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                                                                 EXHIBIT 4.11

                          UNITED AIR SPECIALISTS, INC.

                             1994 STOCK OPTION PLAN



                                   OBJECTIVES


        1.1  The objectives of this Stock Option Plan (the "Plan") are to
enable United Air Specialists, Inc. ("UAS") to compete successfully in
retaining and attracting employees and advisors of outstanding ability, to
stimulate the efforts of employees and advisors toward UAS's objectives and to
encourage ownership of shares of its common stock by its employees and
advisors.


                                   ARTICLE II
                                 ADMINISTRATION


        2.1  Administration. The Plan shall be administered by a committee of
the Board of Directors of UAS (the "Committee") to consist of at least two
directors, each of whom is a "disinterested person" as defined in Rule 16b-3
promulgated by the Securities and Exchange Commission under the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), as such Rule may be
amended from time to time or any successor rule thereto. Subject to and
consistent with the provision of the Plan, the Committee shall establish such
rules and regulations as it may deem necessary or appropriate for the proper
administration of the Plan, shall interpret the provisions of the Plan, shall
decide all questions of fact arising in the application of Plan provisions and
shall make such other determinations and take such actions in connection with
the Plan and the Options granted hereunder as it deems necessary or advisable.

        2.2  Except as specifically limited by the provisions of the Plan, the
Committee shall have exclusive authority to:

             A.  Determine which Eligible Employees or Advisors shall be granted
                 Options;

             B.  Determine the number of Shares which may be subject to each
                 Option;

             C.  Determine the term and the Option Price of each Option;


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                D.  Determine whether an Option is an Incentive Stock Option or
        a Non-qualified Stock Option (except that only Nonqualified Stock
        Options may be granted to Advisors);

                E.  Determine the time or times when Options will be granted;
        and

                F.  Determine all other terms and conditions of each Option,
        including (but not limited to) the time and conditions of exercise or
        vesting and the terms of any Option agreement. The Committee may, in its
        discretion, determine as a condition of any Option that a stated
        percentage of Shares covered by such Option shall be exercisable in any
        one year or other stated period of time. The Committee may also waive or
        amend the terms and conditions of, or accelerate the vesting of, an
        Option under circumstances selected by the Committee.

        2.3  Any action, decision, interpretation or determination by the
Committee with respect to the application or administration of this Plan shall
be final and binding upon all persons, and need not be uniform with respect to
its determination of recipients, amount, timing, form, terms or provisions of
Option.

        2.4  No member of the Committee shall be liable for any action or
determination taken or made in good faith with respect to the Plan or any
Option granted hereunder and, to the extent not prohibited by applicable law,
all members shall be indemnified by the Company for any liability and expenses
which they may incur as a result of any claim or cause of action or threatened
claim or cause of action.

                                  ARTICLE III
                                SHARES ISSUABLE

        3.1  Except as provided in Article XI, the number of Shares which may
be issued under the Plan shall not exceed 437,500 Shares in the aggregate. If
any Option expires or terminates for any reason without being completely
exercised, the Shares with respect to which such Option was not exercised may
again be subject to other Options. Shares tendered or withheld as payment for
the Option Price pursuant to Section 7.1 shall not be available for issuance
under the Plan.

        3.2  No Option shall be granted to any Eligible Employee or Advisor
during any calendar year if the number of Shares for which such Option may be
exercised, plus the aggregate number of Shares for which all other options
granted under the Plan to such person during such calendar year may be
exercised, exceeds the number of Shares which may be issued under the Plan
pursuant to Section 3.1.



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                                  ARTICLE IV
                                 DEFINITIONS

        4.1  For purposes of the Plan each of the following terms shall have
the definition which is attributed to it, unless another definition is clearly
indicated by a particular usage and context.

             A.  "Advisor" means any person who provides bona-fide advisory or
             consulting services to the Company other than services in
             connection with the offer or sale of securities in a
             capital-raising operation.

