The last thing people want to see -- or breathe -- when they escape to the outdoors is air as hazy as the polluted skies they left behind. Among the first lines of defense for the air quality of national parks, wilderness areas and monuments is the UC Davis Air Quality Group, which recently won a competitive five-year extension of its contract to monitor the air quality over public lands. The program is funded jointly by the National Park Service, U.S. Forest Service, Bureau of Land Management, Fish and Wildlife Service and the Environmental Protection Agency. Headed by UC Davis physicist Tom Cahill, the Air Quality Group has helped develop techniques that allow investigators to trace air pollutants back to their sources, which are sometimes halfway around the world, as when they detected smoke in Hawaii from fires in Kuwait. Their methods set the standard for the United Nation's Global Atmospheric Watch. Undergraduate and graduate students comprise about one-half of the research group.