Holding(s) in Company

For filings with the FSA include the annex

For filings with issuer exclude the annex 

TR-1: Notifications of Major Interests in Shares

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

PORVAIR PLC

2. Reason for notification (yes/no)

An acquisition or disposal of voting rights

YES

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

NO

An event changing the breakdown of voting rights

NO

Other (please specify):______________

N/A

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

IMPAX ASSET MANAGEMENT LIMITED

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

Impax Environmental Markets plc, Impax Environmental Markets (Ireland) Fund, Parworld Environmental Opportunities Fund

5. Date of transaction (and date on which the threshold is crossed or reached if different):

16 MAY 2008

6. Date on which issuer notified:

23 MAY 2008

7. Threshold(s) that is/are crossed or reached:

10%

8: Notified Details

A: Voting rights attached to shares

Class/type of shares

If possible use ISIN code

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of shares

Number of voting rights

Number of shares

Number of voting rights

Percentage of voting rights

Direct

Indirect

Direct

Indirect

Ordinary Shares GB0006963689

4,047,250

9.944%

4,147,250

NIL

4,147,250

NIL

10.190%

B: Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ conversion period/date 

No. of voting rights that may be acquired (if the instrument exercised/converted)

Percentage of voting rights

NIL

Total (A+B)

Number of voting rights

Percentage of voting rights

4,147,250

10.190%

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

Impax Environmental Markets plc (2,226,000 shares 5.47%)

Impax Environmental Markets (Ireland) Fund {1,130,750 shares 2.78%)

Parworld Environmental Opportunities Fund (790,500 shares 1.94%)

Proxy Voting:

10. Name of proxy holder:

N/A

11. Number of voting rights proxy holder will cease to hold:

N/A

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

N/A

13. Additional information:

14 Contact name:

Compliance Officer

15. Contact telephone name:

+44 (0) 20 7434 1122