The northernmost node in the Vallejo subnetwork, the node on Dan Mini elementary school sits west of CA 29, and just south of the Napa county border. Because this node is on the water-facing side of CA 29, where the Napa Sonoma Marshes Wildlife Area is located, comparisons of data collected from this node and its neighbor on Elsa Widenmann Elementary (located on the other side of CA 29 and closer to CA 37) provide insight into the emissions generated by traffic on both of these busy regional freeways.