An 'F' in air quality: California national parks top the list for worst pollution

Sequoia National Park air resource specialist Annie Esperanza explains how ozone diminishes the view from Beetle Rock. (Source: Tracie Cone / Associated Press)

Sequoia National Park air resource specialist Annie Esperanza explains how ozone diminishes the view from Beetle Rock. (Source: Tracie Cone / Associated Press)

Via Los Angeles Times

Millions of vacationers escape to national parks each summer to take in the fresh air and scenic vistas.

But a report released Tuesday by a conservation group finds that some of the nation’s most treasured landscapes are plagued with polluted air and hazy skies — and remain decades behind schedule in restoring visibility.

The report by the National Parks Conservation Assn. flunked four national parks in California — Sequoia, Kings Canyon, Joshua Tree and Yosemite — giving them F grades for having levels of ozone that are  unhealthy for visitors during the busy summer season.

Sequoia and Kings Canyon topped the list with the worst air quality in the nation.

The Washington, D.C.-based advocacy group used government monitoring data to assign letter grades to each of the 48 national parks that are supposed to have the best air quality in the nation and are subject to special protections under the Clean Air Act. The report assessed each park according to its levels of haze and ozone — a lung-damaging pollutant in smog — and how it has been affected by climate change, including rising temperatures and shifts in precipitation.

Three-quarters of the parks, which were analyzed using data from 2008 to 2012, had ozone levels that were "moderate" or worse, according to the federal government’s Air Quality Index, the report found.

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