Acadia National Park Air Quality Information
Overview
Although there are not a lot of major pollution sources in Maine, Acadia NP is downwind from large urban and industrial areas in states to the south and west. Periodically, high concentrations of air pollutants blow into the park from these areas.
A National Atmospheric Deposition Program/National Trends Network (NADP/NTN) wet deposition site has been operating in Acadia NP since 1981 (site #ME98). An analysis of the site data indicates wet sulfate concentration and deposition have decreased since 1981. Wet nitrate and ammonium concentration and deposition, however, show no obvious trend.
A Clean Air Status and Trends Network (CASTNet) dry deposition site has been operating in the park since 1998 (site #ACA416). Given the relatively short time of operation, data summaries are not yet available for this site.
Although most watersheds of Acadia NP lie at least partially outside the park boundary, the majority of upland portions are owned by the park. This makes many of the water bodies less susceptible to the effects of household, agricultural, and industrial non-point source pollution. However, atmospheric deposition is of concern. Lake and stream chemistry data have been collected in the park since 1979. These data indicate many surface waters in the park have low buffering capacity, and so are limited in their ability to neutralize acid deposition. In fact, episodic acidification has been documented during snowmelt and runoff. In spite of reductions in sulfate deposition in recent years, there has not been an improvement in pH or acid neutralizing capacity of park lakes and streams. Also of concern is a regional decline in base cation concentrations in surface waters, which has resulted in a decrease in buffering capacity of some sensitive surface waters in the Northeast. The cause of the base cation decline is unclear, but may be associated with atmospheric deposition. The effect of atmospheric nitrogen deposition on park estuaries is unknown, but is also of concern. Long-term data collection is needed to determine the cause and effect of changes in sulfate, nitrogen, and base cation deposition. Research is currently underway to better understand the complex watershed scale processes involved in assessing the impact of atmospheric deposition on freshwater and estuarine resources in the park.
A Mercury Deposition Network (MDN) site has been monitoring mercury associated with wet deposition in the park since 1995 (site #ME98). Almost every weekly sample collected has detectable amounts of mercury, and in many samples, the concentrations are among the highest in the Northeast. Research is underway to assess the major sources and source areas contributing to mercury deposition at Acadia NP and other areas in the Northeast.
Recent studies documented high concentrations of mercury in several freshwater fish species sampled in park lakes. In some warm-water species, e.g., bass, perch, and pickerel, fish had mercury concentrations greater than 1 part per million (ppm). Mercury bioaccumulates in the food chain, so consumption of mercury-contaminated fish can be harmful to humans as well as to other wildlife. In fact, Maine has issued a statewide freshwater fish consumption advisory for mercury. Ongoing studies are examining mercury concentrations in loons, mergansers, and tree swallows in the park.
Ozone has been monitored at Acadia NP since 1982 (site #230090101, #230090102, and #230090103). The data indicate many exceedances of the 1-hr human health-based primary National Ambient Air Quality Standard (NAAQS), as well as exceedances of the new 8-hr primary NAAQS. Seasonal ozone exposures have, at times, been high enough to harm ozone-sensitive plant species in the park.
Ozone-induced foliar injury has been documented on sensitive park vegetation during field surveys and in controlled fumigation studies. Physiological effects were also noted in the fumigation studies.
As part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, visual air quality in Acadia NP has been monitored using an aerosol sampler (1987 through the present), nephelometer (1993 through the present), and 35mm camera (1980 through 1995). The U.S. Environmental Protection Agency's new Regional Haze regulations require improving visibility in Class I air quality areas on both the best visibility and the worst visibility days. Trend data are not currently available for this site.
Management and staff at Acadia NP have taken an active role in documenting the concentrations and effects of air pollutants in the park, relaying that information to the public and regulatory agencies, and reducing in-park emissions. Previous park management committed to a long-term air quality monitoring and research program that has continued for more than 20 years. Interpretive efforts have included issuing ozone advisories to the public and staff on high ozone days, establishing a video display on air quality in the park Visitor Center, providing real-time park visibility photographs on the National Park Service website, and helping fund production of an air issues brochure for the northeast U.S. and Canada. The park, in partnership with the State and nearby towns, developed a free public transportation system for the park and surrounding communities that has resulted in significantly reducing automobile traffic and associated emissions. In 2001, nearly a quarter of a million people rode the propane-powered buses, resulting in a reduction of several hundred tons of air pollutants.
More information relative to air quality and air quality related values is available on the Acadia NP website. Information on air quality public awareness programs can be found on the Acadia NP Air Resource Programs page.