Ah, just breathe in that fresh mountain air! Although you may not think much about it, the air quality in Yosemite National Park will have an enormous impact on your park vacation. Here's a quick look at the air quality issues facing Yosemite today.
Although the park is federally protected by the Clean Air Act, air pollution can sometimes be a problem. Nothing can be as much of a letdown for visitors as stopping at one of Yosemite's famous viewpoints or hiking all day to reach a mountain summit, only to have the Sierra Nevada vistas obscured by haze and air pollution.
When air quality suffers in Yosemite, it can often be attributed to agricultural and urban air pollution from California's Central Valley, which gets blown up into the Sierra Nevada, especially during summer. You can help the park decrease its air pollution by using public transportation whenever possible, especially in the Yosemite Valley.
Not all of the park's air quality issues arise from artificial pollution, however. Sometimes poor air quality is caused by wildfires, either naturally occurring or those that are prescribed by park managers to help keep Yosemite's forests healthy. Natural wildfires often occur following lightning strikes during summer, when the park's vegetation is driest and drought conditions may be present. Particulate matter and ash from both natural and artificial fires around the park can also limit visibility and make it difficult for some people to breathe. If you have concerns, ask about current fire conditions at any park visitor center.