Notice of Ahlstrom Corporation's Extraordinary General Meeting

Ahlstrom Corporation STOCK EXCHANGE RELEASE May 17, 2013 at 10.00

Not for distribution in or into Australia, Canada, the Hong Kong special administrative region of the People's Republic of China, Japan, New Zealand, South Africa or the United States.

Notice is given to the shareholders of Ahlstrom Corporation to the Extraordinary General Meeting to be held on Thursday, July 4, 2013 at 1.00 p.m. in the Helsinki Hall of the Finlandia Hall, Mannerheimintie 13 e, Helsinki, Finland (main entrances M4/K4). The reception of persons who have registered for the meeting and the distribution of voting tickets will commence at 12.00 a.m. Registration for the meeting is requested to be made no later than 12.45 p.m.

A. Matters on the agenda of the Extraordinary General Meeting

At the Extraordinary General Meeting the following matters will be considered:

1. Opening of the meeting
2. Calling the meeting to order
3. Election of persons to scrutinize the minutes and to supervise the counting of votes
4. Recording the legality of the meeting
5. Recording the attendance at the meeting and adoption of the list of votes
6. Resolution on the demerger of the Coated Specialties Business

The Board of Directors of Ahlstrom Corporation and Munksjö Corporation have on May 13, 2013 signed a demerger plan in relation to the combination of Ahlstrom Group's Label and Processing business and Munksjö AB that was announced on August 28, 2012. The demerger plan concerns the Ahlstrom Group's Label and Processing business in Brazil (the "Coated Specialties Business").

Pursuant to the demerger plan ("Coated Specialties Demerger Plan") all the assets and liabilities related to the Coated Specialties Business will, as a result of a partial demerger, be transferred to Munksjö Corporation, a new company established in Finland for these purposes (the "Coated Specialties Demerger").

The Board of Directors proposes to the General Meeting the approval of the Coated Specialties Demerger in accordance with the Coated Specialties Demerger Plan.

Upon execution of the demerger of the Coated Specialties Business, the shareholders of Ahlstrom Corporation shall receive as demerger consideration 0.265 new shares in Munksjö Corporation for each share owned in Ahlstrom Corporation (the "Coated Specialties Demerger Consideration"). In case the number of shares received by a shareholder of the company as Coated Specialties Demerger Consideration would be a fractional number, the fractions shall be rounded down to the nearest whole number. No Coated Specialties Demerger Consideration will be paid on the basis of own shares held by Ahlstrom Corporation.

A shareholder of Ahlstrom Corporation, who has voted against the Coated Specialties Demerger in the General Meeting, has the right mentioned in Chapter 17, Section 13 of the Finnish Companies Act (624/2006, as amended) to demand redemption of his/her/its Coated Specialties Demerger Consideration at the General Meeting.

7. Closing of the meeting

B. Documents of the Extraordinary General Meeting

The aforesaid proposals of the Board of Directors relating to the agenda of the Extraordinary General Meeting as well as this notice are available on the Company's website at www.ahlstrom.com/agm. Other documents, which according to the Finnish Companies Act shall be kept available for the shareholders, will be available on the above-mentioned website as from June 4, 2013, at the latest.

The proposals of the Board of Directors and the other documents mentioned above are also available at the meeting. Copies of these documents will be sent to shareholders upon request. The minutes of the meeting will be available on the above-mentioned website as from July 18, 2013, at the latest.

C. Instructions for participants in the Extraordinary General Meeting

1. The right to participate and registration

Each shareholder, who is registered on June 24, 2013 in the shareholders' register of the Company held by Euroclear Finland Ltd., has the right to participate in the Extraordinary General Meeting. A shareholder whose shares are registered on his/her personal Finnish book-entry account is registered in the shareholders' register of the Company.

A shareholder who wishes to participate in the Extraordinary General Meeting shall register for the meeting by giving prior notice of participation on July 1, 2013 at 4 p.m. at the latest. Such notice can be given:

• on the Company's website www.ahlstrom.com/agm,
• by email to yhtiokokous@ahlstrom.com,
• by mail to Ahlstrom Corporation, EGM, P.O.B. 329, 00101 Helsinki, Finland,
• by telefax to +358 (0)10 888 4789, or
• by phone during office hours to +358 (0)10 888 4726

In connection with the registration, a shareholder shall state his/her name, personal identification number, address, telephone number and the name of a possible assistant or proxy representative and the personal identification number of such proxy representative. The personal data given to Ahlstrom Corporation is used only in connection with the Extraordinary General Meeting and with the processing of related registrations.