             B.  "Code" means the Internal Revenue Code of 1986, as amended.
             Reference to any Section of the Code includes the provisions of
             that Section as it may be amended or replaced by any other
             section(s) of like intent and purpose and also includes any
             regulations or rulings promulgated thereunder.

             C.  "Company" means UAS and any parent or subsidiary of UAS, as the
             terms "parent" and "subsidiary" are defined in Section 424(e) and
             424(f) of the Code.

             D.  "Disability" means permanent and total disability as defined in
             Section 22(e)(3) of the Code.

             E.  "Effective Date of Grant"  means the date on which, or such
             later date as of which, the Committee makes an award of an Option.

             F.  "Eligible Employee" means any individual (other than one who
             receives retirement benefits, stipends, consulting fees,
             honorarium, and the like) who performs services for the Company and
             is included on the regular payroll of the Company.

             G.  "Fair Market Value" means the last sale price reported on any
             stock exchange or on any trading system sponsored by the National
             Association of Securities Dealers, Inc. on which the Shares are
             traded on a specified date or, if there are no reported sales on
             such date, then the last reported sales price on the next preceding
             day on which such a sale was transacted. If the Shares are not then
             traded as described in the preceding sentence, then the average of
             the closing bid and asked prices on the specified date or last
             preceding day on which bid and asked prices were reported, as
             quoted by such source as the Committee may select, shall be used in
             determining Fair Market Value for a Share. If bid and asked prices
             are not then reported at least weekly as described in the preceding
             sentence, then the Fair Market Value for a Share shall be what the
             Committee in good faith determines it to be.


             H.  "Incentive Stock Option" shall have the same meaning as is
             given to that term by Section 422 of the Code.
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                I.  "Nonqualified Stock Option" means any Option other than an
        Incentive Stock Option. 

                J.  "Option" means the right, subject to the terms of this Plan
        and to such other terms and conditions as the Committee may establish,
        to purchase from UAS a stated number of Shares at a specified price.

                K.  "Option Price" means the purchase price per Share subject to
        an Option. The Option Price shall not be less than 50% of the Fair
        Market Value of a Share on the Effective Date of Grant in the case of a
        Nonqualified Stock Option or less than 100% of the Fair Market Value of
        a Share on the Effective Date of Grant in the case of an Incentive Stock
        Option, except as otherwise provided in Section 8.1.

                L.  "Share" means one share of the common stock, no par value,
        of UAS. 


                                   ARTICLE V
                              GRANTING OF OPTIONS

        5.1  Subject to the terms and conditions of the Plan, the Committee
may, from time to time prior to September 1, 2004, grant Options to Eligible
Employees or Advisors on such terms and conditions as the Committee shall
determine. Subject to the restriction of Section 2.2(D), more than one Option
and more than one form of Option may be granted to the same individual. No
director of UAS who is not an employee of the Company and included on its
regular payroll may be granted Options under this Plan.

        5.2  A period of at least six months must elapse from the date of grant
of any Option to a person who is subject to the reporting requirements of
Section 16(a) of the Exchange Act with respect to UAS until the disposition of
the Option (other than upon exercise or conversion) or of any shares acquired
upon exercise of that Option. 

                                   ARTICLE VI
                              EXERCISE OF OPTIONS

        6.1  Any person entitled to exercise an Option may do so in whole or in
part by delivering to UAS, attention Corporate Secretary, at its principal
office a written notice of exercise. The written notice shall specify the
number of Shares for which an Option is being exercised and shall be
accompanied by full payment of the Option Price for the Shares being purchased
in the manner provided in Article VII.


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        6.2  In the sole discretion of the Committee, upon exercise of an
Option, UAS may make payment of cash to the holder of the Option equal to the
difference between the Fair Market Value of the Shares for which the Option is
being exercised and the aggregate Option Price of such Shares. Any such cash
payment shall be in lieu of and in full discharge of any and all obligations of
UAS in respect of the Option being exercised.

