EXHIBIT 99.3 SECURED PROMISSORY NOTE $1,000,000.00 May 9, 2003 FOR VALUE RECEIVED, the undersigned, Kronos Advanced Technologies, Inc., a Nevada corporation ("Borrower") and Kronos Air Technologies, Inc., a Nevada corporation, promise to pay to the order of FKA Distributing Co. d/b/a HoMedics, Inc., a Michigan corporation ("Lender"), at the office of the Lender in the State of Michigan, One Million and 00/100 ($1,000,000.00) Dollars (U.S.) as set forth herein. Interest on the unpaid principal balance from the date of this Note shall accrue at the rate of 6% per annum until maturity, whether by acceleration or otherwise, or until Default, as later defined, and after that at a default rate equal to the rate of interest otherwise prevailing under this Note plus 3% per annum (but in no event in excess of the maximum rate permitted by law). Interest shall be calculated for the actual number of days the principal is outstanding on the basis of a 365/366 day year. No payments shall be required under this Note until August 1, 2004 [the first payment date of that certain Secured Promissory Note in the amount of $2,400,000, dated May 8, 2003 executed by Borrower in favor of Lender (the "$2,400,000 Note")]. Interest accrued during such period shall become part of the principal balance of the Note and shall be included as principal for purposes of calculating amortization. Payment installments of principal and accrued interest due under this Note shall begin on August 1, 2004 and continuing on the first day of each November, February, May and August until paid in full over the remaining period of this Note. The entire remaining unpaid balance of principal and accrued interest shall be payable on the fifth (5th) anniversary of the $2,400,000 Note. If this Note is issued on or after the first anniversary date of the $2,400,000 Note, payments shall be made in equal quarterly installments beginning on the first day of the first quarter month (August, November, February or May) immediately following the issue date, and continuing until the fifth (5th) anniversary of the $2,400,000 Note. A late installment charge equal to 5% of each late installment may be charged on any installment payment not received by the Lender within 10 calendar days after the installment due date, but acceptance of payment of this charge shall not waive any Default under this Note. This Note and any other indebtedness and liabilities of any kind of the undersigned to the Lender, and any and all modifications, renewals or extensions of it, whether joint or several, contingent or absolute, now existing or later arising, and however evidenced (collectively "Indebtedness") are secured by and the Lender is granted a security interest in all property of the undersigned from time to time in the possession of the Lender and by any other collateral, rights and properties described in each and every mortgage, security agreement, pledge, assignment and other security or collateral agreement which has been, or will at any time(s) later be, executed by the undersigned to or for the benefit of the Lender (collectively "Collateral"). If the undersigned (a) fail to pay this Note or any of the Indebtedness when due (after the expiration of the 30 day grace period as set forth in that certain Master Loan and Investment Agreement dated May 8, 2003 among the parties ("Master Loan Agreement")), by maturity, acceleration or otherwise; or (b) fail to comply (after the expiration of the 30 day grace period as set forth in the 1 Master Loan Agreement) with any of the terms or provisions of any agreement between the undersigned and the Lender; or (c) become insolvent or the subject of a voluntary or involuntary proceeding in bankruptcy, or a reorganization, arrangement or creditor composition proceeding, ceases doing business as a going concern, dissolves or, is the subject of a dissolution, merger or consolidation; or (d) if any warranty or representation made by the undersigned in connection with this Note or any of the Indebtedness shall be discovered to be false or misleading in any material respect; (e) or if there is any termination, notice of termination, or breach of any guaranty, pledge, collateral assignment or subordination agreement relating to all or any part of the Indebtedness; or (f) if there is any failure by the undersigned to pay when due (after the expiration of the 30 day grace period as set forth in the Master Loan Agreement) any of its indebtedness (other than to the Lender) in excess of $25,000 or in the observance or performance of any term, covenant or condition in any document evidencing, securing or relating to such indebtedness; or (g) if there is filed or issued a levy or writ of attachment or garnishment or other like judicial process upon the undersigned or any of the Collateral, then the Lender, upon the occurrence of any of these events (each a "Default"), may at its option declare any or all of the Indebtedness to be immediately due and payable, sell or liquidate all or any portion of the Collateral, set off against the Indebtedness any amounts owing by the Lender to the undersigned, charge interest at the default rate provided in the document evidencing the relevant Indebtedness and exercise any one or more of the rights and remedies granted to the Lender by any agreement with the undersigned or given to it under applicable law. All payments under this Note shall be in immediately available United States funds, without setoff or counterclaim. This Note shall bind the undersigned, its successors and assigns. The undersigned waive presentment, demand, protest, notice of dishonor, notice of demand or intent to demand, notice of acceleration or intent to accelerate, and all other notices, and agree that no extension or indulgence to the undersigned or release shall affect the obligations of any of the undersigned. The undersigned agree to reimburse the holder or owner of this Note for any and all costs and expenses (including without limit, court costs, legal expenses and reasonable attorney fees, whether inside or outside counsel is used, whether or not suit is instituted and, if suit is instituted, whether at the trial court level, appellate level, in a bankruptcy, probate or administrative proceeding or otherwise) incurred in collecting or attempting to collect this Note or incurred in any other matter or proceeding relating to this Note. 2 The undersigned acknowledge and agree that there are no contrary agreements, oral or written, establishing a term of this Note and agrees that the terms and conditions of this Note may not be amended, waived or modified except in a writing signed by an officer of the Lender expressly stating that the writing constitutes an amendment, waiver or modification of the terms of this Note. As used in this Note, the word "undersigned" means each maker signing this Note. If any provision of this Note is unenforceable in whole or part for any reason, the remaining provisions shall continue to be effective. THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF MICHIGAN. THE UNDERSIGNED AND THE LENDER ACKNOWLEDGE THAT THE RIGHT TO TRIAL BY JURY IS A CONSTITUTIONAL ONE, BUT THAT IT MAY BE WAIVED. EACH PARTY, AFTER CONSULTING (OR HAVING HAD THE OPPORTUNITY TO CONSULT) WITH COUNSEL OF THEIR CHOICE, KNOWINGLY AND VOLUNTARILY, AND FOR THEIR MUTUAL BENEFIT, WAIVES ANY RIGHT TO TRIAL BY JURY IN THE EVENT OF LITIGATION REGARDING THE PERFORMANCE OR ENFORCEMENT OF, OR IN ANY WAY RELATED TO, THIS NOTE OR THE INDEBTEDNESS. KRONOS ADVANCED TECHNOLOGIES, INC., A NEVADA CORPORATION By: /s/ Daniel R. Dwight -------------------------------------- Name: Daniel R. Dwight Its: President and CEO KRONOS AIR TECHNOLOGIES, INC., A NEVADA CORPORATION By: /s/ Daniel R. Dwight -------------------------------------- Name: Daniel R. Dwight Its: President and CEO 3