OBJECTIVES AND GUIDELINES FOR VARIOUS AIR POLLUTANTS:
Ambient Air Quality Criteria (updated July, 2005)

The following schedule lists maximum time-based pollutant concentration levels for the protection and preservation of ambient air quality within the Province of Manitoba .  Each criterion is classified as an objective, a guideline, or a Canada-wide Standard depending upon several factors.  The objective classification is for those air pollutants sufficiently widespread in presence and potential environmental effect that national limits have been developed.  The guideline classification is used for those pollutants of a more localized presence for which provincial limits have been developed.  A Canada-wide Standard (CWS) is a national standard developed under the Canada-wide Environmental Standards Sub-agreement by the federal, provincial and territorial governments for a contaminant of national priority.

For each of the air contaminants, the amount in the outside ambient air measured in the given units during the time period indicated in the schedule shall not be in greater concentration than one of the following:

• MAXIMUM TOLERABLE LEVEL which denotes a time based concentration of air     contaminant beyond which, due to a diminishing margin of safety, appropriate action is required to protect the health of the general population.

• MAXIMUM ACCEPTABLE LEVEL which is deemed essential to provide adequate    protection for soils, water, vegetation, materials, animals, visibility, personal comfort and well-being.

• MAXIMUM DESIRABLE LEVEL which defines the long term goal for air quality and  provides a basis for an anti-degradation policy for the pristine areas of Manitoba and for the continuing development of control technology.

This schedule is intended to serve as a guide for the evaluation of air quality and for planning purposes.  The selection of the appropriate concentration category will depend upon the degree of protection to be afforded to affected receptors.  Maximum Tolerable Levels are only for evaluation purposes to identify the severity of an anthropogenic or natural phenomenon in order to protect human health and institute appropriate corrective action.  In general, Maximum Acceptable Levels are not to be exceeded in any urban centre including areas that are in the vicinity of industries with atmospheric emissions.  Within rural areas, it is in the goal to maintain pollutant concentrations at or below Maximum Desirable Levels.

This schedule will be updated as new information becomes available; the most recent edition will be posted on the Internet at www.gov.mb.ca/conservation/pollutionprevention/airquality/index.html.  For further information on Manitoba’s ambient air quality objectives and guidelines call (204) 945-1671.

Ambient Air Quality Criteria Table (PDF)