Summary

The atmospheric deposition monitoring program is designed to explore patterns of material deposition across the greater Phoenix metropolitan area and surrounding Sonoran Desert. Wet and dry deposition are collected separately using wet-dry deposition collectors from AeroChem Metrics. These collectors have two side-by-side polyethylene buckets, one each to collect wet and dry deposition. A rain sensor triggers a splash guard so one bucket is exposed only to dry conditions, and one bucket is exposed only during precipitation-producing storms. The dry sample bucket is collected monthly while the wet sample bucket is typically collected within 24-hours of a precipitation-producing storm. 

The sampling locations spanned a transect from outlying areas to the west and east of the metropolitan area and through the urban core. Monitoring at most sampling locations ran from 1999 through the mid-2000s, when sampling was discontinued at several sites. Sampling continued through spring 2016 at the Lost Dutchman State Park, a desert fertilization experiment site focusing on atmospheric deposition. It continues at a location on Arizona State University’s Tempe campus, which was added to the program in 2009.