Typically, Pinnacles National Monument has superb “Class I” air quality. Occasionally north winds and a persistent inversion layer draw air pollutants from the Santa Clara Valley into the Monument. The NPS Air Quality Office and EPA established a monitoring station near the east entrance in 1987. An air clarity study (using a transmissometer) has been completed, but particulate and ozone monitoring continues. Despite the occasional hazy days, the air quality at Pinnacles is a defining feature of the Monument and an important resource.
While Pinnacles enjoys good air quality, the trend has been towards a declining air resource. The encroaching urban landscape will reduce the distance between pollution sources and the Monument.
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 Monument 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 Monument 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 Monument 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 Monument. 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, at study.
A more proactive role in protecting the air resource needs to be taken. Partnerships with local private and public interests need to be established. While interpretation of air quality has recently been addressed with wayside trail exhibits, this effort falls short of what is necessary to alert the public of the impending problem of poor air quality, and educate them on alternatives.
