Air quality objectives and standards

Air quality objectives are non-statutory limits on the acceptable presence of contaminants in the atmosphere. These objectives are established by government agencies to protect:

• Human health
• The environment

They are generally expressed with a combination of:

• A concentration. For example, micrograms per cubic metre, or parts per billion
• A measurement of time. For example, one hour, 24 hours or one year

Objectives are one kind of criteria. Criteria also include:

• Standards 
• Guidelines
• Planning goals

How air quality objectives are used

Air quality objectives are used to guide decisions unless they are written specifically into a permit or regulation at which point they become binding requirements. They are typically used to:

• Assess current or historical air quality
• Guide decisions on the permitting of new or modified facilities
• Guide decisions to issue air quality advisories
• Develop long-term air-management strategies and evaluate progress
• Aid in regulatory development

As even low levels of air pollution can affect some individuals, air quality objectives should not be viewed as levels we can 'pollute up to', but levels to stay well below.

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Objectives and standards

• Provincial Air Quality Objectives Fact Sheet (PDF, 310KB)
• Air Quality Objectives for PM_2.5
• Air Quality Objectives for PM₁₀
• Air Quality Objectives for Formaldehyde

Air Quality Objectives for SO2

• National Air Quality Standards for SO₂ CAAQS (PDF, 330KB) (Canadian Ambient Air Quality Standards) for SO₂ 
• SO₂ Provincial Interim Air Quality Objectives - Application Guidance (PDF, 513.3KB)