Air quality has been horrible this year — and it's not just because of wildfire smoke

Much of the United States has experienced horrible air quality this year due to the Canadian wildfires. It's not only particles from smoke creating pollution, but new research shows there's also an invisible pollution problem causing health concerns: Ozone.  

When ozone is up in the atmosphere, it filters out the sun's harmful ultraviolet rays. When it reaches the ground, it's not healthy for humans.  

According to the U.S. Environmental Protection Agency, ground-level ozone can cause coughing and a sore throat, make it more difficult to breathe deeply, and make the lungs more susceptible to infection.