AIRMoN operated from 1992 until 2019.

Samples were collected daily within 24 hours of the start of precipitation, often providing data for all or part of a single storm. Single-storm data facilitate studies of atmospheric processes and the development and testing of computer simulations of these processes. Making data available for these studies was a principal AIRMoN goal.

The AIRMoN sites were equipped with the same wet-only deposition collector and precipitation gauge used at NADP’s National Trends Network (NTN) sites. Each site also had a National Weather Service standard gauge for reporting storm total precipitation. Samples were refrigerated after collection and were sent in chilled insulated shipping containers to the Central Analytical Laboratory (CAL), where they were kept refrigerated until analysis. Refrigeration retards chemical changes. Chemical analyses and data screening procedures for AIRMoN were similar to NTN, although low-volume AIRMoN samples were not diluted to accommodate a complete analysis, as is standard NTN procedure.