The sky is a pristine blue, a bear lumbers along, and an elk grazes contentedly alongside a body of water. These are the sorts of bucolic landscape scenes from the national parks featured in “What Does the Elk Say?”, a new television spot from the National Association of Manufacturers. The goal: to convince viewers that the Environmental Protection Agency’s proposed ozone limits are too stringent.

There’s “no industrial activity for miles. But under new ozone rules out of Washington, these national treasures would actually violate clean air laws,” the ad’s narrator says. “If national parks can’t comply, how can your community?”

That makes it seem as though the air in places like Yosemite National Park, Zion National Park, and the Grand Canyon is just fine—so the atmosphere in your town is probably perfectly healthy too. However, the ad neglects to mention a basic scientific fact, one that most people learn by the time they leave elementary school: the difference between a solid and a gas.

Air pollution is not the equivalent of a discarded piece of scrap metal. Smog, which makes life miserable for people with asthma and kills 7 million people a year worldwide, travels as the wind blows. That means secondhand smog generated by coal plants in China is floating across the Pacific and showing up on the West Coast of the United States. That air travels to the nation’s 48 national parks too.

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Indeed, a report released in late July by the National Parks Conservation Association found that “pollution seeps into our national parks from sources like coal-fired power plants, vehicles, and the oil and gas industries.” As a result, according to the NPCA, the air quality in 75 percent of the parks is sometimes unhealthy. “Haze pollution limits how far you can see at 100 percent of the parks. And 90 percent are already experiencing a changing climate—weather that’s more extreme than it has been at any other time in the last century,” wrote the report’s authors.

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Places such as Joshua Tree, Sequoia, Kings Canyon, and Yosemite have “air that’s known to be unhealthy for most park visitors and rangers. In some cases, the parks have unsafe air for more than a month each year, usually during the summer,” reads the report.

Given that polluted reality, our guess is that if the elk could say something, the wild creatures might ask for a respirator. As for whether the rest of us will get to breathe cleaner air, the EPA is expected to set its final ozone limits before Oct. 1.