Provincial Air Quality Objective for PM2.5

PM_2.5, or fine particulates, refers to particles that are 2.5 microns or smaller in diameter. PM_2.5 is one of the most important outdoor air pollutants in B.C. from a human health perspective. New ambient air quality criteria for PM_2.5 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
Criteria	Level	Averaging Period
Air Quality Objective	25 µg/m3	24 hours1
Air Quality Objective	8 µg/m3	Annual
Planning Goal	6 µg/m3	Annual

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 PM_2.5 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).