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Air Quality Indicators in Grand Canyon National Park, 2008
Summary
· Clean, clear air is essential for visitors to enjoy Grand Canyon National Park. Air pollutants can dim the colors and textures of canyon vistas, and obscure distant landmarks. Pollutants can also damage park resources, upset ecological processes and injure flora and fauna. At high enough levels, air pollutants can affect visitors’ health.
· Grand Canyon has a long baseline of air quality information. Monitoring began in 1959, with most current monitoring programs initiated during the 1980s.
· The National Park Service Air Resources Division identified ozone, atmospheric deposition, and visibility as key air quality indices under the Government Performance and Results Act (GPRA, Goal 1a3A). Data from 1996-2005 were analyzed for the current GPRA report: (1.76MB PDF File) with data validation and analysis completed in October 2007.
(http://www.nature.nps.gov/air/Pubs/pdf/gpra/GPRA_AQ_ConditionsTrendReport2006.pdf )
· The Department of the Interior set GPRA goals of attaining EPA health and welfare standards (NAAQS) for ozone, fine particulates (PM2.5) and sulfur dioxide as goal 1a3B, and reasonable progress toward the national visibility goal as goal 1a3C.
· Ozone concentrations and exposure indices continue to rise significantly in Grand Canyon. Current exposures are within the range known to cause leaf damage in sensitive plant species, but do not violate standards for human health.
· Grand Canyon’s wet atmospheric deposition levels of nitrate, ammonium, and sulfate have increased, but the ten year trend is not statistically significant.
· Visibility on the best days at Grand Canyon has improved, but the haziest days have not changed.
· Grand Canyon meets Interior’s departmental GPRA Goals 1a3B to protect human health, and 1a3C, to make progress reducing regional haze. Because of climbing ozone concentrations, Grand Canyon does not meet the NPS GPRA Goal 1a3A for stable or declining ozone concentrations, haze levels, and wet atmospheric deposition concentrations.
· In addition to GPRA-related air quality monitoring, Grand Canyon N.P. staff monitor optical visibility through the Interagency Monitoring of Protected Visual Environments, and solar radiation through the U.S. Department of Agriculture’s UV-B Monitoring Program.
· During forest fires in and near the park, Grand Canyon staff utilizes routine visibility monitoring data and deploys portable particulate monitors to assess fire impacts on visibility and human health.
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