It might come as a surprise that California’s crown jewel national parks — Sequoia, Kings Canyon, Joshua Tree and Yosemite — struggle with some of the dirtiest air of any parks in the nation.

Some of this pollution is in the form of fine particulate matter, contaminants that are especially unhealthy for humans, plants and animals. These extremely small air particles and droplets create hazy views and, when inhaled, can lodge deep in our lungs and even enter our bloodstream.

NPCA is urging the San Joaquin Valley Air Pollution Control District and California Air Resources Board to take a significant step toward solving chronic air pollution issues by adopting a plan in 2018 that will sharply reduce fine particulate matter pollution.

Preventable air pollution from cars, trucks, agriculture, dairies, residential wood burning, oil and gas, and industrial biomass in the San Joaquin Valley contributes directly to the ongoing dirty air challenges in the Sierra Nevada Mountains. The San Joaquin Valley Air Pollution Control District and the California Air Resources Board have a legal duty to clean up sources of pollution in the region to protect the health of communities in the valley as well as our national parks.

Hazy Skies: Visitors hoping for unspoiled long-range views at these four national parks all too often encounter disappointingly hazy skies. In fact, Sequoia and Kings Canyon National Parks are two of the worst in the country, with over 90 miles of views regularly shrouded in haze. Similarly, in Yosemite National Park, visitors regularly miss out on around 60 miles of the stunning vistas that make this park so famous.

Unhealthy Air: Sadly, Sequoia, Kings Canyon, Joshua Tree and Yosemite National Parks regularly experience levels of air pollution that are unhealthy for most park visitors and rangers — especially for those who are exercising and for vulnerable populations like children, the elderly and those with asthma. In some cases, these four crown jewel parks have air that is unhealthy to breathe for over a month each year, usually during the summers. Fine particulate matter and ozone pollution can lead to serious breathing problems, chronic heart and lung diseases, and even premature death.

Ecosystem Impacts: Just as poor air quality can be unhealthy and dangerous for humans to breathe, air pollution can be harmful to plant life as well — stifling their growth and interfering with essential biological functions like photosynthesis. According to researchers at the University of California (UC) Merced and UC Riverside, unhealthy air may even be a significant driving force in the ongoing tree mortality crisis devastating the Sierra Nevada region. In addition to being directly toxic to plant life, pollutants like nitrogen oxides and ammonia can also lead to excess nitrogen deposition, which alters natural ecosystem functions and encourages growth of invasive species and algae blooms.

Learn more by reading NPCA’s Polluted Parks report and Clean Air for Parks fact sheets.

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