PM-10 trend fairly flat since 1989. Surface Ozone has been fairly level since 1980. Surface ozone is formed from nitrogen oxides and hydrocarbons emitted by motor vehicles, industry, and auto fueling. Ozone trend fairly level since 1980. Visibility violates the Colorado standard about 122 days each year.
Poor visibility is caused by cars, industry, and woodburning.
Visibility violates the Colorado standard one-third of the year.