Sonoma County earned a perfect score for the fifth straight year in the American Lung Association’s latest air quality report card for the state covering the three years ending in 2016 and not including last year’s wildfires that fouled the region’s air and prompted public health warnings.

The lung association’s “State of the Air 2018” report, released Wednesday, gave Sonoma County an A grade for ozone and an A for particle pollution without a single day of pollution exceeding federal standards.

Only two other California counties — Humboldt and San Francisco — had a similar record.

But the October wildfires, the most deadly and destructive in California history, will make an impact on next year’s report, lung association officials said. As the blazes raged, the Bay Area Air Quality Management District reported conditions comparable to Beijing, China and called it the worst air ever recorded in some parts of the Bay Area.

A study based on emergency room visits during California’s 2015 fire season found smoky air was associated with a 42 percent higher risk of heart attack compared to smoke-free air and a 22 percent higher relative risk of emergency visits for coronary artery disease.

The study was published last week by the Journal of the American Heart Association.

In the air quality report card, the San Francisco Bay Area, including San Joaquin County, ranked 13th nationally for ozone pollution, sixth worst for short-term particle pollution and tied for 10th for year-round particle pollution.

Los Angeles, the state’s most populous metropolitan area, led the nation for ozone pollution, faring worse than it did in last year’s report.

More than 35 million Californians, 90 percent of the population, live in counties affected by unhealthy air, the new report said.

Particle pollution, also known as soot, comes largely from diesel engines and wood-burning stoves and fireplaces.

Ozone, known as smog, comes primarily from tailpipe emissions in hot weather.

Sonoma County owes its consistently clean air to ocean winds that blow pollution east, contributing to poor grades in other counties.

Check back for more details on this story.