                                  ARTICLE VII
                            PAYMENT OF OPTION PRICE

        7.1  In the sole discretion of the Committee and subject to such
conditions as the Committee may impose relating to the use of Shares as
payment, payment of the Option Price may be made in cash, by the tender of
Shares, by directing that a portion of the Shares to be issued upon exercise of
the Option be withheld by UAS as payment (to the extent permitted by law) or by
a combination of the foregoing. If payment by the tender of Shares or the
withholding of Shares is permitted, the value of each Share shall be deemed to
be the Fair Market Value of a Share on the exercise date.

                                  ARTICLE VIII
             INCENTIVE STOCK OPTIONS AND NONQUALIFIED STOCK OPTIONS

        8.1  Any option designated by the Committee as an Incentive Stock
Option will be subject to the general provisions applicable to all Options
granted under the Plan. In addition, an Incentive Stock Option shall be subject
to the following specific provisions:

                A.  No Incentive Stock Option may be exercised after the
        expiration of ten years from the Effective Date of Grant.


                B.  At the time the Incentive Stock Option is granted, if the
        Eligible Employee owns, directly or indirectly, stock representing more
        than 10% of the total combined voting power of all classes of stock of
        the Company then:

                        (i)  The Option Price must equal at least 110% of the
                Fair Market Value on the Effective Date of Grant; and

                        (ii)  The term of the Option shall not be greater than
                five years from the Effective Date of Grant.


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                C.  The aggregate Fair Market Value (determined as of the
        Effective Date of Grant) of the Shares with respect to which Incentive
        Stock Options are exercisable for the first time by any holder during
        any calendar year (under all plans of the Company) shall not exceed
        $100,000.

        8.2  If any Option is not granted, exercised or held pursuant to the
provisions of Code Section 422, it will be considered to be a Nonqualified
Stock Option to the extent that any or all of the grant is in conflict with
those provisions.

                                   ARTICLE IX
                           TRANSFERABILITY OF OPTIONS

        9.1  During the lifetime of an Eligible Employee or Advisor to whom an
Option has been granted, such Option is non-assignable and non-transferrable and
may be exercised only by such individual or that individual's legal
representative or guardian, except that a Nonqualified Stock Option may be
transferred pursuant to a "domestic relations order" as defined in Section
414(p)(1)(B) of the Code. In the event of the death of an Eligible Employee or
Advisor to whom an Option has been granted, the Option shall be transferable
pursuant to the holder's Will or by the laws of descent and distribution and
may thereafter be exercised by the transferee(s) as provided in Section 10.1(C).

                                   ARTICLE X
                             TERMINATION OF OPTIONS

        10.1  Unless earlier terminated pursuant to Article XIII, an Option
granted to an Eligible Employee will terminate as follows:

                A.  During the period of the Eligible Employee's continuous
        employment with the Company, the Option will terminate upon the earlier
        of the date on which it has been fully exercised, it expires by its
        terms or it is terminated by the mutual agreement of the Company and the
        Eligible Employee.

                B.  Upon termination of employment for any reason any
        unexercisable Option shall immediately terminate. Except as provided in
        Section 10.1(C), any Option which is exercisable on the date of
        termination of employment will terminate upon the earlier of its full
        exercise, the expiration of the Option by its terms or the end of the
        three-month period following the date of termination. For purposes of
        the Plan, a leave of absence approved by the Company shall not be deemed
        to be termination of employment.



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            C.   If an Eligible Employee to whom an Option was granted becomes
        subject to a Disability or dies while employed by the Company or within
        three months of termination of employment for any reason, the Option may
        be exercised at any time within one year after the date of death or the
        commencement of Disability, to the extent that the Eligible Employee
        shall have been entitled to exercise it at the time of death or the
        commencement of Disability, by the Eligible Employee or the Eligible
        Employee's legal representative or guardian or by the representative(s)
        of the Eligible Employee's estate or the person(s) to whom the Option
        may have been transferred by Will or by the laws of descent and
        distribution.

        10.2  An Option granted to an Advisor will terminate upon the earlier
of the full exercise of the Option or the expiration of the Option by its
terms.

        10.3  The Committee, at its discretion, may extend the periods for
Option exercise set forth in Sections 10.1 and 10.2 above.


