Hwy 62 – 83 Air Quality

Rehabilitation of Highway 62 West, Crater Lake National Park, Klamath County, Oregon




This section evaluates the potential impacts of alternative B.

Air Quality

Alternative B would temporarily affect local air quality through increased dust and vehicle emissions. Hydrocarbons, nitrous oxide, and sulfur dioxide emissions would be rapidly dissipated by air drainage since air stagnation is rare at the project site.

Fugitive dust plumes from construction equipment would intermittently increase airborne particulates in the area near the project site, but loading rates are not expected to be significant. To partially mitigate these effects, such activity would be coupled with water sprinkling to reduce dust. Impacts from dust and construction equipment emissions would be short term, adverse, and minor along the project corridor.

Hauling material and operating equipment during the construction period would result in increased vehicle exhaust and emissions. There would also be temporary increases in air pollution from queuing of visitor vehicles stopped temporarily during the construction period. The park would apply appropriate mitigating measures limiting idling of construction vehicles. Signs would also be posted for several miles outside the park alerting visitors of the construction and the possibility of 20- to 30-minute delays, and requesting that during any such delay, engines be turned off to eliminate motor vehicle emissions (idling vehicles emit far more air pollutants than moving vehicles).

Overall, there would be a negligible, short-term, adverse degradation of local air quality due to dust generated from road reconstruction activities and emissions from construction equipment and visitor vehicles. These effects would last only as long as road reconstruction activities occurred and the park’s Class I air quality would not be affected by alternative B.

Cumulative Impacts. Air quality at Crater Lake National Park is near pristine with minimal internal and external emissions sources. Past, present, and reasonably foreseeable future actions that would have an effect on air quality include trail rehabilitation and relocation, the reconstruction of the Rim parking lot, the waterline replacement from Munson Springs to Garfield, and the lagoon project at Munson Valley. The effects of these projects would be short term, adverse, and negligible parkwide. Alternative B would only contribute to these actions if they are occurring concurrently, resulting in a short-term, adverse, and negligible parkwide effect.

Conclusion. Overall, there would be negligible, short-term degradation of air quality from construction-generated dust and emissions from construction equipment along the project corridor. Cumulative effects would be short-term, negligible, and adverse only if they are constructed concurrently.

Because there would be no major adverse impacts to a resource or value whose conservation is (1) necessary to fulfill specific purposes identified in the park’s establishing legislation, (2) key to the natural or cultural integrity of the park or to opportunities for enjoyment of the park, or (3) identified as a goal in the park’s General Management Plan or other relevant National Park Service planning documents, there would be no impairment of park resources or values.


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