As part of a national air quality monitoring program, Environment Canada operates several ambient air monitoring networks. The two primary components of this national monitoring program are the National Air Pollution Surveillance (NAPS) network and the Canadian Air and Precipitation Monitoring Network (CAPMoN). In 2006, NAPS and CAPMoN operated 805 continuous monitors measuring ground-level ozone, particulate matter (PM), sulphur dioxide, carbon monoxide, and nitrogen dioxide and 165 air samplers collecting samples used to measure components of PM, various volatile organic compounds (VOCs) and other substances. The provinces also operate a variety of ambient air monitoring networks, some as components of the NAPS network and others intended to monitor air quality around industrial sources and metropolitan or regional areas. Environment Canada provides technical oversight for the operation of most of these networks. Information on national and provincial ambient air monitoring networks is readily available to the public online via websites maintained by national, provincial, or local airshed agencies. Much of the data generated by the various ambient air monitoring networks are also available online, although there is typically a multi-year lag in publication of written reports. Data from continuous monitors are typically available in real-time, but rather than actual concentration measurements, data may be presented as a qualitative assessment of risk ranging from “low” to “very high.” This report provides descriptions of the various national and provincial ambient air monitoring networks as well as links to available online resources for information.