Since the 1970s, ozone high in the atmosphere has been decreasing. This allows more UV solar radiation to reach the earth's surface. The effects of increased UV radiation are not well understood. Several agencies and universities are studying links between UV radiation exposure and skin cancer and eye disorders in humans. UV radiation also has negative effects on plants and aquatic ecosystems.
UV radiation may also influence air quality in the parks. The smog obscuring park views is the result of chemical reactions that take place in the presence of sunlight. More UV radiation may speed up these chemical reactions and could increase the amount of smog and low-altitude ozone present.
In the mid-1990s Sequoia National Park was one of 14 national parks monitoring UV radiation as part of a UV network sponsored by the Environmental Protection Agency and the National Park Service. These measurements helped scientists better understand how changes in UV affect human health and various ecosystem processes. The network data are used for a variety of scientific studies including assessments of the effects of UV radiation on frog populations.
Ultraviolet Radiation Links
Environmental Protection Agency Ultraviolet Monitoring Program