                                   ARTICLE XI
                     ADJUSTMENTS TO SHARES AND OPTION PRICE


        11.1  The Committee shall make appropriate adjustments in the number of
Shares available for issuance under the Plan, the number of Shares subject to
outstanding Options and the Option Price of optioned Shares in order to give
effect to changes in the Shares as a result of any merger, consolidation,
recapitalization, reclassification, combination, stock dividend, stock split,
or other similar event. The determination as to the method and extent of such
adjustments shall be within the sole discretion of the Committee.


                                  ARTICLE XII
                      AMENDMENT OR DISCONTINUANCE OF PLAN


        12.1  The Board of Directors of UAS may at any time amend, suspend or
discontinue the Plan; provided, however, that shareholder approval shall be
required for any amendment if such approval is required to maintain the Plan's
compliance with Exchange Act Rule 16b-3 as that Rule may be in effect and be
interpreted from time to time.

        12.2  No amendment to the Plan shall alter or impair any Option granted
under the Plan without the consent of the holder thereof.


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                                  ARTICLE XIII
                                 CERTAIN EVENTS

        13.1  In the event UAS shall consolidate with, merge into, or transfer
all or substantially all of its assets to another corporation or corporations
(a "successor corporation"), such successor corporation may obligate itself to
continue this Plan and to assume all obligations under the Plan.  In the event
that such successor corporation does not obligate itself to continue this Plan
as above provided, the Plan shall terminate effective upon such consolidation,
merger or transfer, and any Option previously granted hereunder shall
terminate.  If practical, UAS shall give each holder of an Option twenty days
prior notice of any possible transaction which might terminate this Plan and
the Options previously granted hereunder.

        13.2  The grant of Options under the Plan shall in no way affect the
right of UAS to adjust, reclassify, reorganize or otherwise change its capital
or business structure or to merge, consolidate, dissolve, liquidate or sell or
transfer all or any part of its business or assets.


                                  ARTICLE XIV
                                 EFFECTIVE DATE

        14.1  This Plan shall be effective as of September 1, 1994.  If this
Plan is not approved and adopted by a majority vote of the shareholders of UAS
voting thereon at the next annual meeting of such shareholders held after
September 1, 1994, the Plan shall be of no force or effect and all Options
granted on or after September 1, 1994 under the Plan shall be null and void.
No Option shall be granted subsequent to September 1, 2004 or subsequent to any
earlier date as of which this Plan is terminated.


                                   ARTICLE XV
                                 MISCELLANEOUS

        15.1  Nothing contained in this Plan or in any action taken by the
Board of Directors or shareholders of UAS shall constitute the granting of an
Option.  An Option shall be granted only at such time as a written Option
agreement, in such form as the Committee shall determine, shall have been
executed by both the Eligible Employee or Advisor and UAS.

        15.2  Certificates for Shares purchased through exercise of Options will
be issued in the regular course after exercise of the Option and payment
therefor as called for by the terms of the Option but in no event shall UAS be
obligated to issue certificates more often than once each

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quarter of each fiscal year. No persons holding an Option or entitled to
exercise an Option granted under this Plan shall have any rights or privileges
of a shareholder of UAS with respect to any Shares issuable upon exercise of
such Option until certificates representing such Shares shall have been issued
and delivered. No Shares shall be issued and delivered upon exercise of an
Option unless and until, in the opinion of counsel for UAS, UAS has complied
with all applicable registration requirements of the Securities Act of 1933 and
any applicable state securities laws and with any applicable listing
requirements of any national securities exchange on which UAS's securities may
then be listed as well as any other requirements of law.

        15.3  Nothing contained in this Plan or in any Option granted pursuant
to it shall confer upon any person any right to continue in the employ of or
any business relationship with the Company or to interfere in any way with the
right of the Company to terminate employment or a business relationship at any
time. So long as a holder of an Option shall continue to be an employee of the
Company, the Option shall not be affected by any change of the employee's
duties or position.

        15.4  This Plan shall be construed and administered in accordance with
and governed by the laws of the State of Ohio.





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