The node on Helms Middle school is located in the center of the Richmond subnetwork, just north of the city of Richmond and approximately equidistant from the westernmost regions of the Pinole Valley Watershed and the San Pablo Bay. Comparison of this node with those to the south and west gives insight into how quickly emissions from the chevron refinery dissipate, and these emissions can be tracked as they travel to more northern nodes in the Richmond subnetwork. Similarly, comparison of the data from the Helms Middle School node to more eastern and northern nodes can provide information about emissions from traffic on 80, as well as wildfire events taking place North and East of the city of San Francisco.