Air Monitoring Networks and Studies produce data that represent a wide variety of observations and measurements. Multiple data types (also called collections) can be produced by a single network and data collections can have contributions from multiple networks. The data are organised as follows:

1. Atmospheric Gases,

2. Atmospheric Particles,

3. Atmospheric Precipitation Chemistry,

4. Combined Atmospheric Gases and Particles

5. Special Studies of Atmospheric Gases, Particles and Precipitation Chemistry

Networks and Studies contributing to the Canadian National Atmospheric Chemistry Database and Analysis system (NAtChem) are from Canadian federal and provincial networks (past and present) and also include U.S. historical networks (these data are not available elsewhere). Information about these contributing networks, for each of these collection and product groups, can be found in each network's description documentation.