LOS ANGELES – 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.