Air Quality

Pinnacles National Park typically has very good air quality. Occasionally, north winds and a persistent inversion layer draw air pollutants from the Santa Clara Valley into the Park. The NPS Air Quality Office and EPA established a monitoring station near the east entrance in 1987. An air clarity study (uing a transmissometer) has been completed, and particulate and ozone monitoring continues. Despite the occasional hazy days, the air quality at Pinnacles is a defining feature of the Park and an important resource.

Because Pinnacles is a National Park, developers are required by law to consider the effects of the encroaching urban landscape in bringing potential sources of pollution close to the park. The Clean Air Act provides the primary authority for protecting and enhancing the nation's air quality. In 1977, Congress amended the Act to prevent the significant deterioration of air quality in clean air areas of the United States and to protect visibility in certain areas, including Pinnacles. The Clean Air Act established three classifications of varying degrees of restriction of allowable air quality deterioration. Pinnacles National Park was designated a Class I area. This is a mandatory designation, requiring the federal land manager to protect the air quality-related values of the Park from air pollution impacts. Air quality-related values include visibility, plants, animals, water quality, historic and cultural resources, and other resources which could be impacted by air pollution.

Park managers work closely with the state and the Environmental Protection Agency to prevent future and eliminate existing visibility impairment at Pinnacles by participating in regulatory decisions (e.g., air quality permits, plans, and rules). They also work cooperatively with State and private interests to resolve air quality-related resource conflicts and ensure that identified vistas (and any future vistas similarly identified) are adequately protected.

The Park began visibility monitoring in 1986 with the installation of an automatic camera at the Chalone Peak Lookout. The camera location was changed a year later to monitor visibility conditions looking towards the High Peaks. In 1987, particulate and ozone monitoring equipment was installed at an indoor station near the east entrance to the Park. Meteorological parameters monitored include wind speed and direction, temperature, dew point, solar radiation, and precipitation. In 1988, remote visibility began to be monitored with the installation of a transmissometer. The transmissometer was removed in 1993.