to all
rights represented hereby;

                                      149
<PAGE>

            (c) until this Warrant is transferred on the books of the Company,
the Company may treat the registered Holder hereof as the absolute owner hereof
for all purposes, notwithstanding any notice to the contrary; and

            (d) notwithstanding the foregoing, this Warrant may be sold,
transferred or assigned except pursuant to an effective registration statement
under the Securities Act or pursuant to an applicable exemption therefrom.

      12. REGISTRATION RIGHTS. The Company is obligated to register the shares
of Common Stock issuable upon exercise of this Warrant in accordance with the
terms of the Registration Rights Agreement.

      13. WARRANT REDEMPTION. Upon occurrence of the events described in
Sections 3.4 and 10.4(c) of the Purchase Agreement, the Company, at the request
of Holder, shall redeem all outstanding Warrants that remain unexercised at a
redemption price equal to the greater of (x) an appraised value of the Warrants,
as determined by Black Sholes, on the date they are called for redemption and
(y) the number of Warrants being redeemed multiplied by the excess of (A) the
average Closing Bid Price of the Common Stock for the five Trading Days
immediately prior to the date that the Warrants are called for redemption over
(B) the exercise price of the Warrants.

      14. NOTICES, ETC.. All notices and other communications from the Company
to the Holder of this Warrant shall be mailed by first class registered or
certified mail, postage prepaid, at such address as may have been furnished to
the Company in writing by such Holder or, until any such Holder furnishes to the
Company any address, then to, and at the address of, the last Holder of this
Warrant who has so furnished an address to the Company.

      15. MISCELLANEOUS. This Warrant and any term hereof may be changed,
waived, discharged or terminated only by an instrument in writing signed by the
party against which enforcement of such change, waiver, discharge or termination
is sought. This Warrant shall be construed and enforced in accordance with and
governed by the internal laws of the State of Georgia. The headings in this
Warrant are for the purposes of reference only, and shall not limit or otherwise
affect any of the terms hereof. The invalidity or unenforceability of any
provision hereof shall in no way affect the validity or enforceability of any
other provision.

                            [SIGNATURE PAGE FOLLOWS]

                                      150
<PAGE>

      DATED as of September 15, 2000.

                                           eMISSIONS TESTING, Inc.

                                           By: /s/ William S. Estroff
                                              ----------------------------------
                                              Name: William S. Estroff
                                              ----------------------------------
                                              Title: President
                                                    ----------------------------

[Corporate Seal]

Attest:

By:
   -----------------------------------------
         Secretary

                                      151
<PAGE>

                                    EXHIBIT A

                        FORM OF NOTICE EXERCISE - WARRANT
                       (To be executed only upon exercise
                       of the Warrant in whole or in part)

To ____________________________________________

      The undersigned registered Holder of the accompanying Warrant, hereby
exercises such Warrant or portion thereof for, and purchases thereunder,
__________(2) shares of Common Stock (as defined in such Warrant) and herewith
makes payment therefor in the amount and manner set forth below, as of the date
written below. The undersigned requests that the certificates for such shares of
Common Stock be issued in the name of, and delivered to, whose address is
________________________________________.

      The Exercise Price is paid as follows:

      |_| Bank draft payable to the Company in the amount of $_____________.
      |_| Wire transfer to the account of the Company in the amount of $_______.

      Upon exercise pursuant to this Notice of Exercise, the Holder will be in
compliance with the Limitation on Exercise (as defined in the Securities
Purchase Agreement pursuant to which this Warrant was issued).

Date:
     ------------------------------   --------------------------------------
                                      (Name must conform to name of Holder as
                                      specified on the face of the Warrant)

                                      By:
                                         --------------------------------------
                                         Name:
                                              ---------------------------------
                                         Title:
                                               ---------------------------------

                                      Address of Holder:
                                                        ------------------------

                                                     ---------------------------

                                                        ------------------------
 Date of exercise:
                  ------------------

----------

      (2)Insert the number of shares of Common Stock as to which the
accompanying Warrant is being exercised. In the case of a partial exercise, a
new Warrant or Warrants will be issued and delivered, representing the
unexercised portion of the accompanying Warrant, to the Holder surrendering the
same.

                                      152
<PAGE>
                                    ANNEX B

                             WARRANT EXERCISE LEDGER
<TABLE>
<CAPTION>

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                 ORIGINAL NUMBER OF      WARRANTS      EXERCISE PRICE      NEW BALANCE         ISSUER         HOLDER
    DATE              WARRANTS           EXERCISED         PAID            OF WARRANTS        INITIALS       INITIALS
----------------------------------------------------------------------------------------------------------------------
<S>              <C>                     <C>           <C>                 <C>                <C>            <C>
----------------------------------------------------------------------------------------------------------------------

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</TABLE>

                                      153

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