According to the American Lung Association's State of the Air Report, 95% of Nevadans live in a county that failed at least one air quality test.
Reno and Las Vegas landed in the top 25 most polluted cities in the United States for ozone, short term, and annual particle pollution levels.
According to the American Lung Association, transportation and energy in dense areas are contributing the most pollution.
The group says it will take efforts from the entire state in order to see improvements.
"Your own impact that you could be having on air quality, so as I mentioned, carpooling whenever possible, taking advantage of biking or walking, and of course holding our leaders accountable. So calling on our decision makers to do more to address pollution," said Melissa Ramos, Senior Manager of Clean Air Advocacy for the American Lung Association.
According to the report, both Washoe and Clark Counties failed to meet the new Federal Health Protective Standard for year-round particle pollution.
The American Lung Association says medium and heavy-duty vehicles make up about 6% of vehicles on the road in Nevada, but create close to 60% of total ozone and nitric oxide emissions.
To learn more about the American Lung Associations' State of the Air Report, visit www.lung.org/research/sota.
