Air, next to water and soil, is a third critical resource for humans, plants, animals and all other organisms within a natural area. Air must be monitored in order to control and lower pollution levels, control smoke caused by wild land fires, and to monitor air quality. The USDA Forest Service monitors the effects of air pollution that may impair visibility, harm human health, injure trees and other plants, acidify or cause unnatural fertilization of streams and lakes, leach nutrients from soils, and degrade cultural resources, like archeological sites and historical buildings. Forest activities that can affect air quality such as prescribed burning, ski areas, and mining are also monitored to ensure compliance with air regulations for human health and to monitor possible impacts to natural resources. This week Stan Salot and his guest, Linda Geiser, ecologist with the USDA, will discuss our collective environmental responsibility to our planet.