Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

PORVAIR PLC

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

No

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

No

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

No

An event changing the breakdown of voting rights

No

Other (please specify):

Change of ACD for OEIC holding

Yes

3. Full name of person(s) subject to thenotification obligation: iii

 ALLIANCE TRUST PLC

4. Full name of shareholder(s)  (if different from 3.):iv

ALLIANCE TRUST SUSTAINABLE FUTURE UK GROWTH FUND, ALLIANCE TRUST SUSTAINABLE FUTURE MANAGED FUND AND ALLIANCE TRUST SUSTAINABLE FUTURE UK ETHICAL FUND (ALL SUB-FUNDS OF THE ALLIANCE TRUST SUSTAINABLE FUTURE ICVC

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

1 February 2012

6. Date on which issuer notified:

5 February 2012

7. Threshold(s) that is/are crossed orreached: vi, vii

9% of voting rights.

8. Notified details:

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

N/A

N/A

N/A

N/A

N/A

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

N/A

N/A

N/A

N/A

N/A

Nominal

Delta

N/A

N/A

Total (A+B+C)

Number of voting rights

Percentage of voting rights

3,929,155

9.22%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable: xxi

Alliance Trust PLC is the parent of Alliance Trust Asset Management Limited who was appointed Authorised Corporate Director for the Alliance Trust Sustainable Future ICVC on 1st February 2013. These holdings are held within the constituent funds of this ICVC umbrella as listed in 4 above.

Proxy Voting:

10. Name of the proxy holder:

N/A

11. Number of voting rights proxy holder will ceaseto hold:

N/A

12. Date on which proxy holder will cease to holdvoting rights:

N/A

13. Additional information:

14. Contact name:

Chris Tyler

15. Contact telephone number:

01553 765 500