Provincial Air Quality Objective for PM2.5

Ambient Air Quality Criteria for PM2.5

PM2.5, or fine particulates, refers to particles that are 2.5 microns or smaller in diameter. PM2.5 is one of the most important outdoor air pollutants in B.C. from a human health perspective. New ambient air quality criteria for PM2.5 were adopted by the Province of B.C. on April 9, 2009. They are nonstatutory limits used to guide air-management decisions in British Columbia.

Provincial Ambient Air Quality Criteria for PM2.5



Averaging Period

Air Quality Objective

25 µg/m3

24 hours1

Air Quality Objective

8 µg/m3


Planning Goal

6 µg/m3


1 Achievement based on annual 98th percentile value.

The 24-hour and annual air-quality objectives (AQOs) are the primary air management tool, used to guide decisions on environmental impact assessments and authorizations, airshed planning efforts and regulatory development. The 24-hour AQO is also used to guide decisions on whether or not to issue an air quality advisory.

The planning goal is intended as a voluntary target to guide airshed planning efforts and encourage communities to maintain good air quality in the face of economic growth and development.

The new provincial criteria for PM2.5 are in addition to the existing provincial AQO of 50 µg/m3 (24-hour average) for PM10 (i.e., fine particles 10 micrometres or smaller).