Holding(s) in Company

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

YES

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):

NO

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

IMPAX ASSET MANAGEMENT LIMITED

IMPAX ASSET MANAGEMENT (AIFM) LIMITED

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

IMPAX ENVIRONMENTAL MARKETS (IRELAND)

PARVEST ENVIRONMENTAL OPPORTUNITIES FUND

THE ENVIRONMENT AGENCY FUND

IMPAX ENVIRONMENTAL MARKETS PLC

IMPAX GLOBAL RESOURCE OPTIMIZATION FUND

PORTICO BENEFIT SERVICES FUND

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

03/03/2016

6. Date on which issuer notified:

17/03/2016

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

6%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

ORDINARY

SHARES

GB0006963689 LN

3,657,897

3,657,897

2,694,310

2,019,622

674,688

4.50672%

1.50554%

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

NIL

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

NIL

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

2,694,310

6.01226%

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

IMPAX ENVIRONMENTAL MARKETS (IRELAND) (393,431 SHARES 0.877928623%)

PARVEST ENVIRONMENTAL OPPORTUNITIES FUND (368,218 SHARES 0.821666624%)

THE ENVIRONMENT AGENCY FUND (254,204 SHARES 0.56724805%)

IMPAX ENVIRONMENTAL MARKETS PLC (1,413,234 SHARES 3.153586219%)

IMPAX GLOBAL RESOURCE OPTIMIZATION FUND (212,957 SHARES 0.475206696%)

PORTICO BENEFIT SERVICES FUND (52,266 SHARES 0.116629898%)

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:

Based on 44,813,552 issued ordinary shares

14. Contact name:

Rachael Murray - Compliance Manager

15. Contact telephone number:

+44 (0) 20 7432 2633