That clean, fresh air you think you breathe in the mountains may actually be ozone gases, researchers involved in a new project studying mountain air say. These chemicals, which are hazardous for the environment, may be spilling into the mountains from houses on the ground.

It turns out that you can't get away from civilization, even high up in the mountains.

There is ozone all the way up the continental divide, said Gabriele Pfister, one of the lead researchers on the project investigating mountain air. Pfister works at the National Center for Atmospheric Research in Boulder, Colorado.

"People [are] thinking you go into the mountains and you breathe the fresh air - that's not always the case," Pfister said.

Using balloons and aircraft to gather data from high-up sources, as well as looking at ground-level stations, the researchers looked at an area of land that spanned 60 miles, from Denver to Fort Collins. They gathered samples from the area over a period of one month, from July to August.

The research team is still going through the data they gathered and would not reveal much about what they had gleaned.

Ozone pollution can cause breathing problems in humans and can be harmful to flora. Ozone is produced by oil and gas when they react with sunlight, as well as chemicals used in agriculture.

There are regulations in place for how much ozone areas are allowed to produce, but Denver sometimes goes over the limit. The scientists who conducted this research study are hoping to find out more to help federal officials figure out how to make laws to reduce the levels of ozone.

The research team even found ozone in Rocky Mountain National Park, a place that has often been viewed as clean and pure. James Crawford, one of the lead investigators for NASA's component of the project, lamented this.

"We view Rocky Mountain National Park as a refuge, and to learn there are days when it's not as safe as we think of it as, it's something people should know," he said.

The researchers also found that some mountains had the same amount of ozone as there was on the ground, or in some cases even more, which was troubling. The team is still investigating what this discovery means for the mountain ranges. The ozone levels also fluctuated from day to day -- some were "dirty" days, and some were "clean" days, Crawford said.