Ambient Air Quality Objectives (AAQOs) are provincial objectives developed under the Environmental Protection and Enhancement Act (EPEA) for the purposes to protect Alberta's air quality. The AAQOs provide a basis of determining the acceptable level of risk to health and ecosystem. The AAQOs are either developed by Alberta Environment and Parks (AEP) or adopted from other jurisdictions. The current AAQOs are in the form of acceptable concentrations for 50 pollutants varying in averaging periods (1-hour, 24-hour, or annual). Additional guidelines for dustfall, fine particulate matter, and static fluorides serve as indicators for general performance evaluation and airshed planning and management. The numerical values for AAQOs were chosen as a balance of "the need to address public health and environmental concerns against air pollutant levels that can be practically maintained or achieved within a reasonable time period."1
AEP is responsible for implementation of the AAQOs. The most recent update of AAQOs was published on June 29, 2017. Compared to the AAQOs published in 2013, the updated AAQOs added an objective for naphthalene (CAS number 91-20-3) based on health effects. This AAQO became effective on September 1, 2016. Naphthalene is a bicyclic aromatic hydrocarbon with the lowest molecular weight of all polycyclic aromatic hydrocarbons (PAH). Naphthalene exists naturally in fossil fuels and is emitted from incomplete combustion and processing fossil fuels such as petroleum refining and petrochemical manufacturing. The annual naphthalene AAQO established by AEP is 3 µg/m3 on an annual basis. Although the annual indoor air quality guideline by Health Canada was established at 10 µg/m3, AEP recognized the "difference in methodology between Health Canada and other agencies", and contended that "there are no anticipated negative social or economic consequences of having the lower level for outdoor air in Alberta". Other jurisdictions have developed an air quality objective for naphthalene (selected below):
- 10 microgram per cubic meter (µg/m3) on long-term averaging period (e.g., annual) for indoor air quality, by World Health Organization (WHO) and Health Canada;
- 3 µg/m3 on annual basis as the Reference Concentration, by U.S. Environmental Protection Agency (EPA);
- 50 µg/m3 on 10-minute basis and 22.5 µg/m3 on 24-hour basis, Ambient Air Quality Criteria by Ontario Ministry of the Environment and Climate Change.
When a facility intends to obtain EPEA Approvals or renewal, AEP has the authority to request ambient air quality analysis to compare the anticipated ambient air concentrations contributed from industrial facilities to the AAQOs through air dispersion modelling. Site specific monitoring or mitigation plans may be required if air quality analysis indicates possible exceedance of the AAQOs. Please feel free to contact Anna Henolson by email if you have any questions regarding the AAQOs, air dispersion modelling presenting the potential ambient air impact from your facility, or strategies to obtain an EPEA Approval.
1Using Ambient Air Quality Objectives in Industrial Dispersion Modelling and Individual Industrial Site Monitoring, October 1, 2013, Alberta Environment and Sustainable Resource Development (now Environment and Parks).