The Missoula Air Stagnation Zone (MASZ) includes the City of Missoula and roughly four miles outside the city in every direction. The MASZ affects woodstove, paving and outdoor burning rules. Scroll down or choose from the links below to learn more about the MASZ.


Legal Description/Map(s)

Woodstove Rules

Paving Rules

Outdoor Burning Rules


MASZ Legal Description and Map

The Air Stagnation Zone means the area defined by:

T12N R18W Sections 5-8, 17-19;

T12N R19W Sections 1-35;

T12N R20W Sections 1-5, 8-17, 21-28, 34-36;

T13N R18W Sections 4 - 9, 16 - 21, 28-33;

T13N R19W Sections 1 - 36;

T13N R20W Sections 1-4, 9-16, 21-28, 33-36;

T14N R18W Sections 30- 32;

T14N R19W Sections 13 - 36;

T14N R20W Sections 13-15, 21-28, 33-36

Map of the Missoula Air Stagnation Zone

(click to download pdf)

MASZ and Woodstove Rules

Solid Fuel Burning Device Installation

Inside the Missoula Air Stagnation Zone, the only solid fuel burning devices that may be legally installed are permitted pellet stoves from the approved list. Check out the interactive Installation Zones map to find out what kind of device can be legally installed on your property.


Woodstove Removal Program

Upon sale of a property inside the Air Stagnation Zone, most woodstoves and woodstove inserts must be removed from the property. Visit the Woodstove Removal Program website for more information.


Air Pollution Alerts and Warnings

During a Stage I Air Pollution Alert, no visible emissions are allowed from any woodstove or other solid fuel burning device in the Air Stagnation Zone without a valid air alert permit.

During a Stage II Air Pollution Warning, no visible emissions are allowed from any woodstove or other solid fuel burning device inside the MASZ and Impact Zone M without a valid sole source of heat permit.

Visit the Air Pollution Alerts and Warnings page for more information


Paving in the Air Stagnation Zone

With limited exceptions, new roads, parking areas and driveways inside the MASZ must be paved. In addition, the Missoula City-County Health Department may require existing roads to be paved.

Chapter 8, Subchapter 2, of the Missoula City-County Air Pollution Control Program Rules (pdf) contains detailed information about paving requirements inside the Missoula Air Stagnation Zone.


Outdoor Burning in the Air Stagnation Zone

It is illegal to burn piles of leaves or grass inside the MASZ. These burns are typically very smoky. If you are inside the MASZ, dispose of your piles of leaves and grass by composting them or delivering them to a facility such as Eko Compost or Republic Services.

Conditional and Winter Prescribed Wildland outdoor burning permits are not available inside the MASZ.

Visit the Outdoor Burning page for more information about burning in Missoula County.