Another failing grade for Nevada County’s ‘State of the Air’ report |

Another failing grade for Nevada County’s ‘State of the Air’ report

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The American Lung Association’s 20th annual State of the Air report revealed that once again California counties top the list of most polluted in the country, and Nevada County is no exception.

Reflecting the same grades as the 2018 report, Nevada County received an “F” when it came to the number of high ozone days, and a “B” for particle pollution. While ozone and particle pollution threaten the health of everyone, children, seniors, low income families and people with respiratory and cardiac illness are at an increased risk, the report states.

“Nevada County saw a slight improvement in particle levels along with an increase in ozone pollution days compared to last year,” said Will Barrett, a senior policy analyst for the American Lung Association. “The wildfires didn’t have as much of an impact on Nevada County as in other parts of Northern California in this year’s report (which uses air quality data from 2015-2017), but we know that the 2018 Camp Fire had major impacts on air quality across the board.”


“The primary source of ozone pollution in the region and across the state is our transportation sector, increases in driving and our ongoing dependence on fossil fuels,” said Barrett. “We’ve seen widespread increases in ozone pollution across the U.S., California and the Sacramento region. It is important to note that 2015, 2016, 2017 are the three hottest years on record, and helped to push ozone levels higher as we’ve shown in this year’s report. It goes to show that the progress we’ve seen in the county — and the region — is at greater risk due to climate change.”

Nevada County’s numbers came in at a 52.2 weighted average, reflecting 119 orange days, 25 red days and zero purple days. Using monitored data gathered from the Air Quality Index, a color-coded scale developed by the Environmental Protection Agency is designed to help the public understand daily air pollution forecasts and take precautions, when needed. Each color provides a specific warning about the risk associated with air pollution in that range. For example, green is good, yellow is moderate, orange is unhealthy for sensitive populations, red is unhealthy for everyone and purple is considered very unhealthy.


“We need to maintain focus on all sources of pollution, but especially from the transportation sector that is the leading source of smog, and the major contributor to climate change,” said Barrett. “Unfortunately, Nevada County is subject to both local pollution sources and traffic pollution from Roseville and Sacramento that can be carried in on the wind, where it can be trapped and linger for days.”

Of Nevada County’s 99,814 residents, data gathered by the American Lung Association showed that at-risk populations include 17, 304 under the age of 18; 26,471 age 65 and over; 1,073 with pediatric asthma; 6,748 with adult asthma, 4,799 with COPD, 41 with lung cancer, 7,252 with cardiovascular disease; 11,344 with diabetes and an estimated 10,889 living in poverty.


Ozone, often referred to as “smog,” is a corrosive gas that forms from tailpipes and other pollution sources on hot, sunny days.

“Ozone essentially acts like a sunburn on your lungs and can trigger asthma attacks, worsen COPD and create a host of other health impacts,” said Barrett. “Both ozone and particle pollution threaten the health of all of us, but our kids, seniors, people with respiratory and cardiac illness and lower income communities are more vulnerable to these impacts.”

Particle pollution, or “soot,” is a mix of solid and liquid particles that can be inhaled deep into the lungs, bypassing the body’s defenses. According to the American Lung Association, these particles are so small they can cross into the blood stream. This means they can contribute to both respiratory health impacts as well as heart attacks, strokes and premature death. Diesel trucks, residential wood-burning fireplaces and wildfires are major sources of particle pollution.

As with Nevada County, ozone and particle pollution are the two dominant types of air pollution in the U.S., with nearly 141.1 million people living in counties where monitors show unhealthy levels of one or both. While over the years the Clean Air Act of 1970 was instrumental in bringing pollutant numbers way down, the air a person breathes could still shorten life or cause lung cancer and other harmful effects. And the progress that’s been made is now being challenged due to climate change, as numbers indicate.

“California is making strong progress on cleaning up the air, but has a long way to go to ensure that all Californians can breathe clean, healthy air,” said Barrett. “Nevada County also has seen strong progress in cleaning up ozone pollution, but we have more work to do — and that job is made more difficult due to climate change. Zero emission vehicles, building communities more around walking, biking and transit options and ensuring that California’s stronger clean air programs are maintained are all key strategies to achieving clean, healthy air.”

To contact Staff Writer Cory Fisher, email her at

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