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

British Columbia has adopted air quality objectives and standards for a number of contaminants, including Particulate Matter (PM₁₀and PM_2.5), ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide.

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.