Hawaii Volcanoes National Park Air Quality Information
Overview
Air quality in Hawaii Volcanoes NP is affected by a number of emission sources, primarily Kilauea Volcano. Currently the volcano emits between 1,000 and 2,000 tons of sulfur dioxide each day, as well as other gases, including hydrogen sulfide, hydrogen chloride, hydrogen fluoride, and trace metals like mercury. Sulfur dioxide reacts with sunlight, oxygen, dust particles, and water in the air to form a mixture known as volcanic smog or "vog." The vog not only creates a haze which obscures visibility, but it is very acidic, causing acid rain and affecting human health, cultural resources, and vegetation. Adding to the haze are marine aerosols, which can further diminish visibility. In addition, when hot lava reaches sea water, large clouds of mist are formed, called laze, which contain hydrochloric acid and other airborne contaminants harmful to human health. Although the volcano dominates total emissions, local anthropogenic sources like power generating stations and automobiles can also affect air quality and visibility, releasing nitrogen oxides, particulates, and other pollutants as well as sulfur dioxide.
The air quality related values (AQRVs) of Hawaii Volcanoes NP are those resources that are potentially sensitive to air pollution and include visibility and night skies, water quality, soils, vegetation, wildlife, and cultural resources.
Visibility is a very sensitive AQRV in Hawaii Volcanoes NP. Because the air is generally so clean in the park, just a small amount of pollutant particles can cause a noticeable haze. The Clean Air Act affords special protection to visibility in Class I air quality areas, so the park has a long-term visibility monitoring program. As part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, visibility in Hawaii Volcanoes NP has been monitored using an aerosol sampler (1988-1992; 2001-present) and an automatic 35mm camera (1986-1995).
Sulfur dioxide is a significant health concern in Hawaii Volcanoes NP and downwind, so sulfur dioxide is monitored at two locations, Jaggar Museum and the Kilauea Visitor Center. The park posts current sulfur dioxide concentrations from both monitors on its website.
Estimates of total atmospheric deposition of sulfur and nitrogen compounds can be made by adding wet and dry deposition. Wet deposition has been monitored in Hawaii Volcanoes NP since 2000 as part of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The site ID is HI99. Dry deposition has been monitored at the park (site HVT424) since 1999 as part of the Clean Air Status and Trends Networks (CASTNet). Wet deposition of sulfur is very high, as might be expected because of Kilauea’s sulfur dioxide emissions. Wet deposition of nitrogen is relatively low.
In addition to common pollutants like nitrogen and sulfur compounds, atmospheric deposition of heavy metals and organic compounds from trans-Pacific transport, and trace metals such as mercury from volcanic emissions may affect Hawaii Volcanoes NP aquatic and terrestrial resources and the wildlife that depend on them.
Ozone has been monitored in the park at the Kilauea Visitor Center from 1986-1995 and at Thurston Lava Tube from 1999-present. Ozone concentrations and cumulative doses are well below levels known to cause injury to vegetation.
Ultraviolet (UV) radiation has been monitored in Hawaii Volcanoes NP since 1997 as part of the U.S. Environmental Protection Agency’s UV Monitoring Program. As stratospheric (upper atmosphere) ozone levels decline because of ozone-depleting chemicals, increases in UV exposure are possible. Increased exposure to ultraviolet radiation has negative implications for human health and plant productivity.