Air quality can dramatically impact views of the Seashore

Point Reyes National Seashore is a Class I park and air quality is generally good due to the prevailing westerly marine flows. However, during periods when atmospheric conditions displace the east Pacific high pressure system, air flows from the San Francisco Bay area can degrade the air quality of the seashore. This mainly occurs during the late summer and early fall, when the major atmospheric systems undergo a seasonal change. During this time, the seashore is often impacted by a general haze, which significantly impairs visibility.

Because ambient ozone levels at Point Reyes National Seashore are currently quite low, oxidant injury in vegetation is unlikely at the present time. If there were to be changes in the atmospheric patterns at the Seashore, there are approximately 37 plant and lichen species with known sensitivities to sulfur dioxide, ozone, and nitrogen oxides.

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