Pursuant to Chapter 5, Section 25 of the Companies Act, a shareholder who is present at the Extraordinary General Meeting has the right to request information with respect to the matters to be considered at the meeting.

2. Proxy representative and powers of attorney

A shareholder may participate in the Extraordinary General Meeting and exercise his/her rights at the meeting also by way of proxy representation.

A proxy representative shall produce a dated proxy document or otherwise in a reliable manner demonstrate his/her right to represent the shareholder at the Extraordinary General Meeting. When a shareholder participates in the Extraordinary General Meeting by means of several proxy representatives representing the shareholder with shares at different book-entry accounts, the shares by which each proxy representative represents the shareholder shall be identified in connection with the registration for the general meeting.

Possible proxy documents should be delivered to the address above before the last date of registration. A template for a proxy is available at the Company's website mentioned above.

3. Holders of nominee registered shares

A holder of nominee registered shares is advised to request necessary instructions regarding the registration to be temporarily entered into the shareholders' register, the issuing of proxy documents and registration for the Extraordinary General Meeting from his/her custodian bank well in advance.

If a holder of nominee registered shares is entitled to be registered in the shareholders' register on the record date 24 June 2013, the shareholder may in accordance with the instructions from his/her custodian bank request to be temporarily entered into the shareholders' register of the Company in order to participate in the Extraordinary General Meeting, at the latest on July 1, 2013 at 10.00 a.m. A holder of nominee registered shares is considered to have registered for the Extraordinary General Meeting if he/she has been temporarily recorded in the shareholders' register as described above. Further information on these matters can also be found on the Company's website mentioned above.

4. Other instructions and information

On the date of this notice to the Extraordinary General Meeting, May 17, 2013, the total number of shares in Ahlstrom Corporation amounts to 46,670,608 and said shares have 46,670,608 votes in total.

After the meeting coffee will be served in the lobby of the Finlandia Hall.

Helsinki, May 17, 2013

AHLSTROM CORPORATION

The Board of Directors

For more information, please contact:
Liisa Nyyssönen
Vice President, Communications
Tel. +358 10 888 4757

Ahlstrom in brief
Ahlstrom is a high performance fiber-based materials company, partnering with leading businesses around the world to help them stay ahead. Our products are used in a large variety of everyday applications, such as filters, medical gowns and drapes, diagnostics, wallcoverings, flooring and food packaging. We have a leading market position in the businesses in which we operate. In 2012, Ahlstrom's net sales from the continuing operations (excluding Label and Processing business) amounted to EUR 1 billion. Our 3,800 employees serve customers in 28 countries on six continents. Ahlstrom's share is quoted on the NASDAQ OMX Helsinki. More information available at www.ahlstrom.com.

Disclaimer
This document may not be distributed in or into Australia, Canada, the Hong Kong special administrative region of the People's Republic of China, Japan, New Zealand, South Africa or the United States. The information contained herein shall not constitute an offer to sell or the solicitation of an offer to buy the securities referred to herein in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration, exemption from registration or qualification under the securities laws of any such jurisdiction.

This document is not an offer for sale of securities in the United States. Securities may not be offered or sold in the United States absent registration or an exemption from registration under the U.S. Securities Act of 1933, as amended. Ahlstrom Corporation, Munksjö AB and Munksjö Corporation have not registered, and do not intend to register, any offering of the Munksjö shares in the United States. There will be no public offering of the Munksjö shares in the United States.

This document is only being distributed to and is only directed at (i) persons who are outside the United Kingdom or (ii) to investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the "Order") or (iii) high net worth companies, and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order or (iv) persons who are members or creditors of the company to which this communication relates, falling within article 43(2) of the Order (all such persons in (i), (ii) (iii) and (iv) above together being referred to as "relevant persons"). Any investment activity to which this document relates will be only available to and will be engaged in only with, relevant persons. Any person who is not a relevant person should not act or rely on this document or any of its contents.